Capacitive absolute rotary encoder

Abstract

The invention discloses a capacitive absolute rotary encoder, which consists of two incremental rotary encoders, wherein the two incremental rotary encoders are used for outputting 2N and 2N-1 sine periodic signals respectively per circle, wherein N is a natural number; the difference of two sine periodic signals is the absolute angle of each rotary encoder; a movable polar plate and at least one fixed polar plate are provided; at least one face of the movable polar plate is paved with a reflection electrode; one face, which faces the movable polar plate, of the fixed polar plate is paved with an emitting electrode and a receiving electrode; each incremental rotary encoder consists of a reflection electrode, an emitting electrode and a receiving electrode; the reflection electrodes of the two incremental rotary encoders share one movable polar plate; each reflection electrode is a petal-shaped electrode with a sinusoidal enveloped boundary; the emitting electrodes are grid electrodes which are arranged uniformly and circularly, and are divided into four exciting electrode groups which are connected electrically and are arranged alternatively; the receiving electrodes refer to two annular electrodes which are arranged on the inner sides and the outer sides of the emitting electrodes on the fixed polar plate respectively.

Description

technical field [0001] The invention relates to a rotary encoder, in particular to a capacitive rotary encoder capable of obtaining single-turn absolute angular displacement. Background technique [0002] As a position and speed detection element, rotary encoders are widely used in measurement and control fields such as CNC machine tools, aerospace, industrial robots, new energy, and medical equipment. At present, the rotary encoder market is almost monopolized by photoelectric and electromagnetic encoders. Among them, the photoelectric encoder is the most widely used due to its mature technology and high precision, but because of the optical device, its shock resistance is poor, it is sensitive to dust and condensation environment, and has high requirements on the working environment. Electromagnetic encoders can work in relatively harsh environments, but because they are sensitive to electromagnetic interference, it is difficult to achieve high-precision measurement. In ...

AI Technical Summary

Problems solved by technology

In the US patent US6774642B2, the receiving pole obtains a triangular wave signal, and the angular displacement of the moving plate is determined by measuring the amplitude of the triangular wave. This kind of encoder has poor anti-interference ability, and external mechanical disturbances and interference signals have a great impact on the measurement results.

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