TY - GEN
T1 - Safe joint mechanism using inclined link with springs for collision safety and positioning accuracy of a robot arm
AU - Park, Jung Jun
AU - Song, Jae Bok
PY - 2010
Y1 - 2010
N2 - In recent years, the potential for collision between humans and robots has drawn much attention since service robots are increasingly being used in the human environment. A safe robot arm can be achieved using either an active or passive compliance method. A passive compliance system composed of purely mechanical elements often provides faster and more reliable responses to dynamic collision than an active system involving sensors and actuators. Since positioning accuracy and collision safety of a robot arm are equally important, a robot arm should have very low stiffness when subjected to a collision force capable of causing human injury. Otherwise, it should maintain a very high stiffness. To implement these requirements, a novel safe joint mechanism (SJM-III) consisting of an inclined link, a slider with rollers, and linear springs is proposed. The SJM-III has the advantage of nonlinear stiffness, which can be achieved only with passive mechanical elements. Various analyses and experiments on static and dynamic collisions show high stiffness of the SJM-III against an external torque less than a predetermined threshold torque, with an abrupt drop in stiffness when the external torque exceeds this threshold. The safe joint mechanism enables a robot manipulator to guarantee positioning accuracy and collision safety, and which is simple to install between an actuator and a robot link without a significant change in the robot's design.
AB - In recent years, the potential for collision between humans and robots has drawn much attention since service robots are increasingly being used in the human environment. A safe robot arm can be achieved using either an active or passive compliance method. A passive compliance system composed of purely mechanical elements often provides faster and more reliable responses to dynamic collision than an active system involving sensors and actuators. Since positioning accuracy and collision safety of a robot arm are equally important, a robot arm should have very low stiffness when subjected to a collision force capable of causing human injury. Otherwise, it should maintain a very high stiffness. To implement these requirements, a novel safe joint mechanism (SJM-III) consisting of an inclined link, a slider with rollers, and linear springs is proposed. The SJM-III has the advantage of nonlinear stiffness, which can be achieved only with passive mechanical elements. Various analyses and experiments on static and dynamic collisions show high stiffness of the SJM-III against an external torque less than a predetermined threshold torque, with an abrupt drop in stiffness when the external torque exceeds this threshold. The safe joint mechanism enables a robot manipulator to guarantee positioning accuracy and collision safety, and which is simple to install between an actuator and a robot link without a significant change in the robot's design.
UR - http://www.scopus.com/inward/record.url?scp=77955834373&partnerID=8YFLogxK
U2 - 10.1109/ROBOT.2010.5509492
DO - 10.1109/ROBOT.2010.5509492
M3 - Conference contribution
AN - SCOPUS:77955834373
SN - 9781424450381
T3 - Proceedings - IEEE International Conference on Robotics and Automation
SP - 813
EP - 818
BT - 2010 IEEE International Conference on Robotics and Automation, ICRA 2010
T2 - 2010 IEEE International Conference on Robotics and Automation, ICRA 2010
Y2 - 3 May 2010 through 7 May 2010
ER -