Adaptive backstepping control for linear-induction-motor drive using FPGA

An adaptive backstepping controller is proposed to control the mover position of a linear-induction-motor (LIM) drive to compensate the uncertainties including the friction force. First, the dynamic model of an indirect field-oriented LIM drive is derived. Next, a backstepping approach is designed to compensate the uncertainties occurred in the motion-control system. Moreover, the uncertainties are lumped and the upper bound of the lumped uncertainty is necessary in the design of the backstepping controller. However, the upper bound of the lumped uncertainty is difficult to obtain in advance in practical applications. Therefore, an adaptive law is derived to adapt the value of the lumped uncertainty in real time, and an adaptive backstepping control law is resulted. Then, a field-programmable-gate-array (FPGA) chip is adopted to implement the indirect field-oriented mechanism and the developed control algorithms for possible low-cost and high-performance industrial applications. The effectiveness of the proposed control scheme is verified by some experimental results. With the adaptive backstepping controller, the mover position of the FPGA-based LIM drive possesses the advantages of good transient-control performance and robustness to uncertainties in the tracking of periodic reference trajectories.