Boom lift cartesian control systems and methods

Abstract

Methods and systems for controlling a boom lift, cherry picker, or other similar device are disclosed, including monitoring a controller for an operator desired action; receiving signals from one or more sensors through one or more inputs; using a platform location algorithm and the signals from the one or more sensors to compute current angles and/or lengths of the boom lift; using a platform control algorithm to calculate a control signal to achieve the operator desired action; and using a control signal generator to communicate the control signal to one or more assembly controllers of the boom lift. Other embodiments are desired and claimed.

Claims

1. A system for controlling a boom lift, said system comprising: a) an operator platform including a gyroscopic sensor, an accelerometer, and an electronic controller; b) an upper telescoping assembly attached to said operator platform; c) a lower telescoping assembly attached to said upper telescoping assembly; d) two or more rotary joints positioned on the boom lift, wherein each of said two or more rotary joints serves as an assembly controller configured for adjusting a position of the boom lift; e) a first joystick and a second joystick, said first joystick being configured for implementing movement of said operator platform in an X-Y plane, and said second joystick being configured for implementing movement of said operator platform in a Z plane; f) said electronic controller comprising a processor and a memory unit; g) said electronic controller being adapted to: 1) receive input signals from said gyroscopic sensor and said accelerometer, said input signals from said gyroscopic sensor and said accelerometer being indicative of a current position of said operator platform; 2) receive input signals from at least one of said first joystick or said second joystick, said input signals from at least one of said first joystick or said second joystick including a desired angle and/or length of at least one of said upper and lower telescoping assemblies; 3) calculate the desired angle and/or length of at least one of said upper and lower telescoping assemblies based on said input signals from said at least one of said first joystick or said second joystick; 4) calculate current angles and/or lengths of said upper and lower telescoping assemblies based on said input signals from said gyroscopic sensor and said accelerometer; 5) compare the desired angle and/or length of at least one of said upper and lower telescoping assemblies to the current angles and/or lengths of said upper and lower telescoping assemblies; and 6) communicate a control signal to at least one of said two or more rotary joints to achieve the desired angle and/or length of at least one of said upper and lower telescoping assemblies.

2. The system of claim 1, wherein said gyroscopic sensor and said accelerometer are solid state sensors.

3. The system of claim 1, wherein said system is implemented in a lift vehicle.

4. The system of claim 1, wherein said two or more rotary joints include: a) an uppermost rotary joint that is movable in one axis of rotation; and b) a lowermost rotary joint that is movable in two axes of rotation.

5. The system of claim 1, wherein said electronic controller is further configured to: a) monitor for failure of said gyroscopic sensor and said accelerometer; and b) communicate a safety control signal to said two or more rotary joints.

6. A system for controlling a boom lift, said system comprising: a) an operator platform having a gyroscopic sensor, an accelerometer, and an electronic controller; b) an upper telescoping assembly attached to said operator platform; c) a lower telescoping assembly attached to said upper telescoping assembly; d) two or more rotary joints positioned on the boom lift, wherein each of said two or more rotary joints serves as an assembly controller configured for adjusting a position of the boom lift; e) a joystick being configured for implementing movement of said operator platform in an X-Y plane; f) said electronic controller comprising a processor and a memory unit; g) said electronic controller being configured to store a platform location algorithm and a platform control algorithm; and h) said electronic controller being further configured to: 1) monitor said joystick for an operator desired action, wherein the operator desired action includes desired angles and/or lengths of said upper and lower telescoping assemblies; 2) receive signals from said gyroscopic sensor and said accelerometer; 3) use the platform location algorithm and said signals from said gyroscopic sensor and said accelerometer to compute current angles and/or lengths of said upper and lower telescoping assemblies; 4) compare the desired angles and/or lengths of said upper and lower telescoping assemblies to the current angles and/or lengths of said upper and lower telescoping assemblies; 5) use the platform control algorithm to calculate a control signal to achieve the desired angles and/or lengths of said upper and lower telescoping assemblies; and 6) communicate the control signal to at least one of said two or more rotary joints, wherein said at least one of said two or more rotary joints implements movement of said upper and/or lower telescoping assemblies to achieve the desired angles and/or lengths of said upper and lower telescoping assemblies.

