A dynamic electrically driven soft valve for control of soft hydraulic actuators
A dynamic electrically driven soft valve for control of soft hydraulic actuators
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DOI：
10.1073/pnas.2103198118
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发表时间：
2021-08
期刊：
影响因子：
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通讯作者：
Siyi Xu;Yufeng Chen;N. P. Hyun;Kaitlyn P. Becker;R. Wood
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作者：
Siyi Xu;Yufeng Chen;N. P. Hyun;Kaitlyn P. Becker;R. Wood
重要意义软驱动器由于其健壮性、低机械刚度和低重量，在各种应用中都比传统的刚性机器人具有优势。到目前为止，传统的刚性阀是控制液压软执行器最常用的方法。尽管软阀的设计形式多种多样，但它们并没有达到许多现有液压执行器所要求的压力或流量条件。本文介绍了一种采用动态介质弹性体作动器(DEAS)的电驱动软阀。这些软阀具有快速的响应时间，并能够控制流体压力和流量，以满足带有中尺度通道的液压执行器的需要。DEA阀门为未来的流体软机器人提供了软车载控制的可能性。流体驱动软机器人的调节系统主要由僵硬和笨重的部件组成。这些僵硬的结构极大地限制了这些机器人的适应性和机动性。用于流体执行器的各种形式的软阀已经被开发出来，主要是流体驱动或电驱动。然而，流体软阀需要限制机器人运动的外部压力源。最先进的静电阀不能以足够的流量(>；6毫升⋅min−1)调节超过3.5kpa的压力。在这项工作中，我们提出了一种用于中尺度通道液压执行器的电动软阀，该软阀是基于另一类超高功率密度动态介质弹性体执行器的。动态介电弹性体致动器(DEAS)的激励频率为500赫兹或更高。与以往的动态DEA相比，这些DEA产生的阻塞力提高了300%，其工作状态下的负载功率密度达到290W⋅kg−1。开发的软阀具有紧凑型(7 mm高)和轻量化(0.35g)动态DEAS，能够有效控制高达51 kpa的压力和40毫升⋅Min−1流量，响应时间小于0.1 S。这些阀还可以根据其驱动电压调整流量。利用DEA软阀演示了对不同体积的液压执行器的控制，实现了对单个压力源驱动的多个执行器的独立控制。这种紧凑、轻便的DEA阀能够对液压执行器进行前所未有的电气控制，显示出未来软流体驱动机器人的板载运动控制的潜力。
Significance Soft actuators have advantages over traditional rigid robots in various applications due to their robustness, low mechanical stiffness, and low weight. Thus far, conventional rigid valves are the most common approach to control hydraulic soft actuators. Although soft valves have been designed in various forms, they have not achieved the pressure or flow rate conditions as required by many existing hydraulic actuators. In this paper, we introduce an electrically driven soft valve using dynamic dielectric elastomer actuators (DEAs). These soft valves have a fast response time and are able to control fluidic pressure and flow rates that match the needs of hydraulic actuators with mesoscale channels. The DEA valves enable possibilities for soft onboard controls for future fluidic soft robots. Regulation systems for fluid-driven soft robots predominantly consist of inflexible and bulky components. These rigid structures considerably limit the adaptability and mobility of these robots. Soft valves in various forms for fluidic actuators have been developed, primarily fluidically or electrically driven. However, fluidic soft valves require external pressure sources that limit robot locomotion. State-of-the-art electrostatic valves are unable to modulate pressure beyond 3.5 kPa with a sufficient flow rate (>6 mL⋅min−1). In this work, we present an electrically powered soft valve for hydraulic actuators with mesoscale channels based on a different class of ultrahigh-power density dynamic dielectric elastomer actuators. The dynamic dielectric elastomer actuators (DEAs) are actuated at 500 Hz or above. These DEAs generate 300% higher blocked force compared with the dynamic DEAs in previous works and their loaded power density reaches 290 W⋅kg−1 at operating conditions. The soft valves are developed with compact (7 mm tall) and lightweight (0.35 g) dynamic DEAs, and they allow effective control of up to 51 kPa of pressure and a 40 mL⋅min−1 flow rate with a response time less than 0.1 s. The valves can also tune flow rates based on their driving voltages. Using the DEA soft valves, we demonstrate control of hydraulic actuators of different volumes and achieve independent control of multiple actuators powered by a single pressure source. This compact and lightweight DEA valve is capable of unprecedented electrical control of hydraulic actuators, showing the potential for future onboard motion control of soft fluid-driven robots.