Shape memory alloy （SMA） actuator is a potential advanced component for servo- systems of aerospace vehicles and aircraft. This paper presents a joint with two degrees of freedom （DOF） and a mobility range close t...Shape memory alloy （SMA） actuator is a potential advanced component for servo- systems of aerospace vehicles and aircraft. This paper presents a joint with two degrees of freedom （DOF） and a mobility range close to ±60° when driven by SMA triple wires. The fuzzy proportional-integral-derivative （PID）-controlled actuator drive was designed using antagonistic SMA triple wires, and the resistance feedback signal made a closed loop. Experiments showed that, with the driving responding frequency increasing, the overstress became harder to be avoided at the position under the maximum friction force. Furthermore, the hysteresis gap between the heating and cooling paths of the strain-to-resistance curve expanded under this condition. A fuzzy logic control was considered as a solution, and the curves of the wires were then modeled by fitting polynomials so that the measured resistance was used directly to determine the control signal. Accurate control was demonstrated through the step response, and the experimental results showed that under the fuzzy PID-control program, the mean absolute error （MAE） of the rotation angle was about 3.147°. In addition, the investigation of the external interference to the system proved the controllable maximum output.展开更多
Designing soft robots that are able to perceive unstructured,dynamic environments and their deformations has been a long-term goal.Previously reported self-sensing soft actuators were mostly constructed via integratin...Designing soft robots that are able to perceive unstructured,dynamic environments and their deformations has been a long-term goal.Previously reported self-sensing soft actuators were mostly constructed via integrating separate actuators and sensors.The actuation performances and the sensing reliability are affected owing to the unmatched materials and weak connections.Realizing a seamless integration of soft actuators and sensors remains a grand challenge.Here,we report a fabrication strategy to endow soft actuators with sensing capability and programmable actuation performances.The foam inside the actuator functions as actuator and sensor simultaneously,effectively addressing the conformability and connection reliability issues that existed in current self-sensing actuators.The actuators are lightweight(a decrease of 58%in weight),powerful(lifting a load of 433 times of its own weight),and versatile(coupling twisting and contraction motions).Furthermore,the actuators are able to detect multiple physical stimuli with high reliability,demonstrating their exteroception and proprioception capability.Two self-sensing soft robotic prototypes,including a bionic bicep and a bionic neck,are constructed to illustrate their multifunctionality.Our study opens up new possibilities for the design of soft actuators and has promising potential in a variety of applications,ranging from human-robot interaction,soft orthotics,to wearable robotics.展开更多
Impact detecting and counting are fundamental functions of fuses used in hard target penetration weapons.However,detection failure caused by battery breakdown in high-g acceleration environments poses a vulnerability ...Impact detecting and counting are fundamental functions of fuses used in hard target penetration weapons.However,detection failure caused by battery breakdown in high-g acceleration environments poses a vulnerability for such weapons.This paper introduces a novel supercapacitor that combines energy storage and high-g impact detection,called self-sensing supercapacitor.By deliberately inducing a transient soft short-circuit during shock in the supercapacitor,it is possible to detect external impact by its transient voltage drop.To realize this concept,firstly,by introducing the contact theory and force-induced percolation model,the electrode strength and roughness are found to have key impacts on the formation of soft circuits.Subsequently,to meet the needs for sensitivity and capacity,a high-density porous carbon(HDPC)that combines high mechanical strength and porosity,is selected as a suitable candidate based on the analysis results.Furthermore,a two-step curing method is proposed to prepare the high-roughness HDPC(HRHDPC)electrode and to assemble the self-sensing supercapacitor.Due to the rich specific surface of the electrodes and the high surface strength and roughness conducive to the formation of transient soft short circuits,the self-sensing supercapacitor not only possesses an excellent specific capacitance(171 F/g at 0.5 A/g)but also generates significant voltage response signals when subjected to high-g impacts ranging from 8000g to 31,000g.Finally,the self-sensing supercapacitor is applied to compose a successive high-g impact counting system and compared to traditional solutions(sensors and tantalum capacitors)in the military fuzes.The results show that the self-sensing supercapacitor-based system exhibits advantages in terms of size,power consumption,and counting accuracy.展开更多
Wearable devices,interactive human-machine interface equipment,wireless sensors,and small-scale cleaning devices play crucial roles in biomedical implantation,disease treatment,health monitoring,environmental purifica...Wearable devices,interactive human-machine interface equipment,wireless sensors,and small-scale cleaning devices play crucial roles in biomedical implantation,disease treatment,health monitoring,environmental purification,etc.These devices require a sustainable energy source to work effectively.With the consideration of the global energy crisis and environmental pollution,researchers are exploring new,stable,and environmentally friendly methods to power these low-powered devices.Mechanical energy is one of the most abundant natural energy sources.Converting mechanical energy from the ambient environment or host structures into electrical energy via the direct piezoelectric effect is an efficient energy harvesting technique.This paper reviews the application of advanced piezoelectric materials,and small-scale self-powered and self-sensing piezoelectric devices at the cubic centimeter scale in energy harvesting and health monitoring of human,animal,machinery,roads,bridges,as well as the pollutant degradation of the environment.Some of these devices have the capability to not only harvest mechanical energy but also enable real-time monitoring and analysis of the electrical signals generated by the direct piezoelectric effect,facilitating prompt decision-making and appropriate responses.In addition,potential challenges and future prospects of small-scale self-powered and self-sensing piezoelectric devices are discussed.展开更多
基金co-supported by the National Natural Science Foundation of China (61175104)National Science and Technology Support Program of China (2012BA114B01)
文摘Shape memory alloy （SMA） actuator is a potential advanced component for servo- systems of aerospace vehicles and aircraft. This paper presents a joint with two degrees of freedom （DOF） and a mobility range close to ±60° when driven by SMA triple wires. The fuzzy proportional-integral-derivative （PID）-controlled actuator drive was designed using antagonistic SMA triple wires, and the resistance feedback signal made a closed loop. Experiments showed that, with the driving responding frequency increasing, the overstress became harder to be avoided at the position under the maximum friction force. Furthermore, the hysteresis gap between the heating and cooling paths of the strain-to-resistance curve expanded under this condition. A fuzzy logic control was considered as a solution, and the curves of the wires were then modeled by fitting polynomials so that the measured resistance was used directly to determine the control signal. Accurate control was demonstrated through the step response, and the experimental results showed that under the fuzzy PID-control program, the mean absolute error （MAE） of the rotation angle was about 3.147°. In addition, the investigation of the external interference to the system proved the controllable maximum output.
