Parallel robot platform dynamics inverse solution control method, system and computer readable storage medium

Abstract

The application provides a parallel robot platform dynamics inverse solution control method, a system and a computer readable storage medium, the method can realize the inverse solution of the electric cylinder position, speed, acceleration, thrust and electric cylinder torque by constructing the electric cylinder direction vector relationship and the force system balance equation of the parallel robot platform, realizes the accurate driving of each electric cylinder of the platform, so as to realize the accurate control of the electric cylinder motion, is more accurate when simulating the platform pose change, and can complete the motion simulation in any position and pose, compared with the positive solution operation, the operation solving process is simple, the operation amount and the code amount are less, and it is easy to realize and apply in engineering.

Description

Technical Field

[0001] This invention relates to the field of multi-degree-of-freedom robot technology, and more specifically to a method and system for inverse dynamics control of a parallel robot platform under homogeneous load. Background Technology

[0002] Multi-degree-of-freedom parallel motion platforms, also known as parallel robot platforms, take the most commonly used six-degree-of-freedom platform as an example. It consists of six motion mechanisms as the drive for position changes, forming a six-degree-of-freedom Stewart parallel robot. It consists of a top platform, a bottom platform, six linear motion mechanisms (actuators) supported between the two platforms, and a control system. The bottom platform is fixed to the ground, and the top platform is used to support the load. The control system is programmed to control the stroke and speed of the electric linear motion mechanisms to realize the motion platform in six degrees of freedom (X, Y, Z, α, β, γ) in three-dimensional space. It can freely change its position and attitude, such as moving forward / backward, moving up / down, and translating left / right (swinging) on ​​the three vertical axes. The direction is usually changed by rotating around the three vertical axes, called yaw (normal axis), pitch (lateral axis), and roll (longitudinal axis).

[0003] The six-DOF Stewart parallel robot platform can be applied to flight simulation, driving simulation, road simulation, wave simulation, earthquake simulation, space docking ground test, space vibration isolation, stabilization platform, and virtual simulation game entertainment simulation. By controlling the position and changes in position in space, the six-DOF platform can simulate highly difficult scenarios. Relying on the six degrees of freedom of the platform, it can simulate any posture in the motion space. The motion can be performed individually or in combination of any number of degrees of freedom to achieve complex pose simulation.

[0004] Control of the platform's spatial position and motion pose is achieved through forward and inverse kinematics solutions. This is based on a static coordinate system O-XYZ, with its origin at the platform center, fixed to the lower platform (origin O being the geometric center of the lower platform), and a dynamic coordinate system O1-X1Y1Z1, with its origin at the upper platform center. The dynamic coordinate system is fixed to the upper platform and moves with it, with its origin being the geometric center of the upper platform. When the upper platform is in its initial position, the static and dynamic coordinate systems are aligned, and the Z-axis of the static coordinate system passes through the origin O1 of the dynamic coordinate system. For parallel robot platforms, kinematic analysis and calculation are crucial for driving the platform's precise and stable operation.

[0005] Previous research has focused on the forward motion process, which involves determining the position and orientation of a six-DOF parallel robot given the lengths of its six linear motion mechanisms. Currently, iterative methods are typically used, employing the distribution circle of the upper hinge points and structural constraints to approximate the platform's orientation. Therefore, the forward motion process for a six-DOF parallel motion platform is complex, requiring significant computational effort. In contrast, the inverse motion process, given the position and orientation of the six-DOF parallel robot, involves determining the extension and retraction of the six linear motion mechanisms. Examples include inverse motion algorithms based on DH modeling and iterative methods using Jacobian matrices. It should be understood that the most common method for describing the orientation of a rigid body rotating in space is to define three Euler angles. When the rigid body rotates to a certain orientation, these three Euler angles form a unique rotation matrix. By using this rotation matrix for coordinate transformation, the absolute position of the rigid body can be obtained. Therefore, compared to forward motion, inverse motion is relatively easier to implement, requires less computation, and can directly determine the extension and retraction of linear motion mechanisms (such as electric cylinders), i.e., length changes, thereby achieving precise control. That is, the extension and retraction of each electric cylinder is calculated by the inverse kinematics solution, and this is used as the position command value for each electric cylinder (6 electric cylinders for a six-degree-of-freedom platform). The actual position signal of each electric cylinder detected by the displacement sensor is compared with the given position command signal, so that each electric cylinder forms a displacement closed loop control, thereby achieving precise control of the platform's posture. Summary of the Invention

[0006] According to a first aspect of the present invention, a dynamic inverse control method for a parallel robot platform under homogeneous load is proposed, applicable to flight simulation systems, driving simulation systems, ship simulation systems, and wave simulation systems, wherein the center of gravity of the load on the parallel robot platform coincides with the axis of the parallel robot platform. The inverse control method includes the following steps:

[0007] Step 1: Define the platform state of the parallel robot platform, including the position and attitude curve, motion amplitude in six directions, angular velocity in six directions, and angular acceleration in six directions.

