Heavy lift assist devices are an important part of manufacturing facilities that involve large, heavy or bulky material. Many devices are available that provide lift but not motive force augmentation. In these devices, the physical strength of the operator is used to move and position the work piece. Due to large work piece inertial characteristics, inertial contributions from the lift device itself, and misuse of the assist manipulator, injuries may still occur. In this research, an approach is presented that provides reduced-authority actuation to the motive joints of the lift device that allows for augmentation of the human motion forces, provides a means of correcting injurious ergonomic interactions, and allows for high rate energy dissipation for payload trajectory control and emergency situations. The approach is to provide low torque input controlled by operator hand motions. These hand motions move the payload under a centralized trajectory generation scheme that uses modulated braking commands to impose motion constraints, such as object avoidance, resonance attenuation and ergonomic trajectory enhancement. The system is implemented in an virtual reality robot simulator that allows for the investigation of dynamic characteristics prior to the prototype stage.