New Structural Design of a Compliant Gripper Based on the Scott-Russell Mechanism

Abstract

This paper presents the structural design and analysis of a novel compliant gripper based on the Scott-Russell (SR) mechanism. The SR mechanism in combination with a parallelogram mechanism enables the achievement of a pure translation of the gripper tips, which is attractive for practical micromanipulation and microassembly applications. Unlike traditional pure-translation grippers, the reported SR-based gripper exhibits a simple structure as well as compact dimension because the in-plane space is fully used. The kinematics, statics and dynamics models of the gripper mechanism are established, and finite element analysis (FEA) simulations are carried out to verify the structure design. A prototype has been developed for experimental testing. The results not only demonstrate the feasibility of the proposed SR-based gripper design but also reveal a promising performance of the gripper when driven by piezoelectric stack actuators. Moreover, several variations of the gripper structure are presented as well.

Design and static testing of a compact distributed-compliance gripper based on flexure motion

“…However, lumped-compliance leads to limited motion range, and can cause stress-concentration issues and especially requires a large actuation force. The large actuation force is able to be offered by piezoelectric (PZT) actuators with high-precision [5][6][7][8][9][10]. The use of a PZT actuator requires pre-stressing and particularly needs a displacement amplification mechanism [5][6][7][8][9][10]16] to amplify the input displacement since the PZT actuator only produces tiny displacements.…”

“…Using the kinematics-based substitution method, lumpedcompliance joints (or flexure hinges) [5][6][7][8][9][10] are often chosen since they enable to directly replace their rigid-body counterparts in the traditional parallelogram mechanisms, slider-crank mechanisms, and straight-line linkages [5][6][7][8][9][10], in order to design a compliant gripper. For example, Ref.…”

“…There are mainly two methods to design a compliant gripper: structure optimisation method [12,14,15], and kinematics-based substitution method [5][6][7][8][9][10]13]. The former design approach is to re-consider the design task as an optimal material distribution problem so that the resulting a r c h i v e s o f c i v i l a n d m e c h a n i c a l e n g i n e e r i n g 1 6 ( 2 0 1 6 ) 7 0 8 -7 1 6 a r t i c l e i n f o There are precision issues with traditional rigid-body grippers due to their nature in presence of joints' backlash and friction.…”

“…In addition, CMs can be easily miniaturised, can reduce the number of parts (thereby raising the system reliability) and are free of assembly by a monolithic fabrication. CM-based grippers (compliant gripper) have been successfully used in the applications of precision robotic manipulation, biomedical devices and microelectromechanical systems (MEMS) [5][6][7][8][9][10][11][12][13][14][15].…”

Mechanical design, analysis and testing of a large-range compliant microgripper

“…In some applications, the gripper operating performance is limited by the gripping range. So, many amplification devices, such as bridge-type amplifiers, have been used to enhance the output displacement (Ai and Xu, 2014). These studies are of practical significance for the realization of the microassembly technology.…”