Taking Control of Industrial Automation
Industrial equipment on manufacturing lines, in order to maintain peak performance, must operate within a desired range for a handful of critical variables. These may include velocity, pressure, flow or temperature, and going outside that set range in any one area can slow down or derail a manufacturing operation.
Industrial control technology known as the PID (proportional-integral-derivative) controller helps keep those machines in check. But amazingly, that technology has gone virtually unchanged since 1922!
The key weakness is that PID is a fundamentally passive technology, making corrections when disturbances push these key variables out of whack. By only reacting to the deviations caused by disturbances, this early 20th century technology can lead to unnecessary labor costs, productivity and energy loss.
Zhiqiang Gao, an associate professor of electrical engineering and computer science at Cleveland State University, has spent the past 20 years exploring technologies to increase the efficiency of industrial control and manufacturing equipment.
In his lab, he and his students developed an algorithm to detect the disturbances, that make those process variables go outside of the range necessary for efficient performance. Dubbed Active Disturbance Rejection Control (ADRC), this controller takes an active, rather than passive role in managing changes.
“This was possible because we’re now in the information age,” said Gao. “We have all of this data going into and out of these machines, and this controller can process that data to extract information of disturbance and immediately act on it, rather than allowing performance to degrade.”
With just a few lines of codes and simple, bandwidth-based parameter tuning, this extra layer of intelligence allows ADRC technology to counter the unavoidable disturbances, rejecting them much earlier than before, and greatly reducing the energy required to keep machines running smoothly. In fact, ADRC made its way into Texas Instruments motion control chips, replacing PID, and was utilized across 10 production lines at Parker Hannifin Corp., reducing energy consumption by more than 50 percent. And according to Gao, it more recently improved energy efficiency by as much as 30 percent within a massive server farm.
Today, Gao’s invention represents massive market potential as the only alternative to PID. It was also CSU’s first major research commercialization. In 2008, Early Stage Partners in Cleveland gave CSU $1 million in seed funding to spin off a company, now called LineStream Technologies. Danfoss Group in Denmark, a leader in electric motor controls for manufacturing, recently purchased the company to upgrade the technology in manufacturing lines across the globe.