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Nonskeletal animals such as worms achieve locomotion via crawling. We consider them as an inspiration to design robots that help underline the mechanisms of crawling. In this paper, we aim to identify an approach with the simplest structure and actuators. Our robots consist of cut-and-fold bodies equipped with pneumatically-driven soft actuators. We have developed fabrication techniques for coin-sized robots. Experiments showed that our robots can move up to 4.5 mm/s with straight motion (i.e., 0.1 body lengths per second) and perform cornering and U-turns. We have also studied the friction characteristics of our robots with the ground to develop a multistate model with stick–slip contact conversions. Our theoretical analyses depict comparable results to experiments demonstrating that simple and straightforward techniques can illustrate the crawling mechanism. Considering the minimal robots' structure, this result is a critical step towards developing miniature crawling robots successfully. [ABSTRACT FROM AUTHOR]

Pneumatic soft actuators possess relatively fast response, inherent high flexibility, and achieve extraordinary shape morphing under large deformations. Conventionally, the entire body of soft pneumatic robots needs to be designed for specific applications. Herein, a soft pneumatic actuator design with structured fabrics as actuator skins, which has high bending stiffness variation that can accomplish multiple tasks and different deformation modes in a single body, is proposed. By adjusting the structured skin, the developed soft actuator can be tailored to achieve various deformations. It is experimentally shown that the bending stiffness of the actuator can be adjusted from 108 to 5654 N m−1. The blocking force of the actuator in bending is comparable with that of conventional fabric‐reinforced pneumatic actuators, while the actuator skins are reusable and programmable. In application, the actuators are used to construct a bionic soft gripper with multiple degrees of freedom. By switching between three grasping modes, the gripper successfully fulfills a series of tasks including lifting weights up to 1 kg and grasping objects ranging from a grain of grape to a large iron basin. This work opens up an avenue for designing structured skins for pneumatic robots with programmable deformation modes and versatile functions. [ABSTRACT FROM AUTHOR]

Robots manipulated by humans are being aggressively researched and developed. Such robots have requirements such as a large generative force, high-speed response, good controllability, high safety, low friction and backdriveability. We focused on backdriveability and created a prototype for a novel linear actuator with a new structure that includes an electrorheological (ER) gel, which is a recently designed functional material. The device is an all-purpose actuator that satisfies the demands for application in a human-coexistence welfare robot, such as power-assist systems. This paper presents the original plan for the linear actuator, shows the actuator as currently manufactured and presents the basic characteristics of the actuator as investigated experimentally. We obtained larger force from the linear actuator than the initial target. Additionally, the linear actuator shows possibilities of further improvement of the force-weight ratio by an increase of the ER gel structures. With regard to stabilizing the response of the linear actuator, spring elements contributed to its improvement. However, further stabilization remains as a future issue for practical use in human-coexistence robots. [ABSTRACT FROM AUTHOR]

We are studying the robotic application of ionic polymer–metal composite (IPMC). The characteristics of IPMC greatly depend on the type of counterions, and it is considered that the performance of the actuators can be improved by combining the actuators with several types of counterions and applying an integrated control. IPMC also has a sensor function, as the IPMC film generates an electromotive force when it is deformed. It has the possibility to be integrated into an IPMC actuator with soft actuation. In this paper, we consider an integrated design of an IPMC actuator/sensor, and investigate control of the combined IPMC actuators using H∞ control and the construction of an IPMC sensor system. [ABSTRACT FROM AUTHOR]