A simulation method for tracked vehicle servo system considering torsion axis constraints

Abstract

The present invention proposes a simulation method for a tracked vehicle on-board servo system considering torsion axis constraints. First, based on the RecurDyn simulation platform, a dynamic model of the vehicle body system during movement is established. Then, the dynamic model is used as the control subject, combined with the Matlab\Simulink algorithm module, to establish a tracked vehicle servo system model. Finally, a joint simulation is performed based on the established RecurDyn model and the Simulink tracked vehicle on-board servo system. The multi-body system dynamics model and the input and output interfaces of the tracked vehicle on-board servo system are jointly simulated, and a joint simulation model of the mechatronics of the tracked vehicle is established by combining the dynamic model and the tracked vehicle on-board servo system. This joint simulation model can provide a more realistic tracked vehicle operation condition. The controller designed based on this is more practical and has a wide range of usage scenarios.

Description

Technical Field

[0001] The invention relates to the field of tracked vehicle simulation design, and in particular to a simulation method and system for a tracked vehicle onboard servo system taking torsion axis constraints into consideration. Background Art

[0002] At present, when countries conduct research on tracked vehicles, they generally only design the control system of the tracked vehicle system, and lack the joint simulation of the tracked vehicle multi-body system dynamics model and the on-board servo system. With the development of computers, simulation has also developed to the current stage, covering multiple fields such as machinery, electricity, and control. This application establishes a tracked vehicle multi-body system dynamics model through simulation software, which can well replace the physical object to complete the simulation. Since the simulation of a single field cannot provide a simulation model that is consistent with the actual concept of the product, the present invention, on the basis of establishing the dynamics model of the tracked vehicle, also provides a joint simulation method of the tracked vehicle dynamics model and the on-board servo system. Summary of the invention

[0003] The purpose of the present invention is to provide a simulation method and system of a tracked vehicle servo system taking into account torsion axis constraints.

[0004] The technical solution to realize the present invention is: a simulation method of a tracked vehicle servo system considering torsion axis constraints, comprising the following steps:

[0005] Step 1: Establish a multi-body dynamics model of the tracked vehicle for the platform based on RecurDyn;

[0006] Step 2: Building a dual-channel vehicle-mounted servo system model for a tracked vehicle based on the MATLAB platform;

[0007] Step 3: Establish a mechatronics simulation model for a tracked vehicle, use the tracked vehicle multi-body dynamics model as the interface module of the tracked vehicle dual-channel on-board servo system model, import the tracked vehicle multi-body dynamics model into MATLAB for operation, use the corresponding output variables of the tracked vehicle multi-body dynamics model as the input variables of the tracked vehicle dual-channel on-board servo system model, and feed back the output variables of the tracked vehicle dual-channel on-board servo system model as the input variables of the tracked vehicle multi-body dynamics model;

[0008] Step 4: Set the parameters of the tracked vehicle multi-body dynamics model, run the tracked vehicle mechatronics simulation model, and simulate the driving conditions of the tracked vehicle under different suspension devices and on different working road conditions.

[0009] Furthermore, in step 1, a multi-body dynamics model of the tracked vehicle is established for the platform based on RecurDyn, where:

[0010] The crawler vehicle mainly consists of a chassis, an upper platform and a body tube. The chassis includes tracks, a torsion shaft, a suspension device and a tensioning device. The left and right tracks are composed of 110 track shoes, which are respectively connected to a driving wheel, an induction wheel, 6 road wheels and 3 track rollers. The suspension device adopts a torsion bar independent suspension. The torsion bar is composed of 6 elastic devices and is responsible for the connection between the vehicle body and the 6 road wheels. The torsion bar is simulated by a torsion shaft spring. The track vehicle model under different working conditions is simulated by modifying the torsion shaft spring parameters. The tensioning device adopts Spring Force is used to simulate the vehicle, which is connected to the idler through a translational pair; the track and the driving wheel are fixedly connected through a revolute pair, and the three track rollers are connected to the torsion bar respectively, and the other side of the torsion bar is connected to the vehicle body through a fixed pair; the upper platform is tightly connected to the vehicle body through the seat ring, and moves horizontally relative to the vehicle body, and the barrel is connected to the upper platform through the trunnion, and moves in pitch relative to the upper platform; the contact forces between the track shoes, the track and the ground, the road wheels, the idler wheels, and the track rollers are determined by modifying the damping coefficient and stiffness coefficient respectively;

[0011] The disturbance torque caused by the unevenness of the road surface is transmitted to the tracks on the left and right sides of the chassis, and then transmitted from the left and right tracks to the left and right road wheels of the chassis respectively. The road wheels are connected to the vehicle body by a suspension device, and the disturbance torque is transmitted to the vehicle body through the suspension device, causing the translation and rotation of the vehicle body; the vehicle body and the upper platform are connected through the seat ring bearing, so the position disturbance of the vehicle body will also cause the upper platform to follow the vibration. At the same time, the upper platform will also produce a rotational relative motion relative to the vehicle body due to the existence of factors such as friction torque; the body tube is connected to the upper platform, and the disturbance torque on the upper platform will be transmitted to the body tube through the ear shaft, causing the vibration of the body tube;

[0012] The RecurDyn toolbox is used to build the dynamic model of the tracked vehicle, including the track dynamic model, the superstructure platform and the barrel dynamic model, based on which the overall multi-body system dynamic model of the tracked vehicle is obtained.

