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Ballscrew drive system has high mechanical efficiency and is able to get high gear ratio easily. But it also has non liner friction elements like rolling friction and viscous friction, so it makes ballscrew control accuracy worse. For that reason, it is proposed that inserting disturbance observer into control system and compensating disturbance torque. Generally, rotary encoder is used for position sensor in ballscrew control, but its resolution affects accuracy of drive control and disturbance observer. In this paper, we propose a speed control system using AC servo motor ball screw drive system, compare driving characteristics in low speed range when using low resolution encoder and high resolution encoder as position sensor. Also we examine effects for driving characteristics by using and compensating disturbance observer. These verifications were carried out by simulation and actual machine.

This research is a proposal of a novel transfer device using a Transverse Flux-Flux Reversal Linear Motor (TF-FRLM). Transfer device in this paper is mounted on a carrier apparatus which was operated in parallel synchronous operation. This digest mainly discusses the overview of a novel transfer device and the optimization result of C-core TF-FRLM. The section of new transfer device describes the basic structure and basic operation. In the section on optimization, the results of dimensional change are shown on the graph and the optimum points are discussed. Three-dimensional finite element analysis is used for dimension optimization.

For construction of high precision positioning system with robustness for disturbance, it needs more precision motor drive control. It is requested robust and reliable position sensor when driving the motor in bad condition that have many vibration, so the resolver and R/D converter are mostly used. But for precision motor drive, it needs accuracy of position sensor, which is affected by R/D converter specification when using resolver especially at low speed range. In this paper, we target that realizing precision positioning servo system without affected disturbance, and propose the mechanism integrating PMSM rotor with ballscrew shaft using resolver as position sensor. We examine improving position detection accuracy at low speed range by changing conversion method and excitation method of R/D converter.

Steer-by-wire system (SBW), which is a new steering system, is expected to be adapt automated driving vehicles. However, SBW has problems with increasing cost and redundancy and these hinder its popularization. Recently, a lot of research about SBW has proposed a system using disturbance torque observer to obtain steering torque or reaction torque with low costs. A resolution of a position sensor directly affects the disturbance estimation accuracy at this time, so a high resolution position sensor is required for the system. But it is inappropriate for SBW to adopt it because of increasing costs. In this paper, therefore, we aim to improve the estimation accuracy of disturbance torque observer with keeping low cost. For that purpose, we propose new method which can improve the position information accuracy by using instantaneous speed observer, and we compare the result between new method and conventional one.

The mechanical simulation analysis of a 2-DOF parallel robot with Considering the dynamic disturbance torque was investigated. We devised a method to derive the position of the end effector using forward kinematics. We also requested inverse kinematics. Next, the operation region was calculated using this method. Using the model of the inertial system, we confirmed the difference in motion in the influence of the inertia term. We investigated the possibility of reducing the influence of the inertia term by using the moment of inertia at an appropriate value.

The 10poles-l2slots brushless DC motor is superior as AC servo motor by sine-wave excitation, but its characteristics like efficiency get worse by using as BLDC motor by square-wave excitation. However, 150degree excitation which adjusted excitation angle and excitation phase can increase 3% of efficiency from general120degree excitation, and it can make phase current similar to sine wave. And then, square wave excitation which used hall sensors and counters is simple way of BLDC drives, and it needs less supply voltage than that to drive BLDC by sine-wave excitation. Therefore, we shows that 150degree square-wave excitation is suitable in high efficiency and simple BLDC drive.

Double winding machine is known that these machines have fault tolerant feature, so it is got much attention especially for application which needs failure tolerance like aircraft, electric vehicle, electric rolling stock, and marine ship. Controlling each winding by independent inverters lets improvement drive characteristics like extending speed range, and reducing torque ripples. But controlling each winding by independent inverters expects letting improvement drive characteristics like extending speed range, and reducing torque ripples, so it is widely considered. In this paper, we use 2 inverter which controlled by 1 microcontroller for driving 10poles-12slots double winding PMSM, operate the motor in situation of current phase difference, and operate the motor in situation when 1 inverter is failure. Then we verify fault tolerance characteristics of the PMSM, and examine improving the PMSM torque characteristics by measuring the torque characteristics. Therefore, it is confirmed that double winding PMSM used in this paper with driving by 2 inverter can keep redundancy and get fault tolerant characteristics, and found that it is possible to reduce torque ripple by inverter phase differential operating. In this test motor, it is found that the torque ripple can reduce by exciting current having 30degree of phase difference to the motor.

