CONTROL SYSTEM FOR SELF-MOVING PLATFORMS

Abstract

The preferred field of application of the present invention concerns the control of the ambulation of the self-moving platforms, suitable to move in environments which are not necessarily known. In particular it is disclosed a technical solution that allows at the same time the manual control of the movements of such self-moving platforms (with good precision of control) and the management of the possible accidental collisions. This solution provides that the self-moving robotized platform is covered, at least partially and in its lateral surfaces with a particular coverage that acts simultaneously as a pressure sensor and as a shock-absorbing layer. They are therefore indicated some essential characteristics that make possible the definition of a set of manual intuitive commands, which are suitable to control the ambulation of such a platform. The system conceived in this way, in addition to ensuring a limitation of the damage in cases of collision, allows an operator to move a platform, irrespective of its weight, just by exerting slight thrusts in the desired directions; It will be also possible to give commands for movements along curved trajectories, or to impart rotations to the same platform.

Claims

1. A self-moving robotized platform (100) comprising: a cover configured as a pressure sensor which covers at least part of an outer lateral faces of said self-moving robotized platform (100); a computing unit configured to control trajectories of the motion of said self-moving robotized platform (100) by means of control commands which impose instantaneous speeds computed in real time as a function of an instantaneous pressures detected by said cover configured as a pressure sensor, wherein said cover, configured as pressure sensor, comprises: a first layer configured to constitute one or more electrical components connected in a circuit, whose electrical characterization varies depending on a pressure with which said cover is squeezed, and this variation of the electrical characterization is continuous at least in a range of squeezing pressures which are applied; said first layer, or a second layer external to said first layer, are configured to perform, at least on a portion of the outer lateral faces of said robotized platform (100), a cushioning layer made of a deformable material in a non-permanent way; and said self-moving robotized platform (100) also comprises at least one driving wheel, in which it is implemented a computer procedure that, in function of measured electric quantities, makes an estimate of the components of the pressures exerted orthogonally on the lateral faces of said self-moving robotized platform (100), identifying both the areas where said pressures are exerted and their intensity; and are identifiable both the cases in which pressures are exerted in a single area and cases in which pressures are exerted in a plurality of areas of the lateral surfaces; and said computer procedure computes, in an approximate way, also the directions of movement and the rotations which are compatible with the detected pressures; and said control commands for said at least one driving wheel are suited to move said self-moving robotized platform (100) according to said direction of movement and to said rotation which have been computed so as to be intuitively compatible with the areas of application of the exerted pressures, and the speed and the acceleration of such movements are a function of both the intensity of the detected pressure and of the state of motion of the platform itself.

2. The self-moving robotized platform (100) according to claim 1, in which said first layer comprises a sequence of tactile films (1 10) disposed so as to cover at least part of the lateral faces of said robotized platform (100), and said tactile films (1 10) are made of a conductor or semi-conductor material whose electrical characterization varies continuously depending on the pressure with which said tactile films (1 10) are squeezed.

3. The self-moving robotized platform (100) according to claim 2, in which said tactile films (1 10) are made of a conductor or semi-conductor material having the property of varying its electrical resistance depending on the pressure with which said tactile films (1 10) are squeezed.

4. The self-moving robotized platform (100) according to claim 2, wherein said tactile films (1 10) are connected in at least one powered electric circuit, and said electrical circuit also includes components able to measure analog electrical quantities, and to make such measures available so that they can be automatically processed by computer.

5. The self-moving robotized platform (100) according to claim 2, wherein said layer configured to perform, at least on a portion of the outer lateral faces of said robotized platform (100), a cushioning layer made of a deformable material in a non-permanent way, is a second outer layer (210), external to said first layer, and said second outer layer (210) is constituted by viscoelastic foams, or foam rubber, and these materials are characterized by an elastic coefficient k (21 1), so as they can return to assume the their original shape after having undergone a deformation caused by a pressure, even slight, exerted on their outer surface.

6. The self-moving robotized platform (100) according to claim 1, wherein said layer configured to perform, at least on a portion of the outer lateral faces of said robotized platform (100), a cushioning layer made of a deformable material in a non-permanent way, coincides with the said first layer and it is made of a material electrically sensitive to pressure which, inserted in an electrical circuit, has an electrical characterization depending from the pressures to which it is subjected, and said electrical circuit also includes components able to measure analog electrical quantities and to make them available so that they can be automatically processed by computer; and said material electrically sensitive to pressure also presents a thickness such that, under the effect of such pressures, it assumes an elastic behavior suitable to implement also a cushioning function.

7. The self-moving robotized platform (100) according to claim 1, wherein said speed and acceleration is calculated to determine the motion commands for said self-moving robotized platform (100), and their calculation also depends on parameters which can be settled in the calibration phase.

8. The self-moving robotized platform (100) according to claim 1, wherein said platform, in the presence of pressures exerted in opposite way, and on approximatively the same line, so as to cancel each other, at least partially, said platform (100) performs a process that provides to carry out an estimate of the solicitations on said at least one driving wheel, and to identify the presence, or absence, of components of torques characterized in that: a) they are not entirely attributable to the control commands generated on the basis of other user commands, b) they potentially contribute to a motion of the platform (100) having a component along the direction orthogonal to said line on which said pressures act so as to cancel each other, at least partially; and in case of presence of torques characterized as mentioned in points a) and b), a computing unit comprised in said self-moving robotized platform (100), generates control commands on at least one driving wheel of said self-moving robotized platform (100) suitable for contributing to a motion of the platform (100) having a component along the direction orthogonal to said line on which said pressures act so as to cancel each other, at least partially.

9. The self-moving robotized platform (100) according to claim 1, wherein said control commands for said at least one driving wheel, when a pressure is exerted in at least one area of the lateral surfaces of said self-moving robotized platform (100), are suited to move said self-moving robotized platform (100) in a way which is qualitatively similar to the motion of a very light empty box subjected to a push having a pressure like the one exerted in at least one area of the lateral surfaces of said self-moving robotized platform (100).

