Research On Multi-Axis Synchronous Control Technology Based On Adjacent Cross-Coupling

Since multi-axis synchronous driving of CNC machine tools can significantly improve the efficiency and precision of machining,it is widely used in industrial fields such as highpower and large-span double-drive machine tools and high-precision electronic machining.However,in practical application,problems such as large field noise,unbalanced load disturbance and difficult parameter setting can cause multi-axis synchronization error,thereby affecting the quality of processing,the safety and reliability of machine tools,etc.To solve the above problems,a multi-axis synchronous control method based on adjacent cross coupling is proposed.Based on the three-loop control model of the single axis,the mathematical model of the multi-axis system is studied.And the influencing factors of multi-axis synchronization precision are analyzed.Combined with the multi-axis model and the influence factors,an overall scheme of multi-axis synchronization control based on adjacent cross coupling is proposed.Furthermore,the key technologies mentioned in the scheme are analyzed.Aiming at the problems of low precision and large delay of signal obtained by difference calculation in multi-axis system,a signal observer based on LESO is designed to observe the feedback speed and command acceleration,which can effectively balance the precision and the delay of signal.Therefore,multi-axis synchronous control is provided with accurate signals.The feedback speed signal and command acceleration signal obtained from observation are respectively used in feedforward control,feedback control and synchronous control,to improve the following accuracy and synchronization accuracy of the multi-axis system.In order to solve the problems of slow response and poor performance of dynamic adjustment in the traditional multi-axis synchronous strategy,a two-stage synchronous structure based on coarse and fine tuning and dynamic synchronous compensation coefficient are introduced.Based on this,a multi-axis synchronization control strategy based on improved adjacent cross-coupling is proposed to realize the fast compensation and high precision adjustment of synchronization errors.In addition,a simulation model of the multiaxis synchronous system is established in Simulink,for the verification of the proposed method.In order to solve the problem that the traditional PID cannot adjust the parameters dynamically and in real time,the neural network algorithm is introduced into the multi-axis synchronous control.And a single neuron PID with parameter self-tuning function is designed as a multi-axis synchronization controller.In addition,an adaptive adjustment rule is designed to dynamically adjust the gain K of the single neuron PID,which solves the problem that the synchronous control effect of traditional PID is not satisfactory in the timevarying and nonlinear system.An experiment platform for four-axis synchronization control is built to verify the proposed multi-axis synchronization technology based on the improved adjacent crosscoupling.Then the experiments including signal observation and following control,multiaxis speed synchronization and multi-axis position synchronization are designed and completed.The experimental results show that the maximum synchronization error is reduced by about 60% for multi-axis speed synchronization,and by about 70% for multiaxis position synchronization,which verify the effectiveness of the proposed multi-axis synchronization method.