International Journal of Engineering and Technology

The robots are interacting with humans in various aspects. Safety issues are increased in various robot applications. Many robot arms have been introduced for safety. The passive compliance methods have faster and high reliability than active methods. In this paper, a new safety mechanism based on passive compliance is proposed. The variable stiffness joint employed spring and roller is economical safety joint for robot arm. Also the mechanism works only when the robot arm exerts contact force much more than the human pain tolerance. In order to evaluate the performance of the safety joint, the variable stiffness joint is mounted on robot arm and verified by HIC experiment. It is shown that safety arm using the variable stiffness joint provides higher performance and safe than these using other passive compliance mechanism or active methods.