Human-friendly soft actuator

A human collaboration system must have qualities such as being safe and easy for humans to use which are not common characteristics of general industrial machinery. To build the human collaboration system, a soft actuator can be effectively used rather than a conventional rigid actuator. A pneumatic actuator seems to have the appropriate qualities to be used as a human-friendly soft actuator. In this review paper, the human-friendliness of pneumatic actuators is discussed by formulating a frequency characteristic of the passivity of the actuator based on a linear dynamic model. Also a fundamental control performance of a parallel link type pneumatic manipulator is investigated to examine its suitability for performing tasks that involve contact with humans. Further, as an example of a human collaboration system, a power assist application of a pneumatic rubber actuator is described.