Search

Magnetic soft grippers have attracted intensive interest due to their untethered controllability, rapid response, and biological safety. However, manipulating living objects requires a simultaneous increase in shape adaptability and gripping force, which are typically mutually exclusive. Increasing the magnetic particle content enhances the magnetic strength but also increases the elastic modulus, leading to low adaptability and high impact force. Here, a porous magnetic soft gripper (PMSG) is developed by integrating a porous structure into a magnetic silicone elastomer. The design of porous hard magnetic composite is characterized by high magnetization, low modulus, and rough surface. It offers the PMSG good compliance, high gripping force, and low impact force at fast gripping. The PMSG is capable of performing a variety of tasks, including the fast and gentle grasping of delicate living objects. The study provides insight into the design of novel magnetic grippers and may offer a promising outlook for biomedical or scientific applications in the manipulation of delicate organisms., (© 2024 Wiley‐VCH GmbH.)

The stress-response strategy is one of the nature's greatest developments, enabling animals and plants to respond quickly to environmental stimuli. One example is the stress-response strategy of the Venus flytrap, which enables such a delicate plant to perceive and prey on insects at an imperceptible speed by their soft terminal lobes. Here, inspired by this unique stress-response strategy, a soft gripper that aims at the challenges of high-speed dynamic grasping tasks is presented. The gripper, called high-speed soft gripper (HSG), is based on two basic design concepts. One is a snap-through instability that enables the HSG to sense the mechanical stimuli and actuating instantly. The other one is the spider-inspired pneumatic-powered control system that makes the trigger process repeatable and controllable. Utilizing the stress-response strategy, the HSG can accomplish high-speed sensing and grasping and handle a dynamic grasping task like catching a thrown baseball. Whereas soft machines typically exhibit slow locomotion speed and low manipulation strength for the intrinsic limitations of soft materials, the exploration of the stress-response strategy in this study can help pave the way for designing a new generation of practical high-speed soft robots., (© 2021 The Authors. Advanced Science published by Wiley-VCH GmbH.)

While suction cups prevail as common gripping tools for a wide range of real-world parts and surfaces, they often fail to seal the contact interface when engaging with irregular shapes and textured surfaces. In this work, the authors propose a suction-based soft robotic gripper where suction is created inside a self-sealing, highly conformable and thin flat elastic membrane contacting a given part surface. Such soft gripper can self-adapt the size of its effective suction area with respect to the applied load. The elastomeric membrane covering edge of the soft gripper can develop an air-tight self-sealing with parts even smaller than the gripper diameter. Such gripper shows 4 times higher adhesion than the one without the membrane on various textured surfaces. The two major advantages, underactuated self-adaptability and enhanced suction performance, allow the membrane-based suction mechanism to grip various three-dimensional (3D) geometries and delicate parts, such as egg, lime, apple, and even hydrogels without noticeable damage, which can have not been gripped with the previous adhesive microstructures-based and active suction-based soft grippers. The structural and material simplicity of the proposed soft gripper design can have a broad use in diverse fields, such as digital manufacturing, robotic manipulation, transfer printing, and medical gripping., (© 2021 The Authors. Advanced Science published by Wiley-VCH GmbH.)

Grasping and manipulation are fundamental ways for many creatures to interact with their environments. Different morphologies and grasping methods of "grippers" are highly evolved to adapt to harsh survival conditions. For example, human hands and bird feet are composed of rigid frames and soft joints. Compared with human hands, some plants like Drosera do not have rigid frames, so they can bend at arbitrary points of the body to capture their prey. Furthermore, many muscular hydrostat animals and plant tendrils can implement more complex twisting motions in 3D space. Recently, inspired by the flexible grasping methods present in nature, increasingly more bio-inspired soft grippers have been fabricated with compliant and soft materials. Based on this, the present review focuses on the recent research progress of bio-inspired soft grippers based on impactive gripping. According to their types of movement and a classification model inspired by biological "grippers", soft grippers are classified into three types, namely, non-continuum bending-type grippers, continuum bending-type grippers, and continuum twisting-type grippers. An exhaustive and updated analysis of each type of gripper is provided. Moreover, this review offers an overview of the different stiffness-controllable strategies developed in recent years., Competing Interests: The authors declare no conflict of interest., (© 2021 The Authors. Advanced Science published by Wiley‐VCH GmbH.)

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., (© 2018 The Authors. Published by WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

The design strategy and mechanical response mechanism of light-activated, rapid-response, flexible films are presented. Practical applications as a microrobot and a smart spring are demonstrated., (© 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

A highly versatile soft gripper that can handle an unprecedented range of object types is developed based on a new design of dielectric elastomer actuators employing an interdigitated electrode geometry, simultaneously maximizing both electroadhesion and electrostatic actuation while incorporating self-sensing. The multifunctionality of the actuator leads to a highly integrated, lightweight, fast, soft gripper with simplified structure and control., (© 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

The adhesive characteristics of fibrillar adhesives on a soft deformable membrane are reported. A soft gripper with an inflatable membrane covered by elastomer mushroom-shaped microfibers have a superior conformation to non-planar 3D part geometries, enabling the transfer printing of various parts serially or in parallel., (© 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)