Deadbeat Adaptive Backstepping Design for Tracking Transfer Case Torque and Estimating its Clutch Touchpoint

This research applies the discrete-time adaptive backstepping control scheme to a transfer case clutch actuation system for tracking the reference clutch torque and estimating the clutch touchpoint simultaneously. Note that due to the clutch wear and temperature variation, the transfer case clutch touchpoint is typically unknown and needs to be estimated. Instead of using a seperated algorithm for estimating the touchpoint, the proposed approach utilizes one control scheme for tracking the reference torque and estimating the varying touchpoint at the same time. The deadbeat control law is designed based on a systematic non-Lyapunov-Function-based backstepping control scheme, and the stability of the closed-loop system are guaranteed, where all the closed-loop states are bounded. In addition, due to the deadbeat design, the tracking and estimation convergence rates are quite fast, and as a result, the closed-loop system performance is robust to the external disturbance. The proposed method is validated through simulation study.