Abstract : While there are many types of existing rotary encoders, offering a wide range of choices, they generally suffer from the problem of high power consumption for high sensitivity and correspondingly low sensitivity for low power consumption; the advantages of both are often mutually exclusive. Currently, there is no suitable encoder that combines low power consumption and high sensitivity. Therefore, researching a rotary encoder with low power consumption and high sensitivity has practical value. This paper proposes a design concept for a rotary encoder with low power consumption and high sensitivity based on the principle of LC oscillation. Its key feature is that the attenuation change of the oscillation wave generated when a metal sensor approaches and leaves the inductance of the LC oscillator is used as the encoding sensing state and fed into the code value generation circuit for encoding before outputting the code value. The paper focuses on the encoding principle and error correction methods.
Keywords : LC oscillation; rotation encoding; low power consumption; error correction design
1. Introduction
Rotary encoders can be classified into incremental and full-scale (or absolute) encoders according to their encoding method; and into switch-type (contact) and photoelectric (non-contact) encoders according to their sensing method. Incremental encoders can only generate counting pulses and direction signals (increment/decrease signals). They are simple in structure and inexpensive, but require a counting device. When subjected to large interference and losing data, the encoder itself cannot remember the current encoder position, thus its reliability is slightly lower. Full-scale encoders can generate all encoded signals across the entire range, do not require a counting device, and can remember the current encoder position when subjected to large interference and losing data, thus their reliability is high. However, they are complex in structure and expensive. Both types of encoders can use switches or photoelectric elements for sensing. Switch-sensing encoders use passive sensing elements, making them suitable for low-power applications. However, due to the frictional resistance of brush switches or the cam resistance of limit switches, switch-sensing encoders are generally not suitable for applications requiring sensitive encoding. Photoelectric encoders require a certain amount of current for their light-emitting elements, thus they are generally not suitable for low-power applications. However, since photoelectric elements have no contact resistance (the frictional resistance between the shaft and bearing is negligible), photoelectric sensor encoders can be used in applications requiring sensitive encoding. In summary, existing rotary encoders often cannot simultaneously achieve both advantages. Currently, there is no encoder available that combines low power consumption with high sensitivity.
Research and Design of Rotary Encoder Based on LC Oscillation (Full Text Download)
