CN115060164B - Position and speed detection system and method for high-speed linear motor - Google Patents

Abstract

The present invention discloses a position and speed detection system and method for a high-speed linear motor, the system comprising a grating ruler, a plurality of laser generators, a plurality of receiving devices and a controller. The detection method comprises: the receiving device calculates the position of the mover according to the pulse signal input by each sensor. Then the speed is calculated according to the tracking differentiator corresponding to the output pulse of each sensor. The input pulses of each sensor are independently calculated, and when the output speed of the tracking differentiator algorithm reaches stability, the speed is selected as the final calculated speed of the speed detection system and transmitted to the controller, and the controller selects the receiving device speed and displacement signal to output to the motor control system. The method can effectively reduce the transition process of the tracking differentiator tracking the speed step signal, reduce the time delay, and the pulses output by each sensor are independently calculated, avoiding the speed fluctuation caused by the error of the absolute position of the sensor, and realizing the requirements of high real-time and high-precision measurement of the high-speed linear motor.

Description

A high-speed linear motor position and speed detection system and method

Technical Field

The invention belongs to the field of positioning and speed measurement, and in particular relates to a position and speed detection system and method for a high-speed linear motor.

Background technique

Linear motors are widely used in many situations where linear motion is required due to their simple transmission structure and the elimination of complex intermediate transmission devices. In the field of high-speed linear electromagnetic propulsion, high-speed linear motors are used to drive the mover (including the load) to produce high-speed linear motion under the action of the stable electromagnetic thrust generated by the motor, completing the entire process of the mover acceleration, uniform speed and deceleration within a limited distance and time. Therefore, the motor must be closed-loop controlled, and the accuracy of speed detection is a key factor in the stable operation of the closed-loop system.

According to the classic vector control theory of the motor, the motor control system implements dual closed-loop control of the outer speed loop and the inner current loop to drive the linear motor to generate stable electromagnetic thrust. This requires the sensors of the positioning speed measurement system to accurately measure the running position and running speed of the mover in real time. Especially for linear induction motors, the speed measurement signal needs to be used as the feedback signal of the outer speed loop, and the slip signal needs to be superimposed to enter the motor control system to complete the stable control of the electromagnetic thrust. If the speed measurement signal is inaccurate, it will inevitably be reflected in the final output electromagnetic thrust, resulting in unstable thrust and large fluctuations, which is not expected for high-speed linear electromagnetic propulsion systems, especially when the high-speed motor needs to be safely braked. Therefore, for the entire system, in order to meet the stability of the thrust, it is necessary to control the speed error within a certain range.

The existing positioning and speed measurement scheme, China invention patent CN201910210291.X provides an effective position measurement method and obtains speed information using the differential method, but the differential method is very easy to amplify the measurement noise, which is not considered in this system. Referring to the way that the traditional rotating motor uses encoders, the linear motor mainly uses a detector array to collect the pulse signals generated by each column when the mover passes through a series of detectors, and then uses the fixed angle measurement T method suitable for low speed or the timing angle measurement M method suitable for high speed, see China invention patent CN20180464869.X, the pulse processing device connected to each detector calculates the motor running position and speed. Due to the high running speed of the high-speed linear motor, it is difficult to use the T method for speed measurement throughout the whole process, and it is necessary to switch to the M method for speed measurement in the high-speed section. However, the principle of the M method is to measure the number of pulses in a fixed time period. During high-speed motion, although it can ensure that the number of pulses generated in this period is sufficient to make the calculated speed high in accuracy, due to the extremely large acceleration, it will cause a large speed lag in this time period, and the thrust cannot meet the requirements.

Therefore, there is still a lack of a fully accurate and fast speed measurement method for high-speed linear motors in the art.

Summary of the invention

In order to solve the problem in the prior art, that is, the prior art cannot realize the accurate and fast speed measurement of the high-speed linear motor throughout the whole process. The present invention provides a position and speed detection system and method for a high-speed linear motor. The moving part speed is detected by using a tracking differentiator. Under the premise of ensuring the speed measurement accuracy, the delay of the tracking differentiator in tracking the step signal can be effectively reduced by assigning an initial value to the tracking differentiator, thereby providing an effective speed measurement solution for the high-speed linear motor positioning and speed measurement system.

In order to achieve the above object, the technical solution proposed by the present invention is as follows:

A position and speed detection system for a high-speed linear motor comprises a grating ruler, a plurality of laser generators, a receiving device and a controller; the plurality of laser generators are arranged at fixed intervals on the high-speed linear motor for emitting lasers and keeping them in a constant light state; the grating ruler has grid holes of fixed equal width and equal spacing for shielding and transmitting lasers to generate optical pulse signals; the receiving device comprises a receiving sensor and a signal processor for receiving and calculating optical pulse signals from the plurality of laser generators; the signal processor comprises a photoelectric conversion, a filtering circuit, a high-speed digital processor and a communication module; the receiving sensor is arranged in parallel with the laser generator for receiving optical pulse signals; the high-speed digital processor calculates the speed and position according to the electrical pulse signal and the grid hole spacing of the grating ruler, and then transmits the speed and position signals to the controller through the communication module; the controller is used to receive the speed signal calculated by the receiving device.

