U of G Robot Mimics Heavy-Vehicle Operator Conditions
Monday, May 29, 2006
It’s estimated that six per cent of all Canadian workers are exposed to potentially harmful levels of whole-body vibration – a low-frequency vibration incurred while driving trucks and heavy machinery. Workers exposed to whole-body vibration are about four times more likely to develop low back pain. They may also suffer from other medical problems, including herniated lumbar discs, neck-shoulder pain and intestinal upset, said Prof. Jim Dickey of the Department of Human Health and Nutritional Sciences.
Although it’s known that truck drivers are getting injured from long-term whole-body vibrations, little is known about how vibrations along the body’s three different axes cause pain and discomfort, said Dickey.
Now that U of G has one of only a handful of “six degree of freedom” robots in the world with the capacity to move along the three axes, he and his research team can simulate the motions of a vehicle on unpredictable terrain in his lab.
“We’re going into mines and logging and heavy-construction sites to measure the acceleration, velocities and jerk that drivers are exposed to, then we feed that profile into the robot and the robot re-creates it,” said Dickey. “We’re interested in figuring out the relationship between these motion patterns and comfort.”
The researchers are placing industrial car seats, complete with seat belt, footrest and steering wheel or joystick, on the robot platform to re-create the driver’s environment as closely as possible. Study participants sit in the seats and are taken on what looks like a bucking bronco ride, said Dickey. “The motion is quite irregular; it’s got all sorts of complicated aspects to it. We can’t give people five years worth of exposure, but vibrations that result in injuries are also going to result in discomfort. By rating their discomfort on a scale of one to 10, people can really perceive differences in comfort based on differences in acceleration.”
Vibrations felt by forestry, mining and construction operators are the worst-case scenarios, said Dickey. “Forestry skidders are going over logs and huge bumps, dragging logs from one spot to another. Because it’s an extreme example, the accelerations the operators are exposed to allow us to understand the participants’ responses to vibration along or about the three axes.”
Participants will sit in the different commercially available machinery seats to determine how each one handles the pulses. “Describing the vibration will be a huge help to seat designers because right now they’re designing chairs without knowing the full characteristics of the environment the chairs are working in,” said Dickey.
To learn as much as possible about full-body vibrations, he has assembled a multidisciplinary team of researchers from four universities to look at the issues facing operators from engineering, psychological and biological perspectives. Prof. Michele Oliver of the School of Engineering will be running the forestry part of the study. Prof. Lana Trick in U of G’s Department of Psychology will lend her expertise in the psychology of pain and discomfort. A U of G biophysics PhD candidate is looking at how vibrations transmit up the spine and the role posture plays in a driver’s comfort.