Overhead working vehicle end effector and control method thereof

Abstract

The application discloses an end execution mechanism of an aerial work platform and a control method thereof. The end execution mechanism comprises an upper platform and a chassis coaxially arranged in an up-down direction. Three through holes are formed in the chassis, the included angle between two through holes is 120 DEG, and the distance from each through hole to the center of the chassis is equal. A lower electric cylinder is arranged in each through hole, the upper end of the cylinder barrel of the lower electric cylinder is rotationally connected to the through hole, and the rotation axis passes through the center of the chassis. An upper electric cylinder is arranged at the upper end of each lower electric cylinder, the upper end of the cylinder rod of the lower electric cylinder is rotationally connected to the base of the upper electric cylinder, and the rotation axis is perpendicular to the rotation axis of the lower electric cylinder. The upper end of the cylinder rod of the upper electric cylinder is connected to the bottom surface of the upper platform through a hook hinge, the orientations of the three hook hinges are consistent with the three through holes on the chassis, and the distance from each hook hinge to the center of the upper platform is equal. The chassis is installed at the end of the aerial work platform. An executor tool is installed on the upper platform. The application has good adaptability to the aerial work platform, high degree of freedom utilization rate and low cost.

Description

Technical Field

[0001] This invention relates to aerial work platforms, and more specifically to an end effector of an aerial work platform and its control method. Background Technology

[0002] The end effector of an aerial work platform is a key component, responsible for completing specific tasks, such as painting ship surfaces. Aerial work platform end effectors typically employ a tandem six-DOF robotic arm, such as the technical solution disclosed in CN2133910071U. This approach is not only costly, but the six-DOF robotic arm is also affected by the aerial work platform arm during operation, resulting in limited movement of some joints. Furthermore, for simple tasks like painting, only 3-4 degrees of freedom are needed. In this case, some of the six degrees of freedom are not fully utilized, leading to low degree-of-freedom utilization and wasted freedom. Summary of the Invention

[0003] Objectives of the invention: The first objective of this invention is to provide a low-cost end effector that is well-suited for aerial work platforms; the second objective of this invention is to provide a control method for the end effector.

[0004] Technical Solution: The present invention provides an end effector for an aerial work platform, comprising an upper platform and a chassis coaxially arranged vertically. Three through holes are formed on the chassis, with an included angle of 120° between any two through holes. Each through hole is equidistant from the center of the chassis. A lower electric cylinder is disposed in each through hole, with its upper cylinder barrel rotatably connected to the through hole, and its rotation axis passing through the center of the chassis. An upper electric cylinder is disposed above each lower electric cylinder, with its upper cylinder rod rotatably connected to the base of the upper electric cylinder, and its rotation axis perpendicular to the rotation axis of the lower electric cylinder. The upper cylinder rod is connected to the bottom surface of the upper platform via Hooke hinges. The orientation of the three Hooke hinges aligns with the three through holes on the chassis, and each Hooke hinge is equidistant from the center of the upper platform. The chassis is mounted at the end of the aerial work platform. The actuator tool is mounted on the upper platform.

[0005] Furthermore, the upper platform has a central through hole, through which the actuator tool passes and is fixed to the upper platform by three clamps arranged in a triangular pattern.

[0006] Furthermore, the fixture is threaded with push rods, the outer end of which has a hexagonal handle and the inner end has an arc-shaped block; when the hexagonal handle is rotated, the push rod can move axially; the three push rods clamp the actuator tool from three directions.

[0007] Furthermore, a threaded hole is provided in the center of the chassis, which is fixedly connected to the end of the aerial work vehicle by bolts.

[0008] Furthermore, a U-shaped connector is fixed to the end of the cylinder rod of the lower electric cylinder, and a bolt is fixed on the U-shaped connector. A roller bearing is fitted on the bolt; the base of the upper electric cylinder is fixedly connected to the roller bearing fitted on the bolt.

