Design Analysis of a Variable Stiffness Gripper Based on Flexible Parallel Mechanism

doi:10.3901/JME.2019.21.064

Abstract

Abstract: A novel double-clamping-claw gripper with variable stiffness is proposed. Each clamping-claw of the gripper is a variable stiffness flexible parallel mechanism (VSFPM), which consists of four flexible limbs with symmetrical rotation. The gripper has two driving motors. One motor is employed to control the open-and-close motion of the gripper to adapt to the geometric size of the gripping objects, while the other is employed to control the rotation angle of the flexible limbs to change the stiffness of the clamping-claw in open-and-close direction, so as to realize flexible grasping with variable stiffness and improve the adaptability of the clamping-claw to the geometric shape and material properties of the gripping objects. Based on stiffness projection method, the working principle of the VSFPM is analyzed. Based on adjoint transformation, the stiffness model of the VSFPM is proposed, so that the stiffness of the VSFPM for an arbitrary rotation angle of the rotary limb is obtained. The accuracy of the stiffness model is verified through finite element analysis (FEA). In addition, the FEA results show that the proposed VSFPM has a wide stiffness changing range (0.178-9.663 N/mm). The research provides a new approach for the design and analysis of flexible gripper with variable stiffness.

Key words: variable stiffness gripper, flexible parallel mechanism, stiffness model, finite element analysis

CLC Number:

TG156

LI Jiangang, YANG Guilin, ZHANG Lin, ZHANG Chi. Design Analysis of a Variable Stiffness Gripper Based on Flexible Parallel Mechanism[J]. Journal of Mechanical Engineering, 2019, 55(21): 64-72.

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