Generalizing Torque Control Concepts: Using Well-Established Torque Control Methods on Variable Stiffness Robots

Strict requirements must be met before robotic systems can be implemented in a human environment, for example, as service robots. Robustness, task adaptability, and energy efficiency are key aspects in this regard. Variable stiffness robots have been shown to be one step toward achieving these standards. In this article, we elaborate on the essential control aspects required to operate these robots and generalize well-established torque control methods to a variable stiffness robot, the DLR Hand Arm System (HASy). The adaptation and implementation of several control approaches for the compliant robots are also presented, with a focus on the experimental validation