Modeling and control of a joint driven by pneumatic actuator

Abstract

Recently, research and development has focused on robots that work in place of people. It is necessary for robots to perform the same flexible motions as people. Additionally, such robots need to incorporate high-level safety features in order not to injure people. For creation of such robots, we need to develop a robot hand that functions like a human hand. At the same time, this type of robot hand can be used as an artificial hand. Here, we present artificial muscle-type pneumatic actuators as the driving source of a robot hand that is both safe and flexible. Some development of robot hands using pneumatic actuators has already taken place. However, until now, when a pneumatic actuator is used, a big compressor is needed. Therefore, the driving system also needs to be big, and enlargement of the driving system is a major problem. Consequently, in this research, we develop a low-pressure, low-volume pneumatic actuator for driving a robot hand that works flexibly and safely on the assumption that it will be in contact with people. We develop a five-fingered robot hand with pneumatic actuators. Next, we make a 1-link arm that has one degree of freedom using a pneumatic actuator, and models of the actuator and 1-link arm are constructed. A control PID control system is constructed, and the gains of the PID control system are determined by the simulation that uses the model of the 1-link arm. The step response of the joint angle is examined with the determined gains, and control performance of the PID control system is verified.