No abstract

No abstract

In precision micromanipulation tasks, operation accuracy and anti-disturbance performance of micromanipulators are critical. This paper presents anti-disturbance control for a piezo-driven micromanipulator with a non-minimum phase. The micromanipulator is constructed by mounting a flexible manipulator on a parallel positioning stage. The micromotion and dynamic behavior of the micromanipulator are analyzed. Then, an anti-disturbance control strategy combining H-infinity feedback control and disturbance observer-based control for a non-minimum phase is designed to reduce disturbances and ensure control accuracy. Finally, the experimental measurement and control system is built. The observed phenomena show that sinusoidal disturbances are almost eliminated and the overshoot of step disturbances is significantly reduced. In addition, the time for suppressing the step disturbance is shortened from 0.9 to 0.3 s. Experiments verify the viability of the anti-disturbance control strategy.

The aim of this paper was to improve the automation of track inspection, data utilization rate, informationization of maintenance dispatch. We designed a track inspection vehicle based on multi-sensor information fusion, then gave the method of coordinate transformation and data fusion. And then researched the service of data displaying, data management and data analysis, proposed the system architecture and network topology, realized the system deployment on the cloud. And then demonstrated stability by comparing the results of two machine tests, and proved accuracy by comparing the results of machine tests with manual tests. The result shows that it had a high accuracy and stability. At last, designed the reserve of cloud platform function extension, discussed the method of data analysis. Research shows that, the track inspection vehicle can measure the track geometric parameter. The application of cloud platform technology can reduce the cost of operation, simplify the function extension. The research result has a positive impact on solving the current problem of track inspection, improving passenger comfort and ensuring safe operation.

The article covers structural design and disturbance rejection control of a flexure-based compliant piezoelectric nanopositioning stage. The stage is devised using four-bar amplification mechanisms, auxiliary guiding mechanisms, and a compound parallelogram mechanism. Static and dynamic models of compliant mechanisms are analyzed based on a compliance matrix method. A modified Prandtl-Ishlinskii (PI) model with dead zone operators is used to describe the asymmetric hysteresis. Then, a global electromechanical dynamic model is built and identified. A comprehensive disturbance rejection controller (CDRC) combining a robust H∞ control and a disturbance observer-based (DOB) control is proposed for high trajectory tracking accuracy and anti-disturbance performance. The trajectory tracking accuracy of the stage can be up to 3 nm in experiments. As amplitudes of reference signals increases, relative tracking errors gradually decrease. System instability and oscillation caused by strong external disturbances are also reduced. Experimental results prove the effectiveness of the developed CDRC.