[0009] The control method for the end effector of the aerial work platform vehicle according to the present invention includes:

[0010] (1) Establish a coordinate system for the end effector, determine the coordinates of the three Hooke hinges through DH coordinate transformation, and then determine the coordinates of the center position of the upper platform;

[0011] (2) The elongation of the three upper electric cylinders is solved by inversely based on the coordinates of the center position of the upper platform. Determine the extreme position of the upper platform center to determine the working range of the upper platform, and determine the desired position of the upper platform center within the working range. Then, based on the desired position, the elongation of the three lower electric cylinders is calculated. Ensure the correct movement path is used on the platform;

[0012] (3) Real-time detection of the tilt angle and elongation of each electric cylinder, calculation of the deviation between the actual position and the desired position, and trajectory control using an adaptive PID control strategy.

[0013] Furthermore, with the center of the chassis as the origin O, the vertical direction as the Z-axis, the horizontal direction along the right electric cylinder as the Y-axis, and the horizontal direction perpendicular to this direction as the X-axis, an absolute coordinate system XOY is established; with the center of the rotation position of the three Hooke hinges as the origin o, the horizontal direction of the right electric cylinder as the y-axis, and the horizontal direction perpendicular to this direction as the x-axis, a relative coordinate system xoy is established.

[0014] The coordinates of the three Hooke hinges in the absolute coordinate system are A, B, and C, respectively. , , ;

[0015] Point A The coordinate expression is:

[0016]

[0017] in, The length of the upper electric cylinder; for , The angle between the upper electric cylinder in its normal operating state and the absolute coordinate plane. It is a constant value; It is the angle between the absolute coordinate plane and the electric cylinder below; for It is also a constant value; It is the angle between the upper and lower electric cylinders;

[0018] Simplified to:

[0019]

[0020] in, This refers to the length of the upper electric cylinder itself and the extension / retraction of the cylinder rod; It refers to the extension and retraction of the lower electric cylinder rod;

[0021] Points A, B, and C are equilateral triangularly symmetric about the origin o in space;

[0022] Coordinates of the center position of the upper platform The coordinates of three points A, B, and C are represented as follows:

[0023]

[0024] constraint:

[0025]

[0026] in, This is the vertical distance from the center of the upper platform to the origin o.

[0027] Furthermore, through , , Define the scope of work to be done on the platform:

[0028]

[0029] in, This indicates the distance from the center of the upper platform to the absolute coordinate origin O when the electric cylinder on one side rotates to its left limit position; This is the distance from the center of the lower electric cylinder shaft to the center of the chassis. The length of the upper electric cylinder; The distance between the Hooke hinge and the center of the upper platform; The angle between the electric cylinder on one side and the horizontal direction of the chassis;

[0030]

[0031] in, P represents the distance from the center of the upper platform to the absolute coordinate origin O when the lower electric cylinder extends to its maximum extent; P is the extension of the lower electric cylinder rod.

[0032] This represents the distance from the center of the upper platform to the absolute coordinate origin O.

[0033] Furthermore, the working scope angle of the platform is... , The angle is determined by the rotation angle of the Hooke hinge; the maximum range of movement of the upper platform is... ,in The angle between the upper electric cylinder and the chassis, and the extension of the electric cylinder. change, It also changes accordingly; the vertical range of the upper platform is... .

[0034] Furthermore, the adaptive PID control strategy is as follows:

[0035]

[0036] in, Is it applied to the first Control signals for each electric cylinder , , In order, they are proportional gain, integral gain, and differential gain; It is a positional error.

[0037] Beneficial effects: Compared with the prior art, the present invention has the following significant advantages:

[0038] (1) It has good compatibility with aerial work platforms. The present invention provides a parallel end effector with a large working space and range of motion, and high flexibility. After being connected to the end of the aerial work platform, it is subject to fewer constraints during operation than the serial six-degree-of-freedom robotic arm, and the moving joints are not affected by the constraints of the aerial work platform.

[0039] (2) The end effector can provide six degrees of freedom, which can be fully utilized even when performing simple tasks such as spraying, and is less expensive than a serial six-degree-of-freedom robotic arm.

[0040] (3) Good stability. Parallel end effectors have advantages such as strong load-bearing capacity, high rigidity and low inertia.

