Human–robot cooperation control based on a dynamic model of an upper limb exoskeleton for human power amplification

•A human–robot cooperation controller is developed for the purpose of lifting heavy objects.•This controller is based on a dynamic model of force control and was designed to easily reflect the human motion intent.•For the stability of the control at a singular point, singularity avoidance was applied by using the DLS method.•The external load compensation was applied to the controller by using the value measured by a force sensor. In this paper, we propose a human–robot cooperation controller for the motion of the upper limb exoskeleton. The system permits three degrees of freedom using an electrical actuator that is mainly controlled by force sensor signals. These signals are used to generate the torque required to drive the exoskeleton. However, singularities exist when the force signals in the Cartesian coordinate system are transformed into torques in the joint coordinate system. Therefore, we apply the damped least squares method. When handling a load, torque compensation is required about its mass. Therefore, we installed a force sensor at the point of the robot’s end-effector. It measures the forces between the exoskeleton and the load. Then, these forces are used to compensate within a static model for handling loads. We performed control stability and load handling experiments to verify the effectiveness of the controller. Via these, we confirmed the effectiveness of the proposed controller.