A new ATC (Automatic Train Control) system has been developed with solutions to realize short train headway by assured braking utilizing digital data transmission via rails; the digital data for the ATP (Automatic Train Protection) function; and to achieve EMC features for both AC and DC sections. The DC section is of the unprecedented DC traction power supply system utilizing IGBT PWM converter at all DC substations. Within the AC section, train traction force is controlled by PWM converter/inverters. The carrier frequencies of the digital data signals and chopping frequency of PWM traction power converters on-board are decided via spectral analysis of noise up to degraded mode cases of equipment. Developed system was equipped to the Tukuba Express Line, new commuter line of Tokyo metropolitan area, and opened since Aug. 2005.
Redundant manipulator is useful for posture control with keeping the desired end-effector position by using its redundancy. This makes it possible to realize dexterous motion such as obstacle avoidance motion with achieving the target task. However, the more degree-of-freedom motion increase, the smaller the stiffness of redundant manipulator is. This induces unacceptable vibration in the manipulator motion. To address this issue, this paper describes a strategy of vibration suppression by using workspace observer and resonance ratio control based nullspace control. The validity of the proposed approach is confirmed by simulations and experiments.
With recent popularization of the Internet, bilateral control systems which are robust to fluctuant and unpredictable time delay are desirable. In such a situation, communication disturbance observer (CDOB) has been proposed as a control method for fluctuant and unpredictable time delay in bilateral teleoperation. It compensates time delay using disturbance observer by considering the effect of communication delay on the system as acceleration dimensional disturbance. Since this method cannot separate network disturbance from contact force exerted on a slave, force response of the slave transmitted to the master side is not precise. This paper presents a method for separating network disturbance from the contact force exerted on the slave. By producing the compensation value using separated network disturbance, the force response value of the slave is transmitted to the master side more precisely. The validity of the proposed method is verified by experimental results.
In this paper, a method to extract function modules from sequential control programs is proposed. A hierarchical structure of a given sequential program can be found by using association graph. If some or more variables are connected each other (strongly connected), the layered structure is not easy to find. Thus, based on the concept of Markov chain, the importance of variables can be conducted. We propose a new method to divide unclear layered variables in more details. An illustrative example of a tank control program is shown as an application of the proposed method.
The efficiency of the electrical GEN-SET (EGS) for speeds with diesel generator (∼3000rpm) and feasibility of high-speed generator with gas turbine (∼30000rpm) and permanent magnet synchronous generator is investigated. Three different configurations of power converter are considered. The paper given an answer to the question if a a full controlled rectifier should be employed or a version with diode rectifier is satisfactory? This is investigated also for high-speed generation. Different current forms for the three defined configurations with their harmonics and influence on generator is given. The efficiency of the overall system is here investigated and an optimal topology is selected. Since the EGS operates very often under low load which does not exceed in average more than 30% of the rated permanent load, a new topology of converter of EGS with high efficiency and low cost is suggested and studied theoretically and experimentally in the paper.
This paper proposes a new simple vector control method for sensorless drive of permanent-magnet synchronous motors (PMSMs). The proposed method takes an approach to estimate directly phase of the quasi-optimal stator current through control of the power factor phase instead of estimation of rotor phase. It is established based on new analysis of motor characteristics and has the following attractive features: 1) it can be applied to both of salient and non-salient pole PMSMs; 2) stator current control quasi-minimizing copper and/or iron loss is directly performed; 3) it is insensitive to motor parameter variation, and does not requires motor parameters with precision; 4) it is simple. Simple and practical rules for selecting design parameters of the method are clearly given based on the analysis. Effectiveness of the analysis and usefulness of the proposed method are verified through experiments.
This paper presents a novel Initial Value Compensation (IVC) using an additional input for the semi-closed control systems. The authors have already proposed the IVC approach using the additional input for residual vibration suppression in the fast and precise positioning control. In the approach, however, an essential subject has been still remained that the positioning control in load side could not satisfy the required performance because the systems have been constructed under the assumption of a semi-closed control system. An improvement of the control performance in load position, therefore, is discussed in the paper, where the appropriate assignments of poles and zeros in IVC are ensured, considering the transfer functions of position in both sensor and load for the control initial values. The effectiveness of the proposed approach has been verified by numerical simulations and experiments using a prototype.
This paper deals with a new resonant gate-drive circuit for power MOSFETs. The proposed gate-drive circuit is characterized by a resonant inductor connected in series to the gate terminal of the MOSFET. It is possible to charge or discharge the input capacitance of the MOSFET by using the resonance between the inductor and the input capacitance. Experimental results are shown to verify the viability of the resonant gate-drive circuit. As a result, the proposed resonant gate-drive circuit reduces its power consumption to one tenth, compared with a conventional one. It was experimentally clarified that the proposed circuit makes it possible to improve efficiency of a high-frequency inverter using MOSFETs.
Usually, the resonant filter is composed of several resonators which is made of dielectric and metal, and is applied to high frequency B.P.F. (Band Pass Filter). Although a resonant filter has simple structure, it is very difficult to obtain the optimal geometry experimentally, because its filter characteristic is greatly influenced by the material and the structure. This paper presents an analysis method for the high frequency resonant filter by using the method of moment (MOM). The computed characteristics of the resonant filter are in good agreement with the measured ones. Furthermore, the influences of design parameters of the filter on the characteristics are investigated.
We have been studying a linear actuator for the thermostatic switch using temperature-sensitive magnetic material (TSMM). In this paper, the effect of the geometry of TSMM on response time is investigated by computing the dynamic characteristics of the actuator employing the 3-D finite element method coupled with the equations of magnetic field, heat transfer and motion. As a result, it is found that the response of the actuator is greatly improved. The validity of the computation is clarified though the comparison with the measurement of a prototype.