Systems and hybrid position force control processes of an industrial robot

A control process for an industrial robot, the industrial robot comprising:

• a multi-axis robot arm comprising at least two electric actuators each configured to move one part of the multi-axis robot arm with respect to another part of the multi-axis robot arm about or along an axis of movement, each electric actuator being associated with a sensor configured for measuring articular positions of the associated electric actuator,
• an effector placed at an end of the multi-axis robot arm,
• a robot control system comprising:
• a central unit and a single auxiliary unit, the central unit and the auxiliary unit being in communication by means of a data bus,
• an axis controller module configured for calculating control setpoints of power units which deliver an appropriate electric current to the electric actuators according to an articular force setpoint and implemented by said single auxiliary unit, and a calculation module configured for determining articular force setpoints for the axis controller module, the calculation module being connected to the axis controller module,
• a data acquisition interface configured for receiving and sending the articular positions of the electric actuators measured by the sensors associated with the electric actuators, to the calculation module and to the axis controller module,
• a multi-axis force sensor configured to measure multi-dimensional external forces exerted on the multi-axis robot arm and to send the multi-dimensional external forces to the axis controller module;
• wherein the control process comprises:
• calculating, in the calculation module, an articular force setpoint for controlling the axis controller module, and
• calculating, in an articular converter implemented by the central unit, an articular conversion matrix from the measured articular positions, the articular conversion matrix being sent to the auxiliary unit,
• providing the axis controller module with the multidimensional external forces exerted on the effector,
• calculating, in the axis controller module, a vector of articular forces according to the external forces exerted on the effector, by using the articular conversion matrix,
• calculating, in the axis controller module, current loop control setpoints taking into account the vector of articular forces and the articular force setpoint,
• calculating, in the axis controller module, control setpoints of the power units according to control setpoints for the current loops, and
• applying the control setpoints of the power units to command the multi-axis robot arm.