Research On Motion Control System Of Wafer Transmission Platform

The integrated circuit is the core of electronic information industry.As the raw material of the integrated circuit manufacturing,the characteristic size of the chip is getting smaller and smaller,while the diameter of each chip is getting larger and larger to save the manufacturing cost.Therefore,the electronic information industry is relying more and more on robots for production.Wafer transfer robot is an equipment used to transfer wafers between process points.Its performance directly affects the production quality and efficiency of integrated circuits.For purpose of boosting the efficiency of wafer transmission,this paper research the means of smooth trajectory planning and active control under the condition of super-speed operation to realize stable and efficient transmission of wafer.The major task is as follows:First,the mechanical structure and the control system of the wafer transfer platform on account of pose adjustment are analyzed,and a wafer transfer platform with pose adjustment is set up.For the purpose of boosting wafer transfer efficiency,the structure of the friction end effector was devised and its rationality was verified.By analyzing the force on the wafer during the horizontal pose and pose adjustment,the equivalent friction coefficient between the microstructure and the wafer,and the maximal acceleration of the wafer transmission and the joint angle of the end effector are acquired.It is theoretically proved that the method of microstructure and pose adjustment can effectively enhance wafer transmission acceleration,which provides a test platform and theoretical basis for subsequent research.Secondly,the dynamic model of the wafer transfer platform was established,and the high-speed even trajectory was planned.According to the movement characteristics of the wafer transfer platform,the Lagrangian method is used to derive the dynamical model of the wafer transfer test platform under the impact of model errors and ambient disturbance.By analyzing the advantages and disadvantages of common linear trajectory planning algorithms,in the light of the requirements of wafer position and pose adjustment transmission platform,the S-type acceleration and deceleration trajectory with position and pose adjustment was designed.The simulation results show that the planned trajectory is smooth and has no sudden changes,and when the stroke is 500 mm,the running time is reduced by 28 ms compared with that without pose adjustment.Then,directing at the nonlinear coupling characteristics of the wafer transmission platform with adjustable pose,the limitations of traditional PD control are analyzed.The system is converted into a simple linear system through the linear feedback decoupling method.Then the disturbance observer is used to compensate the system parameter error and external disturbance in real time.Finally,the integral sliding control is used to ensure the dynamic quality of the trajectory tracking algorithm.This method can minish or eliminate the chattering phenomenon of sliding mode control,give full play to the superiority of sliding mode control,and enhance the robustness of the motion control system.Finally,the consequence of simulation and experimental indicate that the friction microstructure and pose adjustment algorithm can effectively improve the transmission acceleration of the wafer,thus advancing the wafer transmission workpiece ratio.The linearized feedback integral sliding mode control algorithm based on the interference observer can be used in the presence of interference to track the desired motion trajectory and achieve efficient wafer transfer under stable conditions.