High Performance Motion Control

What trends do you see that impact higher performance at the motor level?

There is the normal improvement of materials. The magnet capability for the permanent magnet side is getting better. Two years ago they announced something very new with nanostructure neodymium iron boron magnets. They essentially doubled the energy product, the amount of energy you can get out of a magnet from a theoretical limit of 67 up to 95. The Chinese now have all the manufacturing along with the Japanese. The Chinese have decided that it is going to be their critical technology because they control 50 percent of the material in their western mountains.

Could this extend higher performance to a broader range of motors?

We are getting into a lot of interesting things. We can make a smaller motor do the same thing it could do before or we could make a larger motor do more or a same size motor do more. The limits now are soft iron not in the magnets. It outperforms the ability of the iron laminations to carry the flux.

Is that a design opportunity?

It is. A lot of guys are looking at slotless brushless because of this. If you are going to saturate the iron anyway, why not go slotless. It means you eliminate the lamination teeth, you have a larger air gap, and you reduce cogging and eddy current losses — the losses you get at the low end, the cog, and the losses you get at the high end, the eddy currents. So, there are all kinds of possible new things that are going to happen because of what materials are doing.

How about performance improvements at the drive level?

It's going towards the modular approach. When you put the intelligence close to the drive, it's easier for the customer to handle. You can tie the drive and the motor together. You can take all the parameters of the motor, download them together in the memory on the drive, and personalize it. There is software involved in that as well — software to integrate the drive and the motor performance characteristics together more efficiently. That's one of the trends I see.

Are there other performance advantages to integration?

If you are integrating it, you are putting the controller right on the motor with the drive. You have that trend continuing. Now it is a motor-drive-control system. The leads are now two-inches long, so you don't have an antenna anymore. You meet RFI/EMI very quickly and effectively. It is now self-contained, so you can filter it better and it has all kinds of secondary advantages.

What about software's influence on performance?

What you are trying to do is limit the hardware and make the software work harder where you can. That's one way of shifting the paradigm. And if you can integrate the parts, it makes it easier to use software, because you don't have to have as wide a variety in the number of commands. You don't have to be universal for everybody anymore.

Are there any major regional differences regarding higher performance?

I took the equation performance divided by cost. It is a basic, simple equation. In America it reads small performance divided by capitalized cost. In Germany, it means capitalized performance divided by small cost. In Japan, I think they're both capitalized or they're both small. I am still sorting that one out. Probably in China they're both small and in Japan they're both capitalized. It's a simplistic way of looking at things but it ain't a bad start.