Patent ID: 9007057
Filing Date: 2015-04-14
Classification: G01D

Abstract:
1. A high resolution encoder device to measure the angular position of a rotating element, comprising: a) a rotating disc fixed to the rotating element, said rotating disc including a circular track having sections of a first property and sections of a second property according to a given pattern; b) a plurality of fixed sensors positioned in proximity to said circular track, each sensor outputting an electrical signal having a maximal value when in proximity to a section of the circular track of said first property and a minimum value when in proximity to a section of the circular track of said second property, and continuously and monotonously changing intermediate values in between said maximal value and said minimum value when said rotating disc rotates from a position for which said sensor is in proximity to a section of said first or said second property to a position for which said sensor is in proximity to a section of the other property; c) a memory to store pre-recorded encoder characteristics; and, d) processing means to process values of said electrical signals of said sensors, and wherein, in a first processing step, a bit is set for each sensor as a result of a comparison of said electrical signal of a respective sensor to a pre-defined threshold stored in said memory, and all bits of all sensors are combined in a word, the value of this word defining a code, wherein two electrical signals are associated to each code value, wherein, in a second processing step, said two electrical signals associated to said code are compared, and an electrical signal having the closest value to the threshold is selected, and wherein, in a third processing step, a high resolution angular position of the rotating disc is deduced from the code and said selected electrical signal.