Multi-joint robot and control program thereof

Abstract

The present invention provides a multi-joint robot that, when the loads acting on some of joints are overloaded, controls the joints so as to continue the work as far as possible while easing the overloaded state. The load estimate unit () estimates the load acting on each joint, and the overloaded joint specifying unit () specifies an overloaded joint of which the estimated load is greater than a threshold. The storage unit () stores a target state vector of an end link of the robot and stores a predetermined priority with respect to the components of the vector. The component extracting unit () extracts the same number of components as that of non-overloaded joints from the target state vector in order of a higher priority. The force control calculating unit () determines the target drive quantity for driving the overloaded joint in the same direction as that of the load. The inverse transformation unit determines the target drive quantities with respect to the non-overloaded joints so as to realize the extracted components. Thus, the non-overloaded joints can be controlled so as to follow the target state vector as far as possible, while the overloaded joints are controlled in a direction to reduce the load.