[0013] Furthermore, in step 2, a dual-channel on-board servo system model of a tracked vehicle is constructed based on the MATLAB platform, wherein the dual-channel on-board servo system of the tracked vehicle adopts a fully electric servo control system, and its structure is "permanent magnet synchronous motor + inverter + SVPWM control", specifically:

[0014] Based on SVPWM control, the current loop, speed loop and position loop controllers are designed respectively, among which the current loop controller and the speed loop controller both adopt PI control; the position loop controller adopts P controller;

[0015] The input of the position loop is the pitch angle / azimuth of the tracked vehicle tube, the output of the position loop is used as the input of the speed loop, the output of the speed loop is used as the input of the current loop, the current loop outputs the signal to the SVPWM controller, the SVPWM controller controls the speed of the permanent magnet synchronous motor through the inverter, the speed of the permanent magnet synchronous motor is fed back to the pitch angle / azimuth of the tracked vehicle tube, thereby controlling the pitch angle and rotation of the tube to achieve closed-loop control;

[0016] Furthermore, in step three, a mechatronics simulation model of the tracked vehicle is established by performing a joint simulation based on the tracked vehicle multi-body dynamics model and the tracked vehicle dual-channel onboard servo system model. The specific method is as follows:

[0017] (1) In RecurDyn, create and name POUT. The angular displacement / angular velocity change of the horizontal azimuth of the body tube of the tracked vehicle dynamics model and the geodetic coordinates is used as the output variable POUT1 / POUT2, and the angular displacement / angular velocity change of the pitch azimuth of the body tube and the geodetic coordinates is used as the output variable POUT3 / POUT4. POUT completes the real-time control of the tracked vehicle dual-channel onboard servo system in step 2.

[0018] (2) In RecurDyn, PINs are established between the vehicle body and the upper platform, and between the upper platform and the barrel. First, the PIN names are defined. Then, the controlled parameters of the tracked vehicle multibody dynamics model, namely, the relative motion between the vehicle body and the upper platform in the horizontal direction, and the relative motion between the upper platform and the barrel in the pitch direction, are associated with the input variables PINs after the name definition is completed, so as to realize the input of control signals of the tracked vehicle dynamics model by the dual-channel vehicle servo system.

[0019] (3) After establishing PIN and POUT, the tracked vehicle multi-body dynamics model is imported into the MATLAB software to generate a Simulink submodule, whose corresponding output is used as the input of the position loop of the dual-channel vehicle servo system; the output of the servo motor in the dual-channel vehicle servo system is used as the input of the generated Simulink submodule;

[0020] (4) Based on the vehicle position information and target position information output by the dynamic model, the azimuth and pitch angles of the target in the geodetic coordinate system are obtained. The dual-channel vehicle-mounted servo system completes the joint simulation by controlling the pitch motion of the barrel and the upper platform relative to the vehicle body coordinate system.

[0021] Furthermore, in step 4, the parameters of the multi-body dynamics model of the crawler vehicle are set, and the mechatronics simulation model of the crawler vehicle is run to simulate the driving conditions of the crawler vehicle under different suspension devices and on different working conditions. The specific method is as follows:

[0022] The load-bearing wheel is connected to one end of the torsion bar through a revolute pair, and the other end can be connected to a fixed pair or a torsion shaft spring. When the torsion bar is connected to the vehicle body through a fixed pair, the torsion shaft is in full stiffness condition. When the torsion bar is connected to the vehicle body through a torsion shaft spring, different parameters of the torsion shaft spring are modified to simulate different working conditions of the tracked vehicle suspension device, and to realize the analysis of the simulation results of the tracked vehicle under the corresponding working conditions.

[0023] A simulation system for a tracked vehicle servo system considering a torsion axis constraint is provided, and a simulation method for a tracked vehicle servo system considering a torsion axis constraint is implemented to achieve the simulation of the tracked vehicle servo system, including:

[0024] Dynamic model building module, which builds a multi-body dynamic model of the tracked vehicle for the platform based on RecurDyn;

[0025] Servo system model building module, which builds a dual-channel vehicle-mounted servo system model for tracked vehicles based on the MATLAB platform;

[0026] The joint simulation module performs joint simulation based on the tracked vehicle multi-body dynamics model and the tracked vehicle dual-channel on-board servo system model to establish a mechatronics simulation model of the tracked vehicle.

