This paper proposes a capacitor current reduction method using real-time model predictive control (MPC) for a double three-phase permanent magnet synchronous motor (DTPPMSM) drive system. Capacitor current reduction for volume minimization of DTP-PMSM drive system is important issue. Optimizing switching timings by MPC is promising approach. However, it is difficult to implement ideal MPC in a real system because it requires a huge amount of calculation to predict the capacitor current. In this paper, we propose a new method that is possible to search optimal switching timing for reducing the capacitor current by using the MPC, whose calculation amount can be implemented in real-time. This paper shows the possibility of realizing an capacitor current reduction method with high control performance by reducing the amount of computation for MPC.

The initial position estimation is an important issue in position sensorless control, which is also applied to Triple Three-Phase Surface-mounted Permanent Magnet Synchronous Motor (TTP-SPMSM). It is thought to be difficult to estimate SPMSM's initial position because of the lack of saliency. This paper proposes an initial position estimation method for TTP-SPMSM based on high-frequency voltage injection. The inductance spatial harmonics in the considered TTP-SPMSM enables estimation of the initial position. This paper presents the principle and verification in the simulation of the proposed method.

Sensorless control has become a popular research area for ac drives. However, most of the works are attributed to conventional three-phase drives. Given that applications of multiphase machines keep spreading, studies of position sensorless for them are necessary. For the object in this paper, some studies for sensorless control in middle/high speed region are reported. To accomplish a full-speed range sensorless control, a study about the standstill/low speed sensorless control of the target motor is proposed in this paper. Particularly, conventional signal injection methods utilized in three-phase ac drives meet a new issue caused by the inner magnetic couplings of the system when applying to the object in this paper. It may lead to failure of sensorless control and torque ripple enlargement. Therefore, analyses to solve the issue become the main interest of this paper, simulation results are demonstrated in the last section.

Performance of Superconducting Submillimeter-Wave Limb Emission Sounder (SMILES) onboard International Space Station was discussed from the analysis of random errors of Chlorine monoxide (ClO) in the stratosphere and mesosphere. Some lessons learned from the SMILES operation in space are discussed.

The Superconducting Submillimeter-Wave Limb-Emission Sounder (SMILES) observes 03 and other minor chemical species in the stratosphere and mesosphere. Limb observation of SMILES is sensitive to the quality of the tangent altitude retrieval. To obtain better retrieval result, knowledge of initial tangent height and antenna pattern should be as precise and accurate as possible. It was concluded that initial tangent height is calculated by using ISS attitude and mirror pointing angle, and ISS position. Antenna pattern assuming 6 points moving average was applied to the retrieval and showed reasonable results.

In this paper, we discuss a method to achieve safe autonomous robot system coexistence (or Kyozon in Japanese). First, we clarify human pain tolerance and point out that a robot working next to an operator should be covered with a soft material. Thus, we propose a concept and a design method of covering a robot with a viscoelastic material to achieve both impact force attenuation and contact sensitivity, keeping within the human pain tolerance limit. We stress the necessity of a simple robot system from the viewpoint of reliability. We provide a method of sensing contact force without any force sensors by monitoring the direct drive motor current and velocity of the robot. Finally, we covered a two-link arm manipulator with the optimum soft covering material, and applied the developed manipulator system to practical coexistence tasks.

Deals with a multi-sensor system for controlling a two-fingered hand to grasp various objects. The multiple sensors are grasping force sensors, a friction coefficient sensor, and a weight sensor, which are mounted on the hand. Algorithms to recognize objects and to control grasping force of the hand by integrating the detected sensory information are also presented. Experimental results of case studies show that the ability to detect grasping force of wide dynamic range, friction coefficient, and weight allows a hand to grasp many different objects.>