| Desktop robot, because of its high degree of maneuverability and advantages of flexibility and adaptability, is widely used in solder, cutting, assembly, and other fields. In these areas tendeding to the development of intelligent, high refinement, robot position control precision is also put forward higher requirements, and desktop robot position between each axis synchronization control is key to improve the control precision.In order to improve the control precision of the position control of the desktop robot, the synchronization technology is introduced into the control of the desktop robot.Based on the desktop robot synchronous control technology as the starting point, on the basis of consulting foreign and domestic literature, the desktop robot position synchronous control algorithm was thoroughly studied. By analyzing the performance index for desktop robot position synchronization control, the position synchronization control structure is improved, and the position synchronization control algorithm is designed and optimized.In the design of the feedback loop, in view of the problem that the inter-axis error cannot be effectively compensated when gain constant is too large or too small in the process of traditional cross coupling control, a synchronization control algorithm for sliding mode based on integral separation PID is proposed to reduce the overshoot of control process and eliminate the static error.In the design of the control structure, after analysis of the control characteristics of the commonly used synchronous control structure, aiming at meeting the precision requirement which cannot be lived up to by parallel structure, master-slave structure, cross coupling structure, adjacent cross coupling structure or deviation coupling structure due to their week coupling relationship, the deviation coupling structure is employed to be improved. The coupling error is redefined as the average value obtained by adding the errors of each shaft, and this modification not only realizes the linear definition of the coupling error and also includes the position error and synchronization error within, strengthening the inter-axis coupling connection, simplifying the control law design, and enhancing the efficiency of operation.In control loop algorithm design, for tackling the control complexity and taking account of the time-variable and strong coupling characteristics of the desktop robot, an algorithm based on inversion of control is proposed. The controlled object is handled by order-reduction and decomposed into several subsystems, and respectively for each subsystem a virtual control expression and Lyapunov function are tried, until the whole system achieves stability conditions. And then, the virtual control expression of the last subsystem is taken as the switching function for sliding mode control, realizing the convergence along the designed sliding surface. Also adding the fuzzy control theory into sliding mode control, the method weakens the chattering in sliding mode, ensuring the robustness and anti-interference of the designed algorithm.Finally, a simulation model is built on the MATLAB software platform, with a written m-function, and is verified respectively under the conditions with low speed reference signals and load mutation. At the same time, a comparison with the representative sliding mode synchronization algorithms is made. The experimental results show that the designed algorithm is of rationality and validity, and greatly reduces the convergence time and improves the synchronization performance of the system. |
PDF Full Text Request