[0027] A computer device comprises a memory, a processor and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, the simulation method of the tracked vehicle onboard servo system considering the torsion axis constraint is implemented to realize the simulation of the tracked vehicle onboard servo system.

[0028] A computer-readable storage medium stores a computer program. When the computer program is executed by a processor, the simulation method of a tracked vehicle onboard servo system considering torsion axis constraints is implemented to achieve the simulation of the tracked vehicle onboard servo system.

[0029] Compared with the prior art, the present invention has the following significant advantages:

[0030] (1) The design of the tracked vehicle system often only involves the design of the control system without considering the control of the main mechanical structure. By establishing a dynamic model of the mechanical structure through simulation software, the design quality of the system can be better evaluated.

[0031] (2) For the tracked vehicle servo system, which is a control object with strong nonlinearity and strong coupling, the joint simulation of Matlab\Simulink program and RecurDyn program can provide various parameters that are more consistent with the actual product concept.

[0032] (3) The joint simulation technology was used to study the on-board servo of the tracked vehicle, which greatly reduced the experimental cost and improved the analysis efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 It is the working principle diagram of the vehicle-mounted servo system joint simulation.

[0034] Figure 2 It is the implementation flow chart of vehicle servo system joint simulation.

[0035] Figure 3 It is the track dynamics model.

[0036] Figure 4 It is a dynamic model of the upper platform and barrel of a tracked vehicle.

[0037] Figure 5 It is the overall multi-body system dynamics model of the tracked vehicle.

[0038] Figure 6 It is the structure diagram of three-loop PID controller.

[0039] Figure 7 It is the simulation block diagram of the tracked vehicle's onboard servo system.

[0040] Figure 8 It is the current loop transfer function model.

[0041] Fig. 9 It is the current loop output curve.

[0042] Fig.10 It is the speed loop transfer function model.

[0043] Fig.11 It is the speed loop output curve.

[0044] Fig.12 It is the position loop transfer function model.

[0045] Fig.13 It is the position loop output curve diagram.

[0046] Fig.14 It is the overall framework of the vehicle servo system joint simulation model.

[0047] Fig.15 It is a joint simulation model diagram of the vehicle servo system.

[0048] Fig.16 It is the target azimuth tracking error curve under standard stiffness grade C road surface.

[0049] Fig.17 It is the target azimuth tracking error curve under full-stiffness C-level road surface.

[0050] Fig.18 It is the target azimuth tracking error curve under standard stiffness grade D road surface. DETAILED DESCRIPTION

[0051] In order to make the purpose, technical solution and advantages of the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific implementation described herein is only used to explain the present application and is not used to limit the present application.

[0052] The present invention is based on a simulation method for a tracked vehicle on-board servo system considering torsion axis constraints. Firstly, according to the multi-body system dynamics theory, the multi-body system dynamics model of the tracked vehicle is designed using RecurDyn as a platform; secondly, the tracked vehicle dynamics model is used as the control subject, and the design of the vehicle-mounted servo system of the vehicle body is established using Matlab\Simulink as a platform; then a joint model combining the tracked vehicle dynamics model and the on-board servo system is established; finally, based on the joint simulation model, the tracked vehicle is simulated and analyzed under different working conditions. Figure 1 The working principle diagram of the joint simulation of the vehicle servo system, Figure 2 Vehicle servo system joint simulation implementation flow chart. The main implementation steps are as follows:

[0053] Step 1: Build a multi-body dynamics model of the tracked vehicle based on RecurDyn, which mainly includes the chassis, upper platform, suspension device, and body tube.

[0054] The specific method is:

[0055] The crawler vehicle mainly consists of a chassis, an upper platform, and a body tube. The chassis includes tracks, a torsion shaft, a suspension device, and a tensioning device. The left and right tracks are composed of 110 track shoes, which are connected to a driving wheel, an induction wheel, six road wheels, and three support wheels. The suspension device of the vehicle chassis adopts a torsion bar independent suspension. The torsion bar is composed of 6 elastic devices and is responsible for the connection between the vehicle body and the 6 road wheels. The torsion bar is simulated by a torsion shaft spring. By modifying the parameters of the torsion shaft spring, the track vehicle model under different working conditions can be simulated; the tensioning device is simulated by Spring Force, and is connected to the inducer through a translation pair; the track and the driving wheel are fixedly connected through a revolute pair, and the three track rollers are respectively connected to the torsion bar, and the other side of the torsion bar is connected to the vehicle body through a fixed pair; the upper platform is tightly connected to the vehicle body through the seat ring and moves horizontally relative to the vehicle body, and the body tube is connected to the upper platform through the ear shaft and makes pitch motion relative to the upper platform. The body tube has a very high degree of freedom through dual-axis rotation motion; the contact forces between the track shoes, the track and the ground, the road wheels, the inducer wheels, and the track rollers are determined by modifying parameters such as the damping coefficient and the stiffness coefficient.