7. The system of claim 6, wherein said gyroscopic sensor and said accelerometer are solid state sensors.

8. The system of claim 6, wherein said joystick includes a toggle control, said toggle control being operable to implement movement of said operator platform in a Z plane.

9. The system of claim 6, wherein said system is implemented in a lift vehicle.

10. The system of claim 6, wherein said two or more rotary joints include: a) an uppermost rotary joint that is movable in one axis of rotation; and b) a lowermost rotary joint that is movable in two axes of rotation.

11. The system of claim 6, wherein said electronic controller is further configured to: a) monitor for failure of said gyroscopic sensor and said accelerometer; and b) communicate a safety control signal to said two or more rotary joints.

12. A system for controlling a boom lift, said system comprising: a) an operator platform including a gyroscopic sensor, an accelerometer, and an electronic controller, wherein said gyroscopic sensor and said accelerometer are solid state sensors; b) an upper telescoping assembly attached to said operator platform; c) a lower telescoping assembly attached to said upper telescoping assembly; d) two or more rotary joints positioned on the boom lift, wherein each of said two or more rotary joints serve as an assembly controller configured for adjusting a position of the boom lift, and wherein said two or more rotary joints include: 1) an uppermost rotary joint that is movable in one axis of rotation; and 2) a lowermost rotary joint that is movable in two axes of rotation; e) a first joystick being configured for implementing movement of said operator platform in an X-Y plane; f) a second joystick being configured for implementing movement of said operator platform in a Z plane; g) said electronic controller comprising a processor and a memory unit; and h) said electronic controller being adapted to: 1) receive input signals from said gyroscopic sensor and said accelerometer, said input signals being indicative of a current position of said operator platform; 2) receive input signals from at least one of said first joystick and said second joystick, said input signals from at least one of said first joystick and said second joystick including a desired angle and/or length of at least one of said upper and lower telescoping assemblies; 3) calculate the desired angle and/or length of at least one of said upper and lower telescoping assemblies based on said input signals from said at least one of said first joystick or said second joystick; 4) calculate current angles and/or lengths of said upper and lower telescoping assemblies based on said input signals from said gyroscopic sensor and said accelerometer; 5) compare the lengths desired angle and/or length of at least one of said upper and lower telescoping assemblies to the current angles and/or lengths of said upper and lower telescoping assemblies; and 6) communicate a control signal to at least one of said two or more rotary joints to implement movement of the boom lift to achieve said desired angles and/or lengths of said upper and lower telescoping assemblies.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is a simplified view of a vehicle 10 that embodies and incorporates and uses embodiments of the invention shown with the lower and upper telescoping boom assemblies partially extended.

(2) FIG. 1A is a simplified schematic representation of the electronic controller and various related components of the disclosed system.

(3) FIG. 2 is a flowchart of the method steps in the operation of the system controlled by the apparatus of the present invention.

(4) FIG. 3 is a simplified view of a control panel 300 for use with embodiments of the invention.

DETAILED DESCRIPTION

(5) Reference is made first to FIG. 1 for a brief description of the overall structure of the components of the lift vehicle 10 of the preferred embodiment, wherein lift vehicle 10 includes boom lift 12. The operator platform 50 is attached to the upper telescoping assembly 30, which is in turn attached to the lower telescoping assembly 20. The method of attachment is as is known in the art. Additionally, the number of telescoping assemblies can vary by the requirements for the lift vehicle 10. The operator platform 50 contains the electronic controller 80 as well as the gyroscopic sensor 51 and accelerometer 52. In preferred embodiments, the gyroscopic sensor 51 and accelerometer 52 are solid state sensors. In alternate embodiments, gyroscopic sensor 51 and accelerometer 52 are conventional sensors as would be understood by one of ordinary skill in the art. The actual locations of the electronic controller 80 as well as the locations, types, and number of sensors can vary in alternate embodiments of the invention. Additionally, alternate embodiments can substitute non-telescoping assemblies for the upper and lower telescoping assemblies as well as vary the number of such assemblies. Such alternatives should fall within the scope of some (but not necessarily all) aspects of the present invention, except to the extent clearly excluded by the claims.

