Jun Zhang

Robotic artificial muscles are a subset of artificial muscles that are capable of producing biologically inspired motions useful for robot systems, i.e., large power-to-weight ratios, inherent compliance, and large range of motions. These actuators, ranging from shape memory alloys to dielectric elastomers, are increasingly popular for biomimetic robots as they may operate without using complex linkage designs or other cumbersome mechanisms. Recent achievements in fabrication, modeling, and control methods have significantly contributed to their potential utilization in a wide range of applications. However, no survey paper has gone into depth regarding considerations pertaining to their selection, design, and usage in generating biomimetic motions. In this paper, we discuss important characteristics and considerations in the selection, design, and implementation of various prominent and unique robotic artificial muscles for biomimetic robots, and provide perspectives on next-generation muscle-powered robots.

Moravec's paradox shows that low-level sensorimotor skills are more difficult than high-level reasoning in artificial intelligence and robotics. So simplifying every sensing unit on electronic skin is critical for endowing intelligent robots with tactile and temperature sense. The human nervous system is characterized by efficient single-electrode signal transmission, ensuring the efficiency and reliability of information transmission under big data conditions. In this work, we report a sensor based on a single-electrode piezoelectric nanogenerator (SPENG) by electrospun polyvinylidene fluoride (PVDF) nanofibers that can realize steady-state sensing of pressure integrating cold/heat sensing on a single unit. Piezoelectric signals appear as square wave signals, and the thermal-sensing signals appear as pulse signals. Therefore, the two signals can be acquired by a single unit simultaneously. The SPENG overcomes the shortcoming of electronic skins based on a single-electrode triboelectric nanogenerator (STENG), which can sense only dynamic movement and cannot sense temperature variations. The new sensor configuration uses a capacitor instead of the STENG's ground wire as a potential reference, allowing it to be used for truly autonomous robots. At the same time, the traditional advantages of polymer piezoelectric materials, such as flexibility, transparency, and self-powered advantages, have also been preserved.

Biomass has the potential to become an important source of energy for future automotive fuels. Recent biological and chemical improvements to the conversion of biomass-derived carbohydrates have produced high yields of liquid 2,5-dimethylfuran (DMF). This discovery has made DMF a possible substitute for petroleum-based gasoline, because they share very similar physicochemical properties, which are superior to those of ethanol. In the present study, experiments have been carried out on a single-cylinder gasoline direct-injection (GDI) research engine to study the performance of DMF benchmarked against gasoline and what is considered to be the current biofuel leader, ethanol. Initial results are very promising for DMF as a new biofuel; not only is the combustion performance similar to commercial gasoline, but the regulated emissions are also comparable.