Statically Balancing a Reconfigurable Mechanism by Using One Passive Energy Element Only: A Case Study

Abstract

This paper presents the static balancing design of a special reconfigurable linkage that can switch between two one-degree-of-freedom (DoF) working configurations. We will show that the studied dual-mode linkage only requires one mechanical spring or one counterweight for completely balancing its gravitational effect in theory at both modes. First, the theoretical models of the spring-based and the counterweight-based designs are derived. The proposed design concepts were then demonstrated by a numerical example and validated by software simulation. Experimental tests on both designs were also performed. The result of this study shows that a reconfigurable mechanism with N working configurations can be completely statically balanced by using less than N passive energy elements.

Spring-balanced 3-DoF serial planar manipulators for constant forces in arbitrary directions

“…[10] developed a gravity balanced 2R1T (2 rotations and 1 translation) mechanism and used it on surgery applications. Other applications such as upper arm exoskeletons [11, 12] and lower limb rehabilitation devices [13, 14], with balancing of limbs’ weight, users can perform overhead work or rehabilitation easily.…”

Spring efficiency assessment and efficient use of spring methods of statically balanced planar serial manipulators with revolute joints only

“…In recent decades, new static balancing technologies and system designs have been developed for multiple applications, such as a wearable exoskeleton for rehabilitation and training (Arakelian and Ghazaryan, 2008;Lin et al, 2013;Tschiersky et al, 2019;Kuo et al, 2021) and robotic manipulators (Arakelian, 2016;Kim and Cho, 2017). These manipulators provide a better control of the performance and more efficiency because the actuating force that is sustaining the weight of their system is partially or fully balanced.…”