[0056] The disturbance torque caused by the unevenness of the road surface is transmitted to the tracks on the left and right sides of the chassis, and then transmitted from the left and right tracks to the left and right road wheels of the chassis respectively. The road wheels are connected to the vehicle body by a suspension device, and the disturbance torque is transmitted to the vehicle body through the suspension device, causing the translation and rotation of the vehicle body. The vehicle body is connected to the upper platform through the seat ring bearing, so the position disturbance of the vehicle body will also cause the upper platform to follow the vibration. At the same time, the upper platform will also produce rotational relative motion relative to the vehicle body due to the existence of factors such as friction torque. The body tube is connected to the upper platform, and the disturbance torque on the upper platform will be transmitted to the body tube through the ear shaft, causing the vibration of the body tube.

[0057] The dimensions of each component of the vehicle body are set according to the specific dimensions of the original vehicle. The dynamics model of the tracked vehicle is built using the modules provided by the RecurDyn toolbox. Figure 3 is the track dynamics model, Figure 4 It is the dynamic model of the tracked vehicle upper platform and barrel. Figure 5 It is the overall multi-body dynamics model of the tracked vehicle.

[0058] Step 2: Design a dual-channel vehicle-mounted servo system model for a tracked vehicle based on the MATLAB platform.

[0059] The specific method is:

[0060] In this simulation method, the dual-channel on-board servo system of the tracked vehicle adopts a fully electric servo control system, and its structure is "permanent magnet synchronous motor + inverter + SVPWM control".

[0061] The permanent magnet synchronous motor selects the Permanent Magnet Synchronous Machine module in MATLAB. Ideally, the inverter can be equivalent to a proportional module with a proportional coefficient of 1. For the SVPWM control technology, the existing technology can be used for implementation. The present invention has no improvement on this and will not be described in detail;

[0062] On the basis of SVPWM control, current loop, speed loop and position loop controllers are designed respectively, wherein the input of the position loop is the pitch angle / azimuth of the tracked vehicle body tube in step one, the output of the position loop is used as the input of the speed loop, the output of the speed loop is used as the input of the current loop, the current loop output signal is given to the SVPWM controller, the SVPWM controller controls the speed of the permanent magnet synchronous motor through the inverter, and the speed of the permanent magnet synchronous motor is fed back to the pitch angle / azimuth of the tracked vehicle body tube in step one, thereby controlling the pitch angle and rotation of the body tube to achieve the effect of closed-loop control.

[0063] Regarding the design of the three-loop PID controller, the current loop controller and the speed loop controller of this application both adopt PI control. The control parameter corresponding to the proportional link in the PI controller is KP, and its purpose is to eliminate the deviation. Once the deviation occurs, the controller immediately produces a control action to reduce the deviation; the control parameter corresponding to the integral link is KI, which is mainly used to eliminate static error and improve the zero-difference of the dual-channel vehicle-mounted servo system of the crawler vehicle; the position loop controller adopts a P controller. This model assumes that the azimuth and pitch models are consistent, and the following only describes the pitch. Figure 6 It is the three-loop PID control structure diagram. Figure 7 This is the simulation block diagram of the tracked vehicle's onboard servo system.

[0064] 1. Current loop controller design and simulation

[0065] Figure 8 is the current loop transfer function model.

[0066] Among them, T oi is the current filter time constant, W ACR (s) is the transfer function of the current loop regulator, T s is the inverter delay time, τ e is the electrical time constant of the permanent magnet synchronous motor, R is the load resistance, i q * is the output of the speed loop, and s is a complex variable. The current loop regulator transfer function is shown below, where K i is the proportionality coefficient, τ i is the integration time constant.

[0067]

[0068] Due to T oi and T s It is much smaller than the electrical time constant of the motor. The current loop controller system can be approximated as a first-order inertia link. The inertia time constant is the sum of the two, that is, T ∑i =T s +T oi ; and because τ e Much larger than the inertia time constant T ∑i , configure τ i The larger pole in the open-loop transfer function of the cancellation system, namely τ i =τ e , at this time the system is corrected to a typical type I system. At this time, the transfer function of the current loop controller system is

[0069]

[0070] The open loop gain of the current loop controller system is K I =K i / R i , the inertia time constant is T ∑i According to the relationship between the dynamic following performance index and parameters of the typical type I system, the parameter relationship when the overshoot is 5% is selected, that is, K I T ∑i =1 / 2. At this time, the current loop regulator parameters are as follows

[0071]

[0072] Use Matlab\Simulink to simulate the current loop. The q-axis current loop simulation output curve is as follows: Fig. 9 As shown in Figure 1, the d-axis current loop is similar to it. The current loop responds quickly, has no error in steady state, and the overshoot is about 5%.

