Safe robot joint brake based on an elastic latch module

Abstract

Collaborative robots that share work spaces with human workers should be equipped with joint brakes to safely stop the movement in an emergency situation. Currently, the joint brakes that are used in the field have disadvantages of high cost, heavy weight, or inability to handle stop category 0, which is necessary in extreme situations such as power outage. In order to overcome these problems, we developed a joint brake constructed with a solenoid and an elastic latch module using coil springs. The brake is lightweight and low-cost, but it exhibits good braking performance and durability in the emergency involving stop category 0. In this study, we explain the principle and structure of the developed joint brake, select components based on dynamics simulation, and verify braking performance and durability by repetitive emergency stop experiments on applying stop category 0.