Multi-turn position encoder based on double rotary transformers and decoding method

Abstract

The invention discloses a multi-turn position encoder based on double rotary transformers and a decoding method, and relates to the technical field of motor control, and the multi-turn position encoder comprises a first rotary transformer which is connected with a rotating shaft of a motor; the input end of the multi-stage speed reducing mechanism is connected with a rotating shaft of the motor; and the second rotary transformer is connected with the output end of the multi-stage speed reducing mechanism. According to the invention, the first rotary transformer, the multi-stage speed reducing mechanism and the second rotary transformer are connected according to the specified relationship, and through a specific resolving method, the two single-ring rotary transformer encoders can be utilized to obtain the multi-ring position data, so that the current position of the motor rotor can be obtained at the power-on moment, and the device is simple in structure, high in anti-interference capability and high in reliability. And the environmental adaptability is good.

Description

Technical Field

[0001] The present invention relates to the technical field of motor control, and in particular to a multi-turn position encoder based on a dual rotary transformer and a decoding method. Background Art

[0002] A resolver (resolver / transformer, hereinafter referred to as a resolver) is an electromagnetic sensor, also known as a synchronous resolver. It is a small AC motor used to measure angles, used to measure the angular displacement and angular velocity of the rotating shaft of a rotating object, and consists of a stator and a rotor. The stator winding serves as the primary side of the transformer and receives the excitation voltage, while the rotor winding serves as the secondary side of the transformer and obtains the induced voltage through electromagnetic coupling. Resolvers have the advantages of impact resistance, high temperature resistance, oil resistance, and high reliability, and are widely used in industrial control, military, and space fields.

[0003] Resolvers are single-turn absolute position encoders that can obtain the current position of the motor rotor at the moment of power-on, avoiding the need for photoelectric encoders and Hall encoders to rotate a certain angle to obtain accurate position information. Its disadvantage is that it can only obtain absolute position information of a single turn. For those occasions where the number of motor revolutions needs to be obtained, multi-turn absolute encoders are generally used. They use multiple magnets or multiple groups of gratings. These parts and mechanisms can produce a unique encoding series, and the position information with the number of revolutions can be output through the decoding chip. Some multi-turn absolute encoders are also equipped with batteries to achieve offline memory function.

[0004] However, photoelectric encoders are not resistant to impact and high and low temperatures, and magnetoelectric encoders are easily interfered by external magnetic fields. Both photoelectric and magnetoelectric encoders are active devices. There are electronic components and circuit boards inside the encoders. In some occasions with harsh electromagnetic environments, they are easily interfered by electromagnetic radiation, which can lead to decoding failures or even failure of the entire device. The resolver is a passive device with a simple structure, strong anti-interference ability, good environmental adaptability, and resistance to impact, vibration, high and low temperatures. It is very suitable for use in harsh working environments. Therefore, it is necessary to design a multi-turn position encoder based on a resolver. Summary of the invention

[0005] The technical problem to be solved by the present invention is to overcome the shortcomings of the prior art and provide a multi-turn position encoder based on a dual rotary transformer and a decoding method.

[0006] In order to solve the above technical problems, the technical solution of the present invention is as follows: A multi-turn position encoder based on a dual rotary transformer, comprising: A first rotary transformer connected to the rotating shaft of the motor; A multi-stage reduction mechanism, the input end of which is connected to the rotating shaft of the motor; And, a second rotary transformer is connected to the output end of the multi-stage reduction mechanism.

[0007] As a preferred solution of the multi-turn position encoder based on dual rotary transformers described in the present invention, in an initial state, the zero positions of the first rotary transformer and the second rotary transformer coincide with each other.

[0008] The present invention also provides a decoding method for a multi-turn position encoder based on a dual rotary transformer, comprising: Obtain the reduction ratio n of the multi-stage reduction mechanism; After the rotating shaft of the motor completes the rotation action, obtaining position change data of the second rotary transformer; The position change data of the second resolver is divided by 1 / n×360° to obtain the number of revolutions of the motor shaft.

[0009] As the decoding method of the multi-turn position encoder based on the dual rotary transformer of the present invention, wherein: the obtaining of the position change data of the second rotary transformer comprises: The position change data of the second rotary transformer is obtained through the decoding chip.

[0010] As the decoding method of the multi-turn position encoder based on dual rotary transformers described in the present invention, wherein: the decoding chip is an RDC chip.

[0011] The beneficial effects of the present invention are: The present invention connects the first rotary transformer, the multi-stage reduction mechanism and the second rotary transformer according to a specified relationship and uses a specific solution method to obtain multi-turn position data using two single-turn rotary encoders. Not only can the current position of the motor rotor be obtained at the moment of power-on, but the structure is simple, the anti-interference ability is strong, the environmental adaptability is good, and the resistance to impact, vibration, high and low temperature, etc., is very suitable for use in occasions with harsh working environments. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without paying creative labor.

