To address the degradation in path tracking accuracy caused by conflicts between speed maintenance and turning capability in differential-drive robots operating in complex environments, a combined control strategy integrating active speed adjustment and adaptive-preview Linear Model Predictive Control (AP-LMPC) is proposed. Based on the kinematic model of the robot, a coupling constraint equation between path curvature and feasible longitudinal velocity is first derived, and an active speed adjustment strategy tailored to curvature features is designed. Then, a mapping between driving speed and optimal preview distance is constructed to enable the adaptive-preview mechanism. These components are integrated into an AP-LMPC-based control system to enable adaptive path tracking with active speed regulation. Experimental results demonstrate that the proposed strategy can significantly reduce displacement and heading errors. Specifically, the peak displacement and heading errors are maintained within 0.05 m and 0.09 rad under complex S-shaped and double-lane-change trajectories. Compared with fixed-preview LMPC (FP-LMPC) and nonlinear MPC (NMPC), the displacement error is reduced by over 68% and 48%, respectively.

differential-drive robot, path tracking, linear model predictive control (LMPC), active speed adjustment; adaptive-preview