Integration of Dual-Arm Manipulation in a Passivity Based Whole-Body Controller for Torque-Controlled Humanoid Robots

This work presents an extension of balance control for torque-controlled humanoid robots. Within a non-strict task hierarchy, the controller allows the robot to use the feet end-effectors to balance, while the remaining hand end-effectors can be used to perform Dual-Arm manipulation. The controller generates a passive and compliance behaviour to regulate the location of the centre of mass (CoM), the orientation of the hip and the poses of each end-effector assigned to the task of interaction (in this case bi-manipulation). Then, an appropriate wrench (force and torque) is applied to each of the end-effectors employed for the task to achieve this purpose. Now, in this new controller, the essential requirement focuses on the fact that the desired wrench in the CoM is computed through the sum of the balancing and bi-manipulation wrenches. The bi-manipulation wrenches are obtained through a new dynamic model that allows executing tasks of approaching the grip and manipulation of large objects compliantly. On the other hand, the feedback controller has been maintained but in combination with a bi-manipulation-oriented feedforward control to improve the performance in the object trajectory tracking. This controller is tested in different experiments with the robot TORO.