This paper addresses speed control of permanent magnet synchronous motor under load torque perturbations. The mathematical model is derived using park’s transformation. The load torque disturbance is considered unknown bounded, and states variables are available in feedback. In order to achieve robust speed performance, sliding mode control (SMC) is introduced. However, it is noted that conventional SMC does not provide satisfactory performance under load torque disturbances. To end this, a novel control strategy called disturbance observer SMC (DOSMC) is formulated. It includes an observer that offers a tool to vanish the effect of load torque. The DOSMC technique has two distinguished characteristics: first, the design gains are needed to be greater than the maximum limit of disturbance estimation error instead of disturbances, second; the proposed observer estimates load disturbances and provide a compensator to update sliding surface and control input. The stability analysis of overall control system is verified using Lyapunov theorem. Simulations in MATLAB/Simulink proves efficacy of the proposed scheme.

Disturbance Observer Based Robust Sliding Mode Control of Permanent Magnet Synchronous Motor

Adaptive Backstepping Control for Mecanum‐Wheeled Omnidirectional Vehicle Using Neural Networks

To enhance the system damping,a permanent magnet set which served as an eddy current damper was added to the magnetic levitation positioning stage which consists of a moving table,four Halbach permanent magnetic arrays,four stators and displacement sensors.The dynamics model of this stage was a complex nonlinear,strong coupling system which made the control strategy to be a focus research.The nonlinear controller of the system was proposed based on the theory of differential geometry.Both simulation and experimental results show that either the decoupling control of the movement can be realized in horizontal and vertical directions,and the control performance was improved by the damper,verifying the validity and efficiency of this method.

Control of magnetic levitation positioning stage with an eddy current damper

A rigid-flexible coupling positioning stage (RFCPS) is proposed in this study for long-stoke-high-precision (LSHP) positioning, and its dynamic model is established. The structure of the RFCPS contains three parts: the working stage, the frame and the flexure hinge group. The flexure hinges can provide micro deformation to compensate the positioning error cause by the friction of the mechanical bearing. In order to consider the deformation of the flexure hinges, the flexible multi-body system dynamic analysis method is adopted to establish the dynamic model of the RFCPS. The investigation of the principle model demonstrates that the floating frame of reference formulation (FFRF) has higher accuracy than the absolute nodal coordinate formulation (ANCF) for the deformation analysis of the RFCPS. Sequentially, a finite element based model (FE model) is established by using the FFRF. Numerical simulation results shown that the results of the FE model is consistent to the analytical solution, and the deformation of the flexure hinges is effectively obtained. The establishment of the dynamic model lays the foundation for structural optimization and control system design of the RFCPS.

Shuyuan Ma

Papers

Fuzzy sliding mode control based on PSO for magnetic levitation positioning stage