Another Approach

GM is studying to alleviate ergonomic stress that impairs the performance of its line workers. Another example is the Human Power Extender developed by Homayoon Kazerooni, a professor of mechanical engineering at the University of California, Berkeley. His intelligent-assist tools amplify the force a worker exerts in lifting and moving objects. Last summer GM evaluated the concept to lift and maneuver batteries into automobiles. The extender is programmed to provide automatically a large percentage of the total lift force needed, with a smaller residual load intended to give the operator a feel for the movement of the total load. The correct amount of power to add is calculated instantaneously on the extenders computer. With Power Extenders, a worker can manipulate heavy objects as easily and naturally as a light object, says Kazerooni. The load-sharing feature is essential for ergonomically correct lifting, he says. Operation is user-friendly with no need to manipulate pushbuttons, keyboards, switches, or valves. In addition to an electric model, Kazerooni offers a pneumatic extender module that can be installed on pneumatic manual material-handling devices.