Insect-scale fast moving and ultrarobust soft robot

2019 ◽  
Vol 4 (32) ◽  
pp. eaax1594 ◽  
Author(s):  
Yichuan Wu ◽  
Justin K. Yim ◽  
Jiaming Liang ◽  
Zhichun Shao ◽  
Mingjing Qi ◽  
...  
Keyword(s):  
Polymeric Materials ◽  
Driving Mechanism ◽  
Soft Robot ◽  
Operating Characteristics ◽  
Soft Robots ◽  
Practical Applications ◽  
Flexible Devices ◽  
Amplitude Vibration ◽  
Piezoelectric Structure ◽  
Large Amplitude Vibration

Mobility and robustness are two important features for practical applications of robots. Soft robots made of polymeric materials have the potential to achieve both attributes simultaneously. Inspired by nature, this research presents soft robots based on a curved unimorph piezoelectric structure whose relative speed of 20 body lengths per second is the fastest measured among published artificial insect-scale robots. The soft robot uses several principles of animal locomotion, can carry loads, climb slopes, and has the sturdiness of cockroaches. After withstanding the weight of an adult footstep, which is about 1 million times heavier than that of the robot, the system survived and continued to move afterward. The relatively fast locomotion and robustness are attributed to the curved unimorph piezoelectric structure with large amplitude vibration, which advances beyond other methods. The design principle, driving mechanism, and operating characteristics can be further optimized and extended for improved performances, as well as used for other flexible devices.

Model-Based Nonlinear Control of the Dielectric Elastomer Actuator With High Robustness and Precision

2019 ◽  
Vol 86 (12) ◽  
Author(s):  
Mingqi Zhang ◽  
Xunuo Cao ◽  
Xiangping Chen ◽  
Zhen Zhang ◽  
Zheng Chen ◽  
...  
Keyword(s):  
Feedback Control ◽  
Nonlinear Model ◽  
Control Strategy ◽  
Electromechanical Coupling ◽  
Tracking Error ◽  
Soft Robots ◽  
Practical Applications ◽  
Flexible Devices ◽  
Model Based ◽  
Modeling Uncertainties

Abstract Dielectric elastomers (DEs) is one of the promising artificial muscle for soft robots and flexible devices. As one of the key issues for practical applications, the control of DE actuators remains challenging due to the large actuation, electromechanical coupling, and viscoelastic dissipation. Feedforward control and proportional integral derivative (PID) feedback control are recently studied for the control of DE actuators. The control performance is still limited due to the complex dynamic behavior of DE actuators with both nonlinearities and modeling uncertainties. This paper proposes a model-based feedback control for DE actuator, considering nonlinearity of large deformation, electromechanical coupling, and the modeling uncertainties. A nonlinear motion model is proposed and verified by parameter identification experiments. Based on the nonlinear model, we demonstrate a robust control strategy including nonlinear model compensation and robust feedback to decrease the tracking error. The experimental results verify that the control strategy possesses excellent validity to the DE actuator with improved performance compared to the previous strategy of feedforward and PID feedback control. The system design and control strategy of this paper may guide the future design and application of DE actuators, soft robots, and flexible devices.

scholarly journals Bio-inspired untethered fully soft robots in liquid actuated by induced energy gradients

2019 ◽  
Vol 6 (5) ◽  
pp. 970-981 ◽  
Author(s):  
Liang Xiong Lyu ◽  
Fen Li ◽  
Kang Wu ◽  
Pan Deng ◽  
Seung Hee Jeong ◽  
...  
Keyword(s):  
Energy Density ◽  
Mechanical Performance ◽  
Soft Materials ◽  
High Energy ◽  
High Energy Density ◽  
Soft Robot ◽  
Soft Robots ◽  
Power Sources ◽  
Practical Applications ◽  
Robot Swarm