[0041] (4) The control method of the end effector can accurately control the end movement trajectory and better adapt to the operation requirements. Attached Figure Description

[0042] Figure 1 This is a schematic diagram of the end effector.

[0043] Figure 2 This is a bottom view of the platform.

[0044] Figure 3 This is a schematic diagram of the end effector installed at the end of the aerial work platform vehicle;

[0045] Figure 4This is a schematic diagram of establishing a coordinate system on the end effector;

[0046] Figure 5 (b) in the diagram represents the normal position of the end effector. Figure 5 (a) and Figure 5 (c) in the figure represents the two extreme positions of the end effector, where Figure 5 In (a), the lower side of the electric cylinder is in its initial state. Figure 5 In (c), the electric cylinder on the lower side is in its maximum extension state;

[0047] Figure 6 Is it on the platform? Figure 5 A schematic diagram of the trajectory between the three positions shown;

[0048] Figure 7 This is a positive diagram showing the platform in its normal position and two extreme positions;

[0049] Figure 8 This is a schematic diagram of the positive angular orientation of the upper platform;

[0050] Figure 9 This is a schematic diagram of the working range of the end effector;

[0051] Figure 10 It is the PID control strategy for electric cylinders;

[0052] Figure 11 This is a flowchart of the control method for the end effector;

[0053] Figure 12 This is a schematic diagram of a straight-line spraying path;

[0054] Figure 13 This is a schematic diagram of the arc spraying path. Detailed Implementation

[0055] The invention will now be further described with reference to the accompanying drawings.

[0056] Appendix Figures 1 to 13 The accompanying figure labels are as follows:

[0057] 1-1, Upper platform; 1-2, Fixture; 1-3, Hooke hinge; 1-4, Upper electric cylinder; 1-5, U-shaped connector; 1-6, Chassis; 1-7, Lower electric cylinder; 1-8, Bolt; 1-9, Actuator tool; 1-10, Hexagonal handle; 1-11, Countersunk bolt; 1-12, Push rod.

[0058] like Figure 1As shown, this embodiment of the invention provides an end effector for an aerial work platform, including an upper platform 1-1 and a chassis 1-6 coaxially arranged. The chassis 1-6 has a threaded hole at its center, which is bolted to the end effector of the aerial work platform, ensuring that the chassis 1-6 is absolutely stationary relative to the entire end effector. Figure 3 As shown, the end effector rotates using the turntable of the aerial work platform.

[0059] Three through holes are formed on the chassis 1-6, with an included angle of 120° between any two through holes. The distance from each through hole to the center of the chassis 1-6 is equal. A lower electric cylinder 1-7 is installed in each through hole. The upper end of the cylinder barrel of the lower electric cylinder 1-7 is rotatably connected to the through hole via a rotating shaft, the axis of rotation passing through the center of the chassis 1-6. A U-shaped connector 1-5 is fixed to the end of the cylinder rod of the lower electric cylinder 1-7. A bolt 1-8 is fixed to the U-shaped connector 1-5, and a roller bearing is fitted onto the bolt 1-8. The bolt 1-8 is perpendicular to the axis of rotation of the lower electric cylinder 1-7. An upper electric cylinder 1-4 is installed above each lower electric cylinder 1-7, and the base of the upper electric cylinder 1-4 is fixedly connected to the roller bearing fitted onto the bolt 1-8.

[0060] Combination Figure 2 The upper end of the cylinder rod of the upper electric cylinder 1-4 is connected to the bottom surface of the upper platform 1-1 via threads on the Hooke hinge 1-3. The orientation of the three Hooke hinges 1-3 is consistent with the three through holes on the chassis 1-6. The three threaded connections of the upper platform 1-1 are at 120° angles to each other, and the distance from each Hooke hinge 1-3 to the center of the upper platform 1-1 is equal. The rotation range of the Hooke hinge 1-3 itself is 0~180°.

[0061] The lower electric cylinder 1-7 is initially perpendicular to the chassis 1-6, while the upper electric cylinder 1-4 is at a fixed angle to the chassis 1-6. The extension of the lower electric cylinder 1-7 is only two-thirds of the extension of the upper electric cylinder 1-4.