10. The self-moving robotized platform (100) according to claim 1, wherein said control commands for said at least one driving wheel, when a pressure is exerted in at least one area of the lateral surfaces of said self-moving robotized platform (100), are suited to move said self-moving robotized platform (100) along a direction having a prevalent component which opposes to the detected pressure.

11. The self-moving robotized platform (100) according to claim 1, whenever said detected pressure tends to decrease since the element with which said pressure is exerted tends to move away from said lateral surface, said self-moving robotized platform (100) moves in a way which is qualitatively similar to the motion of a very light empty and sticky box pulled from the point where said pressure which tends to decrease is exerted; and said motion tends to maintain the contact between said self-moving robotized platform (100) and the element with which said pressure is exerted, and also tends to compensate the decrease of the pressure.

12. The self-moving robotized platform (100) according to claim 1, wherein said control commands for said at least one driving wheel are suited to move said self-moving robotized platform (100) in a way which is characterized by having a limited speed and a limited acceleration.

13. The self-moving robotized platform (100) according to claim 1, in which said cover configured as a pressure sensor, is a removable cover which can be applied temporarily to cover at least part of the outer lateral faces of said self-moving robotized platform (100).

14. The self-moving robotized platform (100) according to claim 1, wherein said removable cover configured as a pressure sensor is associated to computing means apt to process the detected information of pressure, and able to interface other systems for the control of the movement of said self-moving robotized platform (100).

15. The self-moving robotized platform (100) according to claim 1, whenever said first layer is configured to perform, at least on a portion of the outer lateral faces of said robotized platform (100), a cushioning layer made of a material deformable in a non-permanent way, said first layer is overlaid on to a further layer, also configured to perform a cushioning layer on the areas covered by said first layer.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0043] This invention has also further advantages which will be made apparent from the following description, which shows more details, from the attached claims, which form an integral part of the same description, and from the illustration of some examples of embodiment described, but not limited to, in what follows, and in the accompanying drawings in which:

[0044] FIG. 1 shows a self-moving robotized platform with some elements characterizing the present invention.

[0045] FIG. 2 shows some examples of motion paths which are determined by particular manual thrusts.

[0046] FIG. 3 shows, in section, a detail of a skin covering the self-moving robotized platform according to the invention.

[0047] FIG. 4 shows an example of a motion path which is a result of a manual action in which the self-moving robotized platform is pulled rather than pushed.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0048] FIG. 1 provides an overall view of a self-moving robotized platform whose shape is roughly constituted by a parallelepiped with four vertical sides.

[0049] Obviously any type of shape is possible, however, the parallelepiped-shaped platform, in addition to allow a clear illustration of the inventive principles of the present invention, also constitutes one of the preferred shapes as it can be conveniently used as a trolley for the transport of payloads, and can also house all the components necessary for the operation of the same platform. In addition, it can be also suitable to accommodate the integration of eventual mechanisms functional in different applications.

[0050] With the number 100 it is then indicated, as a whole, the self-moving robotized platform according to the teachings of the present invention. However, the representation offered in FIG. 1 is essential and partial; they are highlighted only few elements, which are useful to illustrate some important features of said self-moving robotized platform 100 according to the invention.

[0051] With the number 101 it is then represented a wheel, it indicates a possible mean of implementing the ambulation of the platform 100, and with the number 102 it is shown a generic load of the platform 100 which can be, as said, a mere load to be transported as well as a device, for example anthropomorphic, which can be an integral part of the same platform, designed to perform a particular function.

[0052] Finally, with the number 1-10, some tactile films covering all the side walls of the platform 100 are indicated. Such tactile films 1-10, in the example of FIG. 1, take the form of strips, therefore, in the following of this description, they will be often referred to using the expression tactile strips. Such tactile strips 1-10 are the elementary pressure sensors, which constitute an essential part of the pressure sensing system, i.e. the so-called tactile skin of the platform 100.

[0053] As stated above, it said tactile strips 1-10 constitute a known technology and they can be realized with conductive or semiconductor materials whose resistance is variable depending on the squeezing pressure that is exerted on them. However, such use of tactile strips 1-10, based on the property of those materials whose resistance varies according to the pressure to which they are subjected, is just one of the possible choices for realizing the pressure sensors. In theory, also other materials can be used, in fact a pressure applied on a material can also influence other parameters, such as its capacitive characterization or, more in general, its overall electrical characterization, so that, when said material is inserted in a powered circuit, measurable effects take place, and the pressure exerted on it can be estimated. In other embodiments of the present invention, such pressure sensors can be systems more complex than it is a particular material that varies its electrical behavior as a function of the pressure to which it is subjected. Said pressure sensors can be, for example, real circuits that exploit other characteristics, not strictly electrical, of certain materials (for example of optical behavior characteristics), and such circuits can integrate, inside them, measurement subsystems, and/or other circuit components.

[0054] However, for the purposes of this description of the present invention, these pressure sensors can be generically modeled, at a high level, as components of an electrical circuit with an electrical characterization pressure-dependent: it means that a measurement of an electrical quantity can be performed on them, and this measure (e.g. voltage or current levels, or frequency measurements, both continuous and discrete, etc.), which is dependent on the pressure which they are subjected to, is manageable by a computer.

[0055] Coming back still to the case taken as an example, in which the tactile strips 1-10 are composed of variable resistance material, the tactile sensor system works when said tactile strips 1-10 are all connected so as to form an electric circuit crossed by current, in which there are inserted measuring elements capable of detecting, selectively, changes in resistance in each of the various tactile strips 1 10 that substantially cover the entire sides of the self-moving robotized platform 100.

