Choi, Dongeun Choi, Junho Cho, Changhyun Park, Shinsuk Kang, Sungchul 2024-01-20T12:32:54Z 2024-01-20T12:32:54Z 2022-01-25 2013-04 1598-6446 https://pubs.kist.re.kr/handle/201004/128170 This study presents a robot arm equipped with safe joints and multi DOFs gravity compensators. The safe joint, also referred to as "Spring-clutch", is simple passive mechanism that consist of a spring, a cam, and a joint torque sensor. When the torque applied is lower than a pre-set threshold, the Spring-clutch serves as a rigid joint between the input and output. When the applied torque exceeds the threshold, the Spring-clutch is released and is free to rotate like a revolute joint, which significantly reduces the collision force to avoid damage to the robot, as well as to humans. In addition, a compact joint torque sensor is installed in the Spring-clutch to measure the torque at the joint. Also, the analysis of energy and torque shows that the proposed mechanism can function as a gravity compensator capable of static balancing. Since joint torques vary in accordance with the pose of a manipulator (i.e., rotation angles), a Spring-clutch with a constant threshold torque cannot always guarantee the maximum collision torque in some poses of a manipulator. To overcome this limitation, a gravity compensator is adopted to eliminate the gravitational torque. In this research a bevel gravity compensator is applied which can perform static balancing completely. This paper describes the design principles and fabrication of the safety mechanisms and the robot arm. English INST CONTROL ROBOTICS & SYSTEMS, KOREAN INST ELECTRICAL ENGINEERS A Safe Robot Arm with Safe Joints and Gravity Compensator Article 10.1007/s12555-012-0268-x 1 INTERNATIONAL JOURNAL OF CONTROL AUTOMATION AND SYSTEMS, v.11, no.2, pp.362 - 368 INTERNATIONAL JOURNAL OF CONTROL AUTOMATION AND SYSTEMS 11 2 362 368 N scie scopus kci ART001751710 000316818300016 2-s2.0-84879515544 Automation & Control Systems Automation & Control Systems Article DESIGN Gravity compensator joint torque sensor safe joint mechanism safe robot arm