[0062] A clamp 1-2 is installed at the midpoint of each pair of Hooke hinges 1-3 via a countersunk bolt 1-11, with the three clamps 1-2 arranged in a triangular pattern. A push rod 1-12 is threaded onto each clamp 1-2. The outer end of the push rod 1-12 has a hexagonal handle 1-10, and the inner end has an arc-shaped block. When the hexagonal handle 1-10 is rotated, the push rod 1-12 can move axially. A through hole is provided in the center of the upper platform 1-1, through which the actuator tool 1-9 passes. The three push rods 1-12 clamp the actuator tool 1-9 from three directions.

[0063] This invention also provides a control method for the end effector of the aerial work platform described in this invention, comprising the following steps:

[0064] (1) Establish a coordinate system for the end effector, determine the coordinates of the three Hooke hinges 1-3 through DH coordinate transformation, and then determine the coordinates of the center position of the upper platform 1-1;

[0065] Figure 4 The diagram shows the normal position of the end effector. The origin O is the center of the chassis 1-6, the vertical direction is the Z-axis, the horizontal direction along the right electric cylinder is the Y-axis, and the horizontal direction perpendicular to this direction is the X-axis. An absolute coordinate system XOY is established.

[0066] With the center of the rotation positions of the three Hooke hinges 1-3 as the origin o, the horizontal direction of the right electric cylinder as the y-axis, and the horizontal direction perpendicular to this direction as the x-axis, establish a relative coordinate system xoy.

[0067] The coordinates of the three Hooke hinges 1-3 in the absolute coordinate system are as follows: , , .

[0068] Based on the DH coordinate establishment rules, the rods related to point A are identified as upper electric cylinder 1-4, lower electric cylinder 1-7, the intersection of the two cylinders, and the absolute coordinate system XOY. After determining the connecting rods and joints, a relative coordinate system is established, DH parameters are generated, and point A is obtained through coordinate transformations, including rotation and translation transformations. The coordinate expression is:

[0069]

[0070] in, The length of the upper electric cylinder; for , The angle between the upper electric cylinder in its normal operating state and the absolute coordinate plane. It is a constant value; It is the angle between the absolute coordinate plane and the electric cylinder below, which is normally 90°; for It is also a constant value; It refers to the angle between the upper and lower electric cylinders.

[0071] The extension and retraction of the upper electric cylinder rod directly affects the coordinates of point A, and the extension and retraction of the lower electric cylinder rod directly affects the coordinates of point A. Indirectly affecting coordinates and .

[0072] The formula simplifies to:

[0073]

[0074] in, This refers to the length of the upper electric cylinder itself and the extension / retraction of the cylinder rod; It refers to the extension and retraction of the lower electric cylinder rod.

[0075] like Figure 4 Points A, B, and C are equilateral triangularly symmetrical about the origin o in space. In this coordinate system, the relative positions of the three points are fixed. That is, the coordinate expressions of points B and C are almost the same as those of point A. The difference is that the joint angle θ between the absolute coordinate system of each point and the relative coordinate of the electric cylinder below is different.

[0076] Coordinates of the center position of the upper platform The coordinates of three points A, B, and C are represented as follows:

[0077]

[0078] constraint:

[0079]

[0080] in, This is the vertical distance from the center of the upper platform to the origin o.

[0081] (2) The elongation of the three upper electric cylinders is solved by inversely based on the coordinates of the center position of the upper platform. Determine the extreme position of the upper platform center to determine the working range of the upper platform, and determine the desired position of the upper platform center within the working range. Then, based on the desired position, the elongation of the three lower electric cylinders is calculated. Ensure the correct movement path is used on the platform;

[0082] The scope of work on the platform is determined using the following method:

[0083] like Figure 5 The diagram shown is a schematic of one side of the electric cylinder reaching its limit position. Figure 5 In (a), there is an arc with bolts 1-8 as the center of rotation and a radius of R. The extension of the upper electric cylinder rod is 0, while the two lower electric cylinders on the right have a certain extension. Figure 5 (a) in the calculation yields:

[0084]

[0085] in, This indicates that when the electric cylinder on one side rotates to its left limit position, the center of the upper platform is... Figure 6 The distance from the absolute coordinate origin O in the middle; This is the distance from the center of the lower electric cylinder shaft to the center of the chassis. The length of the upper electric cylinder; The distance between the Hooke hinge and the center of the upper platform; The angle between the electric cylinder on one side and the horizontal direction of the chassis.