[0056] Thus, though not shown in FIG. 1, said self-moving robotized platform 100 must also include: motors and any means of transmission to drive the wheels, electrical power supply means, measuring components of electrical quantities and at least one computing unit for reading data and for controlling the platform 100 as a whole. Said computing unit must therefore be capable of generating control commands to be transmitted, directly or indirectly, to the wheels of the robotized platform 100. The wheels can in fact be moved by a motor directly controllable by said computing unit, comprised in said self-moving robotized platform 100, or they can be associated to a specific controller of the wheels, able to receive suitable digital commands, always generated by said computing unit.

[0057] For completeness it has to be stated that the actuation of the movement of a self-moving robotized platform 100, implemented through a control exercised on the wheels, can be conceived in a wide variety of combinations of drive wheels, steering wheels and free wheels (obviously with different control accuracies): from the simplest case in which there is only one driving wheel, to the most complete case in which all the wheels are driving and steering.

[0058] The fact that the tactile strips 1-10 of the example illustrated in FIG. 1 are vertical and approximately corresponding to the entire height of the self-moving robotized platform 100 indicates that they are able to discriminate the point of the perimeter where a pressure is exerted, but they cannot determine the height.

[0059] It is clear that it is possible to create a tactile skin of said self-moving robotized platform 100 also with other arrangements and forms of the tactile strips 1-10, in order to better discriminate the points where a pressure is detected. Even in the presence of such configurations, and even more in the case of greater precision in the detection of pressure points, the inventive principles that characterize the platform 100, as a whole, are applied and remain valid. It should be said that, when the platform is moving on a substantially flat surface, the configuration of pressure sensors arranged as in FIG. 1 can be a realistic and efficient configuration for the easy achievement of the intended purposes.

[0060] FIG. 2 shows three examples of movements which are consequent to the exercise of particular thrust pressures.

[0061] In all three examples [FIG. 2 a), FIG. 2 b) and FIG. 2 c)] it is presented a top view of the self-moving robotized platform 100, whose plant is approximately square. Said platform 100 is represented in an essential way, and the only depicted element is constituted by the wheels, from a top view too, and indicated, as in FIG. 1, with the number 101.

[0062] Even in the examples of FIG. 2 it is assumed that the tactile strips 1-10 are disposed vertically and side by side, and that their length corresponds to the height of the side faces of the self-moving robotized platform 100. It is then also assumed that said platform 100 can move on a plane, then, for the purpose of the movement, it is certainly more important to determine the horizontal position of the push point, rather than its height position.

[0063] In FIG. 2 a), with the number 121, it is shown a hand that pushes said self-moving robotized platform 100 in a central point of one of its four side faces. The number 121 therefore also indicates a pressure, defined in terms of its intensity and zone of application.

[0064] In this case, the tactile sensor system detects the pressure 121. And if the platform was very lightweight, it would move with an approximately rectilinear motion in the direction of the thrust. Said pressure 121, detected by the tactile sensor system, can then be intuitively interpreted as a command for the activation of a rectilinear motion, in which acceleration and velocity are calculated instant by instant as a function of the pressure which is applied. The number 131 indicates an arrow which is representative of rectilinear motion that is put in place, for example, through the drive wheels 101.

[0065] The calculation of the motion 131 can be made in various ways. One way that certainly can be very intuitive is based on the model of the empty box. Applying this model of the empty box, the calculation is reduced to simulate the motion that would occur if a pressure equal to that measured was applied to an empty, very lightweight box, having the same size of the robotic platform 100.

[0066] Once the speed is determined in this way, by means of an automatic control, the appropriate couples can be applied to the drive wheels so that the instantaneous speed of the self-moving robotic platform 100 corresponds to the instantaneous speed calculated with the model of the empty box.

[0067] A slight thrust given at the center of a face of the self-moving robotic platform 100, such as that represented in the examples of FIGS. 1 and 2, thus constitutes a particularly intuitive command to determine a rectilinear motion in the direction of thrust.

[0068] At this point, it is possible to infer how to impart other manual intuitive controls, to determine also curvilinear motions, through a slight pressure. In fact, continuing to imagine an empty box, and applying a pressure, i.e. a push, no longer at the center of a face, but at a point shifted toward an edge of said face, the resulting motion, in the case of an empty box, would be a curved motion which will also tend to rotate this hypothetical empty box.

[0069] Such a case is represented in the example of FIG. 2 b), where the number 122 indicates a pressure exerted in an evidently decentralized point of a side face of the platform 100. As in the case of the example of FIG. 2 a), the pressure 122 can be measured, and the model of the empty box can, once again, be applied for determining the resulting motion if a pressure equal to the measured one is exercised on an empty box. The resulting motion is shown in FIG. 2 b) with the curved arrow indicated with the number 132; and said motion 132 can be embossed to the self-moving robotized platform 100, by the control of the drive wheels 101, as happened in the case of the motion 131 in FIG. 2 a).

[0070] Thus, it is clear that a self-moving robotized platform 100 can be operated manually, making it to follow various types of trajectories, exerting little pressure either in the middle of the side faces, or on more decentralized points. Exerting slight pressures, it is then possible to move the platform 100 very slowly curing the accuracy of movement; while greater accelerations can be imparted by increasing the pressure.

[0071] The calculation of the speeds and accelerations which have to be imparted to the platform 100 as a function of the detected pressures is not deepened beyond, since it is evident that multiple strategies may be adopted. The model of the empty box, which has been previously mentioned, is very intuitive, and it can also be adopted partially, for example limited to a predetermined range of pressures. The partial use of the model of the empty box, in fact, may foresee the insertion of thresholds on the maximum speed or accelerations allowed to the platform.

