In this article, we present a sensorless stiffness control (SC) architecture for a soft dielectric elastomer (DE) membrane actuator. The method relies on a self-sensing algorithm that exploits measurements of electrical quantities (i.e., membrane voltage and current) to perform a real-time estimation of DE displacement and force. By combining self-sensing feedback with a SC algorithm, active shaping of the membrane force-displacement response is achieved without introducing additional electro-mechanical sensors in the system, thus, making it possible to design compact, lightweight, and low-cost DE robotic systems. A description of the novel self-sensing scheme is initially performed. To cope with the strong system nonlinearity, a robust design method to synthesize a SC law is subsequently proposed. An extensive experimental campaign is, then, carried out, with the goal of evaluating the performance of both sensor-based and sensorless SC. Quantitative accuracy of both control architectures is finally assessed and compared.

中文翻译：

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迈向无传感器软机器人：介电弹性体执行器的自感刚度控制

在本文中，我们介绍了一种用于软介电弹性体 (DE) 膜致动器的无传感器刚度控制 (SC) 架构。该方法依赖于利用电量（即膜电压和电流）的测量值来执行 DE 位移和力的实时估计的自感应算法。通过将自感反馈与 SC 算法相结合，无需在系统中引入额外的机电传感器即可实现膜力-位移响应的主动成形，从而可以设计紧凑、轻便且低成本的 DE 机器人系统。最初执行对新颖的自感方案的描述。为了应对强大的系统非线性，随后提出了一种综合 SC 定律的鲁棒设计方法。那么，一个广泛的实验活动是，目的是评估基于传感器和无传感器 SC 的性能。最后评估和比较两种控制架构的定量准确性。