Non-Overshooting Force Control of Series Elastic Actuators
Whenever mechanical devices are used to interact with the environment, accurate control of the forces occurring at the interaction surfaces arises as an important challenge. Traditionally, force controlled systems utilize stiff force sensors in the feedback loop to measure and regulate the interaction forces. Series elastic actuation (SEA) is an alternative approach to force control, in which the deflection of a compliant element (orders of magnitude less stiff than a typical force sensor) placed between motor and the environment is controlled to regulate the interaction forces. The use of SEAs for force control is advantageous, since this approach possesses inherent robustness without the need for high-precision force sensors/actuators and allows for the accurate control of the force exerted by the actuator through position control of the deflection of a compliant coupling element. Here, a non-overshooting force controller is proposed to be embedded into the control structure of SEAs. Such controller architecture ensures safe operations of SAEs by making sure that the force applied to the environment are always bounded from above by the reference forces commanded to the controller.
Cornel Brișan, Vistrian Mătieș, Sergiu-Dan Stan and Stelian Brad
O. Tokatli and V. Patoglu, "Non-Overshooting Force Control of Series Elastic Actuators", Solid State Phenomena, Vols. 166-167, pp. 421-426, 2010