[0008] Step 2: Construct the direction vector relationship of the electric cylinders of the parallel robot platform;

[0009] Step 3: Based on the direction vector relationship of the electric cylinder, construct the lever arm of the electric cylinder component in the XY plane of the parallel robot platform relative to the center of the hinge circle.

[0010] Step 4: Based on the direction vector relationship of the electric cylinder, construct the vector expression of the electric cylinder thrust, and establish the force balance equation of the parallel robot platform accordingly. By solving the force balance equation, obtain the electric cylinder thrust Fi, where i represents the electric cylinder number, i=1,2,3,4,5,6.

[0011] Step 5: Obtain the platform pose at any time time according to the position and attitude curve, obtain the electric cylinder length Li according to the inverse kinematics solution, calculate the platform pose after the preset first millisecond period △t1, obtain the electric cylinder length Li+△Li according to the inverse kinematics solution, and determine the extension and retraction speed of electric cylinder i at any time time based on this.

[0012] Step 6: Obtain the platform pose after a delay of the second millisecond period Δt2 at any given time based on the position and attitude curve, where Δt2 = 2 * Δt1. Obtain the length of the electric cylinder Li + ΔLi + ΔLi' using the inverse kinematics solution, and determine the extension / retraction acceleration of electric cylinder i at any given time and the angular acceleration of the lead screw of electric cylinder i.

[0013] Step 7: Based on the electric cylinder thrust Fi obtained above, determine the electric cylinder torque required for the electric cylinder to generate thrust Fi, and the motor torque consisting of the product of the inertia and angular acceleration of the motor rotor, lead screw, synchronous pulley, and coupling.

[0014] Therefore, the inverse dynamics control method for parallel robot platforms under uniform load proposed in this invention can achieve inverse solutions for the position, velocity, acceleration, thrust, and torque of the electric cylinders, enabling precise driving of each electric cylinder on the platform and precise control of the electric cylinder motion. This method is more accurate when simulating platform pose changes and can complete motion simulation under arbitrary positions and poses. Compared with forward solving, the calculation process is simpler, with less computation and code, making it easier to implement and apply in engineering.

[0015] According to a second aspect of the present invention, a dynamic inverse control system for a parallel robot platform under homogeneous load is also proposed, comprising:

[0016] An initial definition module for defining the platform state of a parallel robot platform, the platform state including position and attitude curves, motion amplitudes in six directions, angular velocities in six directions, and angular accelerations in six directions;

[0017] Electric cylinder direction vector construction module for constructing electric cylinder direction vector relationships for parallel robot platforms;

[0018] A lever arm construction module is used to construct the lever arm of the electric cylinder in the XY plane relative to the center of the hinge circle of the parallel robot platform based on the direction vector relationship of the electric cylinder.

[0019] The force system equilibrium equation construction module is used to construct the vector expression of the electric cylinder thrust based on the direction vector relationship of the electric cylinder, and to establish the force system equilibrium equation of the parallel robot platform accordingly. The electric cylinder thrust Fi is obtained by solving the force system equilibrium equation, where i represents the number of the electric cylinder, i=1,2,3,4,5,6.

[0020] This module is used to obtain the platform pose at any time 'time' based on the position and attitude curve, obtain the electric cylinder length Li based on the inverse kinematics solution, calculate the platform pose after the preset first millisecond period Δt1, obtain the electric cylinder length Li+ΔLi based on the inverse kinematics solution, and determine the extension and retraction speed of electric cylinder i at any time 'time'.

[0021] This module is used to obtain the platform pose after a second millisecond period Δt2 delay at any time 'time' based on the position and attitude curve, where Δt2 = 2 * Δt1. It then uses inverse kinematics to obtain the electric cylinder length Li + ΔLi + ΔLi', and accordingly determines the extension / retraction acceleration of electric cylinder i at any time 'time' and the acceleration acquisition module for the lead screw angular acceleration of electric cylinder i.

[0022] A torque acquisition module for determining the electric cylinder torque required to generate the electric cylinder thrust Fi based on the aforementioned electric cylinder thrust Fi, and the motor torque consisting of the product of the inertia and angular acceleration of the motor rotor, lead screw, synchronous pulley, and coupling.

[0023] In a third aspect of the present invention, a computer system is also provided, comprising:

[0024] One or more processors; and

[0025] Memory stores instructions that can be operated.

[0026] When the instruction is executed by one or more processors, it causes the aforementioned one or more processors to perform operations, including the process of executing the aforementioned inverse dynamics control method for parallel robot platforms under homogeneous loads.