In recently, permanent magnet type linear motors (PM-LSM) which could control high speed have attracted attention in the industrial field. Our laboratory is focusing on conveyance system. In the loading and unloading of the luggage of the transport system, the mover to move repeatedly to “stop-and-go”. This drive occurs each time to move the respective processing sections. This work leads to a reduction of transport efficiency. Therefore, we propose parallel synchronous drive. This method synchronizes the mover of the two LSMs. Because both movers in the synchronized state are the same inertia, luggage may be moved without the movers stop. Main line of the motor called “master motor” and another motor called “slave motor”. The master motor's position is passed Slave motor and parallel synchronous drive is run.

The switched reluctance motor (SRM) is suitable for high-speed driving and enables high output. However, it is less efficient than other motors. This is due to an increase in iron loss caused by high speed operation. Therefore, in this paper, we adjusted firing angle and verified that firing angle realizing maximum efficiency exists by changing current waveform and loss. It was confirmed that the firing angle at the maximum efficiency shifted when the number of revolutions was changed. By separating the loss into copper loss and iron loss, we confirmed how they change depending on the firing angle. Through simulation, we compared it with actual machine and verified its validity.

Because the application range of motors for position control is extending in industry, hybrid stepping motors that can realize position control easily have become popular. However, stepping motors have some disadvantages: the possibility of pull-out under certain load conditions, and low efficiency due to iron loss. Consequently, a system designer must choose the motor-driver combination very carefully. This paper proposes high-efficiency drive of a hybrid stepping motor in a wide speed range by vector control, without the occurrence of pull-out. It is shown that lead angle control is equivalent to flux-weakening control, and that the maximum torque depends on the maximum inverter voltage at high speed. The effect of iron loss suppression by flux-weakening control is verified experimentally. © 2010 Wiley Periodicals, Inc. Electr Eng Jpn, 174(4): 68–74, 2011; Published online in Wiley Online Library (wileyonlinelibrary.com). DOI 10.1002/eej.21022

Application of PM motor has spread from the demand of energy saving by a global warming issue. A SPM motor and the IPM motor of PM motor are typical kinds. This description explains that feature about two motors. The SPM motor explained the winding technology for realizing high efficiency, and the technology of reducing a torque ripple. An IPM motor explains work of reluctance torque and the expansion effect of the control range.

The position control system with the advantage large torque, low vibration, and high resolution can be obtained by the constant current micro step drive applied to hybrid stepping motor. However loss is large, in order not to be concerned with load torque but to control current uniformly. As the one technique of a position control system in which high efficiency is realizable, the same sensorless control as a permanent magnet motor is effective. But, it was the purpose that the control method proposed until now controls speed. Then, this paper proposed changing the drive method of micro step drive and sensorless drive.The change of the drive method was verified from the simulation and the experiment. On no load, it was checked not producing change of a large speed at the time of a change by making electrical angle and carrying out zero reset of the integrator. On load, it was checked that a large speed change arose. The proposed system could change drive method by setting up the initial value of an integrator using the estimated result, without producing speed change. With this technique, the low loss position control system, which employed the advantage of the hybrid stepping motor, has been built.

Because the application range of motors for position control is extending in industry, hybrid stepping motors that can realize position control easily have become popular. However, stepping motors have some disadvantages: there is pull-out phenomenon according to load conditions, and low efficiency originates in the iron loss generating. Consequently, a system designer has to choose motor-driver very carefully. In this paper, the high efficiency drive of hybrid stepping motor on wide speed range by vector control, which has no pull-out phenomenon, is proposed. Furthermore, it was shown that lead angle control is equivalent to flux-weakening control, and it was shown that the maximum torque is decided by the maximum voltage, which an inverter generates at high speed. The effect, which suppresses iron loss by flux-weakening control, was checked from the experiment.

The stationary discontinuous armatures in permanent magnet linear synchronous motors (PM-LSMs), which consist of several stator sections that are distributed along the track and that the mover with PM is running without thrust force between these sections, have been proposed as a driving source for transportation systems. This design is very economical in long-distance transportation systems in factories, because the armature is engaged only when accelerated and decelerated operation is necessary. However, the stationary discontinuous armature PM-LSM contains the outlet edges which always exist as a result of the discontinuous arrangement of the armature. For this reason, the high alteration of the thrust force and the attractive force produced between the armature’s core and the mover’s permanent magnet when a mover goes through the between the armature’s installation part and non-installation part has been indicated as the problem of the stationary discontinuous armature PM-LSM. As a result, the stationary discontinuous armature design involves the velocity ripple of the mover with PM during acceleration when freewheeling changes over to re-acceleration. We have proposed and examined constant load angle control without position feedback in order to suppress the velocity ripple which occurs at the re-accelerator with the aim of achieving smooth drive of the stationary discontinuous armature PM-LSM. This paper describes the examination of constant load angle control without position feedback with the aim of suppressing the velocity ripple, which occurs in the re-acceleration portion. Also, we have examined the analysis of the effect of the outlet edge on the mover’s drive which exists as a result of the discontinuous arrangement of the armature side based on the re-acceleration characteristics obtained using constant load angle control without position feedback.

