Robust Footstep Planning and LQR Control for Dynamic Quadrupedal Locomotion
This work addresses robustness challenges in dynamic locomotion for quadrupedal robots, representing an incremental improvement with specific applications in robotics.
The paper tackled the problem of improving robustness in dynamic quadrupedal locomotion by developing a fast model predictive foothold planning and LQR-based control framework, achieving effective performance on the ANYmal robot under external disturbances and uncertainties.
In this paper, we aim to improve the robustness of dynamic quadrupedal locomotion through two aspects: 1) fast model predictive foothold planning, and 2) applying LQR to projected inverse dynamic control for robust motion tracking. In our proposed planning and control framework, foothold plans are updated at 400 Hz considering the current robot state and an LQR controller generates optimal feedback gains for motion tracking. The LQR optimal gain matrix with non-zero off-diagonal elements leverages the coupling of dynamics to compensate for system underactuation. Meanwhile, the projected inverse dynamic control complements the LQR to satisfy inequality constraints. In addition to these contributions, we show robustness of our control framework to unmodeled adaptive feet. Experiments on the quadruped ANYmal demonstrate the effectiveness of the proposed method for robust dynamic locomotion given external disturbances and environmental uncertainties.