Lifting Objects with Power-Assist: Weight-Perception-Based Force Control Concepts to Improve Maneuverability

We developed a 1-DOF power assist robot system to lift objects of different sizes by human subjects. We adopted a hypothesis that weight perception due to inertia might be different from that due to gravity when lifting an object with a power assist robot because the human feels a difference between the actual weight and the perceived weight of the object. We included this hypothesis in the robot dynamics. We then discussed the suitability of force control for the robot for lifting objects and developed several weight-perception-based force control strategies. These force control strategies may be compared to previously developed position control strategies, and the comparison results may help determine appropriate control for the robot to achieve desired maneuverability. The results, as a whole, may help develop human-friendly power assist devices to handle heavy objects in various industries.