Development of a safe manipulator using spring-clutches

For physical safety of a service robot, various safe mechanisms have been studied and developed. Most researches on safety concentrated on safe joint component, and experimental results in situations that the safety component is well-functioned in 1 joint level. In cases of multi-axis, however, there exist many constraints when the safe component is mounted to the multi-axis manipulator, for example, the weight and/or volume of the component, the degradation of the safety performance due to the influence of the gravity as the pose of manipulator. So, it is realistically difficult to develop the manipulator with the safety component. This paper presents a safe manipulator with safety component at each joint to overcome practical limitations. Through experiments of unconstrained and constrained collision, it is shown that a new safe manipulator is mechanically safe.