Aggogeri Francesco, Pellegrini Nicola, Tagliani Franco Luis
Department of Mechanical and Industrial Engineering, University of Brescia, Via Branze, 38, 25123 Brescia, Italy.
Sensors (Basel). 2021 Nov 20;21(22):7739. doi: 10.3390/s21227739.
The paper aims to present a mechatronic device able to micro-position the workpiece and to reject disturbances due to machining operation. A decoupling method is proposed for a parallel kinematic machine (PKM) fixturing platform composed by a 3-DoF flexure-based piezo-actuated mechanism. The parallel platform, with a vertical motion and two rotations, is described and its kinematics and dynamics are studied. The coupling undesirable effect is investigated based on a set of poses. To improve the quasi-static regulator model for a set-point following system, a bump less switching controller and a fine-tuning procedure, to estimate the parameter uncertainty and enable the external disturbance containment in an extended broadband frequency range, are presented. The platform and the piezo-actuator controllers are modelled based on a gain scheduling, standard ISA form method, to guarantee the stability. The accuracy is demonstrated through a set of simulations and experimental comparisons. A sensitivity analysis that evaluates the tracking performance and the disturbance rejection based on the number of signal amplitudes, frequencies, and phases is discussed. A validation phase has shown that the developed architecture presents a steady state error lower than 1.2 µm, a vibration reduction of 96% at 1130 Hz with a maximum resolving time of 6.60 ms.
本文旨在介绍一种机电一体化设备，该设备能够对工件进行微定位，并消除加工操作产生的干扰。针对一种由三自由度基于柔性铰链的压电驱动机构组成的并联运动机床（PKM）装夹平台，提出了一种解耦方法。描述了具有垂直运动和两个旋转自由度的并联平台，并对其运动学和动力学进行了研究。基于一组位姿研究了耦合不良效应。为改进设定点跟踪系统的准静态调节器模型，提出了一种无冲击切换控制器和一种微调程序，以估计参数不确定性并在扩展的宽带频率范围内实现外部干扰抑制。基于增益调度、标准ISA形式方法对平台和压电致动器控制器进行建模，以确保稳定性。通过一组仿真和实验比较验证了精度。讨论了基于信号幅度、频率和相位数量评估跟踪性能和干扰抑制的灵敏度分析。验证阶段表明，所开发的架构稳态误差低于1.2 µm，在1130 Hz时振动降低96%，最大分辨时间为6.60 ms。
