Method and device for automated robot-cell calibration

A system for calibration of a robot comprising:

• a robot movable within a working envelope and carrying an end-effector having a tool center point (TCP)
• a means for controlling the robot to move the TCP of said end-effector to a plurality of positions within said working envelope;
• a measurement sensor mounted within said working envelope;
• means attached to the robot selectively operable to actuate said measurement sensor at a plurality of positions of said robot thereby generating a plurality of measurements at random locations on said attached means;
• a means for mathematically expressing said locations with respect to said attached means;
• a means for calibrating said robot, the location of said measurement sensor, and said attached means using said mathematical means for calculating said random locations with respect to said attached means at said plurality of robot positions.

A method for calibrating a robot, the TCP (x,y,z and orientation) of said robot, as well as the location of a measurement sensor for accuracy and recovery purposes with a contact surface type measurement sensor wherein said robot carries an end-effector having a tool center point (TCP) and said robot is movable within a working envelope;

• said method including the following steps:
• Step 1:
• Defining the contour of the tip of the end-effector (the portion of the tip, close to the TCP, which is susceptible to contact or intercept the measurement sensor) in 3D space with respect to the coordinate frame associated with the TCP to be calibrated using a parametric function and/or an interpolation table of x, y, z positions F(TCP)
• Step 2:
• Placing the measurement sensor within the working envelope of the robot, in such a manner that the tip of the end-effector can be driven to a plurality of positions, with a plurality of different configurations of the robot, at which there would be contact between the tip of the end-effector and the active sensing area of the sensor;
• Step 3:
• Generating an initial calibration robot program containing positions at which the tip of the end-effector—within its mathematically described 3D contour—makes contact with the active sensing area of the sensor in its mid-range;
• Step 4:
• Executing a calibration/identification procedure for accuracy purposes;
• Step 5:
• Updating the initial robot and TCP parameters on the robot controller including one or more of the following:
• (1) TCP x, y, z (and orientation if applicable);
• (2) “zero offsets” of each of the robot axes;
• or (3) additional kinematic parameters
• Step 6:
• Generating a recovery calibration robot program containing positions at which the tip of the end-effector makes contact with the active sensing area of the sensor in its “mid-range;
• and
• Step 7:
• Periodically executing the recovery calibration program to recalibrate the robot to compensate for changes in the robot and the TCP of the robot caused by temperature or other environmental factors.