A robot link deflection gauge providing precise measurement of the deformation of a robot link due to load and acceleration forces. The robot link deflection gauge of the present invention includes at least one light source, a plurality of lenses and corresponding position sensitive detectors positioned at the ends of the robot arm link to accurately measure the relative position and orientation of a first (or destination) end relative to a second (or source) end of each robot arm link. Each lens has an optical axis which is positioned to receive light from the light source and focus the light into a light spot on the surface of the corresponding position detector. As the robot link is deformed so that the destination end is displaced and rotated relative to the source end, the light is transmitted away from the optical axis of each lens causing the light spot to be displaced along the surface of the respective position sensitive detector. The position sensitive detectors convert the light spots into electrical signals to provide a measurement of the displacements of the light spots relative to a predetermined origin. These displacements are converted to the relative X and Y displacement, rotation, and pitch and yaw of the destination end with respect to the source end.
Ernest Franke; Ashok Nedungadi; Glynn Bartlett