In the computer industry we hear interesting metrics about the ever increasing capabilities of processors and hardware. That capability is usually measured in a performance metric such as MIPS or Million Instructions Per Second. We don’t generally talk about capability per dollar spent. However, the cost of control is a major metric when evaluating control components that go into industrial and commercial machinery.
The cost of control is extremely important in terms of its impact on what is “practical” in the world of production. Even in medical, military and aerospace systems where cost is often a secondary consideration, the actual cost and performance of a new process or piece of equipment has to be gauged against the benefit that it will produce. If the benefit is greater in value than the cost, then funds and effort need to be committed to the new project.
There are significant trends in the marketplace that are constantly changing the cost of control. As we look at the mechatronic arena in particular, recent increasing cost trends for copper wire, lamination steel and permanent magnets have been pushing prices up steadily in the range of 5-6% per year. This situation is expected to continue.
Recent threats from China about restricting export levels for Neodymium magnets have made magnet pricing very speculative, read high as a kite. However, Molycorp and others around the world are bringing Neodymium ore into the market and companies like Arnold Magnetics are gearing up to provide finished products without the use of Chinese sourced material. Good new to those in the motor sector.
On the control side of mechatronics, the power Fet has dropped in cost by 50% in recent years and costs are expected to continue to decline following the traditional cost performance over time that is characteristic of the semiconductor industry. Add to this the incredible cost performance improvement in embedded microcontrollers used in motor control circuits and you have even more good news for the mechatronic suppliers.
Bandwidth for these controllers now provides motor control that operates in the sub-microsecond range with efficient instruction sets and pre-configured PWM macros to make code creation more efficient. Typical pricing for these processors is well under $5 making them ideal for a wide range of applications in industry and commercial white goods. The marriage of low cost motor control cores and reduced cost power electronics should signal declining prices for motor controls for the mid- to high performance applications. This cost improvement should more than offset the price increases expected in the cost of electrically controlled motors.
Some families of processor have native CAN or Ethernet communications interfaces with multi-threading software to guarantee that high priority instructions in the motor control code will not be impacted by messaging from outside applications. Network technology is providing fast, and in some cases, deterministic forms of Ethernet like EtherCat making the servo network the control architecture. This approach to the network demands of high performance control reflects a general shift to low cost, high reliability platforms that are ready to transform the controls landscape in the mechatronic arena.
It’s an interesting time to be in the controls business.