SYSTEM FOR ROBOT-ASSISTED CONTROL OF A TRANSRECTAL PROBE, FOR EXAMPLE FOR USE IN CARRYING OUT PROSTATE ECHOGRAPHY

Abstract

A system for controlling a transrectal probe, for example a transrectal ultrasound probe for echography, comprises a probe and a structure for supporting the probe that is carried by the wrist of a multi-axis manipulator robot. Operatively set between the wrist of the robot and the probe is a load cell. The system further comprises an electronic control unit for controlling the robot and a manual-guide device for guiding the robot, which is connected to the electronic control unit of the robot and comprise a manual-guide member, which can be manoeuvred by an operator for imparting on the robot movements that are function of the movements imparted on the manual-guide member. The electronic control unit of the robot receives signals emitted by the load cell and activates an alarm condition when the load cell signals that a threshold value of the stress detected thereby is exceeded. Preferably, the manual-guide member is pre-arranged for supplying to the operator a haptic feedback, for example of a vibrational type.

Claims

1. A system for controlling a transrectal probe, for example a transrectal ultrasound probe for echography, comprising: a transrectal probe; a supporting structure for supporting said probe; a multi-axis manipulator robot having a wrist that carries said supporting structure of said probe; a load cell operatively set between said robot wrist and said transrectal probe; an electronic control unit for controlling said robot; a manual-guide device for guiding said multi-axis manipulator robot, which is connected to said electronic control unit of the robot and comprises a manual-guide member, which can be manoeuvred by an operator for imparting on the robot movements that area function of the movements imparted on said manual-guide member; said electronic control unit of the robot being programmed for controlling said robot on the basis of the movement imparted manually by an operator on said manual-guide member, in view of driving the probe inside a rectum of a patient; said electronic control unit of the robot being moreover programmed for receiving signals emitted by said load cell and activating an alarm condition when said load cell signals that a threshold value of the stress detected thereby is exceeded.

2. The system according to claim 1, wherein said alarm condition activated by said electronic control unit of the robot causes arrest of the robot.

3. The system according to claim 1 wherein said alarm condition activated by said electronic control unit causes emission of one of a visual alarm signal or an acoustic alarm signal.

4. The system according to claim 1, wherein said manual-guide member is pre-arranged for supplying to the operator a haptic feedback, for example of a vibrational type.

5. The system according to claim 1 wherein said manual-guide device is rigidly connected, directly or indirectly, to said wrist of the robot.

6. The system according to claim 5, wherein said manual-guide device is provided with means for its anchorage to the robot or to said supporting structure of the probe.

7. The system according to claim 4, wherein said manual-guide device is pre-arranged for supplying a haptic feedback of an intensity proportional to the stress detected by said load cell.

8. A method for controlling a system according to claim 1, wherein: said robot is controlled on the basis of the movement imparted manually by an operator on said manual-guide member; and the alarm condition is activated when said load cell signals that a threshold value of the stress detected thereby is exceeded.

9. The system according to claim 2 wherein said alarm condition activated by said electronic control unit causes emission of one of a visual alarm signal or an acoustic alarm signal.

10. The system according to claim 4 wherein said manual-guide device is rigidly connected, directly or indirectly, to said wrist of the robot.

11. A method for controlling a transrectal probe for use with a multi-axis robot, the method comprising: manipulating a manual guide member by a user; sending a control signal to an electronic control unit of a multi-axis robot; sending a control signal from the electronic control unit to a motor connected to an arm of a robot connected to a robot wrist; moving a transrectal probe based on manipulation of the manual guide by the user; sensing through a load cell a resistive force on the transrectal probe based on movement of the transrectal probe; and sending a signal from the load cell to the electronic control unit based on the resistive force on the transrectal probe; and activating an alarm when the resistive force on the transrectal probe exceeds a predetermined threshold value.

12. The method of claim 11 further comprising the step of: sending a haptic signal from the electronic control unit to the manual guide member based on the resistive force sensed by the load cell.

