CN201364163Y - High-precision magnetic encoder - Google Patents

Abstract

The utility model relates to a high-precision magnetic encoder belonging to the technical field of industrial control, which comprises a magnet, a Hall element IC chip, a first digital signal processor, an AD converter and a second digital signal processor, wherein the Hall element IC chip is used for detecting the magnetic field change of the magnet above a device and outputting an SIN value and a COS value of a magnet angle; the first digital signal processor calculates an angle value according to the SIN value and the COS value, and transmits the angle value to the AD converter; the AD converter converts the analog information quantity of the angle value into digital information quantity; and the second digital signal processor further converts the digital information quantity transmitted by the AD converter into a binary value. The high-precision magnetic encoder solves a drift problem of the magnetic encoder in the prior art, simultaneously improves the precision of the magnetic encoder, enlarges the application range of the magnetic encoder, and has broader application prospects than the existing magnetic encoder.

Description

The high precision magnetic encoder

Technical field

The utility model relates to the device in a kind of industrial control technology field, specifically is a kind of high precision magnetic encoder.

Background technology

In the digital transducer, magnetic encoder is a kind of electromagnet element that developed recently gets up, and it is along with the development of optical encoder grows up.The major advantage of optical encoder is to wet gas and pollution sensibility, but poor reliability, and magnetic encoder is not subject to dust and dewfall influence, it is simple and compact for structure simultaneously, can run up, and response speed (reaches 500～700kHz) soon, the volume ratio optical encoders, angle sensors is little, and cost is lower, and easily with a plurality of elements permutation and combination accurately, than with optical element and new function element of the easier formation of semiconductor magneto sensor and multifunction device.In addition, adopt two-layer wiring technology, can also make magnetic encoder not only have the only increment signal of general scrambler and increment signal and exponential signal output, also have the absolute signal output function.So, be optical encoder although account for 90% scrambler at present, undoubtedly, in the kinetic control system in future, the consumption of magnetic encoder will increase gradually.

Because magnetic encoder has above-mentioned plurality of advantages, thereby constantly increase in high-acruracy survey and control Application for Field in recent years, control to the detection and the control of every field rotation amounts (position, speed, angle etc.) such as disk, printer one class business automation equipment, communication equipment, measurement instrument from numerically-controlled machine, robot, the position probing of factory automation relevant device, transmission speed, as a kind of important tool, magnetic encoder has become requisite ingredient, and its market demand every year is with 20%～30% speed increment.Under high-speed, high precision, miniaturization, long-life requirement, in intense market competition, magnetic encoder is unique advantage with its outstanding feature, becomes one of key of development high-tech product.

Magnetic encoder and control microcomputer are integrated, help the simplified control system structure, reduce parts number and duty volume, and this is the direction of encoder applies and control system development.

As shown in Figure 1, in the prior art, the principle of work of magnetic encoder is: utilize the Hall components and parts to go the variation in the magnetic field of detection means upper magnets, the SIN COS value of the angle of output magnet, utilize the algorithm process of back and relevant AD conversion then, obtain the absolute or relative angle value of magnet at last, and, provide the multiple way of output by various computings.In the course of work of magnetic encoder, since temperature, magnet off-centre, and problem such as related chip susceptibility can cause when magnet is static, this device also has certain pulse output, so just causes client's rear end product erroneous judgement disconnected, thereby influences the performance of entire product.

Magnetic encoder majority in the past is a product small-sized, that resolving power is low, price is low, make it to substitute fully high-precision optical encoder, also has many problems to need to solve.At first, magnetic encoder has the problem of drift, and under static state, it also has pulse output, so will use the problem of bringing to the client.Secondly, the magnetic encoder precision on the market is the highest now can only reach 2048ppr, has so just limited the application of magnetic encoder.At last, existing magnetic encoder can only provide the umber of pulse of 2 integral multiple.