The 10poles-12slots brushless DC motor is superior as AC servo motor by sine-wave excitation, but its characteristics like efficiency get worse by using as BLDC motor by square-wave excitation. However, 150 degree excitation which adjusted excitation angle and excitation phase can increase 3% of efficiency from general 120 degree excitation, and it can make phase current similar to sine wave. And then, square wave excitation which used hall sensors and counters is simple way of BLDC drives, and it needs less supply voltage than that to drive BLDC by sine-wave excitation. Therefore, we shows that 150 degree square-wave excitation is suitable in high efficiency and simple BLDC drive.

When the position error becomes small, in a conventional positioning system, its motor cannot obtain sufficient deceleration torque. Hence, the position response becomes slow. There is another positioning system that is to design the position reference using a trapezoidal speed reference. When the load torque and the final goal position are known, this positioning system has a fine response. However, if the load torque and the final goal vary, its position response cannot have the desired response. In order to overcome these problems, this paper proposes a new high-speed positioning system of AC servomotor considering both an unknown friction torque and a windup phenomenon. The proposed system always uses the maximum acceleration, deceleration torque and the maximum speed. © 2006 Wiley Periodicals, Inc. Electr Eng Jpn, 157(4): 66– 74, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.20173

This paper proposes a new speed control method for PM motor using a low resolution encoder and a speed observer. The servo system should be economical and simple. For this purpose, this paper realizes the high performance speed control system using a low resolution encoder, whose performance is nearly equal to the performance of speed servo system using a conventional optical encoder. The speed observer uses the information of motor current and motor voltage. The rotor position is calculated by the estimated value of speed observer. This observer has the influence of electrical parameter variation. This paper proposes the correction algorithm of both the voltage error of PWM Inverter and the electrical parameter variation. The experimental results and numerical simulation results point out that the proposed speed control system has the desired speed response, on condition of parameter variations and load torque perturbation.

Recently, the permanent magnet type linear synchronous motor (PM-LSM) is applied to more and more area. Although the flux density increase with the thickness of a magnet, remanent magnetic flux density has a limit because of characteristic of magnet itself. In order to increase the thrust, a magnetic configuration for double-sided PM-LSM is proposed. This structure can use both magnet torque and reluctance torque.

The motor is desirable high efficiency, because it is consuming about 50% electrical energy. Therefore, Permanent Magnet Synchronous Motor (PMSM) is gathering attention and being widely applied. The vector control of PMSM must have information of magnet pole position. So, it is necessary to attach position sensor. However, several problems occurs by attaching a position sensor. For example that degradation of reliability, adaptability of the environment is reduced, and cost is high. These problems should be solved. Thus, vector control without a position sensor has attracted attention. A compressor is a load of fluctuation torque because it repeats suction and compression of refrigerant gas. When such load is applied to the sensorless control, it becomes unstable. In this paper, the effect of torque fluctuation is checking when the compressor is moved by sensorless control of PMSM.

SRM is possible to high output by high speed drive. However, efficiency decreases for increase of iron loss in high speed drive. Therefore, reduction of iron loss is necessary for high efficiency drive. And, we aim to improve of efficiency by electromagnetic steel sheet of low iron loss. We thought Si6.5% electromagnetic steel sheet is suitable to high speed drive application, because Si6.5%material is superior to characteristic of high frequency in the electromagnetic steel sheet material of low iron loss. In this paper, we compare conventional electromagnetic steel sheet and Si6.5% electromagnetic steel sheet. Also use the Si6.5% electromagnetic steel sheet, with the aim to improve the utilization ratio of energy by controlling the firing angle.

In the drive of an open-loop-controlled stepping motor, it is well known that the natural oscillation of the motor causes harmful phenomena like the low-frequency resonance, the increase of the settling time and the acoustic noise. Microstepping is known as a method for suppression of rotor oscillation; it is effective especially in the constant-speed drive. However, the rotor oscillation occurs in the transient region even in the case of microstepping, provided that the dynamic property of the system is not taken into account.In the present work, the authors suggest to use a pre-compensator to suppress the natural oscillation of the microstepped stepping motor. In the design of the compensator, guarantee of robustness to the variation of the inertial load which causes the variation of oscillatory characteristic is regarded as the main point. In addition, prevention of phase lag to the reference signal which has a harmful influence on the case of path following control is also taken into consideration. The adoption of a preview type FIR low-pass filter is shown to be suitable for the above purpose through the analysis of the system in the frequency domain. The effectiveness of this method is evaluated by the experiment, and it is confirmed that the rotor oscillation is suppressed excellently.