[0013] Figure 1 A schematic diagram of the structure of a multi-turn position encoder based on a dual rotary transformer provided by the present invention; Among them: 1. a first rotary transformer; 2. a multi-stage reduction mechanism; 3. a second rotary transformer; 4. an electric motor. DETAILED DESCRIPTION

[0014] In order to make the content of the present invention more clearly understood, the present invention is further described in detail below according to specific implementation modes and in combination with the accompanying drawings.

[0015] Figure 1 The schematic diagram of the structure of the multi-turn position encoder based on the dual rotary transformer provided in the embodiment of the present application includes: a first rotary transformer 1, a multi-stage reduction mechanism 2 and a second rotary transformer 3.

[0016] For details, see Figure 1 The first rotary transformer 1 is connected to the rotating shaft of the motor 4 , the input end of the multi-stage reduction mechanism 2 is connected to the rotating shaft of the motor 4 , and the output end of the multi-stage reduction mechanism 2 is connected to the second rotary transformer 3 .

[0017] It should be noted that, in the initial state, the zero positions of the first rotary transformer 1 and the second rotary transformer 3 coincide with each other.

[0018] The reduction ratio of the multi-stage reduction mechanism 2 is n. Since the first resolver 1 is directly connected to the rotating shaft of the motor 4, the first resolver 1 also rotates one circle when the rotating shaft of the motor 4 rotates one circle. Due to the deceleration effect of the multi-stage reduction mechanism 2, the second resolver 3 only rotates 1 / n circle, from which the relationship table 1 between the position data of the first resolver and the second resolver can be obtained as follows:

[0019] Table 1 It can be seen from Table 1 that the angular variation of each revolution of the second resolver is 1 / n×360°.

[0020] Therefore, the embodiment of the present application also provides a decoding method for a multi-turn position encoder based on a dual rotary transformer, and the method specifically includes the following steps: Step S101: Obtain the reduction ratio n of the multi-stage reduction mechanism.

[0021] Step S102: After the rotating shaft of the motor completes the rotation action, the position change data of the second resolver is obtained.

[0022] Specifically, after the motor has completed its operation, that is, after the rotating shaft of the motor has completed its rotation, the position change data of the second resolver is acquired through the decoding chip.

[0023] It should be noted that the above decoding chip is a resolver-to-digital converter chip (RDC). By connecting the resolver-to-digital converter chip (RDC) to the resolver, the analog signal (sinθ, cosθ) output by the resolver is decoded in hardware to obtain the angular position signal and speed signal of the resolver rotor. Commonly used RDC chips include AD2S83, AD2S1210, etc.

[0024] Step S103: Divide the position change data of the second resolver by 1 / n×360° to obtain the number of revolutions of the rotating shaft of the motor 4 .

[0025] Specifically, it can be seen from Table 1 that the angle change of each turn of the second rotary transformer 3 is 1 / n×360°. Therefore, after the position data of the second rotary transformer 3 is obtained through the decoding chip, the data can be divided by the equivalent of 1 / n×360° to obtain the number of turns of the rotating shaft of the motor 4.

[0026] Therefore, the technical solution of the present application connects the first rotating transformer, the multi-stage reduction mechanism and the second rotating transformer according to a specified relationship, and through a specific solution method, can utilize two single-turn rotating encoders to obtain multi-turn position data. Not only can the current position of the motor rotor be obtained at the moment of power-on, but also the structure is simple, the anti-interference ability is strong, the environmental adaptability is very good, and it is resistant to impact, vibration, high and low temperature, etc., and is very suitable for use in occasions with harsh working environments.

[0027] In addition to the above embodiments, the present invention may also have other implementation modes; any technical solutions formed by equivalent replacement or equivalent transformation shall fall within the protection scope required by the present invention.

Claims

1. A multi-turn position encoder based on a dual rotary transformer, characterized in that: include: A first rotary transformer (1) connected to a rotating shaft of a motor (4); A multi-stage speed reduction mechanism (2), the input end of which is connected to the rotating shaft of the motor (4); And, a second rotary transformer (3) is connected to the output end of the multi-stage reduction mechanism (2).

2. The multi-turn position encoder based on a dual rotary transformer according to claim 1, characterized in that: In an initial state, the zero positions of the first rotary transformer (1) and the second rotary transformer (3) coincide with each other.

3. A decoding method for a multi-turn position encoder based on a dual rotary transformer according to claim 2, characterized in that: include: Obtaining a reduction ratio n of the multi-stage reduction mechanism (2); After the rotating shaft of the motor (4) completes the rotation action, obtaining position change data of the second rotary transformer (3); The position change data of the second rotary transformer (3) is divided by 1 / n×360° to obtain the number of revolutions of the rotary shaft of the motor (4).

4. The decoding method of the multi-turn position encoder based on the dual rotary transformer according to claim 3 is characterized in that: The step of obtaining the position change data of the second rotary transformer (3) comprises: The position change data of the second rotary transformer (3) is obtained through a decoding chip.

5. The decoding method of the multi-turn position encoder based on the dual rotary transformer according to claim 4 is characterized in that: The decoding chip is an RDC chip.

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