Robot system with supplementary metrology position coordinates determination system

A method for operating a supplementary metrology position coordinates determination system that is utilized with an articulated robot,

• the articulated robot comprising:
• a first arm portion mounted to a first rotary joint at a proximal end of the first arm portion, the first rotary joint having a rotary axis aligned along a z axis direction such that the first arm portion moves about the first rotary joint in an x-y plane that is perpendicular to the z axis, wherein the first arm portion has a second rotary joint located at a distal end of the first arm portion, the second rotary joint having its rotary axis nominally aligned along the z axis direction;
• a second arm portion mounted to the second rotary joint at a proximal end of the second arm portion, such that the second arm portion moves about the second rotary joint in an x-y plane that is nominally perpendicular to the z axis;
• and
• a motion control system configured to control an end tool position of an end tool with a level of accuracy defined as a robot accuracy, based at least in part on sensing and controlling the angular positions of the first and second arm portions about the first and second rotary joints, respectively, using position sensors included in the articulated robot;
• the supplementary metrology position coordinates determination system comprising:
• a first imaging configuration comprising a first camera, the first imaging configuration having an optical axis that is nominally aligned parallel to the z axis and having a range of focus along its optical axis;
• an XY scale comprising a nominally planar substrate arranged nominally perpendicular to the z axis and a plurality of respective imageable features distributed on the substrate, wherein the respective imageable features are located at respective known XY scale coordinates on the XY scale;
• an image triggering portion;
• and
• a metrology position coordinate processing portion,
• wherein the supplementary metrology position coordinates determination system is configured with a movable one of the XY scale or the first imaging configuration coupled to the second arm portion proximate to the distal end of the second arm portion and the other is coupled to a stationary element with the location of the XY scale along the z axis within the range of focus of the first imaging configuration, the stationary one of the XY scale or the first imaging configuration defining a first reference position:
• the method comprising:
• receiving at the image triggering portion at least one input signal that is related to the end tool position and determining the timing of a first imaging trigger signal based on the at least one input signal and outputting the first imaging trigger signal to the first imaging configuration, wherein the first imaging configuration acquires a digital image of the XY scale at an image acquisition time in response to receiving the first imaging trigger signal;
• receiving at the metrology position coordinate processing portion the acquired image and identifying at least one respective imageable feature included in the acquired image of the XY scale, and the related respective known XY scale coordinate location;
• and
• determining a relative position between the movable one of the XY scale or the first imaging configuration and the first reference position with an accuracy level that is better than the robot accuracy, based on determining an image position of the identified at least one respective imageable feature in the acquired image, wherein the determined relative position is indicative of the metrology position coordinates of the end tool position at the image acquisition time, with an accuracy level that is better than the robot accuracy, at least for x and y metrology position coordinates in an x-y plane that is perpendicular to the z axis.

A supplementary metrology position coordinates determination system for use with an articulated robot, the supplementary metrology position coordinates determination system comprising:

• a first imaging configuration comprising a first camera, the first imaging configuration having an optical axis that is nominally aligned parallel to a z axis and having a range of focus along its optical axis;
• an XY scale comprising a nominally planar substrate arranged nominally perpendicular to the z axis and a plurality of respective imageable features distributed on the substrate, wherein the respective imageable features are located at respective known XY scale coordinates on the XY scale;
• an image triggering portion configured to input at least one input signal that is related to an end tool position of an articulated robot and determine the timing of a first imaging trigger signal based on the at least one input signal and output the first imaging trigger signal to the first imaging configuration, the articulated robot including a first arm portion mounted to a first rotary joint at a proximal end of the first arm portion and having a second rotary joint located at a distal end of the first arm portion, a second arm portion mounted to the second rotary joint at a proximal end of the second arm portion and a motion control system configured to control an end tool position of an end tool with a level of accuracy defined as a robot accuracy, based at least in part on sensing and controlling the angular positions of the first and second arm portions about the first and second rotary joints, respectively, using position sensors included in the articulated robot, wherein the first imaging configuration is configured to acquire a digital image of the XY scale at an image acquisition time in response to receiving the first imaging trigger signal, and
• a metrology position coordinate processing portion configured to input the acquired image and identify at least one respective imageable feature included in the acquired image of the XY scale, and the related respective known XY scale coordinate location,
• wherein:
• the supplementary metrology position coordinates determination system is configured with a movable one of the XY scale or the first imaging configuration coupled to the second arm portion proximate to the distal end of the second arm portion and the other is coupled to a stationary element with the location of the XY scale along the z axis within the range of focus of the first imaging configuration, the stationary one of the XY scale or the first imaging configuration defining a first reference position;
• the supplementary metrology position coordinates determination system is configured such that the metrology position coordinate processing portion is operable to determine a relative position between the movable one of the XY scale or the first imaging configuration and the first reference position with an accuracy level that is better than the robot accuracy, based on determining an image position of the identified at least one respective imageable feature in the acquired image;
• and
• the determined relative position is indicative of the metrology position coordinates of the end tool position at the image acquisition time, with an accuracy level that is better than the robot accuracy, at least for x and y metrology position coordinates in an x-y plane that is perpendicular to the z axis.