Method of determining contact positions, calibration parameters, and reference frames for robot assemblies
AssigneeFANUC Robotics North America, Inc.
InventorsH. Dean McGee, Eric C. Lee
Life of this patent
Estimating the term…
Abstract
A method of determining contact positions of a robot relative to a workpiece in a workspace of the robot. The method utilizes the contact positions to determine a location of the workpiece in the robot workspace. The method also monitors an integral operating parameter within the robot, such as motor torque, to determine the contact positions of the robot relative to the workpiece and to locate the workpiece.
Claims47
A method of determining a contact position of a robot assembly relative to an object external to the robot assembly wherein the robot assembly includes at least one arm having a contact surface, and a controller, said method comprising the steps of:
- moving the robot assembly from an initial position where the contact surface is spaced from the external object toward the contact position where the contact surface of the robot arm contacts a point on the external object;
- determining operating values of the robot assembly as the robot assembly moves between the initial position and the contact position;
- establishing at least one operating parameter threshold;
- comparing the operating values to the operating parameter threshold;
- continuing the movement of the robot assembly provided the operating values are less than or equal to the operating parameter threshold;
- recording the contact position of the robot assembly relative to the external object when the operating values of the robot assembly exceed the operating parameter threshold;
- and
- said method characterized by the step of determining operating values of the robot assembly being further defined as monitoring an integral operating parameter within the robot assembly during the movement of the robot assembly between the initial position and the contact position to determine when the robot assembly contacts the external object.
A method of determining a calibration parameter of a robot assembly having a calibration plaque mounted within an operation space of the robot assembly wherein the calibration plaque includes an outer facing, and at least one calibration element defining a bounded void having an inner surface, and wherein the robot assembly includes at least one arm having a contact surface, a controller, and a sensing device that detects contact between the contact surface of the robot arm and the calibration plaque, said method comprising the steps of:
- moving the robot assembly from an initial position toward a contact position;
- detecting when the contact surface of the robot arm contacts a segment on the inner surface of the bounded void with the sensing device;
- continuing the movement of the robot assembly until the contact surface contacts the segment;
- recording the contact position of the robot assembly relative to the inner surface of the bounded void when the sensing device detects contact between the contact surface and the segment;
- utilizing the recorded contact position to determine the calibration parameter;
- and
- said method characterized by the step of moving the robot assembly being further defined as moving the robot assembly from the initial position where the contact surface is spaced from the inner surface of the bounded void toward the contact position where the contact surface of the robot arm is at least partially extended into the calibration element and contacts the segment on the inner surface of the bounded void.
A method of determining a reference frame in an operating space of a robot assembly wherein an object external to the robot assembly is disposed in the operating space of the robot assembly and includes an object contact surface, and wherein the robot assembly includes at least one arm having a contact surface, a controller, and a sensing device that detects contact between the contact surface of the robot arm and the object contact surface, said method comprising the steps of:
- determining a plurality of contact points relative to the reference frame, and determining a first vector approximately normal to one of the contact surface and the object contact surface at one of the contact points;
- determining a geometrical relationship between the robot assembly and at least one of the contact surface and the object contact surface;
- moving the robot assembly from an initial position toward a contact position;
- continuing moving the robot assembly until the sensing device detects contact between the contact surface and the object contact surface;
- recording the contact position of the robot assembly when the contact is detected by the sensing device;
- utilizing the recorded contact position and the determined geometrical relationship to determine the reference frame;
- and
- said method characterized by the step of moving the robot assembly being further defined as moving the robot assembly from the initial position where a second vector, between the contact surface and the contact point, is approximately normal to at least one of the contact surface and the object contact surface along the first vector toward the contact position where the contact surface of the robot arm contacts the object contact surface.
Dependencies are inferred from the claim text.