(6) Reference is made to FIG. 2 for a generalized flowchart providing the basic method steps associated with the operation of the system of the preferred embodiment and its manner of controlling the operator platform 50 in Cartesian space. The basic functionality shown in FIG. 2 begins at Step 101 wherein the electronic controller 80 monitors the system for any operator indication of a desired action. Typically, these actions will involve some sort of directional movement of the operator platform 50 desired by the operator and is indicated in Step 102 by the operator via a controller. Step 103 involves the signal sent to the electronic controller 80 with the desired action.

(7) In Step 104, the electronic controller 80 runs the operator platform control algorithm 70. The operator platform control algorithm 70 is described in more detail below. The electronic controller 80 and its operator platform control algorithm 70 obtain a continual signal from the gyroscopic sensor 51 and accelerometer 52 containing the actual sensed conditions (Step 109). The algorithm 70 uses the actual sensed conditions to calculate an appropriate control signal to achieve the desired action which is then sent to the appropriate controller in Step 105. The electronic controller calculates an anticipated sensed conditions value for the operator platform control algorithm 70 in Step 106. In Step 107, if the anticipated sensed conditions value calculated in Step 106 does not match the actual sensed conditions then the system returns to Step 104. If the value does match, then the system moves to Step 108, wherein the electronic controller determines if the desired action has been completed. If it has not then the system returns to Step 104; if it has then the system returns to Step 101.

(8) The operator platform control algorithm 70 continually refines its estimates of the anticipated sensed conditions value using the data from the actual sensed conditions along with its previous estimates of the anticipated sensed conditions. It should be understood, though, that the sequence and detail of FIG. 2 are merely exemplary, generalized steps of a preferred process. To the extent still within the scope of the invention as defined in any particular claim, each of those steps 101-109 can be subdivided, combined, transposed, intertwined, eliminated or replaced with equivalents or alternates, as would be known or evident from this description to one of ordinary skill in the art, especially pursuant other teachings known or commercially implemented in the pertinent fields.

(9) Electronic Controller

(10) The electronic controller 80 uses one or more presently available computing devices which contain a processor 56, a memory unit 53, one or more input means 55, and one or more output means 54. One example of a controller which is suitable to be programmed for embodiments of the present invention as described herein is any of the HFX series of programmable controllers commercialized by Eaton Corporation [www.eaton.com]. Such controllers incorporate a processor and a memory unit, as well as having capabilities for receiving inputs and for generating outputs. The electronic controller 80 preferably stores part, or all, of the operator platform control algorithm 70. The electronic controller 80 receives information on the sensed conditions and calculates the desired angle(s) and length(s) according to the operator platform control algorithm 70. The electronic controller 80 then uses its control signal generator 81 to communicate a corresponding angle and/or length command to the appropriate rotary joints (61, 62, 63, 64), each of which serves as a controller for adjusting the angular position of the corresponding telescoping assembly. The rotary joints 61, 62, 63, 64 use commercially available or predictable equipment that receives the angle and/or length control signal from control signal generator 81 either by wire or wirelessly and sets or changes the assembly angle and/or length (.sub.1, .sub.2, .sub.3, .sub.4, L.sub.1, L.sub.2) to the commanded angle and/or length. Control signal generator 81 sends electrical drive signals to hydraulic solenoids to control flow of hydraulic fluid for operating upper and lower telescoping assemblies 20, 30. These signals are based on current, such signals being variable and proportional. For instance, a zero current value indicates no hydraulic fluid flow. A positive current value will result in flow in one direction, and a negative current value will result in flow in the opposite direction.

(11) Platform Location Algorithm

(12) Platform 50 includes sensors such as gyroscopic sensor 51 and accelerometer 52. In some embodiments, the sensors on platform 50 are made from the components of a Zero Off module commercially available from Applicant, Enovation Controls, LLC, although the GPS functionality of such modules may be removed as unnecessary for functionality of the present invention. In other embodiments, the sensors may be mounted together on a circuit board. For determining the location of platform 50, rotary joint 61 and/or 62 should be actuated or moved below the extension angle.

