Mi-Ching Tsai

National Cheng Kung University, 臺南市, Taiwan, Taiwan

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Publications (74)64.06 Total impact

  • Mi-Ching Tsai, Po-Wen Hsueh
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    ABSTRACT: Wheelchairs used by disabled people or caregivers are typical human-in-the-loop systems, of which the power-assisted control in accordance to a human’s perception is essential. This paper presents a force sensorless control based on a force/torque observer with a motion coordinate transformation for power-assisted wheelchairs. The output linear movement and angular velocity motions of a power wheelchair can be controlled independently by inherent coupling dual-driving-wheels with this transformation. A force observer design without numerical differentiation, which is utilized to indirectly measure the human’s pushing force, is proposed for realizing the force sensorless power-assisted control. An assistant performance index is adopted to evaluate the validity of the power-assisted control according to a specified power-assisted gain. Experimental results show that the proposed method can effectively estimate the human force exerted on the wheelchair for achieving power-assisted control.
    Mechatronics 12/2013; 23(8):1014–1024. · 1.82 Impact Factor
  • Wu-Sung Yao, Mi-Ching Tsai, Yutaka Yamamoto
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    ABSTRACT: Time-varying periodic motions have appeared in many industrial processes, such as cam-follower systems, in that the control system has to operate at a periodic variable velocity specified in terms of the angular position-domain. This paper employs a repetitive control for rejecting the time-varying periodic disturbances, and presents an implementation technique based on angular position which can generate a fixed number of cycles in real-time. This control technique can accommodate the period variation in a time-varying periodic signal such that variable samples per period for synchronization can be achieved by the regular fixed-time sampling rate. A technique using position information to manipulate the delayed data and an interpolation scheme to properly access data in the buffer memory is proposed. An anti-vibration control system with time-varying periodic disturbances is studied to illustrate control performance. The experimental results are given to illustrate that time-varying repetitive control can effectively eliminate steady-state errors within a few cycles.
    Control Engineering Practice 09/2013; 21(9):1226–1237. · 1.67 Impact Factor
  • Po-Wei Huang, Mi-Ching Tsai
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    ABSTRACT: This paper presents an investigation into the effect of the reactance on a V-shaped line start permanent magnet motor. Five rotor designs with different V-shaped angles are utilized for exploring motor characteristics with the reactance. Performances such as back electromotive force, d- and q-axis reactance, loading capability and efficiency are simulated and analyzed by the torque model and a time stepped two-dimensional finite element software application. According to the comparison, the variations of output behaviors with d- and q-axis reactance can be described. Moreover, the design which features both excellent synchronization capability and high efficiency was verified by experiment on a prototype.
    IEEE Transactions on Magnetics 05/2013; 49(5):2311-2314. · 1.42 Impact Factor
  • Jyun-Ci Chen, Po-Wen Hsueh, Mi-Ching Tsai
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    ABSTRACT: The aim of this study is to develop the control approach of a belt-driven cycling device for lower-limb rehabilitation by providing passive movement therapy training at a stable cycling speed. To achieve stable cycling speed, the speed controller design is based on a two-inertia system model, which is established for the cycling device incorporating the transmission belt. The proposed minimum complexity controller method features a speed control design employing acceleration information feedback to successfully reduce vibration. Simulations and experimental results are presented to validate the feasibility of the proposed control system.
    02/2013;
  • Sheng-He Wang, Mi-Ching Tsai
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    ABSTRACT: Noncontact tweezers using acoustic levitation technology are useful for microhandling processes as they have fewer restrictions with materials or particle shapes. This has significant value in the development of composite materials and biotech industries where the contamination is an issue, such as the production of advanced microbiochips for health diagnostics. This involves the mixing of multiple components in a stable suspension of drops without a container. In this paper, a quasi-standing wave field generated by crossing two ultrasonic waves from piezoelectric transducers is adopted to develop acoustic tweezers. Compared with general single-axis acoustic levitation, the proposed acoustic tweezers can levitate small particles at pressure nodes without the need for a reflector and has the capability of 2-D movement. Additionally, a theoretical model of the proposed acoustic tweezers is derived such that the pressure distribution of the tweezers can be calculated from the operating conditions to determine the trapped position. With a 10° inclination and frequency of 27.6 kHz, a 400 Pa levitated pressure can be generated to float polystyrene spheres with a density of 16.37 kg/m3, and a 2 mm × 3 mm movement of the trapped position is demonstrated by adjusting the relative orientation and the relative distance of the two transducers, respectively. The simulation and experimental results demonstrate the effectiveness of the proposed acoustic tweezers' model to predict particle trapping.
