Elastic energy aggregation and distribution method in load compensation mechanism using linear spring

Abstract

The purpose of this study is to propose a method for deriving a structure that uniquely determines the elastic energy stored in the linear spring used in Mechanical Gravity Canceller (MGC) considering the value of the gravitational potential to be compensated. The conventional multi-DOF MGC has a structure in which each link is compensated individually, and when the gravitational potential to be compensated changes, the elastic energy stored in the multiple linear springs have to be adjusted. Therefore, there is a practical difficulty in adjusting the elastic energy when the multi-DOF MGC is applied to load compensation. In order to solve this problem, an articulated compensation method is discussed, focussing on the total amount of elastic energy required for compensation depends on the gravitational potential of the compensation target. In this method, the elastic energy required for compensation is stored in one linear spring and the appropriate amount of the energy is transferred to each link. First, MGC is tried describing from the view of potential energy. Then, the constraint conditions are derived when there is only one linear spring used for gravity compensation, and Triangular Displacement Adjuster (TDA) is designed as an example of the mechanism to satisfy these conditions. Finally, gravity compensation is successfully realized by the proposed elastic energy aggregation and distribution method using a 2-DOF experiment machine equipped with TDA. From the above, it is achieved that the method in which the elastic energy stored in the linear spring can be uniquely determined in response to changes in the gravitational potential which should be compensated.

Keywords

• mechanical gravity canceller
• gravity compensation mechanism
• linear spring
• energy aggregation and distribution
• displacement transmission