Force-Controlled Handling Apparatus for Robot-Assisted Surface Machining

A system, comprising:

• a handling apparatus having a linear actuator acting between a first flange connectable to a manipulator and a second flange on which a tool, or a machine tool with a tool, can be mounted, wherein the linear actuator is configured to exert a force on the second flange or an end stop in accordance with a control variable;
• a force sensor coupled between the second flange and the tool, wherein the force sensor is configured to measure a force exerted by the handling apparatus on the tool upon contact between the tool and a surface;
• a control unit including a state observer configured to determine, based on the control variable, an estimated value for the force exerted by the handling apparatus on the tool,
• wherein the control unit is further configured to:
• detect a contact between the tool and the surface;
• adjust the control variable based on the estimated value and a target value, as long as no contact is detected;
• and
• adjust the control variable based on the measured force and the target value as long as a contact is detected.

A method of controlling a handling apparatus having a linear actuator acting between a first flange connectable to a manipulator and a second flange on which a tool, or machine tool with a tool, can be mounted, the method comprising:

• controlling the linear actuator with a control variable so that the linear actuator exerts a force on the second flange, or on an end stop, in accordance with the control variable;
• detecting contact between the tool and a surface;
• measuring, in case of contact between the tool and a surface, a force exerted by the handling apparatus on the tool using a force sensor coupled between the second flange and the tool;
• determining an estimated value for the force exerted by the handling apparatus on the tool based on the control variable;
• adjusting the control variable based on the estimated value and a target value as long as no contact is detected, and adjusting the control variable based on the measured force and the target value as long as contact is detected.