Safe joint mechanism using passive compliance method for collision safety

In this paper, the design and implementation of a novel passive safe joint is reported. This safe joint is designed for applications, such as an air hockey playing robot playing against a human, in which the force applied by the linkage should be kept below a certain threshold. The proposed mechanism benefits from the compliance of two ramps controlled by the nonlinear behavior of a spring. The passivity of the design, the small footprint, the low cost of production, and the ability to rotate 360 degrees are the main advantages of this design. The mechanism has been designed, evaluated, implemented and tested showing its effectiveness. Finally it has been incorporated in an air hockey robot showing its capability in action.