Performance Evaluation of a Class of Gravity-Compensated Gear-Spring Planar Articulated Manipulators

This paper is devoted to evaluating the gravity compensation performance of a special class of planar articulated manipulators that are gravity balanced by using a series of gear-spring modules. First, the studied manipulators with one, two, and three DOFs are revisited. Then, the gravity compensation performance of these manipulators is determined via a peak-to-peak torque reduction criterion. As the manipulators were designed via two different approaches, i.e., the ideal balancing approximation and the realistic optimization, the gravity compensation performance of these two approaches is compared. It shows that the perfect balancing approximation can achieve a satisfied performance as nearly same as that of the optimization approach, while it, on the other hand, enjoys a significant reduction of the computational effort for gravity compensation design.