Adaptive Energy Shaping Control of a Class of Nonlinear Soft Continuum Manipulators
Adaptive Energy Shaping Control of a Class of Nonlinear Soft Continuum Manipulators
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DOI：
10.1109/tmech.2021.3063121
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发表时间：
2022-02-01
影响因子：
6.4
通讯作者：
Astolfi, Alessandro
中科院分区：
文献类型：
--
作者：
Franco, Enrico;Garriga-Casanovas, Arnau;Astolfi, Alessandro
软连续体机械臂的特点是刚度低，允许在非结构化环境中安全操作，但会引入欠驱动。此外，通常用于软操纵器的软材料（例如硅橡胶）的特征在于非线性刚度，而气动致动可导致非线性阻尼。因此，在存在干扰的情况下实现这些系统的精确控制是一项具有挑战性的任务。本文研究了具有非线性均匀刚度和非线性阻尼、在内压作用下发生弯曲以及受到时变扰动的柔性连续体机械臂的基于模型的自适应控制问题。一个刚性连接模型与虚拟弹性关节内的端口哈密顿框架内的控制目的。扰动和模型不确定性的影响自适应估计。一个非线性控制器，调节机械手的尖端方向，并补偿干扰和模型不确定性的影响，然后通过使用能量成形无源性为基础的方法构建。稳定性条件进行了讨论，突出非线性阻尼的有益作用。控制器的有效性进行评估与仿真和实验上的软连续体机械手原型。
Soft continuum manipulators are characterized by low stiffness that allows safe operation in unstructured environments but introduces underactuation. In addition, soft materials such as silicone rubber, which are commonly used for soft manipulators, are characterized by nonlinear stiffness, while pneumatic actuation can result in nonlinear damping. Consequently, achieving accurate control of these systems in the presence of disturbances is a challenging task. This article investigates the model-based adaptive control for soft continuum manipulators that have nonlinear uniform stiffness and nonlinear damping, that bend under the effect of internal pressure, and that are subject to time-varying disturbances. A rigid-link model with virtual elastic joints is employed for control purposes within the port-Hamiltonian framework. The effects of disturbances and model uncertainties are estimated adaptively. A nonlinear controller that regulates the tip orientation of the manipulator and that compensates the effects of disturbances and of model uncertainties is then constructed by using an energy shaping passivity-based approach. Stability conditions are discussed highlighting the beneficial role of nonlinear damping. The effectiveness of the controller is assessed with simulations and with experiments on a soft continuum manipulator prototype.