A self-moving ultrasonic actuator (SUA) that operated by the longitudinal traveling wave and possessed high carrying/towing capability is developed in this article. The SUA is constructed by serially clamping two longitudinal transducers onto a rectangular-rod-shaped vibrating body, and its driving feet produce elliptical motions to achieve self-movement. Here, the clamped configuration and longitudinal vibration facilitate the realization of large driving force, and the bar shape brings simple structure and low weight. Initially, the SUA is designed with two developed models to not only enhance the driving force without excessively increasing the weight, but also enable the elliptical motion shapes to approach circular ones. Subsequently, an SUA prototype with the size of 315 × 32 × 30 mm is fabricated, and its vibration properties, self-moving characteristics, and carrying/towing capability are assessed. At ∼27.8-kHz frequency and 800-V voltage, the payload and towing force reached 6 kg and 24.5 N, respectively. Moreover, the SUA yielded the payload-to-weight ratio of 10.2 and the towing force density of 41.5 N/kg, exceeding the values of most conventional ones. This article validates the longitudinal TW's potential to enhance SUAs’ carrying/towing capability, and also provides a new approach to design powerful ultrasonic/piezoelectric actuators.

This article presents the development of a novel tensegrity-based robot, TICBot, which is capable of crawling in tubular environments. Based on the concept of tensegrity, a deformable robotic module consisted of discrete rigid struts and a continuous net of elastic springs is proposed. Then, the in-pipe crawling robot is designed by serially cascading three uniform modules. The mechanical structure of the robotic module is determined using force density method on the basis of kinematic and static analysis. Performance of the robot in aspects of shape changeability, mobility, load capacity, and adaptability are tested on the prototype. Experimental results show that the robot has the abilities to crawl in pipes with different inner diameters and shapes, and to pass through elbow pipes adaptively under the control of a simple actuation sequence. Compared with existing robots, this proposed approach enables more compact structures along with enhanced mobility and adaptability. This article validates the effectiveness of our proposal and provides a new approach for developing in-pipe crawling robots and other bioinspired robots.

Background: High-performance position control of pneumatic artificial muscles is limited by their inherent nonlinearity and hysteresis. Objective: This study aims to model the length/pressure hysteresis of a single pneumatic artificial muscle and to

Compared with traditional in-pipe robots, tensegrity robots have exhibited many advantages such as light-weight, compliant, collapsible, low-cost, and rapidly manufacturable characteristics. However, published tensegrity in-pipe robots still have limited load capacity, because they rely on the stress between obliquely arranged rigid struts and pipe to provide supporting force, and the rigid struts are easy to slide under external loads. In this paper, a soft umbrella-shaped tensegrity robot that use compressed elastic struts to apply stress nearly perpendicular to pipe is proposed to enhance its load capacity. The static and kinematic models guiding the prototyping and controlling of the tensegrity robot are built based on discretization method. To assess the effectiveness of the elastic struts, a prototype is developed and subjected to a series of experiments. The results demonstrate that compared with other tensegrity in-pipe robots, the usage of elastic struts improves the payload-to-weight ratio of the proposed robot by three times, while still maintaining good mobility and adaptability.