Gravity compensation of parallel kinematics mechanism with revolute joints using torsional springs

Abstract

Passive gravity compensation technologies based on counterweight and torsional springs is rarely discussed due to the unavailability of an exact mathematical manipulation to determine the required spring constants to achieve the static balance. This article proposes using these springs for a parallel kinematics mechanism with revolute joints. Either the spring constants or initial spring displacements are determined by a constrained optimization approach aiming at minimizing the total potential energy of the mechanism or the static reaction in the actuation direction at the actuators, along a prescribed trajectory. This results in reduced actuation forces/ torques and hence reduced power consumption.

Keywords:

• Gravity compensation
• static balance
• torsional spring
• parallel kinematics

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This research was partially supported by the Khalifa University Internal Research Fund.