[0027] In a fourth aspect of the invention, a computer-readable storage medium is also provided for storing one or more programs, said one or more programs comprising instructions or instruction sets executable by one or more processors;

[0028] The instructions or instruction set, when executed by one or more processors, perform the aforementioned process of inverse dynamics control of a parallel robot platform under homogeneous load.

[0029] It should be understood that all combinations of the foregoing concepts and the additional concepts described in more detail below may be considered part of the inventive subject matter of this disclosure, provided that such concepts do not contradict each other. Furthermore, all combinations of the claimed subject matter are considered part of the inventive subject matter of this disclosure.

[0030] The foregoing and other aspects, embodiments, and features of the teachings of the present invention will be more fully understood from the following description in conjunction with the accompanying drawings. Other additional aspects of the invention, such as features and / or beneficial effects of exemplary embodiments, will become apparent from the following description or may be learned through practice of specific embodiments according to the teachings of the present invention. Attached Figure Description

[0031] The accompanying drawings are not intended to be drawn to scale. In the drawings, each identical or nearly identical component shown in the various figures may be denoted by the same reference numeral. For clarity, not every component is labeled in each figure. Embodiments of various aspects of the invention will now be described by way of example and with reference to the accompanying drawings.

[0032] Figure 1 This is a schematic flowchart of the inverse dynamics control method for a parallel robot platform under a homogeneous load according to an embodiment of the present invention.

[0033] Figure 2 This is a schematic diagram of the module of the inverse kinematics control system for a parallel robot platform under a homogeneous load according to an embodiment of the present invention.

[0034] Figure 3 This is exemplary code defining the platform state according to an embodiment of the present invention.

[0035] Figure 4 This is exemplary code for constructing a lever arm according to an embodiment of the present invention. Detailed Implementation

[0036] To better understand the technical content of the present invention, specific embodiments are described below in conjunction with the accompanying drawings.

[0037] Various aspects of the invention are described in this disclosure with reference to the accompanying drawings, which illustrate numerous illustrative embodiments. The embodiments of this disclosure are not necessarily intended to encompass all aspects of the invention. It should be understood that the various concepts and embodiments described above, as well as those described in more detail below, can be implemented in any of many ways, because the concepts and embodiments disclosed herein are not limited to any particular implementation. Furthermore, some aspects of the invention disclosed may be used alone or in any suitable combination with other aspects of the invention disclosed.

[0038] {Inverse kinematics control method for parallel robot platform}

[0039] Combination Figure 1 The example shown illustrates the inverse kinematics control method for a parallel robot platform under uniform load according to an embodiment of the present invention. This method is applicable to flight simulation systems, driving simulation systems, ship simulation systems, and wave simulation systems. It achieves inverse kinematics analysis of the platform's electric cylinders, determining the extension / retraction (i.e., the position), velocity, acceleration, thrust, and torque of each electric cylinder. These values ​​are then used as motion command values ​​for each electric cylinder in the subsequent control of the platform. The values ​​are compared with the actual motion state of the electric cylinders to form a closed-loop control of the electric cylinder motion. This closed-loop control includes not only position control but also feedback control of at least one of velocity, acceleration, thrust, and electric cylinder torque, achieving high-precision position control of the platform's posture.

[0040] In an embodiment of the present invention, the aforementioned parallel robot platform takes the six-DOF Stewart parallel robot platform as an example (i.e., a parallel six-DOF motion platform). Six electric cylinders are respectively hinged to the upper and lower platforms via upper and lower hinges, such as Hooke hinges or cross hinges, and are installed on the upper and lower platforms respectively. The lead screw end of the electric cylinder is hinged to the upper platform via the hinge, forming the upper platform hinge point (hereinafter referred to as the upper hinge point). The six upper platform hinge points form the upper hinge circle. Similarly, the bottom end of the electric cylinder is hinged to the lower platform via the hinge, forming the lower platform hinge point (hereinafter referred to as the lower hinge point). The six lower platform hinge points form the lower hinge circle.

[0041] It should be understood that, in the embodiments of the present invention, in the aforementioned flight simulation system, driving simulation system, ship simulation system and wave simulation system, the center of gravity of the load on the parallel robot platform coincides with the axis of the parallel robot platform.

[0042] The load on the platform is usually designed to be equivalent to a homogeneous load.

[0043] The electric cylinder can be a commercially available high-precision electric cylinder, which integrates the servo motor and the lead screw in a modular design. It is driven by the platform's control system to achieve extension and retraction through the rotation of the lead screw.

[0044] In embodiments of the present invention, the electric cylinder is equivalent to a two-force component, bearing only tensile and compressive forces.

[0045] Combination Figure 1 The process shown, as an example of the inverse kinematics control method for a parallel robot platform, includes the following steps:

[0046] Step 1: Define the platform state of the parallel robot platform, including the position and attitude curve, motion amplitude in six directions, angular velocity in six directions, and angular acceleration in six directions.

