Robot system with supplementary metrology position determination system

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

• the robot comprising:
• a movable arm configuration, 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 first rotary 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 a second rotary axis;
• 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 rotates about the second rotary joint;
• and
• an end tool mounting configuration for mounting an end tool, wherein the end tool mounting configuration is located proximate to a distal end of the movable arm configuration;
• and
• a motion control system configured to control an end tool position of the 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 rotary sensors included in the robot;
• and
• the supplementary metrology position determination system comprising:
• first and second two-dimensional (2D) scales, each 2D scale comprising a nominally planar substrate and a plurality of respective imageable features distributed on the planar substrate;
• and
• first and second cameras;
• and
• the method comprising:
• operating the first camera to acquire a first image of the first 2D scale at a first image acquisition time, wherein the first camera is coupled to the movable arm configuration of the robot at a first camera coupling location and defines a first reference position and the first 2D scale is coupled to the movable arm configuration at a first 2D scale coupling location;
• operating the second camera to acquire a first image of the second 2D scale at the first image acquisition time, wherein the second camera is coupled to the movable arm configuration of the robot at a second camera coupling location and defines a second reference position and the second 2D scale is coupled to the movable arm configuration at a second 2D scale coupling location;
• determining a first relative position of the first 2D scale based at least in part on the first image of the first 2D scale as acquired by the first camera at the first image acquisition time;
• and
• determining a first relative position of the second 2D scale based at least in part on the first image of the second 2D scale as acquired by the second camera at the first image acquisition time.

A supplementary metrology position determination system for use with a robot that comprises a movable arm configuration with an end tool mounting configuration for mounting an end tool and a motion control system configured to control an end tool position of the end tool, the supplementary metrology position determination system comprising:

• first and second two-dimensional (2D) scales that are configured to be coupled to the movable arm configuration of the robot at first and second 2D scale coupling locations, respectively, each 2D scale comprising a nominally planar substrate and a plurality of respective imageable features distributed on the planar substrate;
• a first camera for acquiring an image of the first 2D scale at an image acquisition time, wherein the first camera defines a first reference position and the first camera is configured to be coupled to the movable arm configuration at a first camera coupling location;
• a second camera for acquiring an image of the second 2D scale at the image acquisition time, wherein the second camera defines a second reference position and the second camera is configured to be coupled to the movable arm configuration at a second camera coupling location;
• and
• a metrology processing portion configured to:
• determine a first relative position of the first 2D scale based at least in part on a first image of the first 2D scale as acquired by the first camera at a first image acquisition time;
• and
• determine a first relative position of the second 2D scale based at least in part on a first image of the second 2D scale as acquired by the second camera at the first image acquisition time;
• wherein metrology position coordinates of a first end tool position at the first image acquisition time are determined based at least in part on the determined first relative positions of the first and second 2D scales.