Parallel Robot MIMO Adaptive Control System Based On Road Simulation Test

In recent years,with the booming of the automotive industry,accompanied by the increasingly fierce competition in the industry,Automakers are beginning to care about two issues:first,to improve the quality of automotive products,and second,to reduce product development costs.As an indispensable part of the automobile quality inspection process,the automobile road simulation test has received extensive attention.At present,in the selection of indoor road simulation test methods,RPC(Remote Parameter Control)method is mostly adopted at home and abroad.In the road simulation test,the RPC method is based on identifying the frequency response function matrix of the system,and the actual response of the system is approximated to the expected response by repeated iterations in the frequency domain.In the process of its application,people found many problems:1.Before the start of the test,it took a lot of time to complete the iterative operation to approximate the reference signal;2.During the test,the control output signal and the response signal of the vibration platform do not form closed-loop control,which cannot guarantee the control accuracy of the system;3.The local error in different frequencies cannot be corrected,and the local control accuracy is not high.In this paper,a new method is proposed for the limitation of RPC technology.The adaptive control method with unknown model parameters is applied to the control of road simulation test system,and the MIMO(Multiple-Input Multiple-Output)nonlinear control strategy is studied.When the state of the controlled test platform changes during the test,the system can automatically identify the online,and calculate the control parameters in real time through closed-loop feedback,Therefore,the real-time high-precision control requirements of the suspension parallel test system are realized,at the same time,the test accuracy of the actual road working condition test is improved.The main research work of this paper is as follows:(1)Aiming at the limitations of RPC technology,a MIMO adaptive control algorithm is designed.By using closed-loop feedback on the controlled test platform,the control parameters of the system can be calculated online in real time to improve the control accuracy.The MIMO adaptive control system includes a controlled object model,a model parameter identification module,and a controller parameter configuration module.The controlled object model uses a stochastic nonlinear multi-input multi-output model;The model parameter identification module adopts the recursive least squares method,its purpose is to estimate the process control parameters of the controlled object online through the input and output signals of the controlled object model;The controller parameter configuration module adopts a pole placement strategy,its purpose is to dynamically improve the control gain of the controller by dynamically modifying the control gain(Gain)parameters of the controller.(The error less than 5%).(2)The model of MIMO adaptive control system is constructed.The analog road spectrum signal generator module,the controller module and the parallel robot test platform model of the controlled object are built to simulate the industrial control scene.Three different control modes of proportional control,PID control and MIMO adaptive control are designed.The simulation results of Simulink in the mode verify that the control precision of MIMO adaptive control algorithm is high and the control effect is stable(The error is only 1.05%).(3)The software and hardware design of the MIMO adaptive control system is completed.According to the design requirements,the core processor selects the STM32F103VET6 chip,the data acquisition module selects the AD7606 chip,the digital-to-analog conversion module selects the LTC2666 chip,and the communication module designs the RS232,RS485 and CAN communication modes.The schematic design,PCB design and board work are carried out,and the software design of control algorithm,data acquisition and serial communication is completed,and the simple and clear upper computer software is written.(4)The system debugging work in the indoor road simulation test environment are performed.The debugging process of MIMO adaptive control system is introduced,and the test results are analyzed.The control precision of MIMO adaptive control system meets the requirements of real-time high precision of suspension parallel test system(The error is 4.51%).