Xiao Xiao

Bio: Xiao Xiao is an academic researcher from Beijing University of Technology. The author has contributed to research in topics: Actuator & Shape-memory polymer. The author has an hindex of 1, co-authored 2 publications receiving 6 citations.

Flexible Photodriven Actuator Based on Gradient-Paraffin-Wax-Filled Ti 3 C 2 T x MXene Film for Bionic Robots

Abstract: Due to their high flexibility and adaptability, bionic robots have great potential in applications such as healthcare, rescue, and surveillance. The flexible actuator is an essential component of the bionic robot and determines its performance. Even though much progress has been achieved in bionic robot research, there still exists a great challenge in preparing a flexible actuator with a large stroke, high sensitivity, fast response, low triggering power, and long lifetime. This study presents a flexible actuator based on a paraffin wax and Ti3C2Tx MXene (PW-MX) film composite. Such a flexible actuator delivers an excellent actuation performance, including a large curvature change (2.2 × 102 m-1), high thermal sensitivity (4.6 m-1/°C), low triggering power of light (76 mW/cm2), wavelength selectivity, fast response (0.38 s), and long lifetime (>20000 cycles). Due to the high thermal sensitivity and the strong infrared absorption of the PW-MX film, crawling motion of an inchworm robot based on PW-MX film can be triggered by infrared irradiation from the human finger. To mimic living organisms with bioluminescence, we prepared a PW-MX actuator with green fluorescence by doping PW-MX film with CdSe/ZnS quantum dots. The integration of luminescent function enables the PW-MX actuator to deliver information under light stimulation and to camouflage under a background of green foliage actively. With its merits of ease of fabrication and high actuation performance, the flexible PW-MX actuator is expected to lend itself to more applications in the future.

Recent advances for phase-transition materials for actuators

Abstract: Mechanical actuators, which convert external stimuli to motion, play a significant role in medical devices, automobiles, aircrafts, and robots. With their associated advantages of large shape change, high force, and high efficiency, phase transitions are among the most important driving forces in actuation. There are many phase-transition materials suitable for actuators, and many of them find applications in the real world. In this Tutorial, we review some typical phase-transition driving materials for actuators, including shape memory alloys, piezoelectric ceramics, vanadium dioxide, liquid crystal elastomers, hydrogels, shape memory polymers, and paraffin wax. The phase-transition mechanisms of the materials are introduced, and the design principles and related applications of the associated actuators are discussed.

Deep‐Learning‐Assisted Noncontact Gesture‐Recognition System for Touchless Human‐Machine Interfaces

Abstract: Human‐machine interfaces (HMIs) play important role in the communication between humans and robots. Touchless HMIs with high hand dexterity and hygiene hold great promise in medical applications, especially during the pandemic of coronavirus disease 2019 (COVID‐19) to reduce the spread of virus. However, current touchless HMIs are mainly restricted by limited types of gesture recognition, the requirement of wearing accessories, complex sensing platforms, light conditions, and low recognition accuracy, obstructing their practical applications. Here, an intelligent noncontact gesture‐recognition system is presented through the integration of a triboelectric touchless sensor (TTS) and deep learning technology. Combined with a deep‐learning‐based multilayer perceptron neural network, the TTS can recognize 16 different types of gestures with a high average accuracy of 96.5%. The intelligent noncontact gesture‐recognition system is further applied to control a robot for collecting throat swabs in a noncontact mode. Compared with present touchless HMIs, the proposed system can recognize diverse complex gestures by utilizing charges naturally carried on human fingers without the need of wearing accessories, complicated device structures, adequate light conditions, and achieves high recognition accuracy. This system could provide exciting opportunities to develop a new generation of touchless medical equipment, as well as touchless public facilities, smart robots, virtual reality, metaverse, etc.

Actuating Shape Memory Polymer for Thermoresponsive Soft Robotic Gripper and Programmable Materials.

Abstract: For soft robotics and programmable metamaterials, novel approaches are required enabling the design of highly integrated thermoresponsive actuating systems. In the concept presented here, the necessary functional component was obtained by polymer syntheses. First, poly(1,10-decylene adipate) diol (PDA) with a number average molecular weight Mn of 3290 g·mol−1 was synthesized from 1,10-decanediol and adipic acid. Afterward, the PDA was brought to reaction with 4,4′-diphenylmethane diisocyanate and 1,4-butanediol. The resulting polyester urethane (PEU) was processed to the filament, and samples were additively manufactured by fused-filament fabrication. After thermomechanical treatment, the PEU reliably actuated under stress-free conditions by expanding on cooling and shrinking on heating with a maximum thermoreversible strain of 16.1%. Actuation stabilized at 12.2%, as verified in a measurement comprising 100 heating-cooling cycles. By adding an actuator element to a gripper system, a hen’s egg could be picked up, safely transported and deposited. Finally, one actuator element each was built into two types of unit cells for programmable materials, thus enabling the design of temperature-dependent behavior. The approaches are expected to open up new opportunities, e.g., in the fields of soft robotics and shape morphing.

Ultrafast Response and Programmable Locomotion of Liquid/Vapor/Light-Driven Soft Multifunctional Actuators.

Abstract: External-stimuli-driven soft actuators overcome several limitations inherent in traditional mechanical-driven technology considering the coming age of flexible robots, which might face harsh working conditions and rigorous multifunctional requirements. However, how to achieve multi-external-stimuli response, fast speed, and precise control of the position and angle of the actuator, especially working in a toxic liquid or vapor environment, still requires long-term efforts. Here, we report a multi-external-stimuli-driven sandwich actuator with aligned carbon nanotubes as the constructive subject, which can respond to various types of liquids (organic solvents), vapor, and solar light. The actuator has an ultrafast response speed (<10 ms) and can accurately adjust the bending angle range from 0° to 180°. Through manipulating the stimuli positions, actuators can be wound into varied turns when simulating a flexible robotic arm. Hence, liquid/vapor/light-driven actuators are able to support diverse programmable motions, such as periodic blooming, gesture variations, caterpillar crawling, toxic surface evading, and bionic phototaxis. We believe that this multifunctional actuator is promising in supporting a complex scenario to complete a variety of tasks in the fields of healthcare, bioengineering, chip technology, and mobile sensors.