(13) For example, when the rotational position of rotary joint 62 moves, if the extension of telescoping assembly 30 is relatively short, the accelerations measurable at platform 50 are small as compared to a situation when telescoping assembly 30 is fully extended, wherein the accelerations measurable at platform 50 would be much larger. For instance, when the operator commands platform 50 to move upward, telescoping assembly 30 will extend upward. However, when translating platform 50 in a vertical direction, telescoping assembly 30 will also tilt backward while platform 50 is translated upward. It is when rotary joint 62 moves in this rotational fashion, the length of extension of telescoping assembly 30 can be estimated based on the acceleration measurement made at platform 50.

(14) The following represents the mathematical relationships related to platform location algorithm 90:

(15) A 3-axis accelerometer 52 and a 3-axis gyroscopic sensor 51 are positioned on platform 50. Let .sub.1, .sub.2, .sub.3, .sub.4 be measured values using rotational position sensors on each rotary joint. L.sub.1 is fixed and known. L.sub.2 is not measured but will be estimated:

(16) L.sub.2=actual length of L.sub.2 (unknown)

(17) {tilde over (L)}.sub.2=estimate estimated length of L.sub.2

(18) L.sub.2d=desired length of L.sub.2

(19) If lift vehicle 10 is stationary, then a point B on platform 50 can be described relative to a point O at the origin of the XYZ axes as shown in FIG. 1:

(20) P.sub.B=f.sub.P(.sub.1, .sub.2, .sub.3, .sub.4, L.sub.1, L.sub.2)

(21) V.sub.B=f.sub.V(.sub.1, {dot over ()}.sub.1, .sub.2, {dot over ()}.sub.2, .sub.3, {dot over ()}.sub.3, .sub.4, {dot over ()}.sub.4, L.sub.1, L.sub.2, {dot over (L)}.sub.2)

(22) .sub.B=f.sub.A(.sub.1, {dot over ()}.sub.1, {umlaut over ()}.sub.1, .sub.2, {dot over ()}.sub.2, {umlaut over ()}.sub.2, .sub.3, {dot over ()}.sub.3, {umlaut over ()}.sub.3, .sub.4, {dot over ()}.sub.4, {umlaut over ()}.sub.4, L.sub.1, L.sub.2, {dot over (L)}.sub.2, {umlaut over (L)}.sub.2)

(23) {tilde over (P)}.sub.B=f.sub.P(.sub.1, .sub.2, .sub.3, .sub.4, L.sub.1, {tilde over (L)}.sub.2)

(24) {tilde over (V)}.sub.B=f.sub.V( . . . , {tilde over (L)}.sub.2, {dot over ({tilde over (L)})}.sub.2)

(25) .sub.B=f.sub.A( . . . {tilde over (L)}.sub.2, {dot over ({tilde over (L)})}.sub.2, {umlaut over ({tilde over (L)})}.sub.2)

(26) Where the dot notation means:

(27) {dot over (x)}=(d/dt)x

(28) {umlaut over (x)}=(d.sup.2/dt.sup.2)x; where t equals time

(29) And: P.sub.B, V.sub.B, .sub.B=actual position, velocity, and acceleration of point Bboth translational and rotational.

(30) {tilde over (P)}.sub.B, {tilde over (V)}.sub.B, .sub.B=estimated position, velocity, and acceleration of point Bboth translational and rotational. An accelerometer at B will provide the X, Y, Z translational components of .sub.B, and by integration V.sub.B. A velocity gyroscope (common type) will provide the X, Y, Z rotational components of V.sub.B.

(31) The only unknown in {tilde over (P)}.sub.B is {tilde over (L)}.sub.2.

