Topology Optimization and Prototype of a Three-Dimensional Printed Compliant Finger for Grasping Vulnerable Objects With Size and Shape Variations

Abstract

This study presents a topology optimization method to synthesize an innovative compliant finger for grasping objects with size and shape variations. The design domain of the compliant finger is a trapezoidal area with one input and two output ports. The topology optimized finger design is prototyped by three-dimensional (3D) printing using flexible filament, and be used in the developed gripper module, which consists of one actuator and two identical compliant fingers. Both fingers are actuated by one displacement input, and can grip objects through elastic deformation. The gripper module is mounted on an industrial robot to pick and place a variety of objects to demonstrate the effectiveness of the proposed design. The results show that the developed compliant finger can be used to handle vulnerable objects without causing damage to the surface of grasped items. The proposed compliant finger is a monolithic and low-cost design, which can be used to resolve the challenge issue for robotic automation of irregular and vulnerable objects.

Topology Optimization and Prototype of a Multimaterial-Like Compliant Finger by Varying the Infill Density in 3D Printing

“…Different numerical parameters and boundary conditions are used to design the 3D-printed compliant fingers. 9,11 The numerical results show that the recent finger design 11 is with a lower driving force and a lower maximum equivalent stress during operation comparing to the previous design. 8 To regulate the maximum output force, an absorber-type constant-force mechanism 20 is developed and installed on an electric gripper drive to provide passive force control and overload protection during gripping operation; the numerical computation in Ref.…”

“…R obots can be classified as hard or soft on the basis of the compliance of their underlying materials. 1 Generally, materials with elastic moduli in the order of 10 4 -10 9 Pa are considered to be soft materials. 2 Soft and compliant robotic systems generally have the potential to handle unexpected interactions with unstructured environments or humans in more sophisticated ways than rigid robots.…”

“…2 Soft and compliant robotic systems generally have the potential to handle unexpected interactions with unstructured environments or humans in more sophisticated ways than rigid robots. 3,4 rubber-like resins, 12,14 vulcanized rubbers, 18,19 and thermoplastic elastomers (TPEs) 8,9,11,20 are often used in prototyping soft grippers.…”

“…29 The algorithms of topology optimization methods are extensively investigated in the literature over the past several decades [29][30][31][32][33] and have been used in developing various soft robotic grippers. [8][9][10][11]14,16,17,20,[34][35][36][37] For example, Wang et al 10 developed a cable-driven two-finger soft gripper with multiple input ports; a topology optimization method is used to synthesize the compliant finger considering multiple working conditions. A three-finger cable-driven soft robotic gripper presented by Chen et al 35 is prototyped with a 3Dprinted TPE and can be used to grip objects up to 1 kg.…”

Multi-material topology optimization of compliant mechanisms via solid isotropic material with penalization approach and alternating active phase algorithm

“…Liu et al. 6 proposed a new topology optimization method to design a compliant finger which was able to grasp vulnerable objects with different sizes. In their method, they assumed the design domain as a trapezoidal area with one input and two output ports.…”