Air Muscle Controller Design in the Distributed Macro-Mini (DM²) Actuation Approach

Abstract

Recently, on the base of Distributed Macro-Mini Actuation approach (DM 2 ), a new robotic manipulator with hybrid actuation, air muscles-DC motor, has been developed. Among existing actuators, the hybrid actuation employs air muscles because they represent an advantageous tradeoff of performance and safety, due to their power/weight ratio and inherent compliance. The air muscles, however, are limited in bandwidth and their behavior is highly nonlinear. In order to overcome these limitations, the paper presents a torque control strategy based on a pair of differentially connected force-controlled air muscles. This controller was implemented and evaluated on a single joint testbed, first by itself and then as macro component into the Macro-Mini control strategy.

On the Design of Human-Safe Robot Manipulators

“…In practice, this technique seems difficult to implement because it adds complexity to the manipulator's design, especially by doubling the number of required actuators. Recent developments Sardellitti et al (2007) use two antagonistic pneumatic muscles as the macro actuator.…”

“…to detect a collision by monitoring joint torques or a robot skin and quickly react to maintain the contact forces under a certain levelDe Luca et al (2006); 3. to design robots that are intrinsically safe, i.e., that are physically unable to hurt a personChoi et al (2008); Kim et al (2007); Park et al (2009;; Sardellitti et al (2007); Tonietti et al (2005); Zinn, Khatib & Roth (2004).…”

Design and Control of a Bio-inspired Human-friendly Robot

“…8 (a) [20]. When a desired torque is to be produced for the joint, the necessary force difference is symmetrically distributed between the two antagonistic muscles and controlled by force feedback through load cell measurements as shown in Fig.…”

“…11 (a). The force feedback compensates for the pneumatic muscle force/displacement hysteresis phenomenon while also increasing the actuation bandwidth [20]. In order to design the controller, system identification was first conducted to identify the dynamic behavior of the pneumatic muscles and proportional valves.…”

Robot-Environment Interaction Control of a Flexible Joint Light Weight Robot Manipulator

“…One is the so-called passive compliance, in which the end-effector position is accommodated by the contact forces automatically, due to the compliance inherent in the manipulator, such as elasticity in the robot arm, joints and end-effectors [2], flexible rod [3] and mechanical damping adjuster, etc. [4].…”