Tatsuya Kikuchi

DVTS-based remote laboratory across the Pacific over the gigabit network

The objective of this study is to investigate a remote laboratory on electric motors using high-speed networks between Japan and the United States. The client, situated at Stanford University, Stanford, CA, accessed the remote laboratory system set up in Japan. Through this client, the remotely located user operated the motors and conducted experiments. The remote laboratory was conducted over a high-quality digital video conference system, making it possible for both sides to communicate smoothly with each other and for the remote user to observe close-up details of the laboratory, including the motors fine movements. Using a network bandwidth of 15 Mb/s, the authors were able to demonstrate the validity of the remote laboratory experiment.

Remote laboratory for a brushless DC motor

The objective of this study is to investigate remote-learning methods in the context of mechatronics education, and in particular, for the study of brushless DC motors, which are extensively employed in robots, information devices, home appliances and other areas. While hypermedia-based courseware and computer-assisted instruction are widely used in conventional desk-type learning, very few examples exist of remote learning that involve experiments. The authors therefore developed a prototype client-server system for remotely conducting experiments on brushless DC motors, including Web-based courseware and other software. The server computer is connected to the motor laboratory, and the visual image and sounds of the experiment are transmitted to the client computer in real time. The remotely located user can operate the motors and conduct experiments through the client computer. Through demonstrations to a class, the authors conclude that the remote lab combined with a simulation of the motors dynamic behavior can be a quite effective teaching aid for the study of precision motors.

Developing an educational simulation program for the PM stepping motor

A simulation program for the claw-pole permanent-magnet (PM) stepping motor was developed for use in a college sheet classroom. Based on circuit equations and equations of motion, it aims to impart to the student the ability to develop insight into the PM stepping motor, which operates on simple principles but displays sophisticated characteristics when electronically driven. The step-position error caused by cogging torque and assembly error, and measures to reduce such errors, are discussed. It is concluded that this software can provide a useful tool for practical mechatronics design.

In-depth learning of cogging/detenting torque through experiments and simulations

The necessity of in-depth learning of cogging/detent torque for mainly undergraduates is discussed with particular attention to its method and tools. The experimental tools developed include a cogging-torque tester, variable-skew rotors for a DC motor and a three-phase hybrid stepping motor having a special rotor construction to eliminate certain harmonic components of cogging torque. Two pieces of software are presented for use in the class and laboratory to supplement the experiment set-ups: one is a motion simulator for a watch stepping motor to demonstrate the notion of detent torque; and the other is for quick computation of the cogging torque primarily to investigate pole-and-slot number combinations for various pole-arc to pole-pitch ratios. The latter can be used to see the effects of construction asymmetry on the cogging-torques amplitude and frequency. The usage of these tools and software is discussed from the viewpoint of engineering education. The major conclusion is that the variable skew rotor is very suited to in-depth learning of cogging torque but the supplemental use of the computation software is invaluable for gaining deeper insight into this subject.

Developing educational software for mechatronics simulation

The need for a mechatronics simulation software is pointed out with special reference to engineering education, after which the authors present a convenient approach. Their basic algorithm computes the electromechanical behavior of electric motors combined with mechanical components like inertial/frictional/torsional loads, including such transmission elements as gears or lead screw/nuts. The simplicity and utility of their mathematical treatment are discussed in terms of its educational merits. The major theory is developed using a brush-type permanent DC motor, but brushless DC and stepping motors are discussed as well. They present three sample software packages. One is a simple program which demonstrates the computational principles for the electric current in an LRC circuit or the velocity of a suspended mass. The other two simulate the dynamic behavior of a slide table powered by a DC motor via gears and a lead screw. One is written in Microsoft Visual Basic code reflecting the physical meaning of mechanical components and the other is a Visual C++ version using the class library concept. The merits and demerits of these two approaches are discussed from the vantage point of undergraduate education and the retraining of technical instructors and working engineers.