Gravity Compensation News Today

This paper presents a design concept of using permanent magnets for linear-type gravity compensation. The basic idea is to let one permanent magnet (or a group of magnets) carry out the weight to move against a group of another permanent magnets that are fixed on the ground. The fixed magnets are arranged in a special array configuration so that the interactive forces among the magnets can effectively cancel the weight within a certain range of heights. While the concept uses common magnets with...

Designing of spring-balanced linkage mechanisms for gravity compensation is commonly done through an ideal assumption that the springs should have a zero free-length (ZFL). After the design results were generated, the ZFL springs could then be physically implemented on the designed linkages by versatile mechanical arrangement, which, however, will inevitably complicate the mechanism structure. This paper investigates the design performance of gravity compensation (i.e., static balancing) of a sp...

This paper presents the static balancing designs (i.e., gravity compensation) for a rotating link by using a special straight-line geared mechanism with springs. The design scenario is to attach the rotating link yet to balance onto an inverted Cardan gear mechanism which has linear springs installed for balancing the weight of the links. It is found that the whole mechanism can be perfectly balanced in theory through either one or two linear springs. The significance of the proposed designs is ...

This article proposes a method for analyzing the gravity balancing reliability of spring-articulated serial robots with uncertainties. Gravity balancing reliability is defined as the probability that the torque reduction ratio (the ratio of the balanced torque to the unbalanced torque) is less than a specified threshold. In this paper, the reliability analysis is performed by exploiting a Monte Carlo simulation (MCS) with consideration of the uncertainties in the link dimensions, masses, and com...

A modularization approach for gravity compensation of planar articulated robotic manipulators is addressed in this chapter. The modularization is realized by installing a set of gear-spring modules (GSMs) on the manipulator so that the gravitational torques can be eliminated by the spring torques applied on its joints. The design concept and mathematical formulation for the gravity compensation of the GSM are presented. Then, the gravity compensation of the manipulator by using the GSMs is propo...

This paper presents a new class of spring four-bar mechanisms, with fifty-six different mechanism types, for gravity compensation. A synthesized mechanism is realized by linkage combination with a planar four-bar linkage and attachment of a linear spring. The main advantages of the proposed spring mechanisms are their simple architectures and high performances that possess great potential for practical applications. The parameters of the mechanisms for gravity compensation are derived from an op...

Abstract This paper presents a design concept for the gravity compensation of the renowned Delta parallel robot. The design is constructed by using three gear-spring modules, each being installed on the proximal link of each leg of the robot. This implementation can allow the balancing design to merely request a relatively small assembly space on the robot, thereby avoiding mechanical interference between the supplemental structures and robot links during operation. The spring design is realize...