The variable stiffness actuators are devices that change the position
and stiffness of a robot simultaneously. In recent years have been
designed and developed many devices of this type, hoping to ensure
safety in human-robot interaction and improve the dynamic performance of
robots. In this article, we present the control of a variable stiffness
actuator with serial configuration. The control strategy is based on
feedback linearization and adjustment of two linear controllers. This
allows the control, independently, of the stiffness and the equilibrium
position of the joint. Finally, the behavior of this device within the
assistive robot ASIBOT, is simulated in order to assess: the controller
performance, changes in the dynamics of the robot and possible
advantages of a level of safety during physical interaction human-robot.