Identification and Control of a Nonlinear Soft Actuator and Sensor System
Identification and Control of a Nonlinear Soft Actuator and Sensor System
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DOI：
10.1109/lra.2020.2982056
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发表时间：
2020-07-01
影响因子：
5.2
通讯作者：
Rentschler, Mark E.
中科院分区：
文献类型：
--
作者：
Johnson, Brian K.;Sundaram, Vani;Rentschler, Mark E.
软机器人正变得越来越普遍，在医疗设备和可穿戴技术中具有独特的应用。了解非线性软执行器的动力学对于创建可控软机器人至关重要。这封信介绍了可折叠 HASEL（液压放大自愈静电）软执行器的系统识别过程和闭环控制。我们通过线性频率响应测试来表征可折叠 HASEL，并使用静态和动态项的线性叠加对其进行建模。我们还确定了系统的两种反应：激活反应和松弛反应。基于这两个响应，我们开发了一种双模式控制器，该控制器使用缠绕在执行器周围的电容式弹性体应变传感器通过闭环控制进行了验证。使用该集成传感器，我们在负载下实现了快至 0.025 秒的阶跃响应上升时间和快至 0.17 秒的稳定时间。这些系统识别和控制技术可以应用于任何HASEL驱动的软机器人，也可以应用于其他软执行器以实现可控软机器人。
Soft robots are becoming increasingly prevalent, with unique applications to medical devices and wearable technology. Understanding the dynamics of nonlinear soft actuators is crucial to creating controllable soft robots. this letter presents a system identification process and closed-loop control of foldable HASEL (hydraulically amplified self-healing electrostatic) soft actuators. We characterized foldable HASELs with linear frequency response tests and modeled them using a linear superposition of static and dynamic terms. We also identified two responses of the system: an activation and relaxation response. Based on these two responses, we developed a dual-mode controller which was validated through closed-loop control using a capacitive elastomeric strain sensor wrapped around the actuator. Using this integrated sensor, we achieved step response rise times as fast as 0.025s and settling times as fast as 0.17s while under load. These system identification and control techniques can be applied to any HASEL-driven soft robot and could be applied to other soft actuators to enable controllable soft robots.