[0047] Step 2: Construct the direction vector relationship of the electric cylinders of the parallel robot platform;

[0048] Step 3: Based on the direction vector relationship of the electric cylinder, construct the lever arm of the electric cylinder component in the XY plane of the parallel robot platform relative to the center of the hinge circle.

[0049] Step 4: Based on the direction vector relationship of the electric cylinder, construct the vector expression of the electric cylinder thrust, and establish the force balance equation of the parallel robot platform accordingly. By solving the force balance equation, obtain the electric cylinder thrust Fi, where i represents the electric cylinder number, i=1,2,3,4,5,6.

[0050] Step 5: Obtain the platform pose at any time time according to the position and attitude curve, obtain the electric cylinder length Li according to the inverse kinematics solution, calculate the platform pose after the preset first millisecond period △t1, obtain the electric cylinder length Li+△Li according to the inverse kinematics solution, and determine the extension and retraction speed of electric cylinder i at any time time based on this.

[0051] Step 6: Obtain the platform pose after a delay of the second millisecond period Δt2 at any given time based on the position and attitude curve, where Δt2 = 2 * Δt1. Obtain the length of the electric cylinder Li + ΔLi + ΔLi' using the inverse kinematics solution, and determine the extension / retraction acceleration of electric cylinder i at any given time and the angular acceleration of the lead screw of electric cylinder i.

[0052] Step 7: Based on the electric cylinder thrust Fi obtained above, determine the electric cylinder torque required for the electric cylinder to generate thrust Fi, and the motor torque consisting of the product of the inertia and angular acceleration of the motor rotor, lead screw, synchronous pulley, and coupling.

[0053] To facilitate understanding, we will further elaborate and explain the implementation process of this invention in conjunction with specific steps.

[0054] In step 1, the position and attitude curve of the parallel robot platform is defined as a sine curve, and the motion amplitudes in the six directions are Si and Sj respectively. X_MAX S Y_MAX S Z_MAX α _MAX β _MAX γ _MAX The position and orientation of the platform can be expressed as a function:

[0055]

[0056] Among them, S X S Y S Z α, β, and γ represent the motion states of the platform in the six degrees of freedom (X, Y, Z, α, β, and γ), respectively, and are known quantities.

[0057] Taking the first derivative of the position and attitude curve yields the angular velocities in six directions, expressed as:

[0058]

[0059] Where: V X_MAX =S X_MAX ×2πf1;V Y_MAX =S Y_MAX ×2πf²;V Z_MAX =S Z_MAX ×2πf3;ω X_MAX =α _MAX ×2πf4;ω Y_MAX =β _MAX ×2πf5、ω Z_MAX =γ _MAX ×2πf6;

[0060] Taking the first derivative of the function of angular velocity in the six directions, we obtain the angular acceleration in the six directions, which can be expressed as:

[0061]

[0062] Among them, a X_MAX = S X_MAX ×4π 2 f1 2 ;a Y_MAX = S Y_MAX ×4π 2 f2 2 ;a Z_MAX =S Z_MAX ×4π 2 f3 2 ;ε X_MAX =α _MAX ×4π 2 f4 2 ;ε Y_MAX = β _MAX ×4π 2 f5 2 ;ε Z_MAX = γ _MAX ×4π 2 f6 2 .

[0063] It should be understood that Figure 3 Exemplary code for implementing the above platform state definition is provided.

[0064] In step 2, the direction vector relationship of the electric cylinders of the parallel robot platform is constructed, including:

[0065] The direction vector of the electric cylinder i in the parallel robot platform is expressed as:

[0066] [X Pi_New -X Bi Y Pi_New -Y Bi X Pi_New -Z Bi ]

[0067] Where i represents the serial number of the electric cylinder, i=1,2,3,4,5,6;

[0068] (X) Bi Y Bi Z Bi ( ) represents the coordinates of the hinge point of the lower platform;

[0069] (X) Pi_New Y Pi_New X Pi_New The coordinates of the upper platform hinge point at any given moment are obtained from the platform's position and attitude. The initial coordinates of the center of the upper hinge circle formed by the upper platform hinge points are (0, 0, Z0), where Z0 is the coordinate of the platform at its lowest position. After the platform moves, the coordinates of the center of the upper hinge circle are (S... X S Y S Z +Z0).

[0070] In step 3, based on the direction vector relationship of the electric cylinder, the lever arm of the electric cylinder component in the XY plane of the parallel robot platform relative to the center of the hinge circle is constructed, including:

[0071] Establish the equation of the line projected onto the XY plane by the direction vector of electric cylinder i, where i = 1, 2, 3, 4, 5, 6:

[0072]

[0073] Where, k i =(Y Pi_New -Y Bi ) / (X Pi_New -X Bi );

[0074] Because the straight line passes through (X) Pi_New Y Pi_New Therefore: bi = Y Pi_New - k i ×X Pi_New ;

[0075] Based on the formula for calculating the distance from a point to a line, obtain the lever arm of the component of electric cylinder i in the XY plane about the center of the hinge circle at the reference point:

[0076] ;

[0077] Similarly, following the method described above for constructing the lever arm of the electric cylinder's component in the XY plane about the center of the hinge circle, we can continue to construct the lever arm d of the electric cylinder's component in the XZ plane about the center of the hinge circle. xzi And the force arm d of the electric cylinder component on the YZ plane relative to the center of the hinge circle. yzi .

