A Balance-Force Controller for a Legged Robot with Multiple Flexible-Contacts

International audienceIn this paper, we propose a controller for multi-contact legged robots that takes into account the contact compliance. This controller is able to achieve both balance stabilization and force control in the same loop in task space thanks to the use of an explicit contact flexibility model and simplified centroidal dynamics that allow exploiting the redundancy of the kinematic and force feedback. The control problem is formulated as an LQR based on a linearized model of the reduced non-linear model. The performance of the controller with regard to robustness to modeling error and externalperturbations has been tested in simulation, and compared to a stabilizer based on the zero-moment-point feedback within a control that generates the desired contact forces with the environment