(32) An algorithm that can continuously improve the accuracy of the estimated length {tilde over (L)}.sub.2 is called an observer by those of ordinary skill in the art of control theory. One embodiment of such an algorithm can be written as:
{tilde over (L)}.sub.2new={tilde over (L)}.sub.2old+[{dot over ({tilde over (L)})}.sub.2old+K.sub.VM.sub.V(V.sub.B{tilde over (V)}.sub.B)]t;
where t=time step between observer digital updates; K.sub.V=a gain value which can speed up or slow down how quickly estimates are improved; M.sub.V=a mapping matrix which inverts the kinematics of f.sub.V( . . . ).
Clearly, when (V.sub.B{tilde over (V)}.sub.B) is zero, the estimate of {tilde over (L)}.sub.2 is accurate and no additional corrections to {tilde over (L)}.sub.2 are made at each time step other than simple integration of {dot over ({tilde over (L)})}.sub.2.
Operator Platform Control Algorithm

(33) An operator platform control algorithm 70 is preferably implemented in electronic controller 80. The operator platform control algorithm 70 may include any common or advanced control loop transfer function including, but not limited to, series, parallel, ideal, interacting, noninteracting, analog, classical, and Laplace types. In preferred embodiments, the control loop transfer function actuates hydraulic control valves that regulate the flow of hydraulic fluid to the various actuators. When an operator moves joystick 302 and/or 304 (as shown in FIG. 3), the operator platform control algorithm via the control loop transfer function will start hydraulic fluid flowing to the appropriate actuators(s) to implement the desired operator action. If any corrections are required with respect to hydraulic fluid flow, these corrections will be made on the basis of sensed conditions as determined by gyroscopic sensor 51 and/or accelerometer 52. In other words, the appropriate hydraulic fluid flow is based on the observed position of the telescoping assemblies 20, 30.

(34) The operator platform control algorithm 70 calculates the desired assembly angle and/or length (.sub.1, .sub.2, .sub.3, .sub.4, L.sub.1, L.sub.2) based on input information from an appropriate one or more of the sensors (gyroscopic sensor 51 and accelerometer 52) that are available. The operator platform control algorithm 70 receives input information from the device systems and controls that are equipped with such sensors. As used herein, the term sensor is not limited to a single device detecting and reporting a single condition. A sensor may be one or more devices detecting and reporting one or more conditions. As used in the preferred embodiment the gyroscopic sensor 51 is a solid state sensor which detects the rotational motion and magnitude of the operator platform. The accelerometer sensor 52 is preferably a solid state sensor which detects the linear motion and amplitude of the operator platform.

(35) Based on the input information from one or more sensors, the operator platform control algorithm 70 calculates angles and/or lengths for one or both telescoping assemblies 20 and 30. For each telescoping assembly 20 and 30 it is controlling, the operator platform control algorithm 70 calculates an angle and/or length (.sub.1, .sub.2, .sub.3, .sub.4, L.sub.1, L.sub.2) and a corresponding angle and/or length command to achieve as much. The operator platform control algorithm 70 calculates the desired angle and/or length (.sub.1, .sub.2, .sub.3, .sub.4, L.sub.1, L.sub.2) based on the sensed conditions. However, because of the inherent limits of the control systems, the desired angle and/or length (.sub.1, .sub.2, .sub.3, .sub.4, L.sub.2) may not be achievable, either instantaneously or at all. An angle and/or length rate limiting function may also be implemented in the electronic controller 80, in rotary joints 61, 62, 63, 64 by some other means, or may not be necessary based on the type of the devices' pre-existing controls. When the control system relies on the algorithm to limit the rate of change of the angle and/or length (.sub.1, .sub.2, .sub.3, .sub.4, L.sub.1, L.sub.2), the algorithm computes intermediate commanded angles and/or lengths to achieve a desired angle and/or length.

(36) The electronic controller 80 preferably includes a comparator function with which the operator platform control algorithm 70 compares the desired angle and/or length (.sub.1, .sub.2, .sub.3, .sub.4, L.sub.1, L.sub.2) with the current angle and/or length (1, 2, 3, 4, L1, L2) as detected by gyroscopic sensor 51 and/or accelerometer 52 and computed by the platform location algorithm 90. The algorithm 70 produces a series of intermediate commanded angles and/or lengths (1, 2, 3, 4, L1, L2) that achieve the desired angle and/or length (1, 2, 3, 4, L1, L2) without exceeding the control system's maximum permissible rate of change of angle and/or length. Further, the operator platform control algorithm 70 is adapted to limit the commanded angle to the vehicle control system's mechanical limits. The operator platform control algorithm 70 also preferably contains a smoothing function to avoid rapid changes in angle and/or length commands. The smoothing function compensates for noise in sensors or controls and for rapid fluctuations in sensed conditions. Such smoothing function is preferably a standard low-pass filter, the performance of which will be understood by those of ordinary skill in the art.