[0078] As an example, the implementation code for the above lever arm construction and calculation is as follows: Figure 4 As shown.

[0079] In step 4, based on the direction vector relationship of the electric cylinder, a vector expression for the electric cylinder thrust is constructed, and the force balance equation of the parallel robot platform is established accordingly. The electric cylinder thrust Fi is obtained by solving this force balance equation, including:

[0080] Let the thrust of the i-th electric cylinder be Fi, and the vector expression for Fi is:

[0081] ;

[0082] The equilibrium equations for the force system are then established as follows:

[0083] ;

[0084] In the formula, m is the load mass, in kg; a X Let a be the translational acceleration along the X direction; Y a is the translational acceleration along the Y direction; Z ε is the translational acceleration along the Z direction; X ε is the rotational angular acceleration about the X-axis; Y ε is the rotational angular acceleration about the Y-axis; Z ω is the rotational angular acceleration about the Z-axis; r is the height difference between the center of gravity of the load and the center of the upper hinge circle;

[0085] J X J Y J Z These are the moments of inertia for the pitch, roll, and yaw of a six-degree-of-freedom parallel robot motion platform and its load, respectively.

[0086] make:

[0087]

[0088]

[0089]

[0090]

[0091]

[0092]

[0093] The equilibrium equations of the force system are then transformed into matrix form:

[0094]

[0095] Solving the system of matrix equations using Gaussian elimination yields f i And, combined with the aforementioned vector expression for Fi, determine the thrust Fi of the i-th electric cylinder.

[0096] In step 5, the calculation of the platform pose after a preset first millisecond period Δt1, the obtaining of the electric cylinder length Li+ΔLi based on the inverse kinematics, and the determination of the extension / retraction speed of electric cylinder i at any time time based on this, includes:

[0097] Calculate the platform pose (time+0.00005) 0.05 milliseconds after any time *time*. Using the inverse kinematics, obtain the length of the electric cylinder *Li* + Δ*Li*. Then, the extension / retraction velocity of electric cylinder *i* at any time *time* is:

[0098] .

[0099] In step 6, the platform pose after a second millisecond period Δt2 delay at any time 'time' is obtained from the position and attitude curve, where Δt2 = 2 * Δt1. The length of the electric cylinder, Li + ΔLi + ΔLi', is obtained from the inverse kinematics solution, and the extension / retraction acceleration of electric cylinder i and the lead screw angular acceleration of electric cylinder i at any time 'time' are determined accordingly, including:

[0100] The platform pose at any time *time* is obtained from the position and attitude curve. The length *Li* of the electric cylinder is obtained from the inverse kinematics solution. The platform pose is calculated 0.1 milliseconds after the arbitrary time *time*. The length *Li* + Δ*Li* + Δ*Li' of the electric cylinder is obtained from the inverse kinematics solution. Then, the extension and retraction speed of the electric cylinder *i* at time *time* + 0.00005 is:

[0101]

[0102] Then, the extension and retraction acceleration of electric cylinder i at any time time is:

[0103]

[0104] The angular acceleration of the lead screw corresponding to electric cylinder i is:

[0105]

[0106] In the formula, Let be the angular acceleration of the lead screw of electric cylinder i, in rad / s. 2 L represents the lead of the lead screw.

[0107] In step 7, based on the aforementioned electric cylinder thrust Fi, the electric cylinder torque required to generate the thrust Fi is determined, along with the motor torque comprised of the product of the inertia and angular acceleration of the motor rotor, lead screw, synchronous pulley, and coupling, including:

[0108] (1) Based on the electric cylinder thrust Fi obtained above, determine the electric cylinder torque T required for electric cylinder i to generate thrust Fi. 1i ,include:

[0109]

[0110] Where, thrust Fi is in kN; L is the lead of the lead screw of electric cylinder i, in mm; R is the reduction ratio; η is the efficiency coefficient; the electric cylinder thrust Fi is the positive timing, and the electric cylinder torque T is the negative timing. 1i Positive; otherwise, the electric cylinder torque T 1i Negative;

[0111] (2) Determine the motor torque T, which is the product of the inertia and angular acceleration of the motor rotor, lead screw, synchronous pulley, and coupling. 2i ,include:

[0112]

[0113] Where n is the number of structures whose inertia needs to be calculated, including the motor rotor, lead screw, synchronous pulley, and coupling; J n , These are the moment of inertia and angular acceleration of the structure, respectively, in kg·m. 2 and rad / s 2 ;

[0114] Among them, angular acceleration When positive, the motor torque T 2i Positive indicates good torque, negative indicates poor torque. 2i It is negative.

