Högskolan i Skövde

Effective simulation of manual assembly operations considering ergonomic load and clearance demands requires detailed modeling of human body kinematics and motions, as well as a tight coupling to powerful algorithms for collision-free path planning. The focus in this paper is a unified solution that automatically creates assembly motions for manikins taking kinematic constraints, balance, contact forces, collision avoidance and comfort into account. The manikin used in this work has 162 degrees of freedom - six exterior fictitious joints determine the position of the lower lumbar and the remaining ones are interior joints. The inverse kinematic problem leads to an underdetermined system allowing us to pick a solution that maximizes a scalar valued comfort function. The comfort function offers a generic way to give preference to certain poses while avoiding others, typically by considering joint limits, forces and moments on joints, and magnitude of contact forces. In order to avoid collisions, poses close to collision are penalized. The method is implemented and demonstrated on two challenging assembly operations taken from the automotive industry.