Whole-Body Walking Generation using Contact Parametrization: A Non-Linear Trajectory Optimization Approach
This addresses the problem of automating walking motion generation for humanoid robots, which is incremental as it builds on existing trajectory optimization methods.
The paper tackles generating walking trajectories for humanoid robots by modeling robot-ground interaction with a novel contact parametrization, solving an optimal control problem to achieve walking motions automatically with minimal references like a constant desired Center of Mass velocity.
In this paper, we describe a planner capable of generating walking trajectories by using the centroidal dynamics and the full kinematics of a humanoid robot model. The interaction between the robot and the walking surface is modeled explicitly through a novel contact parametrization. The approach is complementarity-free and does not need a predefined contact sequence. By solving an optimal control problem we obtain walking trajectories. In particular, through a set of constraints and dynamic equations, we model the robot in contact with the ground. We describe the objective the robot needs to achieve with a set of tasks. The whole optimal control problem is transcribed into an optimization problem via a Direct Multiple Shooting approach and solved with an off-the-shelf solver. We show that it is possible to achieve walking motions automatically by specifying a minimal set of references, such as a constant desired Center of Mass velocity and a reference point on the ground.