Iterative Periodic Running Control Through Swept Angle Adjustment with Modified SLIP Model

This paper presents a periodic running control strategy based on a modified Spring-Loaded Inverted Pendulum (SLIP) model to achieve stable running at various velocities. While the traditional SLIP model is valued for its simplicity and intuitive representation of running dynamics, its limitations impede its extension and integration with feedback control systems. To address this, we introduce a novel Quasi-Linearized SLIP model (QLSLIP) that incorporates additional forces in the radial and angular directions to enable stable running across various velocities. This model simplifies the analytical representation of the stance phase and defines the required swept angle for maintaining periodic motion during the flight phase. Using this model, we develop a feedback control system that ensures the stability of QLSLIP-based periodic locomotion, even in the presence of external disturbances. This control framework optimizes trajectories and sustains periodic motion in real-time across diverse scenarios. Additionally, we propose an algorithm to extend this approach to articulated leg mechanisms. The effectiveness of the proposed algorithm is validated through simulations under various conditions, demonstrating improvements in the stability and performance of running.