Optimization-free Ground Contact Force Constraint Satisfaction in Quadrupedal Locomotion
This addresses the need for less expensive, optimization-free control in legged systems, though it appears incremental as it builds on existing supervisory control methods.
The paper tackled the problem of enforcing ground contact force constraints in quadrupedal robots without costly optimization algorithms, achieving a faster computation approach using an Explicit Reference Governor and Lyapunov stability.
We are seeking control design paradigms for legged systems that allow bypassing costly algorithms that depend on heavy on-board computers widely used in these systems and yet being able to match what they can do by using less expensive optimization-free frameworks. In this work, we present our preliminary results in modeling and control design of a quadrupedal robot called \textit{Husky Carbon}, which under development at Northeastern University (NU) in Boston. In our approach, we utilized a supervisory controller and an Explicit Reference Governor (ERG) to enforce ground reaction force constraints. These constraints are usually enforced using costly optimizations. However, in this work, the ERG manipulates the state references applied to the supervisory controller to enforce the ground contact constraints through an updated law based on Lyapunov stability arguments. As a result, the approach is much faster to compute than the widely used optimization-based methods.