Laser Tracker inventor, Dr Kam Lau – CEO of API Metrology, recently explained his background that led to the Laser Tracker invention. Its original purpose – to determine the performance of industrial robots. Now some 35 years later the Laser Tracker is taking center stage in robot calibration and dynamic robot tracking as manufacturing industry seeks-out higher accuracy performance of industrial robots for robotic metrology and critical process applications.
Full Circle – Robot Accuracy Verification and Calibration
In April of 1982, a young engineer stands in the basement of the National Bureau of Standards (NBS), which will later become known as the National Institute of Standards and Technology (NIST). The basement has become a junkyard of castoff parts and equipment, long forgotten by most of the NBS employees. The young engineer, however, is not searching for an old part; he’s looking for inspiration in creating something entirely new. He’s come up with a revolutionary idea for a moving laser that can measure and calibrate robotic performance in the manufacturing process, and he’s promised his boss that he can make a functioning model of his design in six months using nothing but the relics now laid out in front of him. What made this seemingly impossible task turn into the first model of the laser tracker that is now found in most tool shops in the world?
The young engineer’s name is Dr. Kam Lau, and he’s done this before.
Dr. Lau was born in the southern Chinese coastal town of Macau when it was still a Portuguese territory in the 1950s. When he was eight, the family moved to Hong Kong, where he spent the rest of his childhood and early adulthood. The youngest of seven children, Dr. Lau learned the value of working with his hands from a young age.
“My father was a carpenter,” Dr. Lau recalls. “And he passed away when I was only ten years old. My two brothers became heroes to me when I was young. I watched all my siblings and how they worked, and I appreciated how they brought back to the family.”
What his siblings brought home were the roots of an inquiring engineering mind. “We weren’t a well-off family by any means,” Dr. Lau remembers. “I was lucky though. I was able to get an education, and I didn’t have to worry about food, but there was never any money for toys. So, I made my own.”
For Dr. Lau, making his own toys meant everything from tying tin cans together to using his father’s tools to take apart pendulum clocks and sewing machines from around the house to put them back together. “My mother’s sewing machine was one of my favorite toys,” Dr. Lau says, laughing. This childhood tinkering sparked a lifelong interest in building and creating.
In his neighborhood, there was a blacksmith, a casting company, and several construction sites. The young Dr. Lau would stand outside these businesses for hours after school watching the machines and tools. “Now I know I wanted to be an engineer, but at the time, I was so young, I didn’t know what engineering was,” Dr. Lau remembers. “I just wanted to build and create and use whatever tools I had.”
This interest in engineering led Dr. Lau to technical college in Hong Kong, where he gained his first hands-on experience designing, machining, and measuring his own parts. It was his first taste of the crucial role accuracy plays in precision machining.
Dr. Lau began researching American universities, eventually landing on the University of Madison-Wisconsin. “I still didn’t have a lot of money,” Dr. Lau says. “But I knew it was a good school, and I thought they would give me the best value for my tuition.” After a year spent in the Lake Superior campus, he transferred over to the main Madison campus where he would stay until he finished his doctorate in 1982. As part of a partnership between the university and NBS, he created a large research project for more than a dozen students. This project landed him a position as a researcher with NBS in January of 1982.
Initially, Dr. Lau was placed on a team creating software. “And I didn’t mind that,” Dr. Lau says. “I was good with software, but eventually I went back to my old habits, to design things, to build things, to be able to touch something.” And his tinkering led him to notice a hole in the manufacturing industry and a revolutionary idea.
In the early 1980s, Robotics were the new idea sweeping through every sector of the manufacturing industry. Yet there were significant issues with this first wave of automation. “They were not very capable of lifting heavy parts,” Dr. Lau remembers. “The vision systems weren’t as agile and capable as they are now. The computer to capture that information and transfer it to the control were very expensive, and they weren’t very high speed.”
As a member of the Department of Commerce, NBS was tasked with clarifying the capabilities of these robots, defining what they can and cannot do. “So, from that I came up with the idea for the laser tracking system, Dr. Lau says. “The idea is that I can direct a laser beam to track the robot, and then can put it in an X,Y,Z grid and see pitch, roll, and yaw to see 6 degrees of freedom for the robot. I can use the information to classify the capability of the robot and use that info in real time to control the robot’s position, making it more precise.”
Dr. Lau took his initial designs to his boss and asked permission to begin working on a prototype design. “He said, ‘Kam, I don’t know how it will work, but go ahead and try it,’” Dr. Lau remembers with a chuckle. “I told him in six months time, I would show him a prototype of the system.”
Which brings us back to the basement. “It was just like when I was young,” Dr. Lau says. “I went through the junkyard of NBS and tried to pick things out. I took a banished laser interferometer, a very old rotary table, and that kind of formed the base of my laser tracking system.”
Six months later to the day, Dr. Lau returned to his boss’ office. It was after 6:30, and most everyone had gone home for the night. Dr. Lau asked his boss if he could come to the basement to see what he had been working on. “He’d forgotten; he had no idea what I was doing,” Dr. Lau laughs. “He was shocked when I showed him this very primitive tracker made from old components that had been thrown away. But I was able to visibly demonstrate the laser interferometer moving back and forth on a rotary table to capture the optical target moving sideways.”
Things moved very quickly from there. Two days later, he was presenting the first design of the laser tracker to the directors of NBS. And he was no longer in the basement; he was in the lab. The following day, Dr. Lau presented the system to representatives from the Army, Navy, and Air Force. The NBS Marketing team came in to take photos and publish stories about the new breakthrough.
“The interest was very high,” Dr. Lau remembers. “And suddenly we had funding. I had been working alone, and now I was placed in charge of a team of four or five people to build the first prototype. I could go into the details of the design and make parts instead of using components from the junkyard.” With this funding came a host of new problems to solve to make the tracker repeatable and applicable to real manufacturing situations. But Dr. Lau was never concerned; he was making his own toys again.
For more information: www.apimetrology.com