Modeling And Control Of A Hybrid Drive Mechatronic System

A hybrid drive mechatronic system is a kind of semi-flexible systems,which is driven by two types of different motors: ordinary constant velocity motor and servo motor.These two types of motors are integrated in the hybrid drive mechanism through the end-effector to achieve semi-flexible motion.The hybrid drive system is in the middle of the traditional rigid machines and the modern flexible machines that make up for the rigidity of traditional machines and the costly nature of flexible machines.Therefore,it is of great theoretical and practical values to study these hybrid drive systems.The introduction of the hybrid drive system has more than 20 years,and most studies focus on configuration of mechanisms and analysis of the motion.Due to the velocity fluctuation and the uncontrollability of the constant velocity motor,there is few research on the control of the hybrid drive system.In this thesis,we discuss the five-bar parallel mechanism configuration,mobility and workspace analysis of hybrid drive system.After that,a double-crank five-bar mechanism is designed and a three-dimensional model of the mechanism is established to provide some physical parameters that will facilitate the simulation analysis for the designed control system.Forward kinematics analysis and inverse kinematics analysis are the theoretical basis for studying the dynamics and control system of the five-bar hybrid drive system.In this thesis,the kinematic model of the five-bar mechanism is established by using the closed vector method,and the relationship between the trajectory of the end-effector and the joint input motion is developed.The dynamic model of the five-bar mechanism is deduced by using the Lagrangian equation,and it is written in the form of the dynamic equation similar to a serial robotic manipulator,which is convenient for the design of the controller and the selection of the control parameters.The dynamic model of the motor is analyzed briefly.Combined with the dynamic model of the five-bar mechanism,an integrated dynamic model of the hybrid drive system is established,which lays the foundation for implementing its control.Trajectory tracking accuracy and contour tracking accuracy are very important indicators of the controlled hybrid drive system.In the past,the design of controller for the hybrid drive system without solving the problem of the uncontrollability of the constant velocity motor.In this thesis,the adaptive proportional differential sliding mode control(APD-SMC control)is applied to the trajectory tracking control of the hybrid drive system for the first time,and the trajectory performance of the end effector is improved by compensating the speed fluctuation of the constant velocity motor.The stability analysis of the APD-SMC controller is carried out.The simulation results are compared with the proportional differential sliding mode control and the pure proportional differential control to verify the effectiveness of the APD-SMC.The influences of different control gains and parameters on the controller performance are examined through simulation study,and the control performance under the initial error condition is presented for different trajectories.It is proved that the APD-SMC has excellent trajectory tracking control performance.Finally,the position domain control concept is introduced and applied in contour tracking of the hybrid drive system.In the position domain control,the constant velocity motor is selected as the master motion that does not produce contour error to the contour of the end-effector.We transform the APD-SMC control from time domain into position domain,and the control is used for linear and circular contours in simulation study.The simulation results show that the position domain controller can greatly improve the contour tracking performances of the hybrid drive system,and demonstrate the effectiveness and robustness.