Abstract Soft robotics with new designs, fabrication technologies and control strategies inspired by nature have been totally changing our view on robotics. To fully exploit their potential in practical applications, untethered designs are preferred in implementation. However, hindered by the limited thermal/mechanical performance of soft materials, it has been always challenging for researchers to implement untethered solutions, which generally involve rigid forms of high energy-density power sources or high energy-density processes. A number of insects in nature, such as rove beetles, can gain a burst of kinetic energy from the induced surface-energy gradient on water to return to their familiar habitats, which is generally known as Marangoni propulsion. Inspired by such a behavior, we report the agile untethered mobility of a fully soft robot in liquid based on induced energy gradients and also develop corresponding fabrication and maneuvering strategies. The robot can reach a speed of 5.5 body lengths per second, which is 7-fold more than the best reported, 0.69 (body length per second), in the previous work on untethered soft robots in liquid by far. Further controlling the robots, we demonstrate a soft-robot swarm that can approach a target simultaneously to assure a hit with high accuracy. Without employing any high energy-density power sources or processes, our robot exhibits many attractive merits, such as quietness, no mechanical wear, no thermal fatigue, invisibility and ease of robot fabrication, which may potentially impact many fields in the future.

scholarly journals Performance-tuning of PVA-based gel electrolytes by acid/PVA ratio and PVA molecular weight

2021 ◽  
Vol 3 (3) ◽  
Author(s):  
Saeideh Alipoori ◽  
M. M. Torkzadeh ◽  
Saeedeh Mazinani ◽  
Seyed Hamed Aboutalebi ◽  
Farhad Sharif
Keyword(s):  
Molecular Weight ◽  
Ionic Conductivity ◽  
Charge Carrier Concentration ◽  
Fine Tuning ◽  
Performance Tuning ◽  
Practical Applications ◽  
High Performing ◽  
Flexible Devices ◽  
Gel Electrolytes ◽  
Ion Conducting

AbstractThe significant breakthroughs of flexible gel electrolytes have attracted extensive attention in modern wearable electronic gadgets. The lack of all-around high-performing gels limits the advantages of such devices for practical applications. To this end, developing a multi-functional gel architecture with superior ionic conductivity while enjoying good mechanical flexibility is a bottleneck to overcome. Herein, an architecturally engineered gel, based on PVA and H3PO4 with different molecular weights of PVA for various PVA/H3PO4 ratios, was developed. The results show the dependence of ionic conductivity on molecular weight and also charge carrier concentration. Consequently, fine-tuning of PVA-based gels through a simple yet systematic and well-regulated strategy to achieve highly ion-conducting gels, with the highest ionic conductivity of 14.75 ± 1.39 mS cm-1 have been made to fulfill the requirement of flexible devices. More importantly, gel electrolytes possess good mechanical robustness while exhibiting high-elasticity (%766.66 ± 59.73), making it an appropriate candidate for flexible devices.

scholarly journals Self-excited air flow passage changing device for periodic pressurization of soft robot

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Toshio Takayama ◽  
Yusuke Sumi
Keyword(s):  
Mobile Robot ◽  
Rotational Motion ◽  
Air Pressure ◽  
Soft Robot ◽  
Pressure Source ◽  
Large Delay ◽  
Soft Robots ◽  
Flow Passage ◽  
Output Pressure ◽  
Air Chamber

AbstractRecently pneumatic-driven soft robots have been widely developed. Usually, the operating principle of this robot is the inflation and deflation of elastic inflatable chambers by air pressure. Some soft robots need rapid and periodic inflation and deflation of their air chambers to generate continuous motion such as progress motion or rotational motion. However, if the soft robot needs to operate far from the air pressure source, long air tubes are required to supply air pressure to its air chambers. As a result, there is a large delay in supplying air pressure to the air chamber, and the motion of the robot slows down. In this paper, we propose a compact device that changes its airflow passages by self-excited motion generated by a supply of continuous airflow. The diameter and the length of the device are 20 and 50 mm, respectively, and can be driven in a small pipe. Our proposed in-pipe mobile robot is connected to the device and can move in a small pipe by dragging the device into it. To apply the device widely to other soft robots, we also discuss a method of adjusting the output pressure and motion frequency.

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