[0072] An important concept can be synthesized and generalized: namely that, on the basis of the information on the extent of pressure manually exerted on a self-moving robotized platform 100, it is possible to conceive the formulas for calculation of the movement commands of said platform 100, and said commands can be intuitive for the operator who have to exert them, and at the same time they may take into account and manage also other application-specific requirements, for example to increase safety.

[0073] In FIG. 2 c) it is finally represented a further example of motion. The number 123 indicates a couple of pressures, i.e. two forces, exerted in opposite directions, but axially offset. If such pressures were exerted on an empty box, they would determine a rotation. This rotational motion is represented in FIG. 2 c) by the circular arrow indicated with the number 133. As a result, similarly to what shown in the previous cases of FIG. 2 a) and FIG. 2 b), the command consisting in the exercise of two light pressures at appropriate points, able to generate a couple of forces, is an intuitive command to impart to the self-moving robotized platform 100 a rotation.

[0074] All the examples shown in FIG. 2 have the main goal of moving the platform 100; and these examples allowed to illustrate how it is possible to define a protocol of intuitive commands to impart with absolute generality the motion of a self-moving robotized platform 100 covered, in all its lateral faces, with a tactile skin.

[0075] It is noted, at this point, as the model of the so-called empty box should not necessarily be understood as a model to be strictly reproduced for the definition of the manual control commands. Rather it is just a model to derive inspiration for conceiving a system of manual and intuitive user commands for the movement of a self-moving robotized platform.

[0076] In short, the self-moving robotized platform 100 according to the teachings of the present invention can be physically maneuvered by generating automatic control commands that determine the directions of movement and the rotations compatible with the manual controls exercised by an operator: in other words, such directions of movement and such rotations are those that the operator can intuitively expect as a consequence of the thrusts he exerts at certain points on the outer surface of the platform 100.

[0077] Once the intuitive nature of the controls is preserved, it is certainly possible, and also recommendable, to tune the functions that provide the calculation of the control commands as a function of applied pressure, by means of calibration processes, which can also be empirical.

[0078] In addition to the problem of the manual control of the movement, it is noted that the so-described system is a platform which also implements an automatic management of collisions. In fact, when a collision (or impact) happens, the skin of the self-moving robotized platform 100 necessarily detects the occurrence of a pressure at a point of its surface. As a consequence of said pressure generated by the impact, the self-moving robotized platform will move in opposition to the movement that caused the bump itself; and consequently the platform 100 will move away from the obstacle bumped. Just detached away from the obstacle, it will no longer sense any pressure, and then it will stop.

[0079] The process synthetized above, therefore, would appear to be already a way for the management of the collisions, it would be enough just to state that the commands generated as a result of pressures on the skin of the platform 100 must override all other controls; In fact, the platform 100 is typically also controllable with other non-manual commands, for example, it can be controlled remotely.

[0080] The above-described management of the bumps, however, presents some obvious drawbacks. In fact, if the bump is just a little violent, the pressure produced by the impact is high and consequently the speed with which the platform 100 is rejected is also high. But then, as soon as the platform detaches from the obstacle, the platform stops, once again rather abruptly due to the total absence of pressure. To avoid such too abrupt behavior, various strategies can be adopted. The expedient adopted according to the teachings of the present invention is illustrated with the support of FIG. 3.

[0081] FIG. 3 proposes a side sectional view of a detail of a self-moving robotized platform 100 according to the teachings of the present invention. As in the previous figures, the number 100 indicates the platform as a whole and the number 101 a wheel of the same.

[0082] The view proposed in FIG. 3 highlights a tactile strip 1-10 shown, in this case, in its thickness, while the number 210 shows a cushioning layer, this also shown in its thickness. And said cushioning layer 210 covers all sides of the platform 100, also covering all the tactile strips 1-10.

[0083] Said cushioning layer 210 can be realized with soft materials, such as foam rubber or particular viscoelastic foams (also called memory foams), and it is characterized by an elastic coefficient k, indicated in FIG. 3 by the reference numeral 21-1.

[0084] If the elastic coefficient k of the cushioning layer 210 is low enough, during a collision, said cushioning layer 210 is compressed by opposing little resistance, and by transferring to the tactile strip 1-10 a pressure initially very mild, however, enough to instantly generate a command to move the platform 100 in opposition the motion of collision.

[0085] Unlike the motion that would be generated as a result of a non-amortized collision, such motion, contrary to the collision, will be soft. Moreover, during said phase of detachment, the cushioning layer 210 must resume its initial shape, and as long as this position is not reached, it continues to exert a pressure, albeit declining, on the tactile strip 1-10, and therefore also the speed of detachment will decrease gradually until the complete separation of the platform 100 from the bumped obstacle.

[0086] The great utility of said cushioning layer 210 is therefore evident on the occasion of collisions: it is an important characteristic for the good functioning of the motion control system of the self-moving robotized platforms 100 according to the teachings of the present invention.

[0087] Said cushioning layer 210 is of great benefit not just on the occasion of collisions, but it is also useful during the manual operations for the control of the platform. In fact, the typical manual sensitivity of most people is not enough to perform very precise controls. It can happen that, in the moment of contact, a manual push may produce a too sudden and intense pressure, enough to determine a sudden leap forward of the platform 100, and if said leap forward determines a loss of contact, the platform would stop abruptly, then maybe it suddenly starts again, if the hand should restore with a contact, and so on as to produce a start of very irregular motion.

[0088] It is possible to choose a compromise by setting quite high thresholds for the pressures able to activate the motion, but considering the fact that the tactile strips 1-10 are typically more sensitive (and accurate) at weak pressures, that choice would give away the possibility to have a precise control of motion.

[0089] But, if very low motion activation thresholds were set, to take advantage of the dynamics of sensitivity of the tactile strips 1-10, the manual control of the platform would be allowed only to operators capable of extremely light touch: so it is clear that this limitation would represent an unacceptable usability limit for the entire system.