[0086] Figure 5 In (b), the instantaneous rotation radius of the platform center is the distance D from the platform to the chassis. Figure 5 In (c), the extension of the lower left electric cylinder rod is the largest, while the extension of the three upper electric cylinder rods is 0, and the extension of the two lower right electric cylinder rods is 0. Figure 5 (c) in the middle calculates:

[0087]

[0088] in, This indicates that when the electric cylinder on one side extends to its maximum length, the distance from the center of the upper platform to... Figure 6 The distance from the absolute coordinate origin O; P is the extension of the lower electric cylinder rod.

[0089] Figure 5 In the diagram, the dashed line represents the trajectory of the upper platform's center position while maintaining relative stillness between the upper electric cylinder and the platform. The extreme positions of the upper platform's frontal face diagonally under the drive of the upper electric cylinder are shown below. Figure 7 As shown.

[0090] like Figure 8 As shown, the working range angle of the upper platform is , The angle is determined by the rotation angle of the Hooke hinge. The maximum range of motion of the upper platform is... ,in The angle between the upper electric cylinder and the chassis, and the extension of the electric cylinder. change, It also changes accordingly; the vertical range of the upper platform is... The entire two-dimensional workspace of the organization is as follows: Figure 9 As shown.

[0091] like Figure 10 As shown, in the initial state, the upper platform is parallel to the spraying target and moves at a speed During the platform movement, the upper platform remains parallel to the target being painted. The three upper electric cylinders are positioned according to the desired location at the platform center. Solve for the length that each upper electric cylinder should be adjusted to. Taking a linear model as an example, the platform obtains contributions in the X, Y, and Z directions, and the inverse kinematic equations can be simplified to:

[0092]

[0093] in, , , It is related to electric cylinder The coefficients related to the contribution of length changes to the X, Y, and Z positions of the platform.

[0094]

[0095] in, For six cylinders; , , These are the coordinates of the 6 moving points on the platform. , , The initial coordinates are given for the following six stationary points. The six moving points include six points at the ends of the six electric cylinder rods, and the six stationary points include six points at the ends of the six electric cylinder bases. These six stationary points are relative stationary points, including three points stationary relative to the three upper electric cylinders and three points stationary relative to the three lower electric cylinders. The lengths of the six electric cylinders are determined using the coordinates of the moving and stationary points.

[0096] The three electric cylinders below are positioned according to the platform's desired location. Solve for the required adjustment length of each lower electric cylinder. Here, the system of equations for solving the spatial position point A is used. The desired position coordinates and the magnitude of the extension of the lower electric cylinder are determined analytically. The nonlinear inverse kinematic equations can be expressed as:

[0097]

[0098] in, It is a nonlinear mapping function from the link length to the platform displacement.

[0099] (3) Real-time detection of the tilt angle and elongation of each electric cylinder, calculation of the deviation between the actual position and the desired position, and trajectory control using an adaptive PID control strategy.

[0100] During platform movement, sensor devices collect real-time motion data of the mechanical system. The collected data is processed and analyzed to extract useful information and calculate the deviation from the desired trajectory. An adaptive PID control strategy is then employed.

[0101]

[0102] in, Is it applied to the first Control signals for each electric cylinder , , In order, they are proportional gain, integral gain, and differential gain; It is a positional error.

[0103] Based on the output of the adaptive PID control algorithm, control commands are generated for the mechanical system. These commands are then sent to the drive cylinders of the mechanical system. The cylinders execute corresponding actions based on the signals from the control algorithm and monitor the motion state of the mechanical system in real time for feedback. The PID controller incorporates the data from the sensors, further outputs results, and generates signals to send to the drive cylinders to execute the actions.

[0104] The end effector provided by this invention is a parallel mechanical structure, which can achieve a wide range of operations and can be used for spraying or grinding. For example, after the mechanical end is fitted with a spray gun, it can be used for spraying the outer plate of a ship.

