This study proposes a switching proportional-derivative (PD) controller for a press platform for inspecting the surfaces of a wind turbine blade. We use the Hunt-Crossley model to represent the probe shape or the nonlinearity of the inspection platform. This model consists of a nonlinear spring and a damper; therefore, it is more accurate than linear spring-damper models. We prove the global asymptotic stability of a PD force feedback controller and a PD position feedback (force) controller. However, both the controllers suffer from implementation-related problems. Specifically, the PD force feedback controller makes the impact force large, and the PD position feedback controller cannot easily measure small position changes when the platform contacts the surface. These problems of each controller are solved by switching the two controllers. The PD force feedback control and PD position feedback control are used when the platform is in the contact and noncontact states, respectively. We prove that the proposed switching PD force/position feedback controller is globally asymptotically stable. Further, simulations show satisfactory performance resulting from stable switching between the two control schemes.

本研究提出了一种用于检测风力涡轮机叶片表面的压力平台的切换比例微分 (PD) 控制器。我们使用 Hunt-Crossley 模型来表示检测平台的探头形状或非线性。该模型由非线性弹簧和阻尼器组成；因此，它比线性弹簧阻尼器模型更准确。我们证明了 PD 力反馈控制器和 PD 位置反馈（力）控制器的全局渐近稳定性。然而，这两个控制器都存在与实现相关的问题。具体来说，PD力反馈控制器使冲击力较大，而PD位置反馈控制器无法轻易测量平台接触表面时的微小位置变化。每个控制器的这些问题都是通过切换两个控制器来解决的。PD力反馈控制和PD位置反馈控制分别在平台处于接触和非接触状态时使用。我们证明了所提出的切换 PD 力/位置反馈控制器是全局渐近稳定的。此外，仿真显示两种控制方案之间的稳定切换产生了令人满意的性能。