Based on the base module of Universal Robotics, this paper deals with a 16-pole, 18-slot fractional-slot concentrated-winding permanent magnet synchronous machine (PMSM) for articulated robot applications considering several pole-slot combinations and using an optimum design. The selected PMSM considering the pole-slot combination is optimized and compared both analytically and experimentally. The experimental results confirmed that the proposed PMSM can achieve improved performance at the rated state. Repeatability test results of the proposed smart actuator with a link-attached sphere-mounted retroreflector sensor met the goal of within 100 μm according to a laser tracker. The analysis results are in good agreement with the experimental results within the maximum 2.5% error in terms of the efficiency. The design, analysis, and experiment with the PMSM for articulated robot applications were conducted successfully.

Smaller and lighter motors are needed to be used for cooperative robots, which are becoming a recent issue among articulated robots. In order to make the motor small, the axial length must be reduced within a limited diameter, so a reduction in the length of the core lamination and the winding end length must be considered. However, loss and thermal analysis are essential in the design process, as loss increases to meet output with excessive volume reduction and may consequently increase temperature severely. In this paper, the magnetic performance for various analytical models studied to reduce the axial length is invested, and the thermal behavior is predicted by the analytical lumped-circuit method. A model with the trade-off between the low temperature-rise and high magnetic performance among several analytical models is selected. The magnetic characteristics and predicted temperature-rise are compared to the measured results and found to be quite consistent.

In order to improve the performance of the wound field synchronous motor (WFSM), the permanent magnet assist (PM-assist) is investigated in this paper. The effect of the PM-assist is dependent on the inserted position of the PMs. Thus, four models whose PMs are inserted at each different position are suggested. Then, the most effective position of the PM is decided by the mean torque per employed amount of the PM. By inserting the PMs into the decided position of a WFSM designed for a small electric vehicle traction, the PM-assisted WFSM is designed. By comparing the torque and the efficiency of the original WFSM and the PM-assisted WFSM, the effectiveness of the PM-assist is figured out. Finally, the validity of this research is verified by the experiment using the manufactured WFSM.

This study focuses on the design of a magnetic sensor (MS) in position detection of a permanent magnet linear motor (PMLM). The MS is composed of a Hall-IC and magnetic materials, and it is well-known as a contactless sensor with a simple structure, and low cost. As a result, it is preferred for precise linear positioning applications. The work presented in this study consists of the following three steps to achieve high accuracy and economy in the mover position detection for a PMLM. Firstly, the initial design of the MS is described which has been optimized using response surface methodology to obtain very low total harmonic distortion value of the sensing signal. Secondly, the leakage flux of PMLM is analytically investigated, from which it is determined that shielding the leakage flux is most appropriate to ensure the accuracy of the MS. Finally, in an attempt to reduce manufacturing cost, three MS prototypes using different materials (silicon steel laminated core, steel solid core, and ferrite solid core) are fabricated and tested. To verify the analytical results, several experiments were conducted. The experimental data proves that the accuracy of the MS is sufficient to use for mover position detection for the PMLM.

This paper presents the design of an axial-flux permanent-magnet (AFPM) generator used for hybrid electric propulsion drone applications. The design objectives of the AFPM generator are high power density, which is defined as output power per generator weight, and high efficiency. In order to satisfy the requirements for the target application and consider the practical problems in the manufacturing process, the structure of the AFPM generator comprising a double-rotor single-stator (DR-SS) was studied. In order to determine the rotor topology and stator winding specifications that had the greatest impact on performance in the DR-SS type design process, we selected three rotor models according to the arrangement of the magnetization direction and three stator models according to the coreless winding specifications. These models were first compared and analyzed. Then, a 3-D finite element method was performed to calculate the magnetic, mechanical, and thermal characteristics of the designed models. By consideration of the output power, efficiency, temperature, and mechanical stability, etc., a topology suitable for the design of generators for UAV systems was determined and manufactured. The reliability of the design result was confirmed through the test.

We have fabricated static induction organic transistor of vertical type in order to improve the problems of conventional organic thin film transistor (OTFT). The vertical type organic transistors were fabricated by using n-type organic semiconductor materials such as F16CuPc, NTCDA and PTCDI C-8. The effects of carrier mobility of organic active materials, the thickness of thin film and gate structure on current–voltage (I–V) and transistor characteristics were investigated. The vertical type organic transistor using PTCDI C-8 exhibited low operation voltage and high on–off ratio. In addition, we have examined the feasibility of application in organic light emitting transistor using a light emitting polymer.