Shape Memory Alloy-Based Soft Gripper with Variable Stiffness for Compliant and Effective Grasping

Advances in soft robotics, materials science, and stretchable electronics have enabled rapid progress in soft grippers. Here, a critical overview of soft robotic grippers is presented, covering different material sets, physical principles, and device architectures. Soft gripping can be categorized into three technologies, enabling grasping by: a) actuation, b) controlled stiffness, and c) controlled adhesion. A comprehensive review of each type is presented. Compared to rigid grippers, end-effectors fabricated from flexible and soft components can often grasp or manipulate a larger variety of objects. Such grippers are an example of morphological computation, where control complexity is greatly reduced by material softness and mechanical compliance. Advanced materials and soft components, in particular silicone elastomers, shape memory materials, and active polymers and gels, are increasingly investigated for the design of lighter, simpler, and more universal grippers, using the inherent functionality of the materials. Embedding stretchable distributed sensors in or on soft grippers greatly enhances the ways in which the grippers interact with objects. Challenges for soft grippers include miniaturization, robustness, speed, integration of sensing, and control. Improved materials, processing methods, and sensing play an important role in future research.

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Section: Gripping By Controlled Stiffnessmentioning

confidence: 99%

“…Wang and Ahn demonstrated another approach of SMP‐based variable stiffness grasping, shown in Figure c. In this case, SMP joints with Ni‐chrome wire heaters are embedded in a layered finger (120 mm length) made of polydimethylsiloxane (PDMS) (Figure d).…”

Section: Gripping By Controlled Stiffnessmentioning

confidence: 99%

Soft Robotic Grippers

et al. 2018

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“…Relatedly, fitting the manipulator with a capable gripper would improve performance. A variety of suitable soft grippers which could be integrated with a continuum manipulator have been described in the literature [27,[35][36][37][38][39][40][41].…”

Section: Limitations and Future Researchmentioning

confidence: 99%

Design and Preliminary Testing of a Continuum Assistive Robotic Manipulator

et al. 2019

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Background: The application of continuum manipulators as assistive robots is discussed and tested through the use of Bendy ARM, a simple manually teleoperated tendon driven continuum manipulator prototype. Methods: Two rounds of user testing were performed to evaluate the potential of this arm to aid people living with disabilities in completing activities of daily living. Results: In the first round of user testing, 14 able-bodied subjects successfully completed the prescribed task (pick-and-place) using multiple control schemes after being given a brief introduction and one minute of practice with each scheme. In the second round of user testing, subjects ( n = 3 ) demonstrated between 29.5 and 48.9 percent improvement in completion time across twelve trials of a peg-in-hole task, and between 8.4 and 33.8 percent improvement across six trials of a task involving opening and closing a drawer. Conclusion: Based on these results, it is posited that continuum manipulators merit further consideration as a safer and more cost-effective alternative to existing commercially available assistive robotic manipulators.

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“…Their actuators have to be activated in sequence to ensure a precise movement (Figure c). Other soft actuators for crawling or grasping are formed by many parts such as SMA springs, SMP, PDMS, their design is also intricate. There are some simple SMA soft actuators capable of bending and twisting, but scientists mainly focus on their deformed configuration and parametric studies not on periodic locomotion such as crawling and grasping.…”

Section: Introductionmentioning

confidence: 99%

A Periodic Deformation Mechanism of a Soft Actuator for Crawling and Grasping

Huang

2019

Adv Materials Technologies

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Periodic locomotion in nature has provided many inspirations for soft actuators. Compared with rigid actuators, soft actuators can transform into versatile shapes to adapt to different working environments and are able to interact with the human in a safer manner because of their compliance. However, soft actuators often suffer from complex structures designs and complicated sequences of stimuli to achieve periodic locomotion. To overcome this shortcoming, a periodic deformation mechanism based on strain energy storing is proposed in this paper. Guided by this mechanism, a simple soft actuator is designed without complicated control systems. The soft actuator involves shape memory alloy and silicon rubber. Crawling and grasping of the soft actuator are achieved by electrical heating methods. The proposed mechanism can provide inspiration for the design of soft actuators, smart wearable equipment, and medical devices.

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Shape Memory Alloy-Based Soft Gripper with Variable Stiffness for Compliant and Effective Grasping

Cited by 273 publications

References 43 publications

Soft Robotic Grippers

Soft Robotic Grippers

Design and Preliminary Testing of a Continuum Assistive Robotic Manipulator

A Periodic Deformation Mechanism of a Soft Actuator for Crawling and Grasping

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