基金supported by the National Natural Science Foundation of China(Grant No.52205073)Zhejiang Provincial Natural Science Foundation of China(Grant No.LD22E050002)+1 种基金China National Postdoctoral Program for Innovative Talents(Grant No.BX2021258)China Postdoctoral Science Foundation(Grant No.2022M710125)。
文摘Designing soft robots that are able to perceive unstructured,dynamic environments and their deformations has been a long-term goal.Previously reported self-sensing soft actuators were mostly constructed via integrating separate actuators and sensors.The actuation performances and the sensing reliability are affected owing to the unmatched materials and weak connections.Realizing a seamless integration of soft actuators and sensors remains a grand challenge.Here,we report a fabrication strategy to endow soft actuators with sensing capability and programmable actuation performances.The foam inside the actuator functions as actuator and sensor simultaneously,effectively addressing the conformability and connection reliability issues that existed in current self-sensing actuators.The actuators are lightweight(a decrease of 58%in weight),powerful(lifting a load of 433 times of its own weight),and versatile(coupling twisting and contraction motions).Furthermore,the actuators are able to detect multiple physical stimuli with high reliability,demonstrating their exteroception and proprioception capability.Two self-sensing soft robotic prototypes,including a bionic bicep and a bionic neck,are constructed to illustrate their multifunctionality.Our study opens up new possibilities for the design of soft actuators and has promising potential in a variety of applications,ranging from human-robot interaction,soft orthotics,to wearable robotics.
基金supported in part by the National Natural Science Foundation of China(No.52007084)by the Young Elite Scientists Sponsorship Program by CAST(No.2023QNRC001).
文摘Impact detecting and counting are fundamental functions of fuses used in hard target penetration weapons.However,detection failure caused by battery breakdown in high-g acceleration environments poses a vulnerability for such weapons.This paper introduces a novel supercapacitor that combines energy storage and high-g impact detection,called self-sensing supercapacitor.By deliberately inducing a transient soft short-circuit during shock in the supercapacitor,it is possible to detect external impact by its transient voltage drop.To realize this concept,firstly,by introducing the contact theory and force-induced percolation model,the electrode strength and roughness are found to have key impacts on the formation of soft circuits.Subsequently,to meet the needs for sensitivity and capacity,a high-density porous carbon(HDPC)that combines high mechanical strength and porosity,is selected as a suitable candidate based on the analysis results.Furthermore,a two-step curing method is proposed to prepare the high-roughness HDPC(HRHDPC)electrode and to assemble the self-sensing supercapacitor.Due to the rich specific surface of the electrodes and the high surface strength and roughness conducive to the formation of transient soft short circuits,the self-sensing supercapacitor not only possesses an excellent specific capacitance(171 F/g at 0.5 A/g)but also generates significant voltage response signals when subjected to high-g impacts ranging from 8000g to 31,000g.Finally,the self-sensing supercapacitor is applied to compose a successive high-g impact counting system and compared to traditional solutions(sensors and tantalum capacitors)in the military fuzes.The results show that the self-sensing supercapacitor-based system exhibits advantages in terms of size,power consumption,and counting accuracy.
基金supported by the National Natural Science Foundation of China(Grant Nos.12072267,12172266)。
文摘Wearable devices,interactive human-machine interface equipment,wireless sensors,and small-scale cleaning devices play crucial roles in biomedical implantation,disease treatment,health monitoring,environmental purification,etc.These devices require a sustainable energy source to work effectively.With the consideration of the global energy crisis and environmental pollution,researchers are exploring new,stable,and environmentally friendly methods to power these low-powered devices.Mechanical energy is one of the most abundant natural energy sources.Converting mechanical energy from the ambient environment or host structures into electrical energy via the direct piezoelectric effect is an efficient energy harvesting technique.This paper reviews the application of advanced piezoelectric materials,and small-scale self-powered and self-sensing piezoelectric devices at the cubic centimeter scale in energy harvesting and health monitoring of human,animal,machinery,roads,bridges,as well as the pollutant degradation of the environment.Some of these devices have the capability to not only harvest mechanical energy but also enable real-time monitoring and analysis of the electrical signals generated by the direct piezoelectric effect,facilitating prompt decision-making and appropriate responses.In addition,potential challenges and future prospects of small-scale self-powered and self-sensing piezoelectric devices are discussed.
