This brief presents the design of a fractional-order (FO) PI <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">λ</sup> D xmlns:xlink="http://www.w3.org/1999/xlink">μ</sup> controller and its application to stabilizing an FO solid-core magnetic bearing (MB) system. A practical numerical search method designing is proposed. By presearching orders λ μ in their calculated ranges, remaining three undetermined parameters can be first analytically solved...

Due to the effects of eddy current, solid-core magnetic bearings (MBs) show fractional-order characteristics. In this paper, a practical strategy for incommensurate system identification is adopted model MB. The structures are firstly determined by selecting number terms numerator and denominator in sequence, then derivative orders derived based on passive search within given range. By using weighed least squares method, coefficients operators calculated. Besides, modified error criterion...

Piezoelectric stack actuators (PESAs) are usually used in applications requiring a fast response, high resolution, and accuracy. Self-heating during continuous drive with large voltage amplitude at frequencies can damage PESAs limit the driving conditions. A sufficient cooling method is necessary to increase frequency amplitude. This paper proposes direct forced liquid system for experimentally numerically evaluates PESA temperatures when employing this system. Silicone oil, which an...

Estimation of the dynamic parameters bearings is essential in order to be able interpret performance rotating machinery. In this paper, we propose a method estimate flexible rotor system. By utilizing electromagnetic excitation generated by built-in PM motor and finite element (FE) modeling rotor, safe, low-cost, real-time monitoring bearing dynamics can achieved. The radial force injecting an alternating d-axis current into windings. FE model measured frequency responses at locations are...

In this paper, we propose a practical method for evaluating the robustness and stability of rotating machines. This entails using electromagnetic excitation measuring frequency response functions (FRFs) rotor system during rotation. The difficulty applying can be solved by utilizing built-in motor with static eccentricity adding sinusoidal sweep d-axis current to motor. A test rig bearingless (BELM) was used verify validity proposed method. consequent-pole-type BELM is combination radial...

Piezoelectric stack actuators (PESAs) are widely used in applications requiring a fast response, high resolution, and accuracy. The self-heating of PESA during continuous drive with large amplitude at frequencies can change its voltage displacement charge characteristics. These changes lead to loss stability inaccurate positioning systems. In this paper, we confirmed that by using our proposed forced liquid cooling, the dynamic characteristics impedance due fact could be reduced. Voltage...

This paper presents the application and design of digital charge control (DCC) for reducing nonlinearity in fast steering mirrors (FSMs) driven by piezoelectric actuators (PEAs). By measuring impedance, equivalent RC parallel circuit model PEA electrical domain is verified DCC evolved from general analog (ACC) a single introduced. To apply this solution to two-degree-of-freedom (2-DOF) FSM with three PEAs, proposed perspective DOFs. Based on an identified model, improved controller taking...

Laser scanning systems for laser micro drilling and optical inter-satellite communication have required fast steering mirrors (FSMs) with a large diameter. However, increasing the mirror diameter makes positioning more difficult because elastic mode of occurs at lower frequency. To solve problem, segmented FSM, in which several small actuators having higher natural frequencies work together to produce same reflective surface as generates, is proposed. The final target this research achieve...

This work proposes a noise suppression and disturbance rejection control (NSDRC) strategy for piezo-actuated nanopositioning stages to achieve high bandwidth, strong ro-bustness, suppression. In NSDRC, reduction observer (NRDO) is designed based on the identified third-order model. Then, design procedure of tracking controller analyzed in error domain. A full-loop optimization scheme developed improve performance. Finally, effectiveness NSDRC verified by simulation time domain frequency...

Abstract In this article, we propose a liquid cooling solution to reduce the temperature rise and expand working range of stacked piezoelectric actuators (PEAs) for high-frequency large-stroke operation. Based on an analysis preliminary testing power dissipation rise, specific single PEA is designed its effectiveness verified through experiments. To incorporate into high-bandwidth fast steering mirror (FSM) system driven by PEAs, compact self-contained unit proposed evaluated. Subsequent...