[0090] Even the hypothetical use of sensors sensitive to touches at higher pressures, would have contraindications, since accidental impacts would be managed only when manifestly vigorous. The presence of a cushioning layer 210 is therefore essential to achieve the precision of manual control without limiting it only to people able to act with very lightweight hand. Indeed, a manual touch, filtered by a cushioning layer 210, always produces a slight pressure on the tactile strips 1 10 as soon as the hand, or the object with which the thrust is exerted, comes in contact with the outer surface of the cushioning layer 210. This gentle pressure slowly starts the motion in the desired direction without causing an unwanted gap between the hand (or the object with which the thrust is exerted) and the platform 100 that has to be handled, and the person who is carrying out the manual control has the time to adjust the pressure with which he intends to push.

[0091] A further benefit determined by the presence of said cushioning layer 210 is given by the fact that it distributes the effect of the exerted pressure over a wider surface. So, if the pressure is exerted, at the outer side, in a very reduced area, for example, if the thrust is carried out with a pointed object, the pressure transferred to the tactile strips 1-10 results exerted in a wider area.

[0092] Without going into the details of the technology of the tactile strips 1-10, which for the purposes of the present invention can be considered as a known and mature technology, it is important to underline that the precision of a tactile strip 1-10, intended as a pressure sensor, generally improves in the case where the pressure is more distributed.

[0093] Anyhow, the interpretation of the output signal coming from the tactile sensor system which constitutes an essential part of the skin of the self-moving robotized platform 100, must be calibrated in the final assembly conditions, then with cushioning layer 210 already applied. And the presence of said cushioning layer 210 also facilitates the calibration process by reducing the number of forms of objects with which to exert the calibration thrusts. In a limit case, especially for the calibration of relatively light pressures, only one contact object can be used (perhaps with a form recalling the thrust carried out with a hand).

[0094] It should be also pointed out, with regards to the calibration phase, that said cushioning layer 210, can also produce a not useful effect when the control is not performed manually. In fact, sudden accelerations and decelerations (e.g. those imparted with remote control) may cause that, by inertia, said cushioning layer 210 determines slight pressures on the underlying tactile strips 1-10: such pressures, not produced by impulses or impacts, should not be considered for purposes of movement control, and therefore it should be set, in the calibration phase, also a minimum activation pressure threshold. Said minimum activation pressure threshold can be much lower the better said cushioning layer 210 is applied, and if it can be maintained low enough it can reasonably be considered useful, since it allows to avoid the generation of motion even when the platform is just lightly touched.

[0095] The motion control system described so far works properly and meets the purposes for which it was designed without the need to synthesize explicitly the piece of information indicating whether a pressure is determined by an accidental collision or by a volunteer thrust. Therefore, it is suited for the implementation of self-moving robotized platforms also extremely simple, where simplicity is certainly an advantage when a satisfactory performance is obtained the same.

[0096] However, the control system, as described so far, has enough information to perform a far more elaborate processing that allows to increase the performance both in the ambulation and in the collision control.

[0097] In particular, it is possible to provide that the control commands generated by the computing unit, besides being dependent on the sensed instantaneous pressures, also depend on the state of motion of the platform itself.

[0098] In fact, a pressure directed against the motion generates a braking, in this case a quite high maximum deceleration may be set, both in the project and during the calibration: this is to allow a sudden braking and to limit the damage from a collision. In the case of a pressure exerted to initiate a motion, instead, lower permissible accelerations should be imposed, so as to have always more sweet starts, also in case of possible abrupt pushes which could be applied unintentionally.

[0099] It is clear then, that the functions that bind the generation of the movement commands with the state of motion of the platform 100 may significantly depend on the context of application; and the availability of a self-moving robotized platform 100, designed according to the teachings of the present invention, is well suited to support very flexible implementations of the motion functions: a fine tuning can take place both in the design refinement phase and in in-field calibration phase. A further clarification is about the choice of the skin that serves as a pressure sensor. The implementation shown in FIG. 3 is based on two overlapping layers: the first, very thin, which implements the function of the pressure sensor, the second more thick, that implements the cushioning function. The choice of the double layer is dictated by the performance, also in terms of quality and cost of the technologies that are more convenient and effective at the state of the art.

[0100] However, it is not excluded that both functions can be guaranteed, in the future, with higher quality and at competitive costs, also with different materials that can implement both functions (sensory and cushioning) in an integrated way.

[0101] For example, there are known piezo-electric or piezo-resistive materials with which it is possible to realize the pressure sensors, and these materials are also sufficiently deformable so that they can be manufactured with thicknesses suitable to implement also the damping function. At the time, these materials are still a bit too hard, they have not yet adequate sensitivity in the range of pressures of interest for the application of the present invention, and also the costs are not competitive compared to implementation with the bilayer solution.

[0102] However, the technological evolution may propose, in the future, materials with characteristics suitable for achieving a skin able to serve as a pressure sensor by the use of a single layer made with a material with performance (in terms of quality and cost) better than that currently available. Then it will be possible to resort to a solution of implementation based on a single-layer coverage, without departing from the inventive concepts developed in the present invention. Again, a further implementing option can occur in the case in which particular technologies for implementing the pressure sensors are available. In fact, it is possible to hypothesize a further case in which the layer that implements the function of the sensor is made with materials that confer elasticity and flexibility, consequently this layer can be deformed, even significantly, when subjected to a pressure, and then return to its initial shape.

[0103] A pressure sensor of this type can therefore perform, to a certain extent, also the cushioning function. However, unlike in the previously illustrated variant of implementation, in which the possibility of having a cover formed with a single layer is mentioned, in many cases the elastic characteristics and the thicknesses of these layers are not suitable for the realization of a tactile cover able to implement a cushioning function sufficient for the purposes of the present invention. In such cases it is therefore necessary to increase the cushioning function by the addition of a further layer that performs a purely cushioning function, which can be typically placed below the layer that implements the function of the sensor.