13. The method of claim 12 wherein the haptic signal varies in level of intensity based on the value of the resistive force sensed by the load cell.

14. The method of claim 11 wherein the alarm comprises: arresting movement of the multi-axis robot.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Further characteristics and advantages of the invention will emerge from the ensuing description with reference to the annexed drawings, which are provided purely by way of non-limiting example and in which:

[0020] FIG. 1 is a schematic view of the system according to the invention;

[0021] FIG. 1A is a view at an enlarged scale of some details illustrated in FIG. 1;

[0022] FIG. 2 is a block diagram that illustrates operation of the system of FIG. 1; and

[0023] FIGS. 3 and 4 show two perspective views of a manual-guide device illustrated in FIG. 1.

DETAILED DESCRIPTION

[0024] FIG. 1 illustrates a system 1 according to the present invention, for robot-assisted control of a transrectal probe. The example illustrated herein regards the case of an ultrasound probe that can be used, for example, for carrying out a prostate biopsy. Any ultrasound probe of a known type may be suitable for the purpose. For example, the present applicant has conducted first experiments with an ultrasound probe produced by the company BK Ultrasound Systems and marketed under the tradename BioJet Fusion. It should in any case be noted that the present invention is of general application and is suited to being used for controlling a transrectal probe of any type.

[0025] The system 1 comprises a multi-axis manipulator robot 4. In the example illustrated, the robot 4 is an anthropomorphic robot having a base 41 and a column 42, which is rotatably mounted on the base 41 about a first axis I directed vertically. The robot 4 has an arm 43 mounted on the column 42 articulated about a second axis II directed horizontally. Designated by the reference 44 is a forearm mounted on the arm 43. The forearm 44 is articulated about a third axis III, which is also directed horizontally; the forearm 44 moreover has the possibility of rotating about its longitudinal axis IV. The forearm 44 of the robot 4 is provided at its end opposite to the arm 43 with a wrist 6 mounted with possibility of rotation about two mutually orthogonal axes V, VI. According to the known art, each of the six axes I, II, III, IV, V, and VI of the robot is controlled by a respective electric motor (in the drawing only the electric motor M that controls the first axis I is visible) via a respective reducer. The electric motors of the robot are controlled in a way in itself known by an electronic control unit E (illustrated in the block diagram of FIG. 2). In an example of embodiment that has formed the subject of the studies and experiments conducted by the present applicant, the robot produced by the present applicant under the tradename RACER 3 has proven particularly suited.

[0026] In accordance with the known art, provided at the distal end of the robot wrist 6 is a flange for attachment of the tool carried by the robot. In the case of the present invention, instead of a tool, associated to the flange of the robot 4 is a supporting structure 3 carrying a transrectal ultrasound probe 2. In the embodiment illustrated in FIG. 1, the supporting structure 3 is constituted by a substantially L-shaped main body 31, associated to which is a supporting frame 32 connected on which is the transrectal probe 2. It is, however, to be noted that the structure 3 for supporting the probe 2 may have any configuration different from the one illustrated herein purely by way of example.

[0027] According to an essential characteristic of the present invention, the system 1 further comprises a load cell 5 operatively set between the wrist 6 of the robot 4 and the transrectal probe 2. FIG. 1A is a schematic view at an enlarged scale of the terminal end of the robot 4, which shows in particular the load cell 5 set between the flange at the distal end of the robot 4 and the main body 31 of the structure 3 that supports the probe 2. More in general, it is necessary for the load cell 5 to be interposed in any point of the chain of elements that mechanically connect the probe 2 to the distal end of the robot 4.

[0028] The load cell 5 is used in the system 1 in order to detect, preferably in a continuous way, the load exchanged between the transrectal probe 2 and the wall of the patient's rectum. In the present description, and in the ensuing claims, by the expression load cell is meant any type of sensor device designed to detect a force or a load. This expression encompasses the case of a unidirectional sensor, designed to detect forces acting only in one direction (for example, the longitudinal direction of the probe 2) and the case of a sensor, or system of sensors, designed to detect forces and/or couples acting in a number of directions.

