Question:
Tell us about motor control technology.

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How to control a motor is a major technological topic.  There are several types of motor control, including vector control that obtains the optimum operation from the voltage and current of the so-called drive circuits, and speed sensorless vector control with the encoder removed.  To achieve the optimal motor operation, what is important is whether the motor captures its own state when the load fluctuates, and then control its own operation optimally.

With this kind of control technology the motor itself is the sensor, and if that sensor is able to monitor the voltage, current, phase angle, and speed, it has all the parameters needed to understand the state changes of the motor and control it. With sensorless vector control, control on the secondary side results in sensitivity to parameter variations but responsiveness is good, and control on the primary side results in resistance to parameter variations but responsiveness is poor, so various mixtures of the two methods are being proposed.  I think electric motors and motor control are technologies that will continue to progress.

Question:
Yaskawa Electric wins many awards every year for its technology, but from an academic perspective, what is the state of research in other countries?

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Many articles have appeared in scientific journals overseas regarding sensorless vector control technology.  Research is being done on motor control and mechanical motion control to learn how to somehow control machines smoothly.  I have seen quite a number of papers on how to stop robot arms from swaying. German universities and laboratories have a high level of electric motor control technology, and in fact they were the first to produce fundamental research on vector control. Recently, academicians in Korea and China are also doing quite a bit of research. Being geographically close, Yaskawa has engaged in joint research with Seoul University in some areas. Japan is superior in synthetic technology, but I think other countries are catching up.

Question:
Yaskawa Electric has had many successes in the field of mechatronics.  What is the next step for your business?

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Our “Win21 Plus” midterm business plan for the period from 2003 to 2005 shows how we will transform ourselves into a highly profitable industry leader through four key structural reforms (administrative, corporate, managerial, and financial).

In the motion control division, we are working tirelessly towards the ability to offer optimal solutions in the form of network-linked systems centering on servos, inverters, and machine controllers.  Working together with partners such as Yokogawa Electric I think has helped us to develop easy-to-use systems, especially the MECHATROLINK motion field network. The advantage of a network, from the customer's point of view, is that you have good transparency to all that is going on with the terminal devices, and I think a major topic will be in what way individual technologies can contribute to the overall harmony of networked systems.

* MECHATROLINK: An open, high-speed field network that emphasizes speed and precise synchronized control across multiple servos.

Question:
For my last question, what kinds of things will you be looking for in measuring instruments?

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First of all in terms of servos, the time axis would be slow but we would like to be able to analyze mechanical and other kinds of movements within systems on multiple channels.  I think it would also be convenient if the instrument included a full set of functions that would allow us to perform evaluations at the actual location where the system is installed.  Secondly in terms of amp design, I think it would be good if we could observe rapid changes in voltage and current at once.

Motor and inverter technology supports many industries.  We are looking forward to seeing the energy-saving, highly efficient technologies produced by Yaskawa in the future. Thank you very much for speaking with us today.

(Interviewer: Mr. Susumu Matsukura, Division Manager of the Communications and Measurement Department, T&M Business Div., Yokogawa Electronic Corp.)
* Date and location: September 2003, Iruma Office, Yaskawa Electric Corporation