Design and Control of a Waterproof Robot Arm Applying the Gravity Compensator

This study is about the design and control of waterproof 4-axis robot arm that allows underwater operation. To enhance the load capacity of the robot arm, a module-type gravity compensator (GC) is designed and applied to each joint. The dynamic equation of the robot arm was set up and analyzed by including frictional force of waterproof apparatus and compensating force of the GC. A SMC was designed and its performance was tested through simulation to track a target trajectory despite disturbance such as friction in joints.