The utility model content

The purpose of this utility model is at above-mentioned deficiency of the prior art, has proposed a kind of high precision magnetic encoder, to solve intrinsic drift and the low problem of resolution of magnetic encoder.

The utility model is achieved by the following technical solution, the utility model comprises: second digital signal processor of magnet, Hall element IC chip, first digital signal processor that connects described Hall element IC chip, the AD converter that connects described first digital signal processor, the described AD converter of connection, wherein:

Described Hall element IC chip is responsible for the variation in the magnetic field of detection means upper magnets, the SIN value and the COS value of the angle of output magnet;

Described first digital signal processor is tried to achieve angle value according to SIN value and COS value, and angle value is transferred to AD converter;

Described AD converter is converted to amount of digital information with the analog information amount of angle value;

Described second digital signal processor further is converted to binary value with the amount of digital information that AD converter sends.

Described AD converter adopts the high-precision A conversion chip greater than 13, to solve the low bottleneck of scrambler product resolution.In the prior art, because chip supplier's technology, the restriction of algorithm and IP, peripheral high-precision A chip has been adopted in the only integrated AD conversion that is up to 13 in the utility model, utilize DSP to handle then, just can obtain a lot of product of resolution height.

Described first digital signal processor, it is responsible for trying to achieve angle value according to SIN value and COS value, and the expression formula of asking for angle value is specific as follows:

Wherein, A represents to take measurement of an angle, and α is the anglec of rotation of magnet,

Represent the amplitude peak value of sin and cos signal respectively, φ represents the deviate of sin-and cos-signal and desirable phase shift, Offs _Sin, Offs _CosThe amplitude error of representing sin and cos signal respectively.

Described second digital signal processor is the natural binary input MCU (microprogram control unit) that obtains, by MCU with the binary mode data processing after, the data that obtain walking abreast are with the way of output that makes things convenient for client and existing photoelectric encoder compatibility mutually.

Described second digital signal processor, the signal of its output are by the RC oscillatory circuit, and the precision of RC oscillatory circuit is 5%, by less error reducing influence, and by measuring the pulsewidth t of PWM to the pulsewidth of the sampling rate of PWM and PWM _OnAnd t _OffAnd pulse width period, obtain general ± precision of 0.5 °, specific as follows:

12-bit PWM：Position＝((t _on×4097)/(t _on+t _off))-1。

Described second digital signal processor, the signal of its output is by external active or passive low ventilating filter, and wave filter is averaged to pwm signal, produces simulation output.

Described second digital signal processor after it receives the angle absolute figure, utilizes the algorithm of looking into benefit, obtains the corresponding increment ABZ way of output, and the way of output of this mode and photoelectric encoder is coincide.So scrambler of replaceable this class.

Compared with prior art, the utlity model has following beneficial effect:

The utility model has solved the drifting problem of magnetic encoder in the prior art, has improved the precision of magnetic encoder simultaneously, has enlarged the range of application of magnetic encoder, compares existing magnetic encoder and has more wide application prospect.

Description of drawings

Fig. 1 is the fundamental diagram of magnetic encoder of the prior art;

Fig. 2 is a structured flowchart of the present utility model;

Fig. 3 is the structural representation of scrambler among the utility model embodiment:

Among the figure, figure (a) is a front view, (b) is stereographic map, (c) is vertical view, (d) is upward view;

Fig. 4 is the signal schematic representation of absolute serial output among the utility model embodiment;

Fig. 5 is the circuit and the curve map of simulation output among the utility model embodiment;

Fig. 6 is the signal schematic representation of increment output among the utility model embodiment.

Embodiment

Below in conjunction with accompanying drawing embodiment of the present utility model is elaborated: present embodiment is being to implement under the prerequisite with technical solutions of the utility model; provided detailed embodiment and concrete operating process, but protection domain of the present utility model is not limited to following embodiment.