[0029] In a simplified example of embodiment, the load cell 5 is provided with one or more electrical strain gauges. The mechanical stress on the probe 2 is measured in a way in itself known, via detection of a variation of electrical resistance in the electrical circuit of the strain gauges.

[0030] As already mentioned, the transrectal ultrasound probe for echography may be of any known type available on the market. The probe is available in association with a processing and display device and a corresponding processing program. The processing and display device may, for example, be in the form of a portable personal computer, such as the one designated by 9 in FIG. 1.

[0031] According to a further important characteristic of the invention, the system 1 comprises a manual-guide device for guiding the multi-axis manipulator robot 4, which is connected to the electronic control unit E of the robot (see also the block diagram of FIG. 2) and comprises a manual-guide member, which can be manoeuvred by the physician for imparting on the robot 4 movements that are a function of the movements imparted on the manual-guide member.

[0032] Once again with reference to FIG. 1, illustrated simultaneously therein are two different manual-guide devices 7 and 8 of the robot, which can be used as an alternative to one another. The preferred embodiment is the one that makes use of a manual-guide device 7 associated to the distal end of the robot. FIGS. 3 and 4 illustrate two perspective views of the manual-guide device 7 that is of the known type illustrated in the document EP 2 194 434 A1 filed in the name of the present applicant. In the example illustrated in FIG. 1, the manual-guide device 7 is associated to the supporting structure 3 of the probe 2. According to what is already known from the document EP 2 194 434 A1, the guide device 7 has inside it a microprocessor electronic control system of a programmable type, and permanent rewriteable memory means. Designated by the reference 71 is the manual-guide member of the device 7, which is constituted by a knob with a number of degrees of freedom. The device 7 further comprises some pushbuttons, amongst which a pushbutton 72 for switching on and switching off the device 7 and a storage pushbutton 73 that can be used by the operator for storing co-ordinates of path of the manipulator robot 4. The device 7 is also conveniently provided with a connector 74 for connection to a charging device of a known type (not represented herein).

[0033] Once again in the case of the preferred embodiment, the manual-guide device 7 is provided with wireless-communication means in order to establish a wireless-communication channel with the electronic control unit of the robot E. For this purpose, designated by the reference 75 is a wireless transceiver module, which is connected to the electronic control unit E.

[0034] The device 7 illustrated in FIGS. 3 and 4 further comprises a casing of a prismatic shape 76 present within which is the corresponding control system and carried on which is the knob 71. The control circuit of the device 7 is of a miniaturized type so that the dimensions of the casing 76 are rather small.

[0035] The device 7 is moreover provided with a plurality of straps 77 for quick fixing to the supporting structure 3. Of course, instead of the straps 77 there may be used other mounting means suitable for use on the supporting structure 3.

[0036] In the example of FIG. 4, the casing 76 has a respective base 78 that defines one or more engagement seats 79, which are designed to receive respective portions 79a of the mounting base 79b on which the straps 77 are applied.

[0037] The knob 71 preferably has six degrees of freedom. For example, by exerting a pressure or else a pull in the axial direction on the knob 71 there is brought about advance or recession of the forearm 44 of the manipulator robot 4. By pressing the knob to the right or to the left there is obtained, respectively, a displacement to the right and to the left of the forearm 44. Likewise, by pushing the knob downwards (i.e., towards the south of the knob) or upwards (i.e., towards the north of the knob) there are obtained the corresponding movements of the forearm 44. The knob 71 may moreover be rotated in a clockwise and counterclockwise direction to obtain corresponding relative movements of rotation.