    IEEE/ASME Transactions on Mechatronics 01/2013; 18(3):1019-1026. · 3.14 Impact Factor
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    ABSTRACT: Torque ripple is a very essential index for evaluating the effectiveness of a switched reluctance motor (SRM). Many common design strategies for reducing torque ripples of a SRM are (i) changing the excitation trigger angle of stator windings, (ii) delaying the cut-off time of winding excitation, (iii) adjusting the ratio of the arc angle between the stator and rotor, and (iv) changing the geometric shape of the rotor. However, the output torque or the efficiency of the SRM may drop as the above design strategies are solely adopted. In this paper, a hybrid design model which is obtained by the Taguchi Method for optimally designing a SRM with lower torque ripple and higher efficiency is presented. An 8P12S motor is taken as a study case, and the 3D finite element method (FEM) is applied to analyze the characteristics of the motor and optimize the design process. The results show that the proposed method can achieve the design goal of obtaining a high-performance SRM for light electric vehicle applications.
    Electrical Machines and Systems (ICEMS), 2013 International Conference on; 01/2013
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    ABSTRACT: The ability to sustain a smooth-running practice is very important in dentistry. Because of this reason, Electric handpieces driven by permanent magnetic synchronous motors (PMSMs) have been increasingly applied in dentistry and have replaced air-driven ones due to their high efficiency and ability to sustain constant speed while operating. Additionally, they produce little noise compared to the high pitched whine of their air-driven counterparts. As is well known, the rotor position is the necessary information for driving a PMSM. Unfortunately, a dental handpiece requires repeated heat sterilization that will break down the Hall sensors, and further, lacks the space to install an incremental encoder. Therefore, sensorless speed control of a PMSM is the key technology for an electric dental handpiece. In this paper, a sliding mode observer is used to implement an electric dental handpiece. Moreover, a prototype of the electric handpiece system has been designed and built. Experimental results are presented to verify the feasibility.
    Industrial Electronics (ISIE), 2013 IEEE International Symposium on; 01/2013
  • Po-Wei Huang, Mi-Ching Tsai
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    ABSTRACT: This paper presents the design of an actuator with high efficiency and auto-locking ability which features an additional holding force in the power-off condition. The operating principle of the auto-locking structure is based on the concept of flux switching. In the paper, an analytical method for computing the cogging torque of the two operating states (the moving and holding states) is developed. It is investigated that the actuator develops a holding force in the power-off condition which can be safely turned on using the auto-locking mechanism The torque characteristics for the auto-locking structure are also investigated using analytical and finite element analysis methods (using ANSYS 3D FEA software). A prototype is constructed and the experimental results are used to verify and validate the simulation results.
    IEEE Transactions on Magnetics 11/2012; 48(11):4622-4625. · 1.42 Impact Factor
  • Mi-Ching Tsai, Po-Wen Hsueh
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    ABSTRACT: How to maintain the speed and direction of a wheelchair simultaneously in an unknown environment is essential. This paper presents a prototype of the wheelchair driven by dual direct-drive wheel motors, and the synchronized control scheme of the wheelchair system according to the motion mode of a joystick is proposed. By analyzing the dynamic behavior of a wheelchair, the synchronized error of dual direct-drive wheel motors is derived and a synchronized motion control method is utilized to coordinate the output of a pair of wheel motors to significantly reduce the synchronized error. Simulation and experimental results are given to validate the performance of the synchronized motion control for the wheelchair system.
    Advanced Intelligent Mechatronics (AIM), 2012 IEEE/ASME International Conference on; 01/2012
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    ABSTRACT: It is known that permanent magnetic couplers (PMCs) are widely used for torque and speed transmissions. However, the current losses and the increased temperatures reduce the transmitting power of PMCs significantly. Therefore, in this paper, a slotted-type PMC is proposed mainly for improving the transmitting power and efficiency. To implement the proposed PMC structure, a mathematical model of the PMC is presented to obtain the design parameters. The simulation results show that the proposed PMC structure could offer higher torque under low slip speeds and can be applied in higher power-transmitting situations.
