Q: What technologies have caught your eye in surveying motion control trends?
A: You have to understand that the motion control business is not revolutionary. You can't point to a product that is going to shake up the whole world. Instead, we have incremental improvements in products, as well as cost savings. But having said that, I would point out that, for precise motion control in applications ranging from disk drives to medical to packaging machinery, the permanent magnet brushless dc motor has emerged as the clear winner. That's despite all the talk about other types, such as switched-reluctance motors and slotless motors, which are rarely seen in real-world applications. Brushless permanent magnet linear motors also are coming into their own, with some companies offering models with incredible precision at very attractive prices.
Q: What is the impact of specialized microprocessors?
A: Digital signal processors are having a tremendous impact, and it all boils down to delivering more features for less money. Who would have ever thought of putting a DSP in a sump pump for a house? But if you've got an expensive home, you want a pump that is not only reliable but has memory and communication capabilities. As costs of DSPs have fallen from $30 to $1.50, these very fast microprocessors are providing many rich features for motion control, such as higher speeds, programmable inputs/outputs, diagnostics, error history, coordinated motion, communications, and noise control. The leading DSP manufacturers—Texas Instruments and Analog Devices—are stressing these benefits, with the goal of putting a DSP in every motor. If you are a design engineer and are not considering a DSP in your motion control system, you are missing the boat.
Q: What impact is globalization having on motion control?
A: China is becoming more and more of a factor. It is a major supplier of precise, powerful, and low-cost permanent magnets for motors as well as machined motor parts, such as stators and rotors. In the motion control business, it is getting to be the case that, if you don't have China in the equation, you are going to lose.
Q: Are you seeing more applications with distributed control?
A: Often, the ideal solution is distributed control, especially for more sophisticated, multiaxis systems. The question is: Can you afford it? But we are seeing progress here, too. For example, you now see more motors with integrated controls that are performing functions that once were the responsibility of the central controller.
Q: With all the changes in motion control, isn't it becoming more difficult for design engineers to keep up?
A: That is particularly true of smaller companies, which is why more of them are turning to integrators for assistance. But there is a cost associated with this, with markups ranging from 30 percent to 100 percent. Many large companies, however, still have the resources to hire in-house specialists to handle motion control tasks. Most engineers can handle simple, straightforward motion control applications, such as open-loop systems that operate at lower speeds and do not require high precision. Here, stepper motors are still the best solution.
Q: In selecting motion control vendors, is the design engineer better off going to one vendor for a turnkey solution?
A: Engineers may find it very convenient to deal with a company that can provide all the components needed, such as a Parker, a Danaher, or a Bosch-Rexroth. These companies have well trained application engineers, and you know exactly who to go to if something goes wrong. On the other hand, the Internet has made it a lot easier for engineers to compare products and prices from vendor to vendor. If you have a very high volume application, it may make sense to deal with best-in-class. Otherwise, you are probably better off sticking with one vendor who can provide the turnkey solution.
Muhammad Mubeen is senior research associate for Motion Tech Trends, a consulting firm that provides engineering, marketing, and strategic planning services in the motion control field. Mubeen's 20-year career in motion control includes marketing and exe
cutive positions with Honeywell, Gould, and Kollmorgen.