[0104] Therefore, generally speaking, the implementation of the cover of the self-moving robotized platform (100) which serves as a pressure sensor can also be implemented according to a further variant with respect to the preferred implementation illustrated in FIG. 3, with two layers where a first layer is outermost and implements both the pressure sensor function (fully), and the cushioning function (partially), while the additional layer is the innermost and completes the implementation of the cushioning function. Even in implementations according to this latter variant, however, the solution is implemented in accordance with the essential concept that characterizes the present invention, which consists in conceiving a self-moving robotized platform (100) whose motion can be manually controlled by an operator with commands imparted touching the platform itself in an absolutely intuitive manner.

[0105] FIG. 4 shows a particular type of contact that may take place when a person wishes to move the self-moving robotized platform 100 in an intuitive way by pulling (instead of pushing) it. As in all the other figures, the number 100 indicates the platform as a whole, while the number 101 a wheel of said platform. The number 124 indicates two hands exerting a type of contact different from those considered until now. The contact indicated with the number 124 is therefore a type of contact that a person can exert on the platform 100 when he wants, in an intuitive and natural way to pull it towards him. The number 131 indicates an arrow that is representative of a rectilinear motion.

[0106] Unlike the rectilinear motion 131 exemplified in FIG. 2 a), which was determined by a thrust, in the case of FIG. 4, the operator is expected that such a substantially rectilinear motion 131 takes place because he pulls the platform.

[0107] The case of FIG. 4 is representative of a set of cases in which multiple contacts are exerted on the platform 100. In general, since it is possible to evaluate both the area where the contacts take place, and their intensity, an initial simple processing consists in calculating the resultant of the exerted forces. The case, already illustrated, in FIG. 2 c), is the application of two contacts, indicated with the couple of thrusts 123, which generate a torque that puts the platform 100 in rotation; in the case in which the two thrusts 123 are also equal in intensity, the resultant will not present any suitable component in the translational motion of the platform 100, which therefore will be affected only by a motion of rotation.

[0108] Unlike the case of FIG. 2 C), the case of FIG. 4, however, may generate a null, or almost null, resultant, because the forces exerted on the two sides of the platform 100, with the two contacts 124, oppose to a great extent, then their effect vanishes without giving rise to a significant torque, as they are exerted on approximately the same direction, and therefore they contribute nor to the generation of any displacement, nor to any rotation.

[0109] The processing of data about the pressures exerted on the skin of the platform 100, however, not only allows to calculate a resultant of the applied forces, but also allows to detect the extent of the forces which, while exerted on the sides of the platform, are opposed canceling each other.

[0110] The case in which the entity of the forces which cancel, tightening the platform 100, is decidedly prevailing with respect to the possible formation of small torques, corresponds to a sort of intention of grabbing the platform 100, by the operator who is manipulating it.

[0111] And, therefore, such intention of grabbing the platform 100 can be synthesized through the processing of the data from the skin (it is recalled that it is nothing else than a system of analog touch sensors, sensitive to pressure), and the cases in which two opposing forces are exerted roughly on the same line can be identified: approximations are necessary because the evaluations have to do with the interpretation of manual and spontaneous controls. In order to preserve the prerogative that imposes just manual controls designed to be intuitive, it is then appropriate to consider the event that an operator, acting with spontaneity, and wanting to move the platform 100 by pulling it toward him, tightens it between his hands and pulls.

[0112] The interpretation of such behavior, would require a skin composed by tactile sensors able to measure not just the pressure but also the components of force parallel to the surface. It is theoretically possible to use sensors of this type, but they do not constitute a low-cost technology and easy to be supplied (they are mostly laboratory material), and furthermore, even if available, their exploitation would require a considerable complexity, even circuital.

[0113] Although not excluding, in principle, the possibility of using such advanced skins also sensitive to the forces exerted by friction and having components parallel to the surfaces covered by such skins, the system implemented according to the teachings of the present invention can support the interpretation of a manual command imparted as depicted in FIG. 4 (i.e. two hands tightening a platform 100 and pulling it), also using the most common and simple tactile sensors, which are sensitive only to the pressure (i.e. just forces perpendicular to the surfaces). Thus, as noted above, through the processing of data only considering the pressures on surfaces, it is still possible to identify cases in which a kind of grab is exerted on the platform. Having such information (i.e. the presence of a grab), can be implemented a specific program, which, only when there is the presence of said grab, such program considers other input data, easily available in the self-moving robotized platforms, such as, for example, the data about the torques acting on the wheels. As explained above, the techniques for the manual control of a platform based on the knowledge of the torques on the wheels are known techniques, whose contraindications reside in less accuracy and in the fact that they require a good modeling of the environment and of the platform itself.

[0114] However, in the case in which these techniques based on the analysis of the torques generated on the wheels are used in combination with the techniques based on the detection of the contacts on the surface of the platform 100, the drawbacks can be significantly limited, as the analysis of the torques on the wheels can be considered, and used, to derive only a specific component of the motion desired by the operator, who may continue to dictate the other components of the motion by the aid of the tactile sensor system.

[0115] For example, rotations can be obtained by adjusting the pressure of the grip in points not perfectly opposite, thus giving rise to a resultant of the pressures which also provides a torque, or an oblique motion can be obtained by exerting a different pressure with the two hands, thus only the pressure exerted by one side vanishes, while the pressure exerted on the opposite side is not completely compensated.