[0038] As indicated previously, in FIG. 1 designated by the reference 8 is a second type of manual-guide device alternative to the manual-guide device 7. The manual-guide device 8 is of the 6-degrees-of-freedom mouse type and is constituted by a base 81 of a cylindrical shape which can be constrained to a plane surface (in the example of FIG. 1, the base 81 is constrained to a table on which the computer 9 rests). Connected to the base 81 is a mobile arm 82 connected to the terminal end of which is the guide member 83, which, in the embodiment illustrated in FIG. 1, is a lever control device of a joystick type. Like the device 7 described previously, also the device 8 has relatively contained dimensions. A device of this type that is currently available on the market is the device BioJet Fusion manufactured by the company BK Ultrasound Systems. For this reason, the constructional details of this device are not illustrated any further herein.

[0039] FIG. 2 illustrates a functional diagram of the system 1 according to the present invention. The lines L indicate from the functional standpoint the fact that the load cell 5 is set between the flange at the distal end of the robot 4 and the probe 2. The electronic control unit E of the robot 4 receives control signals G from the manual-guide device 7 or 8 following upon manual actuation of the corresponding guide member by the physician. The electronic unit E sends control signals C to the robot 4 on the basis of the control signals G coming from the manual-guide device 7 or 8. In this way, the physician can control movement of the probe in an easy and intuitive way and without having to make any effort. In the case of an ultrasound probe, the operator drives the probe via the manual-guide device, controlling in real time the image of the organ (for example, the prostate) obtained via the probe.

[0040] According to a further characteristic of the invention (see once again FIG. 2), the electronic control unit E is programmed for receiving the signals S emitted by the load cell 5 and for activating an alarm condition in the case where the stress detected by the load cell 5 exceeds a predetermined threshold value. The alarm condition activated by the electronic unit E may consist in arrest of the robot 4 and/or in activation of a visual and/or acoustic alarm, for example emitted by an emitter pre-arranged on the manual-guide device 7 or 8. Thanks to the above characteristic, the system according to the invention guarantees the necessary safety for the patient, notwithstanding the fact that the operator moves the transrectal probe via the robot 4.

[0041] According to a further characteristic of the preferred embodiment of the system according to the invention, the manual-guide member (71 or 83) of the manual-guide device (7 or 8) is pre-arranged for supplying the operator with a haptic feedback, for example of a vibrational type, which is generated on the basis of a signal F produced by the electronic control unit E as a function of the signals S coming from the load cell 5.

[0042] In this way, use of the system according to the invention is even easier and more intuitive, in so far as the operator is provided with a direct feel of the degree of resistance that the probe encounters in its movement.

[0043] According to this preferred characteristic of the invention, the guide member 71, 83 consequently comprises inside it a haptic device of any known type so that the operator can receive tactile sensations in response to the displacements of the probe 2. Haptic devices have been known and used for some time now. These devices may, for example, make use of piezoelectric elements pre-arranged under the outer surface of a knob and designed to be set in vibration following upon an electrical signal sent to them.

[0044] The system may be pre-arranged for generating the haptic feedback only when the aforesaid threshold value of the stress detected by the load cell 5 is exceeded. However, preferably, the system is pre-arranged for generating a haptic feedback on the guide member 71, 83, such as a vibrational haptic feedback, which is of an intensity that increases proportionally to the stress detected by the load cell 5. In this case, the operator can receive an increasing haptic signal even before the alarm condition is reached.

[0045] Preferably, the electronic unit E is programmed for getting the robot 4 to carry out an automatic initial manoeuvre of approach of the probe 2 to its starting position, where then the operator assumes total control of the probe via the manual-guide device of the robot.

[0046] As is evident from the foregoing description, the system according to the invention enables a robot-assisted control of a transrectal probe of any type, which is extremely convenient and intuitive to use for the physician and at the same time guarantees the necessary safety for the patient. The system according to the invention moreover enables an extremely precise control of the movement and positioning of the probe and makes use of means that are relatively simple and inexpensive.

[0047] Of course, without prejudice to the principle of the invention, the structural details and the embodiments may vary widely with respect to what has been described and illustrated herein merely by way of example, without thereby departing from the scope of the present invention as specified in the ensuing claims.