[0115] It should be understood that in step 7, the moment of inertia of the motor rotor can be obtained from the motor catalog, and the moment of inertia of the lead screw and other structures is calculated using the following formula:

[0116]

[0117] In the formula, m is the mass of the lead screw and other structures, in kg; r is the radius of the lead screw and other structures, in m.

[0118] {Parallel Robot Platform Dynamics Inverse Control System}

[0119] Based on the inverse kinematics method of the above embodiments of the present invention, a parallel robot platform dynamics inverse kinematics control system 100 is also proposed, comprising:

[0120] An initial definition module 101 is used to define the platform state of a parallel robot platform, the platform state including position and attitude curves, motion amplitudes in six directions, angular velocities in six directions, and angular accelerations in six directions.

[0121] Electric cylinder direction vector construction module 102 for constructing electric cylinder direction vector relationships for parallel robot platforms;

[0122] Module 103 is used to construct the lever arm construction module 103 for constructing the component of the electric cylinder in the XY plane of the parallel robot platform relative to the center of the hinged circle based on the direction vector relationship of the electric cylinder.

[0123] The force system equilibrium equation construction module 104 is used to construct the vector expression of the electric cylinder thrust based on the direction vector relationship of the electric cylinder, and to establish the force system equilibrium equation of the parallel robot platform accordingly. The electric cylinder thrust Fi is obtained by solving the force system equilibrium equation, where i represents the number of the electric cylinder, i=1,2,3,4,5,6.

[0124] The electric cylinder extension speed acquisition module 105 is used to obtain the platform pose at any time time based on the position and attitude curve, obtain the electric cylinder length Li based on the inverse kinematics solution, calculate the platform pose after the preset first millisecond period △t1, obtain the electric cylinder length Li+△Li based on the inverse kinematics solution, and determine the extension speed of electric cylinder i at any time time based on this.

[0125] The acceleration acquisition module 106 is used to obtain the platform pose after a second millisecond period Δt2 delay at any time 'time' based on the position and attitude curve, where Δt2 = 2 * Δt1. The electric cylinder length Li + ΔLi + ΔLi' is obtained from the inverse kinematics solution, and the extension / retraction acceleration of electric cylinder i and the screw angular acceleration of electric cylinder i at any time 'time' are determined accordingly.

[0126] The torque acquisition module 107 is used to determine the electric cylinder torque required for the electric cylinder to generate the thrust Fi based on the aforementioned electric cylinder thrust Fi, and the motor torque composed of the product of the inertia and angular acceleration of the motor rotor, lead screw, synchronous pulley, and coupling.

[0127] It should be understood that each module of the above system can be implemented in the form of a computer program instruction set, and when executed, it performs the corresponding process and completes the corresponding function according to the corresponding steps of the parallel robot platform dynamics inverse control method of the foregoing embodiment.

[0128] {Computer System}

[0129] Based on the inverse solution method of the above embodiments of the present invention, a computer system is also proposed, comprising:

[0130] One or more processors; and

[0131] Memory stores instructions that can be operated.

[0132] When the instructions are executed by one or more processors, they cause the aforementioned one or more processors to perform operations, including the process of executing the parallel robot platform dynamics inverse control method of the aforementioned embodiments.

[0133] {Computer-readable storage medium}

[0134] Based on the reverse engineering method of the above embodiments of the present invention, the embodiments of the present invention also propose a computer-readable storage medium for storing one or more programs, wherein the one or more programs include instructions or instruction sets that can be executed by one or more processors.

[0135] The instructions or instruction set, when executed by one or more processors, perform the process of executing the parallel robot platform dynamics inverse control method of the aforementioned embodiments.

[0136] While the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the invention. Those skilled in the art can make various modifications and refinements without departing from the spirit and scope of the invention. Therefore, the scope of protection of the present invention shall be determined by the claims.

