Energy-Saving Control of DC Motor Speed via Adaptive Fixed-Time Sliding Mode

Abstract

This article presents an adaptive fixed-time sliding mode energy-saving control method for DC motors (DCMs) under parameter uncertainties and load disturbances. A terminal sliding surface is designed to guarantee fixed-time convergence of speed tracking errors independent of initial states. Adaptive laws (ALs) estimate key parameter variations online to enhance robustness. A gradient-descent-based term $u_{energy}=-\lambda u$ is embedded into the control voltage to minimize copper loss $E=\int u^{2}dt$ . Lyapunov analysis proves global fixed-time stability and derives the sufficient condition $\lambda \lt 2K/\| u \|_{max}^{2}$ . Experiments on a DCM system show that, compared with PID and traditional sliding mode control (SMC), the proposed methods reduce convergence time (CT) by 71.93%, tracking error under load disturbances by 69.87%, energy loss by 15.02%, and improve closed-loop bandwidth by 42.5%. The synergistic design achieves high precision, strong robustness, and low energy consumption, offering an effective solution for high-performance motor control.