Robotic technologies are being increasingly utilized for medical treatments to support surgeons and reduce the burden to patients. Flexible endoscopic surgical systems with an endoscope and flexible forceps robots are state-of-the-art devices that are expected to realize more difficult and less invasive surgery. Surgeons teleoperate these flexible forceps robots as their own hands and conduct various medical tasks. The wire-driven mechanism is applied to many flexible forceps robots to transmit the driving force to the tip of the robots in a narrow space. However, the flexible structure makes it difficult to control the wire-driven robots and implement the haptic technologies to realize safer surgery. In this paper, a force sensor-less, small-diameter flexible forceps robot with the ability to transmit haptic sensation is presented. The driving part at the tip of the flexible part, composed of a small actuator with a reduction mechanism, realizes the miniaturization of the robot. Haptic information is estimated by low resolution position information. The bending of the flexible part with electric wires does not deteriorate the performance of the end effector. The performance of the haptic flexible forceps robot is evaluated through experiments.
This paper proposes a new inductance-identification method for synchronous motors including permanent-magnet synchronous motor (PMSM), synchronous reluctance motor, and PMSM with double three-phase windings. The proposed method is based on the generalized flux estimation method instead of the adaptive parameter identification methods, and has the following features: the inductance is identified online during the rotating operation; it uses the so-called “D-filter” and can reduce the effects of noise and harmonics on the identified values; it can be applied to motors with magnetic saturation and dq-axis flux coupling characteristics; and it can be applied in the transient state as well as in the steady state. The propagation of errors due to other parameters into the identified inductance is analyzed. The effectiveness and usefulness of the proposed method are verified through extensive simulations.
A modular multilevel cascade converter based on single-delta bridge cells, hereinafter referred to as an SDBC converter, is a prospective power converter for a STATCOM (STATic synchronous COMpensator) intended for voltage regulation and stability improvement. However, the SDBC converter cannot exchange a non-zero active power with a three-phase ac mains unless energy-storage elements such as batteries are connected to the dc side of each bridge cell. This paper presents a dc/1ϕ/3ϕ power converter combining the SDBC converter and a medium-frequency single-phase transformer with an operating frequency of 150Hz. It is characterized by controlling a non-zero active power between the dc side and the three-phase ac mains via the transformer, contributing to the enhancement of voltage regulation and stability improvement. The operating principles and the control method are discussed in this paper, followed by computer simulations using the “PSCAD/EMTDC” software package and experiments using a 110-V, 10-kVA downscaled model.
In the conventional bus voltage controller, the concentration of heat generation in a specified circuit has been an obstacle to miniaturization. In this paper, we describe the control algorithm and the experimental result of the direct and distributed switching control (DDSC) method devised to disperse the generation of heat. Additionally, to improve the transient response while reducing the steady state switching frequency, which can reduce the generation of heat, we investigated the application of a transient mode that temporarily speeds up the control cycle when load fluctuation is detected. We also report the calculation of the heat reduction effect that can be achieved by combining these methods.
This study proposes improved parallel reactive hybrid particle swarm optimization (IPRHPSO) using an improved neighborhood schedule generation method for the integrated framework of optimal production scheduling and operational planning of an energy plant in a factory. Conventionally, in an energy plant, fixed loads of various tertiary energies have been utilized to solve the optimal operational planning of an energy plant so far. Additionally, in production lines, only the minimization of production time has been yet considered. Therefore, the secondary energy cost of a factory cannot be reduced accurately. However, in this study, the loads of various tertiary energies are calculated according to the candidates of production scheduling and the optimal operational planning of an energy plant is determined using the tertiary energies. This can explicitly reduce the secondary energy cost of a factory. The proposed method was applied to ten jobs and machine JSPs each. Accordingly, it was verified that it can minimize the secondary energy cost and production time, simultaneously, and realize fast computation through parallel computation using IPRHPSO.
We have developed a high-efficiency (IE5 class), 11kW axial-flux permanent magnet motor (AFPM) with ferrite magnets and amorphous cores. In this study, we examined a high-power AFPM under the same volume as the 11kW AFPM. To increase the motor power, the torque and rotation speed were improved more than those of the 11kW AFPM. In particular, Sm-Fe-N (Samarium-Iron-Nitrogen) magnets are used in rotors to improve the torque. Consequently, the prototype of 44kW (85Nm, 4950r/min) AFPM could achieve efficiency standard IE 5 (>96.0%).
Our research focuses on the nonlinear dynamics of power electronic circuits and clean energy power generation systems. In this report, we introduce examples of the industrial applications, which are the circuit simulator and circuit design. Moreover, we introduce activity in our laboratory.