As shown in Figure 2, present embodiment comprises: second digital signal processor of magnet, Hall element IC chip, first digital signal processor that connects described Hall element IC chip, the AD converter that connects described first digital signal processor, the described AD converter of connection, wherein:

Described Hall element IC chip is responsible for the variation in the magnetic field of detection means upper magnets, the SIN value and the COS value of the angle of output magnet;

Described first digital signal processor is tried to achieve angle value according to SIN value and COS value, and angle value is transferred to AD converter;

Described AD converter adopts 13 high-precision A conversion chip, and the analog information amount of angle value is converted to amount of digital information;

Described second digital signal processor further is converted to binary value with the amount of digital information that AD converter sends.

As shown in Figure 3, it is the structural representation of the magnetic encoder of present embodiment, among the figure, Hall element IC chip 2 is arranged on magnet 1 below, Hall element IC chip 2 is fixed on the substrate 3, first digital signal processor and AD converter are integrated in the chip 5, second digital signal processor is a chip 4, and chip 5 and chip 6 all are arranged on the below of substrate 3.

Among Fig. 3 (b), the function of eight ports 6 is as follows respectively: 1.+5v, 2.GND, 3.A+/CLK+/NC, 4.A-/CLK-/NC, 5.B+/Data+/NC, 6.B-/Data-/NC, 7.Z+/NC/Analog, 8.Z-/NC/NC

In addition, the scrambler pin in the present embodiment is provided with as shown in the table:

The definition of table 1 pin

Function	Pin	Color	Function	Pin	Color
						POWER
	1	Red	ENCODE6	8	Blue
						GND	14	Black	ENCODE5	7	Indigo
ENCODE11	13	Pink	ENCODE4	6	Purple
						ENCODE10	12	D-Green	ENCODE3	5	Brown
ENCODE9	11	Orange	ENCODE2	4	Grey
						ENCODE8	10	Yellow	ENCODE1	3	White
ENCODE7	9	Green	ENCODE0	2	D-Blue

Present embodiment can have following four kinds of way of outputs:

1. absolute serial output

Second digital signal processor is converted to the angle value that obtains and is natural binary output, as shown in Figure 4.

2. absolute PWM (width modulation) output

Second digital signal processor is 5% RC oscillatory circuit with the signal of output by precision, by less error reducing influence, and by measuring the pulsewidth t of PWM to the pulsewidth of the sampling rate of PWM and PWM _OnAnd t _OffAnd pulse width period, obtain general ± precision of 0.5 °, specific as follows:

12-bit PWM：Position＝((t _on×4097)/(t _on+t _off))-1。

3. simulation output

Second digital signal processor, the signal of its output is by external active or passive low ventilating filter, and wave filter is averaged to pwm signal, produces simulation output.Analog output voltage is directly proportional with angle: 0o=0V; 360o=VDD5V, as shown in Figure 5.

4. increment output

Second digital signal processor after it receives the angle absolute figure, utilizes the algorithm of looking into benefit, can obtain the corresponding increment ABZ way of output, and as shown in Figure 6, the way of output of this mode and photoelectric encoder is coincide.So replaceable photoelectric encoder.

Claims (2)

1, a kind of high precision magnetic encoder, it is characterized in that, comprise: second digital signal processor of magnet, Hall element IC chip, first digital signal processor that connects described Hall element IC chip, the AD converter that connects described first digital signal processor, the described AD converter of connection, wherein:

Described Hall element IC chip is responsible for the variation in the magnetic field of detection means upper magnets, the SIN value and the COS value of the angle of output magnet;

Described first digital signal processor is tried to achieve angle value according to SIN value and COS value, and angle value is transferred to AD converter;

Described AD converter is converted to amount of digital information with the analog information amount of angle value;

Described second digital signal processor further is converted to binary value with the amount of digital information that AD converter sends.

2, high precision magnetic encoder according to claim 1 is characterized in that, described AD converter adopts the AD conversion chip greater than 13.

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