[0073] 2. Speed ​​loop controller design and simulation

[0074] The speed loop controller is designed based on the current loop controller. When the following price reduction approximation condition is met, the current loop can be simplified, the high-order terms can be ignored, and the speed design can be simplified.

[0075]

[0076] where ω cn is the open-loop cutoff frequency of the speed loop. At this time, the closed-loop transfer function of the current loop is

[0077]

[0078] The simplified current loop is used as the inner loop of the speed loop, and the speed loop transfer function model is as follows: Fig.10 shown.

[0079] Where T on is the filtering time constant, K t is the motor torque coefficient, J is the moment of inertia of the upper platform, T em is the load torque, W ASR (s) is the speed loop regulator, which adopts PI control, as shown in the following formula, K n is the proportionality coefficient, τ n is the integration time constant, ω m * It is the position loop output.

[0080]

[0081] Similar to the current loop design, T on and 1 / K I Approximately treated as a first-order inertia link, the inertia time constant is the sum of the two, that is, T ∑n =1 / K I +Ton =2T ∑i +T on .

[0082] When designing the speed loop, there is no need to consider the load torque T em , at this time, the open-loop transfer function of the speed loop controller system is

[0083]

[0084] From the above formula, we can see that at this time, the speed loop is corrected into a typical type II system, and the open loop gain of the system is K N =K n K t / (Jτ n ), the inertia time constant is T Σn A very important parameter in the design and analysis of a typical type II system is the intermediate frequency bandwidth h = τ n / T ∑n , which is the width of the mid-frequency band with a slope of -20dB / sec (logarithmic coordinates).

[0085] According to the relationship between the indicators of the typical type II system's dynamic following performance and dynamic anti-interference performance and the parameter h, h=5 is selected. The formula for calculating the typical type II system parameters in the engineering design method is shown as follows:

[0086]

[0087] Therefore, the speed loop regulator parameters are:

[0088]

[0089] Use Matlab\Simulink to build the speed loop simulation block diagram, and reference the permanent magnet synchronous motor model provided in Simulink. According to the above derivation, set the corresponding parameters to meet the model requirements.

[0090] Given a 40° / s step signal, the output result is as follows Fig.11 The speed loop is steady-state with no error, and the overshoot is about 6.25%, which meets the overshoot requirement when h=5, and the time required to reach 40° is about 0.2s.

[0091] 3. Position loop controller design and simulation

[0092] Fig.12 is the transfer function model of the position loop.

[0093] The position loop is designed based on the speed loop. The closed-loop transfer function of the speed loop is:

[0094]

[0095] W APR (s) is the position loop regulator, using P controller, the proportional coefficient is K p i is the reduction ratio of the transmission, θ L * is the given motor speed. When the upper platform rotates to the command position, it needs to accelerate for T1 seconds, and then maintain a uniform speed of T2 seconds after reaching the maximum gun adjustment speed. Then, it decelerates for T3 seconds. The upper platform gradually decelerates to zero. The integral of the upper platform speed curve is the angle, that is, the upper platform speed is converted into the rotation angle of the upper platform through the integral link shown in the figure. The critical condition for the upper platform to start decelerating is:

[0096]

[0097] where n max (r / min) is the speed limit. In order to prevent the upper platform from overshooting, it should also be ensured that:

[0098]

[0099] According to the above formula, K p Should meet:

[0100]

[0101] Build a simulation model in Matlab\Simulink, input a step signal of the maximum rotation angle of the upper platform of 90°, and output the following Fig.13 As shown, the upper loading platform takes about 2.25 seconds to reach the specified position without overshoot, and the steady-state error is less than 1 mil.

[0102] The established digital all-electric control system must include speed and position loop control. The three-loop PID control is only a control structure established in this example to illustrate the problem.

[0103] Step 3: Perform joint simulation processing on the input and output interfaces of the model definitions established in steps 1 and 2 to establish a mechatronics simulation model of the tracked vehicle.

[0104] The most important part in establishing a joint simulation model is to establish the input and output interfaces of each module of the dynamic model in the connection between RecurDyn and Simulink. The tracked vehicle dynamics model in RecurDyn uses the speed values ​​of the left and right track drive wheels as input to control the movement of the tracked vehicle chassis. The speeds on both sides are generally the same to ensure that the tracked vehicle travels in a straight line. They can also take different values ​​to achieve the movement and steering of the tracked vehicle. At the same time, in order to establish a joint simulation channel, PlantInputs (PIN) in RecurDyn is used as the input variable of the tracked vehicle multi-body dynamics model in step one, and PlantOutputs (POUT) is used as the input variable of the tracked vehicle dual-channel on-board servo system in step two. Fig.14 It is the overall framework of the joint simulation model of the vehicle servo system.

