Approximate Simulation for Template-Based Whole-Body Control
This work addresses robustness issues in controlling high degree-of-freedom legged robots, which is crucial for applications in robotics and automation, though it appears incremental as it builds on existing template-based control frameworks.
The paper tackled the problem of robustness in template-based whole-body control for legged robots by proposing a method grounded in approximate simulation, exploiting Hamiltonian structure, resulting in a passive controller that is more robust to disturbances, uneven terrain, and modeling errors compared to standard methods, with simulation experiments on a 30 degree-of-freedom humanoid model.
Reduced-order template models are widely used to control high degree-of-freedom legged robots, but existing methods for template-based whole-body control rely heavily on heuristics and often suffer from robustness issues. In this letter, we propose a template-based whole-body control method grounded in the formal framework of approximate simulation. Our central contribution is to demonstrate how the Hamiltonian structure of rigid-body dynamics can be exploited to establish approximate simulation for a high-dimensional nonlinear system. The resulting controller is passive, more robust to push disturbances, uneven terrain, and modeling errors than standard QP-based methods, and naturally enables high center of mass walking. Our theoretical results are supported by simulation experiments with a 30 degree-of-freedom Valkyrie humanoid model.