VARIABLE STIFF REVOLUTE JOINT FOR COMPLIANT ROBOT

Over the past decades industrial robot manipulators have expanded throughout the automation landscape with their high degree of repeatability and accuracy. For safety reasons these robots are not allowed to share their workspace along with humans, which limits the various tasks that can be performed by a human-robot collaboration. To circumvent this limitation, a new kind of variable stiffness series elastic actuator is proposed as a joint actuator. This variable stiffness series elastic actuator has an ability to servo-control its joint stiffness, and provide a measure of the instantaneous joint torque. Soft joint intrinsically enhances safety by providing compliance in the event of an impact. These unique abilities play a crucial role in an intelligent robot control design that can scale down the risk factors in a field where humans and robots collaborate. This article presents the design of variable stiffness series elastic actuator, mathematical modeling, and calibration of the variable stiffness series elastic actuator.