High-Precision Synchronous Control Technology For Multi-Axis Systems

Since motion precision of mechanical systems directly affects production efficiency and product quality, the high-precision control of mechanical system has been one of hot issue for control theory and application. In order to improve the control quality of multi-axis systems, we should consider not only a single axis motion accuracy, but also the coordination performance between each axis. However, in most traditional controllers for multi-axis systems, the control loop of the actuator does not receive information from other actuators. The lack of synchronization amongst control loops degrades the overall motion performance. Furthermore, the lack of synchronization may result in large unwanted interaction forces amongst each other and hence, in excessive wear of the actuators and mechanical components. The synchronization technique provides an opportunity to solve the synchronization problem of multi-axis systems. Application of the synchronization control technique to the high-performance controller design of robot multi-axis systems is important for both theoretical analysis and practical implementation. Multi-axis synchronization control technology is not only the key technology to reduce the synchronization error and guarantee the machining accuracy, but also an important development direction of the current mechanical design and manufacturing technology.This thesis presents several effective synchronization control algorithms for high-precision synchronous control of multi-axis systems.For the problem of position control, to ensure the accuracy of the premise control and taking into account the real-time engineering practice affected by gravity, combined to make the designed controller simple and feasible in engineering practice, we propose a NPID position synchronization control method. Lyapunov direct method and La Salle invariance principle are used to prove the global asymptotic stability of the closed-loop system.For the problem of trajectory tracking control, taking into account the mathematical model uncertainties, an adaptive synchronization tracking control algorithm is proposed. Barbalat lemma is employed to prove that the control method can implement globally asymptotically stable synchronous tracking; Finally, taking into account the multi-axis system is disturbed, combined the sliding mode control technology and synchronous control technology, we propose sliding mode dispersion NPD synchronous tracking control method. Global asymptotic stability is proven following Lyapunov direct method and La Salle invariance principle.Numerical simulations indicate that the above control algorithms can ensure theprecision of synchronization control and achieve the high-precision synchronizationcontrol of multi-axis systems.