    Electrical Machines and Systems (ICEMS), 2012 15th International Conference on; 01/2012
  • Mi-Ching Tsai, Cheng-Chi Huang
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    ABSTRACT: This paper presents a mechanical device with controllable inertia, in which a magnetic planetary gearbox (PG) is employed to hold two free terminals (the carrier and sun gear) and one feedforward control terminal (the ring gear). Based on the concept of inerter design and impedance control, the ring-gear motor controls the equivalent inertia of the carrier. The sealless nature of the proposed noncontact magnetic PG provides a low-inertia design ability and an over-load protection characteristic for a high-torque transmission. The control block diagram technique is utilized to represent the dynamic model of the variable-inertia device for the equivalent-inertia derivation and computer simulation, in which its equivalent inertia can be found by the transfer function from the torque to the acceleration at the carrier. Finally, the dynamic model is verified by experiments, and the controlled range of the equivalent inertia is illustrated.
    IEEE/ASME Transactions on Mechatronics 01/2012; · 3.14 Impact Factor
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    ABSTRACT: In this paper, a motion trajectory detecting method that permits tracking of magnetic objects is investigated by the magnetic flux density of a 3-D Hall probe. Inaccurate motion trajectory information may be produced physically due to the measured magnetic field signal altering as the distance between the Hall probe and the object changes. A magnetic flux feedback control is proposed such that the motion command of the control system is generated in real time by the coordinated geometry of the Hall probe and the magnetic object. The magnetic tracking control system consists of an inner position/velocity control loop and an outer magnetic control loop that employs a position vector expressed in terms of the magnetic flux density to detect the relative distance between a magnetic object and the Hall probe. The measurement of the Hall probe can, hence, be kept within an effective distance such that the motion trajectory of the measured magnetic object can be detected accurately for the case of large movements. An experimental setup with a five-axis servo mechanism is constructed for the validation study, in which the three-axis moving table is utilized to control the motion of the Hall probe, and the other two-axis moving table facilitates the movement of the magnetic object. A circular motion and a rhomboidal path are given to verify the improvement of the proposed detecting method.
    IEEE/ASME Transactions on Mechatronics 01/2012; 17(4):709-716. · 3.14 Impact Factor
  • Yu-Sheng Hsu, Mi-Ching Tsai
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    ABSTRACT: This paper presents a novel transverse flux motor (TFM) which can significantly reduce the volume of the permanent magnets compared to conventional TFMs. To speed up the design process, an analytical technique based on a simplified two-dimensional model is developed to estimate the flux density and determine suitable parameters. The finite element analysis is then employed to refine the calculations and validate the analytical design. Excellent agreement between the simulation and experimental result shows that the proposed wheel motor design is suitable for direct-drive applications such as light electric vehicles.
    IEEE Transactions on Magnetics 11/2011; · 1.42 Impact Factor
  • Sheng-He Wang, Mi-Ching Tsai
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    ABSTRACT: This paper aims to provide an alternative method to determine the characteristics of a piezoelectric transducer from measurement. A block diagram approach is proposed to analyze the dynamic characteristics of a thickness-mode piezoelectric transducer at its resonance frequency. Based on the feedback loop framework, the input-output relations of the electromechanical interaction of the transducer are described in terms of linear block diagram models. Furthermore, the closed-loop relations from external force to vibration velocity and electric current from generated voltage are easily found by Mason's rule to characterize the equivalent mechanical admittance and electrical impedance, respectively. An example of a Langevin transducer with 28.15kHz resonance frequency is illustrated for dynamics analysis. The frequency responses of the piezoelectric transducer, resulting from a force and current input, are respectively measured to identify the system parameters of the feedback model. The experimental results demonstrate the effectiveness of the proposed method.
