LAUSR

In recent years, human-robot cooperation has enhanced productivity and achieved high payload, speed, and accuracy. Integrating typical industrial robots in human-robot cooperation is challenging because their arms may cause serious injuries to humans during a collision due to malfunction or errors due to robot operators. Therefore, counterbalance robot arms that are capable of counterbalancing the gravitational torques due to the robot mass have been developed to decrease the required capacity of the motors and speeds of these robots. In this research, we propose an advanced counterbalance mechanism using gear units and springs to improve the durability and reliability compared to the previously proposed wire-based counterbalance mechanism, which is difficult to apply to a commercialized product because it can easily be broken or stretched when an excessive force is applied for a long period. Moreover, our proposed method was extended to a multi-DOF system using a parallelogram mechanism based on a timing belt and pulleys to achieve multi-DOF robotic arms. A 2-DOF counterbalanced arm was designed to verify the effectiveness of the proposed mechanism. The simulations and experimental results showed that the proposed mechanism effectively reduced the gravitational torques of each joint of the multi-DOF arm.