[0105] Based on the above establishment of the simulation channel, the specific steps are as follows:

[0106] 1. In RecurDyn, create POUT and name it. The angular displacement / angular velocity change of the horizontal position of the barrel of the tracked vehicle dynamics model and the geodetic coordinates is used as the output variable POUT1 / POUT2, and the angular displacement / angular velocity change of the barrel and the geodetic coordinates pitch position is used as the output variable POUT3 / POUT4. POUT completes the real-time control of the dual-channel vehicle servo system of the tracked vehicle in step 2.

[0107] 2. In RecurDyn, establish PINs between the vehicle body and the upper platform, and between the upper platform and the barrel. First, define the PIN names. Then associate the controlled parameters of the tracked vehicle multibody dynamics model (i.e., the relative motion between the vehicle body and the upper platform in horizontal orientation, and the relative motion between the upper platform and the barrel in pitch orientation) with the input variables PINs after the name definition is completed, so as to realize the input of control signals of the tracked vehicle dynamics model by the dual-channel vehicle servo system.

[0108] 3. After establishing PIN and POUT, import the tracked vehicle dynamics model into MATLAB software and generate Simulink submodules, such as Fig.14 As shown in the RecurDyn module on the left, its corresponding output is used as the input of the position loop of the dual-channel vehicle servo system; the output of the servo motor in the dual-channel vehicle servo system is used as the input of the generated Simulink sub-module.

[0109] 4. The vehicle position information and target position information output by the dynamic model can obtain the azimuth and pitch angle of the target in the geodetic coordinate system. The control motor of the dual-channel vehicle servo system can complete the joint simulation by controlling the pitch motion of the barrel and the upper platform relative to the vehicle body coordinate system. Fig.15 This is the joint simulation model diagram of the vehicle servo system.

[0110] Step 4: Simulate the mechatronics simulation model designed in step 3 and analyze the simulation results under various working conditions.

[0111] For the multi-body dynamics model of the tracked vehicle, the parameters of the suspension device can be modified to simulate the movement of the tracked vehicle under real working conditions, such as Figure 3 The load-bearing wheel is connected to one end of the torsion bar through a revolute pair, and the other end can be connected to a fixed pair or a torsion shaft spring. When the torsion bar is connected to the vehicle body through a fixed pair, the torsion shaft is in full stiffness; when the torsion bar is connected to the vehicle body through a torsion shaft spring, different parameters of the torsion shaft spring can be modified to simulate different working conditions of the tracked vehicle suspension device, and to realize the analysis of the tracked vehicle simulation results under the corresponding working conditions.

[0112] The vehicle center of mass coordinate value (-2.18, 1.06, 0) m of the tracked vehicle multibody dynamics model in RecurDyn is set as the starting position of the movement. The target is directly in front of the vehicle body. The angle information of the line connecting the vehicle center of mass coordinate and the target point coordinate is used as the input of the control system. The tracked vehicle fire line tracking process meets the requirement that the barrel moves within the rotation range.

[0113] To simulate the speed of a tracked vehicle on the road, a cubic polynomial is used in RecurDyn to approximate the step function STEP(x,x0,h0,x1,h1) to achieve speed control of the left and right drive wheels. Among them, x represents the independent variable, usually time, indicating that the value of the step function will change at a specific time point; x0 represents the time point when the state of the step function begins to change; h0 represents the value of the step function before x0; x0 represents the time point when the state of the step function ends the change; h1 represents the value of the step function after x1. Changing the parameters can achieve speed change. The specific formula of the step function is as follows.

[0114]

[0115] Now use the STEP(time,0.1,0,5,2540D) (D represents the speed of the crawler vehicle) function as the speed input of the driving wheels on both sides, and then perform uniform acceleration motion. After five seconds, the speed reaches 40km / h and then maintains a constant speed.

[0116] In the above process, the present invention performs simulation analysis on the full stiffness and the torsion axis spring respectively by setting the standard torsion axis stiffness of 31.85 kN·m / rad (defined as: standard stiffness). Fig.16 , Fig.17 Error curves of the vehicle servo system tracking the target corresponding to the standard stiffness and full stiffness of the torsion axis of the suspension device in the joint simulation of the C-class road. Fig.18For the D-class road surface, the torsion axis of the suspension device has standard stiffness, and the on-board servo system tracks the error curve of the target.

