Mechanical manipulators are commonly used in manufacturing applications to aid in the handling of large, bulky, or dangerous materials. Often these heavy lift assist devices are designed to lift a variety of payloads and are controlled by a human operator A recent trend has been to automate more of the function of the manipulator and collocate the human input with the payload. In this research, an existing heavy lift assist device is equipped with joint actuators and a force transducer to allow the operator to move the payload in a natural and intuitive manner. Intelligence is added to the assist device by inserting impedance fields in the workspace to affect the trajectory commanded by the operator. Repulsive fields are used to avoid obstacles and attractive fields are added to help the operator reach desired positions. Simulation results are compared to experimental results for the system under operation.