[0105] The high-altitude work robot with the end effector structure of the present invention is as follows: Figure 11 The process is as follows: Step 1: Parameter initialization, task start. Step 2: The aerial work robot uses sensors to visually scan the target outer panel, moves its body, and rotates the turntable to move the connected end-effector mechanical structure near the target. Step 3: Determine if the distance between the robot and the target meets the requirements of the end-effector mechanical structure. If not, adjust the aerial work robot. If it does, proceed to Step 4: Transmit the target outer panel coordinates to the end-effector mechanical structure. Step 5: Calculate the optimal path for the platform's end-effector to move further near the target using a PID algorithm and implement the movement. Step 6: The platform uses radar ranging to calculate the working angle between the platform and the target to ensure the spray gun operates. Step 7: The visual sensor detects the area of ​​the outer panel centered on the target that is larger than the target plane, and the feedback system calculates the start and end points of the platform's spraying path. The spray gun begins operation, and the mechanical structure moves according to the planned spraying path. Proceed to step 8 to determine if the current path endpoint is the final task endpoint. If not, proceed to step 9. Step 9 involves determining if the platform needs to approach its limit position. If so, return to step 7, and the aerial work robot's main arm quickly moves to the platform's spraying path endpoint calculated by the feedback system. During this process, the spray gun and platform continue to work, and the platform's movements remain unchanged. The feedback system re-provides the spraying path start and end points, the spray gun continues to work, and the platform moves according to the planned path. If not, the platform continues to work and returns to step 8. If the task is about to end, proceed to step 10, where the platform completes the remaining part of the task. Proceed to step 11, the feedback system sends information to the control unit, controlling the platform to return to its initial position, the aerial work robot exits, and finally, proceed to step 12, where the task ends.

[0106] Figure 12The straight line shown illustrates the spraying path during the spraying process. The aerial work platform moves its mechanical end effector to the target's first movement starting point. The controller plans the first movement trajectory and endpoint position and executes the command. The platform moves using linear interpolation. As it approaches the endpoint of the first movement, the controller uses that endpoint as the starting point for the second movement and plans the second movement trajectory and endpoint position. If the distance of a single movement exceeds the platform's own limit range S, then as the platform approaches the limit position, the controller pre-calculates the spraying trajectory and issues a command to control the aerial work platform robot to move its mechanical end effector for a second movement.

[0107] Figure 13 The curve shown illustrates the spraying path and spraying process. The aerial work platform moves the mechanical end to the target's first movement starting point. The controller plans the starting point, ending point, and circular interpolation algorithm movement path along the tangent direction of the desired curve for the first movement. During the movement, it continuously acquires two points on the curve and performs tangent interpolation until it reaches the end point of the curve.

Claims

1. A control method of an end effector of an aerial work platform, characterized by, The end effector of the aerial work platform comprises an upper platform and a chassis coaxially arranged in an up-down direction, three through holes are formed in the chassis, the included angle between two of the through holes is 120°, and the distance from each through hole to the center of the chassis is equal; a lower electric cylinder is arranged in each through hole, the upper end of the cylinder barrel of the lower electric cylinder is rotationally connected to the through hole, and the rotation axis passes through the center of the chassis; an upper electric cylinder is arranged at the upper end of each lower electric cylinder, the upper end of the cylinder rod of the lower electric cylinder is rotationally connected to the base of the upper electric cylinder, and the rotation axis is perpendicular to the rotation axis of the lower electric cylinder; the upper end of the cylinder rod of the upper electric cylinder is connected to the bottom surface of the upper platform through a hook joint, the orientations of the three hook joints are consistent with the three through holes on the chassis, and the distance from each hook joint to the center of the upper platform is equal; The chassis is mounted at the end of the aerial work platform, and the actuator tool is mounted on the upper platform; The control method comprises: (1) establishing a coordinate system for the end effector, determining the coordinates of the three hook joints through D-H coordinate transformation, and further determining the position coordinates of the center of the upper platform; (2) According to the upper platform center position coordinates inverse solution of three upper electric cylinder elongation , determine the limit position of the upper platform center to determine the working range of the upper platform, within the working range to determine the expected position of the upper platform center , according to the expected position inverse solution of three lower electric cylinder elongation , ensure the correct path of the upper platform movement; (3) detecting the inclination angle and elongation of each electric cylinder in real time, calculating the deviation between the actual position and the expected position, and adopting an adaptive PID control strategy for trajectory control.

