An Improved Design of Gravity Compensators Based on the Inverted Slider-Crank Mechanism

The static balancing of mechanical systems is an important issue because it allows one to significantly decrease the size of actuators for equivalent displacements of the end effector. Indeed, the actuators do not have to produce the required input energy to counterbalance the variation of the potential energy of the robot. However, the literature review shows that in many cases the gravity balancing of mechanical systems is carried out by neglecting the masses of auxiliary links associated with the principal mechanism. For many balancing schemes, it is a source of errors.

This paper deals with an improved solution for gravity compensators based on the inverted slider-crank mechanism considering the masses of the coupler and the spring. To achieve this, the torques are determined due to auxiliary links. Subsequently, they are introduced into the balancing equation for minimization of the residual unbalance. Hence, a more accurate balancing of gravity compensators based on the inverted slider-crank mechanism can be achieved. The efficiency of the suggested approach is illustrated by numerical simulations.