[0117] From the above multiple figures, we can see that the average error of the azimuth axis stable tracking stage and the average error of the pitch axis stable tracking stage are both less than 1mil, and the tracked vehicle servo system can ensure stable tracking of the target on both bidirectional stable axes; Fig.17 By comparison, when the torsion axis of the tracked vehicle model suspension device is set to standard stiffness, the error of the tracked vehicle pitch axis stable tracking stage is smaller than the stable tracking error of the full-rigid pitch axis, which preliminarily proves the effectiveness of the joint simulation model.

[0118] The technical features of the above embodiments can be realized in multiple combinations. To make the description concise, similar possible combinations of the technical features in the above embodiments are not described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

Claims

1. A simulation method for a tracked vehicle servo system considering torsion axis constraints, characterized in that: The steps include: Step 1: Establish a multi-body dynamics model of the tracked vehicle for the platform based on RecurDyn; Step 2: Building a dual-channel vehicle-mounted servo system model for a tracked vehicle based on the MATLAB platform; Step 3: Establish a mechatronics simulation model for a tracked vehicle, use the tracked vehicle multi-body dynamics model as the interface module of the tracked vehicle dual-channel on-board servo system model, import the tracked vehicle multi-body dynamics model into MATLAB for operation, use the corresponding output variables of the tracked vehicle multi-body dynamics model as the input variables of the tracked vehicle dual-channel on-board servo system model, and feed back the output variables of the tracked vehicle dual-channel on-board servo system model as the input variables of the tracked vehicle multi-body dynamics model; Step 4: setting the parameters of the crawler vehicle multi-body dynamics model, running the crawler vehicle mechatronics simulation model, and simulating the driving conditions of the crawler vehicle under different suspension devices and on different working conditions. Step 1: Build a multi-body dynamics model of the tracked vehicle for the platform based on RecurDyn, where: The crawler vehicle has a chassis, an upper platform and a body tube. The chassis includes tracks, torsion shafts, suspension devices and tensioning devices. The left and right tracks are composed of 110 track shoes, which are respectively connected to 1 driving wheel, 1 induction wheel, 6 road wheels and 3 track rollers. The suspension device adopts a torsion bar independent suspension. The torsion bar is composed of 6 elastic devices, which is responsible for the connection between the vehicle body and the 6 road wheels. The torsion bar is simulated by a torsion shaft spring. The tracked vehicle model under different working conditions is simulated by modifying the torsion shaft spring parameters. The tensioning device adopts Spring Force is used to simulate the vehicle. It is connected to the idler wheel through a translation pair. The track and the driving wheel are fixedly connected through a rotation pair. The three track rollers are connected to the torsion bar respectively. The other side of the torsion bar is connected to the vehicle body through a fixed pair. The upper platform is tightly connected to the vehicle body through the seat ring and moves horizontally relative to the vehicle body. The barrel is connected to the upper platform through the trunnion and makes pitching motion relative to the upper platform. The contact force between the track shoes, the track and the ground, the road wheels, the idler wheel and the track roller is determined by the damping coefficient and the stiffness coefficient. The disturbance torque caused by the unevenness of the road surface is transmitted to the tracks on the left and right sides of the chassis, and then transmitted from the left and right tracks to the left and right road wheels of the chassis respectively. The road wheels are connected to the vehicle body by a suspension device, and the disturbance torque is transmitted to the vehicle body through the suspension device, causing the translation and rotation of the vehicle body; the vehicle body and the upper platform are connected through the seat ring bearing, so the position disturbance of the vehicle body causes the upper platform to follow the vibration. At the same time, the upper platform produces a rotational relative motion relative to the vehicle body due to the existence of friction torque; the body tube is connected to the upper platform, and the disturbance torque on the upper platform is transmitted to the body tube through the ear shaft, causing the vibration of the body tube; Use the RecurDyn toolbox to build a multi-body dynamics model of a tracked vehicle, including the tracked vehicle dynamics model, the upper platform, and the barrel dynamics model; Step 2: Based on MATLAB, a dual-channel on-board servo system model for a tracked vehicle is established. The dual-channel on-board servo system model for a tracked vehicle adopts a fully electric servo control system, and its structure is "permanent magnet synchronous motor + inverter + SVPWM control", specifically: On the basis of SVPWM control, the current loop controller, speed loop controller and position loop controller are designed respectively, among which the current loop controller and speed loop controller both adopt PI control; the position loop controller adopts P controller; The input of the position loop controller is the pitch angle / azimuth of the tracked vehicle tube, the output of the position loop controller is used as the input of the speed loop controller, the output of the speed loop controller is used as the input of the current loop controller, the current loop controller outputs a signal to the SVPWM controller, the SVPWM controller controls the speed of the permanent magnet synchronous motor through the inverter, the speed of the permanent magnet synchronous motor is fed back to the pitch angle / azimuth of the tracked vehicle tube, thereby controlling the pitch angle and rotation of the tube to achieve closed-loop control; Step three, establish a mechatronics simulation model of the tracked vehicle, use the tracked vehicle multi-body dynamics model as the interface module of the tracked vehicle dual-channel on-board servo system model, import the tracked vehicle multi-body dynamics model into MATLAB for operation, use the corresponding output variables of the tracked vehicle multi-body dynamics model as the input variables of the tracked vehicle dual-channel on-board servo system model, and feed back the output variables of the tracked vehicle dual-channel on-board servo system model as the input variables of the tracked vehicle multi-body dynamics model. The specific method is as follows: (1) In RecurDyn, create POUT and name it. The angular displacement / angular velocity change of the horizontal azimuth of the body tube of the tracked vehicle multibody dynamics model and the geodetic coordinates is used as the output variable POUT1 / POUT2, and the angular displacement / angular velocity change of the pitch azimuth of the body tube and the geodetic coordinates is used as the output variable POUT3 / POUT4. POUT completes the real-time control of the tracked vehicle dual-channel vehicle servo system model in step 2. (2) In RecurDyn, PINs are established between the vehicle body and the upper platform, and between the upper platform and the barrel. First, the PIN names are defined. Then, the controlled parameters of the tracked vehicle multibody dynamics model, i.e., the relative motion between the vehicle body and the upper platform in the horizontal direction, and the relative motion between the upper platform and the barrel in the pitch direction, are associated with the PINs with the defined names. This enables the tracked vehicle dual-channel onboard servo system model to input control signals to the tracked vehicle multibody dynamics model. (3) After establishing PIN and POUT, the tracked vehicle multi-body dynamics model is imported into the MATLAB software to generate a Simulink submodule, whose corresponding output is used as the input of the position loop controller of the tracked vehicle dual-channel vehicle-mounted servo system model; the output of the servo motor in the tracked vehicle dual-channel vehicle-mounted servo system model is used as the input of the generated Simulink submodule; (4) Based on the vehicle position information and target position information output by the tracked vehicle multi-body dynamics model, the azimuth and pitch angles of the target in the geodetic coordinate system are obtained. The tracked vehicle dual-channel onboard servo system model completes the joint simulation by controlling the pitch motion of the barrel and the upper platform relative to the vehicle body coordinate system.