2. The control method of the end effector according to claim 1, characterized by, An absolute coordinate system XOY is established with the center position of the chassis as the origin O, the vertical direction as the Z axis, the horizontal direction along the right electric cylinder as the Y axis, and the horizontal direction perpendicular to the direction as the X axis; a relative coordinate system xoy is established with the center of the rotation position of the three hook joints as the origin o, the horizontal direction of the right electric cylinder as the y axis, and the horizontal direction perpendicular to the direction as the x axis; The coordinate points A, B and C of the three Hooke joints in the absolute coordinate system are in sequence 、 、 ; Point A The coordinate expression of point A is: wherein, is the length of the upper cylinder; is , is the angle between the upper cylinder in its normal state and the absolute coordinate plane, is a constant; is the angle of rotation of the absolute coordinate plane with respect to the lower cylinder; is is also a constant; is the angle of rotation of the upper cylinder with respect to the lower cylinder; Simplify as: wherein, is the length of the upper electric cylinder itself and the extension amount of the cylinder rod of the upper electric cylinder; is the extension amount of the cylinder rod of the lower electric cylinder. Points A, B and C are symmetrically equilateral triangular about the origin o in space; Upper platform center position coordinates Expressed by three-point A, B, C coordinates: Constraints: wherein is the vertical distance from the center of the upper platform to the origin o.

3. The control method of the end effector according to claim 2, characterized by, By , , determining the working range of the upper platform: wherein, represents the distance from the center of the upper platform to the origin O of the absolute coordinate when the upper side cylinder rotates to the left limit position; represents the distance from the axis of the lower cylinder to the center of the chassis; represents the length of the upper cylinder; represents the distance from the center of the upper platform to the origin O of the absolute coordinate when the upper side cylinder rotates to the left limit position; represents the angle between the upper side cylinder and the horizontal direction of the chassis. wherein, represents the distance from the center of the upper platform to the origin O of the absolute coordinate when the maximum elongation of the lower electric cylinder is on one side; P represents the elongation of the lower electric cylinder rod. represents the distance from the center of the upper platform to the absolute coordinate origin O.

4. The control method of the end effector according to claim 3, characterized by, The working range angle of the upper platform is , The angle size is determined by the rotation angle of the Hooke joint; the maximum moving range of the upper platform is , wherein is the included angle between the upper electric cylinder and the chassis, and the extension amount of the electric cylinder changes , and the vertical direction change range of the upper platform is .

5. The control method of the end effector according to claim 1, characterized by, The adaptive PID control strategy is: wherein, is a control signal applied to the first electrical cylinder, , , are, in sequence, proportional, integral, derivative gains; is a position error.

6. The control method of the end effector according to claim 1, characterized by, The upper platform is provided with a central through hole, the actuator tool passes through the central through hole and is fixed to the upper platform through three clamps, and the three clamps are triangularly distributed.

7. The control method of the end effector according to claim 6, characterized by, A push rod is threadedly connected to the clamp, the outer end of the push rod has a hexagonal handle, and the inner end has an arc block; when the hexagonal handle is rotated, the push rod can move along the axial direction; the three push rods clamp the actuator tool from three directions.

8. The control method of the end effector according to claim 1, characterized by, A threaded hole is arranged at the center of the chassis, and the threaded hole is fixedly connected to the end of the aerial work platform through a bolt.

9. The control method of the end effector according to claim 1, characterized by, A U-shaped connecting piece is fixedly connected to the end of the cylinder rod of the lower electric cylinder, a bolt is fixedly connected to the U-shaped connecting piece, and a roller bearing is sleeved on the bolt; the base of the upper electric cylinder is fixedly connected to the roller bearing sleeved on the bolt.

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