    Ultrasonics 07/2011; 51(5):617-24. · 2.03 Impact Factor
  • Yu-Sheng Hsu, Mi-Ching Tsai, Min-Fu Hsieh
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    ABSTRACT: The rare-earth permanent magnets adopted in transverse flux motors (TFMs) may cause manufacturing problems due to their strong magnetismasthemotorsizeandoutputpowerincrease.Forexample,largemagneticforcesmayattractferrousdebrisduringtheprocess of handling and assembling, and, hence, increase manufacturing cost. To solve the aforementioned problems, this paper applies the subassembly magnetization (SAM) strategy for a TFM. Finite element analysis was employed to design the SAM fixture such that the desired magnetization can be achieved. The SAM approach is advantageous for manufacturing the presented TFM using a ring magnet as the rotor. Simulation results confirm that the permanent magnet of the TFM can be successfully magnetized. Index Terms—Finite element analysis (FEA), subassembly magnetization (SAM), transverse flux motor (TFM).
    IEEE Transactions on Magnetics 01/2011; 47(10):3681-3684. · 1.42 Impact Factor
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    ABSTRACT: Generally, poor machining performance may occur due to the abrupt change of acceleration at the portion of a curve with large curvature. In order to deal with this problem, this paper presents a modified trajectory planning scheme based on PH (Pythagorean Hodograph) curves for sharp corner angle contouring tasks. The main idea of the proposed method is to force the actual toolpath trajectory closer to the original command path by exploiting a modified command trajectory (a C2 PH spline curve) at the sharp corner in advance, so that the corner contouring accuracy can be further improved. Finally, several different sharp corner contour-following experiments were conducted on dual servo motors to evaluate the effectiveness of the proposed approach. Experimental results indicate that the proposed approach can indeed reduce contour error in sharp corner-angle contour-following applications.
    01/2011;
  • Hang-Sheng Chen, D.G. Dorrell, Mi-Ching Tsai
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    ABSTRACT: Skewing the magnets in a brushless interior permanent-magnet motor can be difficult. One method to overcome this problem is to use axial segments that are rotated (“twisted”) with respect to each other. Compared to other methods of rotor skewing, this method may reduce manufacturing cost and the complexity of the rotor. This paper addresses the use of two axial segments and the associated effects on the back-electromotive force (EMF) waveform and motor performance. The back-EMF waveforms of an interior permanent-magnet motor are deeply influenced by the tooth-slot and winding harmonics. They should be sinusoidal to reduce torque ripple for ac motor servo drives and other applications where smooth operation is required. In the paper, we present the two-segment rotor structure together with a simple technique for reducing high-order back-EMF harmonics, and we derive the optimal twisted angle of the proposed two-segment rotor. This minimizes the total harmonic distortion of the back-EMF waveform due to tooth-slot effects. We examine cogging torque and the reduction in cogging torque. We apply the twisted angle rotor to two different compressor motors. In addition to the back-EMF, we address the torque ripple under load and the effect of twist on back-EMF constant. We examine the results using finite-element analysis and validate them by experimental measurement.
    IEEE Transactions on Magnetics 10/2010; · 1.42 Impact Factor
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    ABSTRACT: Intelligent buildings are able to improve living condition and at the same time saving energy, and has therefore become one of the popular topics recently. In order to minimize the waste of energy, it is necessary to auto-detect user's position inside the building, and then adjust the living condition accordingly. In this paper, a harvesting floor is designed with piezoelectric material, which can convert extra energy of walking motion into electrical energy. The generated electricity is then used to drive a wireless transmitter module to detect user's current position. Moreover, under low frequency condition, the energy generation from piezoelectric material has a low efficiency that is insufficient to drive a wireless module. In order to elevate the energy power of piezoelectric, this research adopted the plucked method, which is approximately 10 times the electricity compare with the forced method (conventional methods).
    01/2010;
  • Mi-Ching Tsai, Cheng-Chi Huang, Bor-Jeng Lin
    Journal of Mechanical Design - J MECH DESIGN. 01/2010; 132(6).
  • Po-Wei Huang, Mi-Ching Tsai, Ming-Yang Cheng
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    ABSTRACT: To extend the driving range of an electric scooter, the high efficiency direct-drive wheel motor has become an attractive alternative. For this reason, high quality silicon steel plates are applied to the wheel motor in order to reduce iron loss. However, finding a suitable steel plate with the characteristics of high efficiency, high output power and low manufacturing cost, is difficult. This paper investigated variations of the eddy current loss and iron loss characteristics in a wheel motor with six types of silicon steel plates under different operating conditions. Results of this study could provide a useful reference for material selection during the process of the wheel motor design.
    01/2010;