1. Simultaneous force and stiffness control of a pneumatic actuator
- Author
-
Shen, Xiangrong and Goldfarb, Michael
- Subjects
Pneumatic actuators -- Design and construction ,Servomechanisms -- Design and construction ,Engineering and manufacturing industries ,Science and technology - Abstract
This paper proposes a new approach to the design of a robot actuator with physically variable stiffness. The proposed approach leverages the dynamic characteristics inherent in a pneumatic actuator, which behaves in essence as a series elastic actuator. By replacing the four-way servovalve used to control a typical pneumatic actuator with a pair of three-way valves, the stiffness of the series elastic component can be modulated independently of the actuator output force. Based on this notion, the authors propose a control approach for the simultaneous control of actuator output force and stiffness. Since the chievable output force and stiffness are coupled and configuration-dependent, the authors also present a control law that provides either maximum or minimum actuator output stiffness for a given displacement and desired force output. The general control and maximum/minimum stiffness approaches are experimentally demonstrated and shown to provide high fidelity control of force and stiffness, and additionally shown to provide a factor of 6 dynamic range in stiffness. [DOI: 10.1115/1.2745850]
- Published
- 2007