Claims

1. A method for inverse dynamics control of a parallel robot platform, applicable to flight simulation systems, driving simulation systems, ship simulation systems, and wave simulation systems, wherein in the flight simulation system, driving simulation system, ship simulation system, and wave simulation system, the center of gravity of the load on the parallel robot platform coincides with the axis of the parallel robot platform, characterized in that, Includes the following steps: Step 1: Define the platform state of the parallel robot platform, including the position and attitude curve, motion amplitude in six directions, angular velocity in six directions, and angular acceleration in six directions. Step 2: Construct the direction vector relationship of the electric cylinders of the parallel robot platform; Step 3: Based on the direction vector relationship of the electric cylinder, construct the lever arm of the electric cylinder component in the XY plane of the parallel robot platform relative to the center of the hinge circle. Step 4: Based on the direction vector relationship of the electric cylinder, construct the vector expression of the electric cylinder thrust, and establish the force balance equation of the parallel robot platform accordingly. By solving the force balance equation, obtain the electric cylinder thrust Fi, where i represents the electric cylinder number, i=1,2,3,4,5,6. Step 5: Obtain the platform pose at any time time according to the position and attitude curve, obtain the electric cylinder length Li according to the inverse kinematics solution, calculate the platform pose after the preset first millisecond period △t1, obtain the electric cylinder length Li+△Li according to the inverse kinematics solution, and determine the extension and retraction speed of electric cylinder i at any time time based on this. Step 6: Obtain the platform pose after the second millisecond period △t2 at any time according to the position and attitude curve, △t2=2*△t1. Obtain the electric cylinder length Li+△Li+△Li' according to the inverse kinematics solution, and determine the extension and retraction acceleration of electric cylinder i at any time and the lead screw angular acceleration of electric cylinder i. as well as Step 7: Based on the electric cylinder thrust Fi obtained above, determine the electric cylinder torque required for the electric cylinder to generate thrust Fi, and the motor torque consisting of the product of the inertia and angular acceleration of the motor rotor, lead screw, synchronous pulley, and coupling. In step 1, the position and attitude curve of the parallel robot platform is defined as a sine curve, and the motion amplitudes in the six directions are Si and Sj respectively. X_MAX S Y_MAX S Z_MAX α _MAX β _MAX γ _MAX The position and orientation of the platform can be expressed as a function: ； Among them, S X S Y S Z α, β, and γ represent the motion states of the platform in the six degrees of freedom (X, Y, Z, α, β, and γ), respectively, and are known quantities. Taking the first derivative of the position and attitude curve yields the angular velocities in six directions, expressed as: ； Among them: V X_MAX =S X_MAX ×2πf1;V Y_MAX =S Y_MAX ×2πf2;V Z_MAX =S Z_MAX ×2πf3;ω X_MAX =a _MAX ×2πf4;ω Y_MAX =b _MAX ×2πf5;ω Z_MAX =c _MAX ×2πf6; Taking the first derivative of the function of angular velocity in the six directions, we obtain the angular acceleration in the six directions, which can be expressed as: ； among them, a X_MAX = S X_MAX ×4π 2 f1 2 ;a Y_MAX = S Y_MAX ×4π 2 f2 2 ;a Z_MAX =S Z_MAX ×4π 2 f3 2 ;e X_MAX = a _MAX ×4π 2 f4 2 ;e Y_MAX = b _MAX ×4π 2 f5 2 ;e Z_MAX = c _MAX ×4π 2 f6 2 ; In step 2, the direction vector relationship of the electric cylinders of the parallel robot platform is constructed, including: The direction vector of the electric cylinder i in the parallel robot platform is expressed as: [X Pi_New -X Bi ,Y Pi_New -Y Bi ,Z Pi_New -Z Bi ]; Where i represents the serial number of the electric cylinder, i=1,2,3,4,5,6; (X) Bi ,Y Bi Z Bi ( ) represents the coordinates of the hinge point of the lower platform; (X) Pi_New ,Y Pi_New Z Pi_New The coordinates of the upper platform hinge point at any given moment are obtained from the platform's position and attitude. The initial coordinates of the center of the upper hinge circle formed by the upper platform hinge points are (0, 0, Z0), where Z0 is the coordinate of the platform at its lowest position. After the platform moves, the coordinates of the center of the upper hinge circle are (S... X ,S Y ,S Z +Z0); In step 3, based on the direction vector relationship of the electric cylinder, the lever arm of the electric cylinder component in the XY plane of the parallel robot platform relative to the center of the hinge circle is constructed, including: Establish the equation of the line projected onto the XY plane by the direction vector of electric cylinder i, where i = 1, 2, 3, 4, 5, 6: ； Where, k i =(Y Pi_New -Y Bi ) / (X Pi_New -X Bi ); Because the straight line passes through (X) Pi_New Y Pi_New Therefore: bi = Y Pi_New - k i ×X Pi_New ; Based on the formula for calculating the distance from a point to a line, obtain the lever arm of the component of electric cylinder i in the XY plane about the center of the hinge circle at the reference point: ； Following the method described above for constructing the lever arm of the electric cylinder's component in the XY plane relative to the center of the hinge circle, we continue to construct the lever arm d of the electric cylinder's component in the XZ plane relative to the center of the hinge circle. xzi And the force arm d of the electric cylinder component on the YZ plane relative to the center of the hinge circle. yzi .