Stationary discontinuous armatures that are used in permanent magnet linear synchronous motors (PM-LSM) have been proposed as a driving source of transportation systems. However, the stationary discontinuous armature PM-LSM contains the outlet edges which always exist as a result of the discontinuous arrangement of the armature. These edges become a problem because the cogging force that they exert influences the controllability of the motor. This paper presents the results of three-dimensional numerical analysis by the finite-element method of the cogging force exerted by the outlet edge

Previously, our laboratory has proposed a Intermittent Stator permanent magnet linear synchronous motor as long-distance conveying equipment of industrial equipment. The sensor to detect the mover position uses the linear encoder so far. Because the wiring for this linear encoder limits the movement of the mover, it is unsuitable as the sensor of the long distance transportation device. Therefore, this paper proposes the mover position detection with the hall element as a position detector that takes the place of the linear encoder.

A cylindrical linear pulse motor (CLPM) of a new construction is proposed in this paper. The conventional CLPM, which has a permanent magnet between A-phase and B-phase stators, has a problem: thrust unbalance occurs because the magnetic flux of the outer poles is longer than that of the inner poles. This paper proposes a CLPM of completely new construction, in which the field magnetic flux and the armature magnetic flux perpendicularly intersect each other as a result of a restructured magnetic circuit. This new CLPM has the same magnetic field as the stepping motor, and has the distinctive characteristic of being available in a multiphase design, as well as the conventional two-phase design. A five-phase 10-pole CLPM was experimentally manufactured and the static thrust was measured to identify its basic characteristics. The experiment confirmed the theory that the torque did not differ from phase to phase and that controllability equal to that of the stepping motor was obtainable. The CLPM proposed here is effective as an alternate linear electromagnetic actuator for electrical servos of air actuators (such as air cylinders).

A cylindrical linear pulse motor (CLPM) of a new construction was proposed in this paper. The conventional CLPM, which has a permanent magnet between A phase and B phase stator, has a problem that thrust unbarance occurs becouse the magnetic flux pass of out or pole is longer that of the inner poles. This paper proposes a CLPM of completely new construction, in which the field magnetic flux and the armature magnetic flux are perpendicularly intersecting each other as a result of a restructured magnetic circuit. This new CLPM has the same magnetic field as the stepping motor, and has the distinctive characteristic of being available in a multi-phase design as well as the conventional two phase design. A five phase ten pole CLPM was experimentally manufactured and was measured the static thrust to identify its basic characteristics. The experiment confirmed the theory that the torque did not differ from phase to phase and that controllability equal to that of the stepping motor was obtainable. The CLPM we proposed here is effective as an alternate linear electromagnetic actuator for electrical servos of air actuators such as air cylinderes.

Generally the magnetic steel sheet was used for the stator core material of the motor so far. In recent years, Soft Magnetic Composite (SMC) attracts attention as a material replaced with the magnetic steel sheet. Magnetic property depends for SMC on fabrication density. The fabrication density of SMC goes up by improvement in manufacture technology, and it is becoming close to the magnetic property of the magnetic steel sheet. In this paper, the influence which it has on the motor property of the fabrication density of SMC is discussed. Property comparison by Ring Test Piece and a motor was done about the fabrication density of 7.5g/cm3, 7.7g/cm3 SMC, and the magnetic steel sheet. When it was 7.7g/cm3 in fabrication density as a result, it was shown that it is in a practical use level as a motor core.

This paper describes the basic design of Switched Reluctance Motor, and the characteristics of drive. Switched reluctance motor is one motor belonging to rare earth free. We built the test motor by performing the basic design of the Switched Reluctance motor is possible. And since the good result was obtained when characteristics of the test motor were measured and the characteristics were compared with PMSM of same size, we report.

This paper describes the characteristics of reactor using boost converter. We produced boost converter as evaluation method of a reactor. We calculated about We calculated about DC superposition characteristic of a reactor and iron loss of a reactor using boost converter. We measured the efficiency and reactor current of the circuit for boost converter. Therefore we verified ferrite and soft magnetic composite used for reactor material. Since we can verify the superiority of soft magnetic composite from comparison of ferrite and soft magnetic composite, we report this paper.