Generalized Predictive Cross-coupling Position Control Of Biaxial Motion System

Biaxial linkage system is widely used in precision machining CNC machine tools,mechanical arm tracking operation,radar tracking,positioning and other various positioning control field.The rapid development of modern equipment manufacturing industry puts forward higher requirements for the position control precision and control performance of the system.But in the actual work process,track turning,biaxial load imbalance,friction and other factors will lead to the contour error,position tracking effect,which leads to a series of problems,increase the rate of defective products processing machinery,arm track positioning accuracy decline,severe cases may even cause damage to the equipment.Therefore,the research of position tracking control strategy of dual axis linkage system is of great significance to industrial technology and economic development.In the dual axis position control system,when the single axis is disturbed or the turning point is encountered,the output position of the shaft will have a large tracking error,which leads to the large deviation of the position of the double axis from the given trajectory.In order to improve the tracking accuracy,on the one hand,it is necessary to improve the single-axis tracking capability,that is,to improve the single-axis dynamic performance so as to reduce the single-axis tracking error and then reduce the contour error;on the other hand,the coordination between two axes needs to be strengthened,Axes cooperate with each other to speed up the contour error convergence speed and reduce the contour error.In the traditional PID cross coupled position control system,each axis adopts the position-speed-current three closed loop cascade control structure,and the cross coupling controller feedback the contour error to the input of each shaft to compensate the position.The cascade control structure has a slow response speed.When the trajectory turns or suffers disturbance,there are some problems such as large error and slow convergence.Generalized predictive cross coupled robust control is proposed in this paper uses GPC algorithm to model the position loop and the velocity loop of the traditional method as a whole and enhances the uniaxial response speed.At the same time,the cross-coupling is used to feed back the contour error,so the giving trajectory can realize self-correction.The modified control amount can be obtained through online prediction and optimization calculation of generalized prediction algorithm to improve the coordination ability of biaxial.At the same time,when there is load disturbance in the system,the load torque observer can observe and compensate the system load to improve the robustness of the system.The experiment of traditional PID cross-coupling control,GPC control,GPCCC control and with load observer was carried out on the experimental platform of the biaxial linkage system.Finally,the experimental results show that the proposed control strategy not only improves the tracking accuracy,but also improves the dynamic response at the turning point and the load disturbance and reduces the contour error.