Force Allocation Control for Redundant-Torso Biomimetic Quadrupeds via Virtual Force and Fully Actuated System Approach
Zhiqin Zhuo, Ke Huang, Zhigang Wu, Jianping Jiang
AI summary
Problem
Applying the Fully Actuated System Approach (FASA) to legged robots is hindered by hybrid actuation and structural redundancy, which violate FASA's full-actuation assumptions and complicate real-time force control.
Approach
VF-FASA introduces virtual forces to satisfy FASA's full-actuation requirements under hybrid contact, then uses a matrix-weighted pseudoinverse optimization to optimally map these virtual inputs to actual joint torques and foot contact forces.
Key results
- A unified VF-FASA framework extending FASA to redundant-torso quadrupeds
- Virtual force construction strategy enabling full-actuation under hybrid actuation
- Matrix-weighted pseudoinverse optimization for efficient force-torque allocation
- Simulation-validated robust trajectory tracking and whole-body coordination
Why it matters
It expands FASA to legged systems, offering a computationally efficient and robust control framework for researchers and engineers developing dynamic, biomimetic quadruped robots.
Abstract
Fully actuated system approach (FASA) provides a promising control framework for robots with redundant actuation, offering simplified controller design and increased design freedom. However, its application to legged robots remains challenging due to hybrid actuation from intermittent ground contact and redundant inputs. To address this, we propose Virtual Force-based FASA (VF-FASA), which introduces virtual forces as intermediaries to construct full-actuation conditions required by FASA. FASA generates virtual control laws based on a simplified torso dynamics model, and a matrix-weighted pseudoinverse optimization is employed to map these virtual inputs into actual torso joint torques and foot contact forces. This method achieves coordinated control of both the floating base and redundant torso, effectively leveraging joint redundancy for improved whole-body motion. Simulation results on a redundant-torso quadruped robot demonstrate robust trajectory tracking and effective whole-body coordination under dynamic locomotion. The framework expands FASA to legged systems, providing an effective approach for controlling quadruped robots.