The accuracy of DD motors includes repeatability, absolute positioning accuracy, and mechanical accuracy of the mounting surface.
First, regarding the relationship between resolution, repeatability, and absolute accuracy, the resolution of a motor differs from the accuracy of an encoder. Generally, encoders have many error factors, such as encoder mounting accuracy, subdivision accuracy, and electrical noise. The diagram below explains the concepts of absolute accuracy/repeatability.
Repeatability measurement method:
Absolute accuracy measurement method:
Mounting surface mechanical precision Runout
The axial and radial mechanical accuracy of DD motors can reach below 10µm. The specific measurement method is as follows:
