EffeCts of Pacing When Using Material Handling Manipulators

摘要

Common manipulator-assisted materials handling tasks were performed in a lab- oratory simulation at self selected and faster (paced) speeds. The effects of pac- ing on peak hand forces, torso kinematics, spine moments and forces, and muscle antagonism were determined, along with any influences of several task variables on these effects. The faster trials were performed 20/100 more rapidly than the self paced trials. It was found that (a) achieving this level of perfor- mance required --10/100 higher hand forces and 5/100--l0/100 higher torso moments, (b) consistent torso postures and motions were used for both speed conditions, and (c) the faster trials resulted in --l0/100 higher spine forces and --l5/100 higher levels of lumbar muscle antagonism. On whole, these results suggest a higher risk of musculoskeletal injury associated with performance of object transfers at faster than self selected speeds with and without a manipulator. Further analysis provided evidence that the use of manipulators involves higher levels of motor coordination than do manual tasks. Several implications regarding the use of material handling manipulators in paced operations are discussed. Results from this investigation can be used in the design, evaluation, and selection of material handling manipulators.