Design and Fabrication of Universal Soft Robotic Gripper

Lee, Chun Wai (2024) Design and Fabrication of Universal Soft Robotic Gripper. Final Year Project (Bachelor), Tunku Abdul Rahman University of Management and Technology.

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Abstract

The universal soft gripper represents a significant advancement in the realm of robotics, showcasing its potential to delicately manipulate a diverse array of objects, making it applicable in various domains, such as manufacturing and healthcare. This study’s primary objective was to conceptualize and assess the feasibility of a universal soft robotic gripper, amenable to a wide range of applications, fabricated through 3D printing using Thermoplastic Polyurethane (TPU) and silicone rubber moulding. The proposed design incorporates a modular mechanism to facilitate easy gripper insertion and replacement, coupled with a secure pneumatic connection. Through meticulous research, the moulding method was effectively employed to create the universal soft robotic gripper, demonstrating exceptional pneumatic air-tightness during actuation, thus averting any leakage concerns and exhibiting the capacity to securely grasp objects weighing up to 500 grams. The study conducted a comprehensive analysis integrating experimental findings with static structural simulations via ANSYS, revealing a maximum percentage error of 14.61% under an applied pressure of 0.1 bar, underscoring the importance of simulation validation. Additionally, the investigation unveiled a significant correlation between the thickness of the air chamber wall and the bending angle of the soft finger, with thinner walls yielding greater bending angles. Specifically, a 25mm wall thickness emerged as the optimal choice for effectively gripping objects ranging from 5mm to 125mm in size. Fluid-structure interaction (FSI) simulations using ANSYS CFX identified the presence of eddy currents within the internal cavities, potentially impacting gripper performance, calling for future design optimization efforts to mitigate these eddies. Despite encountering setbacks in 3D printing attempts for the TPU finger, a series of simulations provided valuable insights into the behavioural disparities between silicone and TPU materials. Notably, even under identical pressure levels, the silicone soft finger exhibited more pronounced deformation and bending than its TPU counterpart. Overall, this study effectively achieved its objectives of designing an air-actuated universal soft robotic gripper, fabricating it using 3D printing and silicone rubber moulding, and rigorously evaluating its functionality. The comprehensive research outcomes contribute invaluable knowledge to the evolving field of soft robotics, shedding light on gripper behaviour and functionality, and paving the way for future advancements in this domain.