Control of Four-Wheel Independent Steering Motors under Sudden Load

This research addresses the issues of permanent - magnet synchronous motor parameter matching and sudden - load compensation in four - wheel independent steering systems and proposes a composite control strategy. By analyzing their dynamic characteristics, it is found that traditional rotational inertia identification methods and existing load observers have deficiencies. The research uses the gradient correction algorithm to construct an online rotational inertia identification model, achieving real - time parameter identification with the characteristics of adjustable parameters and low computational complexity. At the same time, a load observer is designed based on the terminal sliding - mode control theory to solve the problem of observation lag in sudden - load conditions and provide timely compensation. Simulation and experimental results show that after a sudden load is applied, the angle - tracking error of this method is reduced to ±0.12°, the convergence time of rotational inertia identification is shortened by 140 ms, and the response time of sudden - load observation is stable within 50 ms, improving the dynamic response characteristics and control robustness of the system.