Dynamic Torque Control Incorporating Tracking Differentiator for Motor-Driven Load Simulator

Widely used in the static/dynamic stiffness test of aircraft actuation systems, Motor-driven load simulator (MDLS) simulates the aerodynamic load and exerts the load on actuation system. MDLS endures position coupling disturbance from active motion of actuation system, and this inherent disturbance is called extra torque. However, to eliminate the influence of extra torque is the key issue regarding to the MDLS controller design, as the extra torque may degrade the performance of MDLS seriously. A compound torque control algorithm based on tracking differentiator (TD) is proposed for MDLS in this paper. This algorithm reflects the essential characteristics of MDLS and guarantees transient tracking performance as well as final tracking accuracy. In detail, firstly, the mathematical models of MDLS are derived, and the influence of the extra torque is also studied. Tracking differential filter is then utilized to identify the actuator’s velocity, acceleration and jerk, which can compensate the extra torque. Finally, based on the structural invariability theory, a compound controller is developed, which consists of forward path corrector, feed-forward controller and differential tracking filter. Simulation and experiment comparative results are obtained to verify the high-performance nature of the proposed control strategy; the tracking accuracy and bandwidth are greatly improved.