2. The inverse kinematics control method for parallel robot platforms according to claim 1, characterized in that, In step 4, the vector expression of the electric cylinder thrust is constructed based on the direction vector relationship of the electric cylinder, and the force balance equation of the parallel robot platform is established accordingly. The electric cylinder thrust Fi is obtained by solving the force balance equation, including: Let the thrust of the i-th electric cylinder be Fi, and the vector expression for Fi is: ； The equilibrium equations for the force system are then established as follows: ； In the formula, m is the load mass, in kg; a X Let a be the translational acceleration along the X direction; Y a is the translational acceleration along the Y direction; Z ε is the translational acceleration along the Z direction; X ε is the rotational angular acceleration about the X-axis; Y ε is the rotational angular acceleration about the Y-axis; Z ω is the rotational angular acceleration about the Z-axis; r is the height difference between the center of gravity of the load and the center of the upper hinge circle; J X J Y J Z These are the moments of inertia for the pitch, roll, and yaw of a six-degree-of-freedom parallel robot motion platform and its load, respectively. make: ； ； ； ； ； ； The equilibrium equations of the force system are then transformed into matrix form: ； Solving the system of matrix equations using Gaussian elimination yields f i And, combined with the aforementioned vector expression for Fi, determine the thrust Fi of the i-th electric cylinder.

3. The inverse kinematics control method for parallel robot platforms according to claim 2, characterized in that, In step 5, the calculation of the platform pose after a preset first millisecond period Δt1, obtaining the electric cylinder length Li+ΔLi based on the inverse kinematics solution, and determining the extension / retraction speed of electric cylinder i at any time time based on this, includes: Calculate the platform pose (time+0.00005) 0.05 milliseconds after any time *time*. Using the inverse kinematics, obtain the length of the electric cylinder *Li* + Δ*Li*. Then, the extension / retraction velocity of electric cylinder *i* at any time *time* is: 。 4. The inverse kinematics control method for parallel robot platforms according to claim 3, characterized in that, In step 6, the platform pose after a second millisecond period Δt2 delay at any given time is obtained from the position and attitude curve, where Δt2 = 2 * Δt1. The length of the electric cylinder Li + ΔLi + ΔLi' is obtained from the inverse kinematics solution, and the extension and retraction acceleration of the electric cylinder i at any given time and the angular acceleration of the lead screw of the electric cylinder i are determined accordingly, including: The platform pose at any time *time* is obtained from the position and attitude curve. The length *Li* of the electric cylinder is obtained from the inverse kinematics solution. The platform pose is calculated 0.1 milliseconds after the arbitrary time *time*. The length *Li* + Δ*Li* + Δ*Li' of the electric cylinder is obtained from the inverse kinematics solution. Then, the extension and retraction speed of the electric cylinder *i* at time *time* + 0.00005 is: ； Then, the extension and retraction acceleration of electric cylinder i at any time time is: ； The angular acceleration of the lead screw corresponding to electric cylinder i is: ； In the formula, Let be the angular acceleration of the lead screw of electric cylinder i, in rad / s. 2 L represents the lead of the lead screw.

5. The inverse kinematics control method for parallel robot platforms according to claim 4, characterized in that, In step 7, based on the aforementioned electric cylinder thrust Fi, the electric cylinder torque required to generate the thrust Fi is determined, along with the motor torque comprised of the product of the inertia and angular acceleration of the motor rotor, lead screw, synchronous pulley, and coupling, including: (1) Based on the electric cylinder thrust Fi obtained above, determine the electric cylinder torque T required for electric cylinder i to generate thrust Fi. 1i ,include: ； Where, thrust Fi is in kN; L is the lead of the lead screw of electric cylinder i, in mm; R is the reduction ratio; η is the efficiency coefficient; the electric cylinder thrust Fi is the positive timing, and the electric cylinder torque T is the negative timing. 1i Positive; otherwise, the electric cylinder torque T 1i Negative; (2) Determine the motor torque T, which is the product of the inertia and angular acceleration of the motor rotor, lead screw, synchronous pulley, and coupling. 2i ,include: ； Where n is the number of structures whose inertia needs to be calculated, including the motor rotor, lead screw, synchronous pulley, and coupling; J n , These are the moment of inertia and angular acceleration of the structure, respectively, in kg·m. 2 and rad / s 2 ; Among them, angular acceleration When positive, the motor torque T 2i Positive indicates good torque, negative indicates poor torque. 2i It is negative.

6. A computer system, characterized in that, include: One or more processors; as well as Memory stores instructions that can be operated. When the instruction is executed by one or more processors, it causes the aforementioned one or more processors to perform operations, including the process of executing the inverse dynamics control method for the parallel robot platform according to any one of claims 1-5.

7. A computer-readable storage medium for storing one or more programs, characterized in that, The one or more programs include instructions or instruction sets that can be executed by one or more processors; Wherein, when the instruction or instruction set is executed by one or more processors, it performs the process of the inverse dynamics control method for the parallel robot platform as described in any one of claims 1-5.

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