Imposition of Kinematic Constraints for Robotic Stability and Support
We consider a constrained robotic system with constraints which may be imposed or removed under control. It is desired to control the robot to withstand disturbances and to preserve contact forces with the environment. The main idea of this paper is to show that we can achieve this goal by imposing additional kinematic constraints. We demonstrate the feasibility of such an approach for postural adjustments of biped robots by proposing two control designs.The first controller is defined so that robot stability is guaranteed. In the second design, the controller simultaneously stabilizes the robot and imposes an additional kinematic constraint. The controller is equipped with an additional input whose sole purpose is to maintain the kinematic constraint, i.e to ensure that the center of gravity of the biped robot remains above the base of support when the biped is disturbed from its equilibrium posture. Digital simulations are conducted with both controllers when the biped is disturbed from equilibrium and show the effectiveness of the proposed control.
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