This research develops a computer-aided system for health professionals which helps them to prevent injury related to manual lifting by workers in a manufacturing operation. The heart of the system is a computer program which prescribes the motion that a given person should follow while lifting an object according to different conditions. The system compares the prescribed path to the true motion data taken from a motion tracking system so the health professional can make suggestions on how the person should modify his/her movement.
The prescribed motion is generated with a new technique called spacetime optimization. The health professional describes the simplified characteristics of the human subject such as sex, height, weight, and harmful conditions that the subject should avoid, such as maximum low back stress or shoulder stress. He/she also describes the task involved, such as the starting and ending positions of the load, its shape and weight, and the positions of any intermediate obstacles in the path. The spacetime optimization engine generates the path that the person should follow in order to minimize the harmful conditions according to an objective function and constraints.
In this research, two dimensional dynamic human models are used and a graphical user interface is added to this system to display and compare the motion between real motion and simulation models.