Modeling and Control of Artificial Muscles Actuated Systems with Applications to Biomedical Systems

在过去的十年里，电活性聚合物，一个新的家庭的智能材料，已收到巨大的兴趣，其潜在的应用在传感，驱动，和能量收集。其中，离子聚合物-金属复合材料（IPMC）形成电活性聚合物的重要类别，并且具有内置的致动和感测能力。由于IPMC的柔软性、弹性、生物相容性和在低动作电压下产生大变形的能力，IPMC作为生物医学应用中的致动器或传感器的材料以及用于开发人工肌肉或仿生机器人的材料是非常有吸引力的。然而，IPMC驱动系统反映了高度非线性特性，包括蠕变，滞后，结构非线性，和时变行为，等等，严重限制了系统的性能。如果没有反馈控制技术的帮助来克服这些影响，则仅可能实现有限的定位精度。由于现有的控制方法大多只适用于光滑可微的系统，因此对具有迟滞非线性的IPMC驱动系统的控制是一个非常困难的问题。然而，新的方法是非常需要的，因为滞后非线性往往严重限制了反馈系统的性能，如果他们没有得到适当的控制。因此，IPMC驱动系统的特性和控制技术的发展是有意义的理论和实际应用的兴趣。本研究的目的是进行基础研究的IPMC驱动系统的建模和控制，涉及复杂的滞后模型的不确定性的存在。目标应用包括生物医学系统，如人工肌肉驱动单元和仿生机器人。

Over the last decade, electroactive polymers, a novel family of smart materials, have received tremendous interests for their potential applications in sensing, actuation, and energy harvesting. Therein, ionic polymer-metal composites (IPMCs) form an important category of electroactive polymers and have built-in actuation and sensing capabilities. Owing to the IPMCs' softness, resilience, biocompatibility and the capability of producing large deformation under a low action voltage, IPMCs are highly attractive as a material for actuators or sensors in biomedical applications and for developing artificial muscles or biomimetic robots. However, the IPMC actuated systems reflect highly nonlinear characteristics observed in both electrical and mechanical responses including creep, hysteresis, structural nonlinearity, and time-varying behaviors, and so on, which severely limits system performance. Without the aid of feedback control techniques to overcome the these effects, it is only possible to achieve limited positioning accuracy. Control of the IPMC actuated systems including hysteresis nonlinearity are very difficult problems because the vast majority of existing control methods are only applicable to systems that are smooth and differentiable. New methods, however, are greatly needed because hysteresis nonlinearities often severely limit the performance of feedback systems if they are not controlled properly. Therefore, the development of characterizing and control techniques for IPMC actuated systems is of significant theoretical and practical interest for their applications. The objective of this research is to conduct fundamental research related to modeling and control of the IPMC actuated systems involving complex hysteresis in the presence of model uncertainties. The targeted applications includes biomedical systems such as artificial muscle actuating units and biomimetic robots.