| 摘要 |
The device to measure the absolute rotation angle of a rotating shaft includes a rotating disc, fixed to the shaft. A group of permanent magnets of different sizes and polarities is disposed on a circular track. Further, a group of Hall sensors, fixed to a static part of the device, are disposed on a circular path, in proximity of the rotating disc magnets tracks, and generate electric signals proportional to the strength of the magnetic field produced by the magnets in proximity. The signs of these electric signals are used to calculate a code characteristic of a low resolution absolute angular position. Two analog signals are associated to the obtained code, according to a pre-defined table. The associated analog signal having the closest value to zero is used as an entry to a pre-recorded table containing the correspondent angular position of the shaft. |
| 主权项 |
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. |
