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Soft actuators and microrobots that can move spontaneously and continuously without artificial energy supply and intervention have great potential in industrial, environmental, and military applications, but still remain a challenge. Here, a bioinspired MXene-based bimorph actuator with an asymmetric layered microstructure is reported, which can harness natural sunlight to achieve directional self-locomotion. We fabricate a freestanding MXene film with an increased and asymmetric layered microstructure through the graft of coupling agents into the MXene nanosheets. Owing to the excellent photothermal effect of MXene nanosheets, increased interlayer spacing favoring intercalation/deintercalation of water molecules and its caused reversible volume change, and the asymmetric microstructure, this film exhibits light-driven deformation with a macroscopic and fast response. Based on it, a soft bimorph actuator with ultrahigh response to solar energy is fabricated, showing natural sunlight-driven actuation with ultralarge amplitude and fast response (346°in 1 s). By utilizing continuous bending deformation of the bimorph actuator in response to the change of natural sunlight intensity and biomimetic design of an inchworm to rectify the repeated bending deformation, an inchwormlike soft robot is constructed, achieving directional self-locomotion without any artificial energy and control. Moreover, soft arms for lifting objects driven by natural sunlight and wearable smart ornaments that are combined with clothing and produce three-dimensional deformation under natural sunlight are also developed. These results provide a strategy for developing natural sunlight-driven soft actuators and reveal great application prospects of this photoactuator in sunlight-driven soft biomimetic robots, intelligent solar-energy-driven devices in space, and wearable clothing.

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Developing self‐oscillating soft actuators that enable autonomous, continuous, and directional locomotion is significant in biomimetic soft robotics fields, but remains great challenging. Here, an untethered soft photoactuators based on covalently‐bridged black phosphorus‐carbon nanotubes heterostructure with self‐oscillation and phototactic locomotion under constant light irradiation is designed. Owing to the good photothermal effect of black phosphorus heterostructure and thermal deformation of the actuator components, the new actuator assembled by heterostructured black phosphorus, polymer and paper produces light‐driven reversible deformation with fast and large response. By using this actuator as mechanical power and designing a robot configuration with self‐feedback loop to generate self‐oscillation, an inchworm‐like actuator that can crawl autonomously towards the light source is constructed. Moreover, due to the anisotropy and tailorability of the actuator, an artificial crab robot that can simulate the sideways locomotion of crabs and simultaneously change color under light irradiation is also realized.

In order to transport materials flexibly and smoothly in a tight plant environment, an omni-directional mobile robot based on four Mecanum wheels was designed. The mechanical system of the mobile robot is made up of three separable layers so as to simplify its combination and reorganization. Each modularized wheel was installed on a vertical suspension mechanism, which ensures the moving stability and keeps the distances of four wheels invariable. The control system consists of two-level controllers that implement motion control and multi-sensor data processing, respectively. In order to make the mobile robot navigate in an unknown semi-structured indoor environment, the data from a Kinect visual sensor and four wheel encoders were fused to localize the mobile robot using an extended Kalman filter with specific processing. Finally, the mobile robot was integrated in an intelligent manufacturing system for material conveying. Experimental results show that the omni-directional mobile robot can move stably and autonomously in an indoor environment and in industrial fields.

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Material properties of the components of magnetorheological (MR) fluids are critical to their control accuracy and service life. The aim of this study was to reveal the effects of temperature on the material properties of MR fluid components. In this paper, a detailed introduction to the components of MR fluids, including main performance indicators and commonly used materials, was presented at first. Then, theoretical analysis and experimental investigation were performed on the temperature-dependent material properties of MR fluid components. These material properties included the magnetization properties of the magnetic particle, as well as the shear viscosity and thermal expansion of the carrier fluid. Experimental results indicated that both the mass magnetization and coercivity of MR particles decreased as the temperature increased and the phenomenon was particularly obvious at high temperatures. Moreover, an increasing temperature could lead to a severe decrease of the shear viscosity and a relatively large thermal expansion of the carrier fluid. Research results from this study may serve to provide a theoretical and an experimental basis for the preparation of MR fluids with high thermal stability.

An automatic design platform capable of automatic structural analysis, structural synthesis and the application of parallel mechanisms will be a great aid in the conceptual design of mechanisms, though up to now such a platform has only existed as an idea. The work in this paper constitutes part of such a platform. Based on the screw theory and a new structural representation method proposed here which builds a one-to-one correspondence between the strings of representative characters and the kinematic structures of symmetrical parallel mechanisms (SPMs), this paper develops a fully-automatic approach for mobility (degree-of-freedom) analysis, and further establishes an automatic digital-analysis platform for SPMs. With this platform, users simply have to enter the strings of representative characters, and the kinematic structures of the SPMs will be generated and displayed automatically, and the mobility and its properties will also be analysed and displayed automatically. Typical examples are provided to show the effectiveness of the approach.