(37) The operator platform control algorithm 70 also includes internal limitations for other operating and safety considerations. For example, regardless of sensed conditions, the operator platform control algorithm 70 never commands an angle and/or length in excess of the mechanical or safety limits of the telescoping assemblies 20 and 30. In case of certain sensor failures, the electronic controller informs the operator a failure has occurred and commands the telescoping assemblies 20 and 30 to a safe angle and/or length with a safety control signal. In case of electronic controller failure, a fail-safe operates to disable Cartesian movement and allow the vehicle's manual steering system to resume unaided control of the telescoping assemblies 20 and 30.

(38) Turning now to FIG. 3, there is shown a simplified control panel 300 of platform 50. Joysticks 302 and 304 are shown on control panel 300 for implementing Cartesian movement of the operator platform 50. Those of ordinary skill in the art will recognize that numerous other control features besides the illustrated joysticks 302, 304 may be incorporated into control panel 300.

(39) Joystick 304, shown on the left side of control panel 300, operates to move operator platform 50 in the z plane of Cartesian movement. In other words, as indicated by arrows 314, 316, joystick 304 implements vertical movement (up and down) of operator platform 50. With respect to joystick 302, movement can be implemented in the x-y plane of Cartesian movement. In other words, as indicated by arrows 306, 308, joystick 302 can implement movement of operator platform 50 in a forward and reverse direction, respectively. Furthermore, if joystick 302 is moved in accordance with arrows 310, 312, operator platform may be moved in a lateral or a left or right direction. Although not shown in FIG. 3, alternate embodiments may also include a twist function of one or the other of joysticks 302, 304. Such twisting function would provide an operator the capability of turning operator platform 50 in a rotational manner. As is typical and would be understood by those of ordinary skill in the art, movement of joysticks 302 and 304 provide proportional outputs.

(40) Although FIG. 3 illustrates two joysticks for implementing Cartesian movement of operator platform 50, alternate embodiments may eliminate joystick 304. In its place, joystick 302 could have a toggle control 303 (shown in dashed-line black box form in FIG. 3) mounted on its top surface for raising and lowering operator platform 50.

(41) The system and methods of the present invention therefore provide a control mechanism whereby the operator is able to operate the operator platform 50 in Cartesian space, requiring only the indication of which direction the operator desires the operator platform 50 to travel in. Although the present invention has been described in conjunction with particular preferred structures, and in conjunction with generalized, preferred methods of operation for these structures, those skilled in the art will recognize many other modifications to the structures and methodology that still fall within the scope of the invention. The specific electrical and electronic functionality associated with components like the electronic controller 80, the gyroscopic sensor 51, and the accelerometer 52 may, for example, be implemented in any of a number of different ways using a variety of different electronic and/or mechanical components. As long as the electronic controller 80 is appropriately programmed or electronically structured to receive the signals or electrical characteristics from these electronic devices and sensors, then any of a number of different electrical components may be used for these two inventive elements. In some cases, electrical or electronic devices may be used in place of the mechanical linkages described herein. Hard wired connections can also be replaced with wireless connections to the extent not clearly forbidden by the properly construed claims. Certainly, modifications as to geometry, shape, and size could and likely would vary according to the size and placement of the existing control systems associated with a particular device.

(42) In all respects, it should also be understood that the drawings and detailed description herein are to be regarded in an illustrative rather than a restrictive manner, and are not intended to limit the invention to the particular forms and examples disclosed. Rather, the invention includes all embodiments and methods within the scope and spirit of the invention as claimed, as the claims may be amended, replaced or otherwise modified during the course of related prosecution. Any current, amended, or added claims should be interpreted to embrace all further modifications, changes, rearrangements, substitutions, alternatives, design choices, and embodiments that may be evident to those of skill in the art, whether now known or later discovered. In any case, all substantially equivalent systems, articles, and methods should be considered within the scope of the invention and absent express indication otherwise, all structural or functional equivalents are anticipated to remain within the spirit and scope of the present inventive system and method.