[0116] The cited example is then generalizable, and indicates a further possibility of control offered by the self-moving robotized platform 100 made according to the teachings of the present invention. Such command opportunity allows to preserve the spontaneous and typical behavior that an operator can put in place when it intends to manually maneuver the movement of the platform 100. And this possibility is given by the fact that the movement to be imparted to the self-moving robotized platform 100 can be calculated not only by determining the resultant of the pressures applied on the surface; in fact, the analysis of these pressures, when exercised in more points, can also reveal the presence of grabs, namely the presence of components of forces that oppose without necessarily generate significant torques (so rotations), and in the presence of such grabs can therefore provide other information for the analysis, such as the occurrence of torques applied on at least one wheel of the platform. The occurrence of such a type of torque, applied on at least one wheel, allows to detect intention of operator of imparting a component of motion in the direction perpendicular to the force components which vanish each other by opposing.

[0117] And so, it is then possible to transform the identification of this intention into a corresponding movement command.

[0118] The analysis of torques present on the wheels is also useful as it allows to distinguish the case in which an operator pushes (intentionally or for distraction) the platform against an obstacle. In fact, also in this case, the tactile sensor system detects opposite forces that cancel each other: the thrust exerted by the operator and the opposite resisting force from the obstacle. However, in such cases, it doesn't arise on the wheels a torque corresponding to a movement perpendicular to the force components which are opposed, and the case can thus be managed and treated differently.

[0119] Depending on the complexity of the processing, and on the accuracy of the data coming from the measurement of the torque variations on the wheels, a more or less precise control can be achieved. However, the compromise in precision is certainly acceptable with respect to the achievable result, which is to devise a system capable of interpreting with completeness a great variety of spontaneous manual controls that can be given by an operator.

[0120] Even in the case that some of the platform motions are imparted as a result of these gripping command, the system can be calibrated once assembled, this calibration phase can be designed so as to take account of the typical use cases, and in this way also the precision achievable with this type of command can be further improved.

[0121] It has been underlined in many parts of this description that the leading goal that has guided the implementation of the commands for the control of the motion of the self-moving robotized platform according to the teachings of the present invention, was to conceive an intuitive set of control commands that enable an operator, even after a very short period of practice, to manually operate the platform.

[0122] This objective can be achieved, as mentioned above, inspired by a very intuitive model, such as the model of the empty box. It means that, the operator has the ability to impart the movement control commands simply imagining to push or pull a lightweight box, while, in many cases, it is actually a platform having considerable weight and inertias.

[0123] Well, the self-moving robotized platform according to the present description (i.e. provided with a tactile skin sensitive to pressure and associated to appropriate processing means suitable to generate commands for the movement of the platform itself) can support the generation of commands which may be inspired to other intuitive models. In fact, the empty box might be imagined to be sticky too, as well as lightweight; having surface completely sticky, or sticky only in some parts appropriately identified. It is therefore possible to refer to a model, intuitive again, such as the model of the sticky empty box.

[0124] Such model is intuitive as it is immediate to imagine what can happen by touching a lightweight box, but very sticky. In this case, after the touch with a hand, it would remain stuck to the box, and withdrawing said hand quite slowly, the box would continue to remain attached to the hand, and then, being said box actually light, it would be pulled, even in the absence of handles.

[0125] Otherwise, if the hand was withdrawn with a sudden movement it probably would detach without pulling the box with continuity.

[0126] Then it is obvious to think that, if the hand continues to push, the box would move in the direction of the thrust, exactly as in the cases discussed extensively in the previous part of this description.

[0127] The intuitive behavior described above, which regards a sticky empty box can be easily implemented, with more or less approximation, in the platform conceived in accordance with the present invention.

[0128] In fact, since the various pressures exerted on the side surfaces of the platform are known as well as the pressure points (for the presence of the tactile skin), it is also possible to determine whether or not a pressure is exerted in a sticky point. In this case, in addition to the control commands generated as explained above, consistent with the model of the simple empty box, additional commands must also be generated in correspondence to the changes of pressure that are determined by the movement of withdrawal of the hand (or of the object with which the platform had been touched). The commands, which have to be generated in this case, control the motion of the platform in order to determine a movement similar to the one which would occur if the platform were pulled from the contact point (sticky).

[0129] Slow movements of retraction allow the platform to follow the hand (or the object used to touch the platform) maintaining a contact and preserving a light pressure. Then, if the movements allowed to the platform implemented in this way are quite smooth, by placing a limit on the permitted speed and acceleration, an eventual abrupt retraction movement of the hand (or the object used to touch the platform) could not be followed by the platform, there would be the detachment and the platform would no longer be pulled thanks to the so-called sticky effect.

[0130] The mode of detachment indicated above is absolutely intuitive, and it is also easily implementable in the self-moving platform realized in accordance with the present invention; nevertheless, there are other ways, just as easily implementable and equally intuitive. For example, an operator may detach the hand by touching the platform at another point to hold it: it is evident that, being possible to detect also this further touch, it is easy to interpret the will of detachment from the operator.

[0131] Definitively, the intuitive sticky empty box effect is easily deployable and also useful in a number of circumstances where it is not easy neither push in the right direction nor even grabbing the platform. For example, in cases where a platform is parked in a sort of niche (in which it was uncomfortable to grab and pull it out), it may be particularly convenient, just to touch the platform, remain stuck, and pull it out slowly. The implementation of this sticky empty box effect is, as already said, very simple. It is sufficient to determine whether a pressure is exerted at a point to be considered sticky, and to interpret appropriately the pressure variations in the sense of their reduction, as indicators of a command of pulling the platform (in the case of slow movements) or as indicators of release intention (fast movements). In general, particular pressures on the self-moving platform (100), defined by their point of application, by their intensity or variation of intensity, can thus be associated with movements of the platform in the direction towards the operator; the operator can interpret these movements intuitively by making a more or less faithful analogy with the behavior of a lightweight object that remains stuck to him in the contact point.

[0132] The points, or the circumstances, in which the lateral surface of the platform is sticky can be determined by many variants of implementation. Among these, few example may be cited: the simplest is the definition of permanent sticky areas (possibly highlighted graphically on the side surfaces of the platform), or a sticky area may be activated on request by additional commands (e.g. a voice command).

