Applied Mechanics and Materials Vols. 416-417

Abstract: This paper presents the design and control of a magnetically suspended ceiling actuator which combines four iron-cored linear actuators and a checkerboard permanent magnet array for an infinite planar stroke. When the actuators are rotated with respect to the PM array, it is shown that the thrust and normal force produced by the three-phase linear actuators can be controlled by applying Park's transformation. The design of the iron-cored linear actuators is optimized for minimum losses when the translator inside the ceiling actuator and a payload are accelerated in the xy-plane. The optimization is performed using an analytical model is. Simulations of the optimized design with a 3D FE-model, show a maximum tracking error of 1 μm and rotations of 30 μrad when the translator is moved and controlled in 6 DOF.

Abstract: A high efficient current control strategy of the Stirling linear generators was investigated in this paper. The structure of the linear generator was introduced and mathematical model was built. The efficiency of the system is compared in different current modes. The highest efficiency control strategy is calculated in the conditions of without magnetic saturation, iron-loss, mechanical loss and treating inductance as a constant. At the same time, the maximum ratio of the electromagnetic power to current control is realized. Finally, this algorithm was validated in the simulation and experiment.

Abstract: electromechanical actuator (EMA) as the integrated actuation system used in more aircraft has the advantages of both small size and high power density. Dual-redundancy permanent magnet brushless machine system used in EMA improves aircraft control actuator working reliability. The system topology is proposed by the analysis of different kinds of redundancy running modes and structures of dual-redundancy machine. The cause and consequence of unequal torque in two redundancy machines are analyzed. The equal torque is realized by using crossed-feedback control and piecewise linear interpolation methods. Experimental results show that the method can effectively eliminate torque unequal. The experimental results show that the proposed control strategies are suituble for this system operation under different various complicated conditions such as in the rated operation, step response and frequency response.

Abstract: The hoist system driven by Permanent Magnet Linear Synchronous Motor (PMLSM) is a revolutionary new technology for high-rise buildings and ultra-deep mine, but also requiring new technology to enhance reliability and improve customer service. Condition monitoring (CM) is a technique or a process of monitoring the operating characteristic of a physical system. By studying on the structure and operating characteristics of PMLSM driven hoisting system, the paper proposes an on-line condition monitoring system for PMLSM driven hoisting system, which can monitor the operation parameters, give faults have occurred, and identify the root cause of the fault. The fault models and condition monitoring soft are designed. The obtained results are expected to be useful for PMLSM driven hoisting system.

Abstract: A novel control platform for the permanent magnet linear synchronous motor (PMLSM) drive system has been built up based on virtual instrument (VI) and relavant data acquisition card (DAQ) devices. In the traditional control platform, it mostly depends on digital signal processor (DSP), which needs a lot of time to further develop the interface between the personal computer (PC) and operators, and its computational capability is not strong than computer. To overcome these shortages, a novel control platform is presented on the base of one PC, one LabVIEW, and one multifunctional data acquisition card. Firstly, a space vector pulse width modulation (SVPWM) signal source is executed in the VI. Then in order to improve the precision of control system, the field oriented control (FOC) is proposed for the PMLSM. Finally comprehensive experiments verify with relative simulations.

Abstract: Traditional space vector pulse-width modulation (SVPWM) algorithm included complex calculations like triangle functions and square root, which increased execution time of the program. A novel SVPWM algorithm calculating modulation functions of three phases through stationary αβ components of reference voltage vectors was proposed here to solve the problem, which was composed of only simple four arithmeticoperations. The method simplified traditional SVPWM and improved real-time performance of digital control system. However, dead-time effect still existed in novel SVPWM algorithm. And it will lead to distortions of low speed direct-drive PMSM phase currents, brought increase of speed fluctuation, resulted in unstable operating of servo system. This paper analyzed details of error voltage vectors led by dead-time effect, researched relationship between error voltage vectors and polarities of three phase currents, and put forward a novel dead-time compensation strategy that decreased influence of zero current clamping. Simulation results showed that this strategy can effectively compensate effects of dead-time error voltage vector and improve wave forms of phase currents, which increased operating performance of low speed direct-drive PMSM.

Abstract: In this paper, the multi-segmented PMLSM mathematics model of dual inverters power supply strategy is established through the profound research on the changing rules of inductance and coupling flux linkage, based on the mechanical and electromagnetic structural characteristics of the motor. Meanwhile, according to the model, the thesis puts forward the novel combined direct thrust control (DTC) algorithm for both contiguous segment observed flux linkage and thrust, which overcome the practical difficulties of conventional DTC algorithm applied for multi-segmented PMLSM. Theoretical analysis illustrates that this algorithm not only maintains high-transient response of DTC but also minimizes inter-segment thrust ripple in segmented PMLSM. Simulation demonstrates that this controlled method presents the favorable effects of the steady and transient states even in the process of mover operations between segments.

Abstract: The ultrasonic technique is a new method for detecting the borehole sediment thickness and has been gradually developed in recent years. However, there are still several key technologies needing to be further studied and developed. This paper focuses on studying and designing the ultrasonic processing circuits including the mono-stable flip-flop circuit, the driving circuit, the amplification filtering circuit and the automatic gain control circuit. Under the environment of Multisim10.0, the designed circuits are simulated. The results show that the deigned ultrasonic driving circuit has a strong driving capacity and is capable of completely meeting the bandwidth requirements in measuring the sediment thickness by ultrasonic. The automatic gain control circuit is capable of strengthening the ultrasonic signal in a time varying mode so that the output signal can be kept stable within the given range. So it has a significant effect on the ultrasonic measurement of sediment; the designed amplification, filter bandwidth and the quality value can all meet the system requirements. Meanwhile, the integrated filter is adopted and few peripheral components are used, therefore, the system design is greatly simplified.

Abstract: A three-degree-of-freedom (3-DOF) dynamic model based interval type-2 recurrent fuzzy neural network (IT2RFNN) control system is proposed in this study for a gantry position stage. To consider the effect of inter-axis mechanical coupling, a Lagrangian equation based 3-DOF dynamic model for gantry position stage is derived first. Then, to minimize the synchronous error and tracking error of the gantry position stage, the 3-DOF dynamic model based IT2RFNN control system is proposed. In this approach, the adaptive learning algorithms of the IT2RFNN on-line are derived from the Lyapunov stability theorem. Finally, some experimental results of optical inspection application are illustrated to show the validity of the proposed control approach.

Abstract: In this paper, a novel current control strategy of precise current source is presented, which combines switch power conversion mode with linear amplification mode. The linear power amplifier is used as the power converter in the current loop. The current controller is a double cascaded PI (DCPI) controller which is put up by the way of analog circuit, it can suppress the high frequency disturbance signal effectively. The switch-filter circuit can generate a special power supply for linear power amplifier, the voltage of this special power supply changes as the load voltage does. The topology of four-level H-Bridge works as the power converter of the switch power amplifier, the LC filter circuit can eliminate the current ripple caused by the PWM chopper.The simulation and experimental results verify that the Switch-Linear Hybrid (SLH) scheme is of high efficiency and output quality. The bandwidth of the precise current source is 5.4 kHz and the phase margin is 42 degree.