2. The simulation method of the crawler vehicle servo system considering the torsion axis constraint according to claim 1 is characterized in that: Step 4: Set the parameters of the crawler vehicle multi-body dynamics model, run the crawler vehicle mechatronics simulation model, and simulate the driving conditions of the crawler vehicle under different suspension devices and on different working conditions. The specific method is as follows: The load-bearing wheel is connected to one end of the torsion bar through a revolute pair, and the other end is connected to a fixed pair or a torsion shaft spring. When the torsion bar is connected to the vehicle body through a fixed pair, the torsion shaft is in full stiffness. When the torsion bar is connected to the vehicle body through a torsion shaft spring, different parameters of the torsion shaft spring are modified to simulate different working conditions of the tracked vehicle suspension device, and to realize the analysis of the simulation results of the tracked vehicle under the corresponding working conditions.

3. A simulation system for a tracked vehicle servo system taking into account torsion axis constraints, characterized in that: Implementing the simulation method of the tracked vehicle onboard servo system considering the torsion axis constraint as described in any one of claims 1-2 to realize the simulation of the tracked vehicle onboard servo system, comprising: Dynamic model building module, which builds a multi-body dynamic model of the tracked vehicle for the platform based on RecurDyn; Servo system model building module, which builds a dual-channel vehicle-mounted servo system model for tracked vehicles based on the MATLAB platform; Combined simulation module, establish the mechatronics simulation model of the tracked vehicle, use the tracked vehicle multi-body dynamics model as the interface module of the tracked vehicle dual-channel on-board servo system model, import the tracked vehicle multi-body dynamics model into MATLAB for operation, use the corresponding output variables of the tracked vehicle multi-body dynamics model as the input variables of the tracked vehicle dual-channel on-board servo system model, and feed back the output variables of the tracked vehicle dual-channel on-board servo system model as the input variables of the tracked vehicle multi-body dynamics model; set the tracked vehicle multi-body dynamics model parameters, run the tracked vehicle mechatronics simulation model, and simulate the driving conditions of the tracked vehicle under different suspension devices and on different working conditions.

4. A computer device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein when the processor executes the computer program, the simulation method of a tracked vehicle onboard servo system taking into account torsion axis constraints as described in any one of claims 1 to 2 is implemented to achieve the simulation of the tracked vehicle onboard servo system.

5. A computer-readable storage medium having a computer program stored thereon, wherein when the computer program is executed by a processor, the simulation method of a tracked vehicle onboard servo system considering torsion axis constraints as described in any one of claims 1 to 2 is implemented to achieve the simulation of the tracked vehicle onboard servo system.

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