[0133] Also the detachment can occur according to many variants. In addition to the examples already mentioned with abrupt movement, or by retaining the platform with the other hand, it is also possible to imagine other possibilities, based on commands of another type (e.g. a voice command) with which to inhibit the stickiness, or with other types of movement, such as a swiping movement, which, moreover, would be fairly intuitive (in fact, you can detach from a sticky surface swiping over it). A further option of implementation, which may be useful in many applications, and that therefore it is worth to mention explicitly, is to conceive of a tactile skin sensitive to pressure, but removable and applicable on different platforms or even (when convenient) directly on the payload that is placed on the platform itself. An example well illustrates this option of implementation.

[0134] It is then considered, but not limited to, the example of a self-moving cart controlled by a more or less remote control. Continuing to remaining within the considered example, for certain uses, it is convenient that said self-moving cart is provided with the possibility to be controlled, as well as remotely, also manually, and in an intuitive manner, by an operator. In this case, a wrapper constituted by a removable tactile skin, sensitive to pressure, as described in the present invention, can be applied on said self-moving cart when required.

[0135] For example, said removable tactile skin can be applied so as to surround the platform (possibly already loaded) along its perimeter, and placed in such a position that covers the surfaces in the zones on which is comfortable to manually push the cart. Said removable tactile skin, applied so as to be well-fitting, would work exactly as in previously described cases (cases in which the said tactile skin sensitive to the pressure is instead permanently applied on the self-moving platform), and would provide the pressure information that are necessary (and sufficient) to generate the control commands for the platform movement, as previously illustrated for the case of fixed tactile skins.

[0136] Such pressure information should be processed appropriately, not for the direct generation of the control commands for the movement, but rather to generate intermediate commands; for example, commands to be transmitted to the existing remote control, so that the latter generates the control commands for the movement of the platform, according to the intuitive model which is adopted (empty box, or sticky empty box, or others).

[0137] Therefore, by synthesizing the just exposed variant, in order to catch a generalization from the foregoing by way of example, it can be concluded that generic self-moving platforms can be equipped, even temporarily, with a removable tactile skin sensitive to the pressure, so that they are, however, self-moving platforms according to the teachings of the present invention.

[0138] In order to allow the overall system to work properly, it is obviously useful to devise a removable system that also includes, in addition to the removable tactile skin, appropriate computing means and interface means suitable to support communications and data exchanges. Said computing means perform an initial processing of the data provided by the system of the sensors of the tactile skin; while said interface means are suitable to be coupled to other control systems. In fact, the application of a removable tactile skin requires to integrate the processing of the pressure data detected by said tactile removable skin into the procedures of the control systems for the movement of the considered self-moving platform (control systems which are typically already present in the platform). Therefore, these removable tactile skins sensitive to the pressure must always be associated with the appropriate drivers specific for the platform on which they are applied, so as to adapt the processes executed at the level of skins with the control system of the platform on which they are applied. Obviously, many of the properties listed to describe the option based on the removable tactile skin are also found in implementations with permanent tactile skin. In particular, the decoupling between the processing of the data coming from the pressure sensors (according to the interpretation of an intuitive model, e.g. the model of the empty box) and the generation of the control commands on the motors of the wheel, is an implementation choice which can also be adopted in self-moving platforms (100) with permanent tactile skins.

[0139] However, such a definite decoupling, which also provides for the use of distinct computing means and needs a suitable physical interface, is a typical option for implementations based on removable tactile skins.

[0140] What is important to point out is the fact that the availability of continuous information about the extent of the contact pressure, allows an effective integration of control methodologies also based on many sensors, by performing the coherent interpretations of the operator's will, and by distinguishing the different cases, which is often not possible by the use of mere Boolean sensors of contact.

[0141] In general, it is noted that an interesting prerogative of the present invention is that of being easily integrable with other complementary solutions, in order to translate the commands given by the user manually or intuitively into the motion control commands of a self-moving robotized platform 100.

[0142] For example, if the platform has handles, protruding edges, or other points that are suitable to be grasped, or in general utilized by an operator to intuitively control the movements of such platform, these parts of the platform may be equipped with suitable sensors which detect these actions by the operator (typically other pressure sensors), and the detected signals can be used to elaborate the corresponding automatic control commands of movement.

[0143] It is clear that the number of forms in which these additional gripping points can be implemented is extremely diverse, each can have unique characteristics and may or may not be relevant to the management of collisions, and therefore the measurement data must be interpreted and managed in a specific way for each case. What matters to highlight here is the fact that even these options, useful to improve the overall usability of the final implementation of a self-moving robotized platform 100, as well as useful, are also very easily integrable in a self-moving robotized platform 100 that is designed according to the teachings of the present invention.

[0144] The invention just described can also lend itself to numerous variations that may offer additional advantages compared to those previously mentioned. And these further variants can be developed by the man skilled in the art without departing from the invention as it is clear from the present description and the claims appended hereto. Therefore, the arrangement of some described elements can be changed; and each element can be developed in different materials, size or shape; furthermore, the invention may be implemented in a partial way as well as other described details may be replaced by technically and functionally equivalent elements.

[0145] In particular, and as already said above, the particular technologies concerning the use of specific materials is not a characterizing issue of the present invention and therefore, if were to be available in the future more advantageous materials than those indicated in preferred implementations, or if the current technologies relating to the sensors and to the numerical control evolve towards better performance or best quality-price ratios, so as to apply more efficiently the different controls required, further improvements could be made in the embodiment of the present invention without in any way changing the inventive nature.

[0146] Finally, the described invention may incorporate and support further measures aimed to further improve the performance and the functions that can be implemented by a self-moving robotized platform whose motion can be adequately controlled: these measures, not described here, may eventually be the subject of further patent applications associable to this invention.