Research On Trajectory Tracking Control Algorithm For CD Player Arm

The CD player arm system is an industrial control object with multivariable characteristics.The system has two inputs and two outputs.The input is the mechanical joint rotation torque of the arm.It is used to determine the movement track of the arm.The output is the joint position and speed of the arm,which is used to quickly locate the area where the CD needs to read information.Due to the existence of various external disturbances and changes in internal system parameters,the depth of focus changes,the robot arm can not drive the single-beam receiver to track the actual position of the disc surface,resulting in missing information read and write,low reliability,so CD player arm trajectory tracking has important research significance.In this paper,the CD player arm is taken as the research object,and its trajectory tracking control algorithm is systematically studied.The main contents are as follows:1)The research background and significance of CD player arm are described.The research status of the trajectory tracking control algorithm of the robot arm at home and abroad is introduced.The main research contents of this paper are summarized.2)The composition of the CD player system and its working principle are analyzed,and the dynamic structure of the CD player arm is given.The rod point velocity,joint kinetic energy and potential energy of the CD player arm are calculated,the dynamic model of the CD player arm is established according to the Lagrangian method.3)Aiming at the problem of limited actuator torque of CD player arm,a control input limited inversion sliding mode control algorithm is proposed.Firstly,considering the saturation characteristics of the manipulator actuator,linearizing the dynamic equation of the manipulator,establishing a globally stable error dynamic equation,introducing the control input is limited,so that the manipulator control input torque is bounded and the limit is adjustable;Unknown uncertainty,the state space model of the system is given,the virtual control quantity is introduced,and the Lyapunov function is selected by stepwise recursion,combined with the control input constrained design to invert the sliding mode controller.In order to weaken the chattering phenomenon caused by sliding mode control,the sliding surface with steepness is defined,and the switching control law is designed by means of the hyperbolic tangent function in the control input limitation.At the same time,the parameter adaptive law is introduced to estimate the upper bound of uncertainty.Simulation results verify the effectiveness of the algorithm.4)A new robust adaptive iterative learning control algorithm is presented for the trajectory tracking of CD player arm.The CD player system structure is analyzed,the system model is established according to the characteristics of motion of mechanical arm,the trajectory tracking control scheme of mechanical arm is provided,and the robust adaptive iterative learning control algorithm is designed based on the structural characteristics of mechanical arm.The algorithm consists of a variable gain PD controller,a feedforward learning controller and a robust control term.The variable gain PD control flexibly adjusts the control gain to guarantee the stability of the system status according to the gain switching technique,the feedforward learning control calculates the desired feedforward torque at each iterative step by a learning rule to compensate the model uncertainty,the robust control ensures the robustness of the system under external random disturbances.Experiments show that the proposed control algorithm can accelerate the convergence and improve the tracking performance.