The present invention also provides a detection method for a position and speed detection system of a high-speed linear motor, wherein the position detection method is: the receiving device determines the real-time position of the mover of the high-speed linear motor according to the number of pulses of the pulse signal, the grid hole spacing of the grating ruler and the absolute position of the receiving sensor, including:

The real-time position of the mover = the absolute position of the receiving sensor + the number of signal pulses × the grid hole spacing of the grating ruler;

The speed detection method comprises:

Step S1, determining that the grating hole spacing of the grating ruler is w, the spacing between two adjacent receiving sensors is l ₁ , and the multiple receiving sensors are defined in order as a first receiving sensor, a second receiving sensor, to an mth receiving sensor;

Step S2, the receiving device receives the input pulse signals of each receiving sensor and performs photoelectric conversion; the receiving device first performs speed detection according to the output pulse of the first receiving sensor, and uses the grating scale grid spacing and the rising edge time of two adjacent pulses to obtain the speed v _{1_1} , v _{1_2} ...v _{1_n} corresponding to each pulse in the continuous n pulses;

Step S3, obtaining an average speed v _{T — 1} corresponding to n pulses continuously output by the first receiving sensor, wherein v _{T — 1} =(v _{1 — 1} +v _{1 — 2} +…+v _{1 — n} )/n;

Step S4, taking the average speed v _{T_1} corresponding to the output pulse of the first receiving sensor as the initial value of the tracking differentiator, and performing the initial value assignment operation on the tracking differentiator; after the initial value assignment is completed, combining the grating scale grid spacing w and the number of output pulses N ₁ of the first receiving sensor, according to the relative displacement formula w×N ₁ , the relative displacement X ₁ of the mover plate detected by the first receiving sensor is obtained as the input of the tracking differentiator, and the tracking differentiator calculation program is started to obtain the speed v _{G_1} calculated by the tracking differentiator corresponding to the output pulse of the first receiving sensor;

Step S5, when the second receiving sensor continuously outputs n pulses, according to the method of the above steps S3 to S4, the average speed v _{T_2} corresponding to the n pulses continuously output by the second receiving sensor is obtained; when the third receiving sensor outputs a pulse, according to the method of the above steps S3 to S4, the average speed v _{T_3} corresponding to the n pulses output by the third receiving sensor is obtained; and so on, when the m-th receiving sensor outputs n pulses, the average speed v _{T_m} corresponding to the n pulses continuously output by the m-th sensor is obtained;

Step S6, when the second receiving sensor continuously outputs n pulses, according to the method of step S4, the speed v _{G_2} of the second sensor output pulse calculated by the tracking differentiator is obtained; when the third receiving sensor outputs n pulses, according to the method of step S4, the speed v _{G_3} of the third receiving sensor output pulse calculated by the tracking differentiator is obtained; and so on, when the m-th sensor outputs n pulses, according to the method of step S4, the speed v _{G_m} of the m-th receiving sensor output pulse calculated by the tracking differentiator is obtained;

Step S7, during the movement of the mover, when v _{G_1} tracks the actual speed and becomes stable, v _{G_1} is selected as the detection result v _f ; when v _{G_2} becomes stable, in the overlapping area of v _{G_1} and v _{G_2} , v _{G_2} is selected as the detection result v _f ; when v _{G_3} becomes stable, in the overlapping area of v _{G_2} and v _{G_3} , v _{G_3} is selected as the detection result v _f ; and so on, the receiving device transmits v _f to the controller;

Step S8: The controller selects v _f uploaded by different receiving devices, and finally realizes speed detection in the whole range.

Furthermore, the discrete form of the tracking differentiator is expressed as:

in: fhan(x ₁ ,x ₂ ,u,r,h) is the discrete fastest control comprehensive function, and its algorithm formula is as follows:

In order to express fhan(x ₁ ,x ₂ ,u,r,h) concisely, d, d ₀ , y, a ₀ , a are introduced as intermediate variables; is a sign function, where x is y or a; u is the position input signal, _x1 is the position tracking signal, which is an intermediate variable, _x2 is the speed output signal, r is the speed factor, and h is the filter factor. The two are adaptive functions of the speed output signal _x2 and parameters _γ1 and _γ2 . r increases rapidly with the increase of _x2 , and h decreases rapidly with the increase of _x2 . _γ1 and _γ2 are adjustable parameters. Adjusting their sizes can change the change rates of r and h respectively. At the same time, _γ1 and _γ2 control the range of the tracking differentiator passband. Therefore, they need to be adjusted according to the frequency spectrum of the input signal u so that the differentiator has a good differential effect on the input signal u and can filter out the high-frequency noise of the input signal u. A is the range of r, T is the discretization step size, and k is the discrete time (k=0, 1, 2, 3······). The tracking differentiator adopts the form of parameter adaptation and can output a fully accurate speed signal.

Furthermore, the operation of assigning an initial value to the tracking differentiator in step S4 includes:

Step S40: the receiving device calculates the average speed v _{T — 1} corresponding to the n pulses continuously output by the first receiving sensor as the initial value v ₀ of the tracking differentiator speed signal, that is, the initial value of the tracking differentiator speed signal x ₂ (k) is x ₂ (0) = v _{T —} 1 ;

Step S41: the receiving device assigns an initial value to the position input initial value of the tracking differentiator, that is, the initial value u(0) of u is 0;

Step S42: The receiving device assigns an initial value to the position tracking signal of the tracking differentiator, that is, the initial value of the intermediate variable position tracking signal x ₁ (k) is:

Wherein, y=x ₁ (0)-u(0)+hx ₂ (0); the values of x ₁ (0) in the above three cases are calculated, and the corresponding values satisfying the constraints are selected.

Furthermore, the pulse signals output by each receiving sensor are processed and calculated independently to avoid speed fluctuations caused by errors in the absolute positions of the receiving sensors.

Furthermore, the length of the grating ruler is greater than the spacing between adjacent receiving sensors to ensure that the detection result is continuous. The present invention has the following beneficial effects:

The present invention can ensure the quality of the speed detection results of the high-speed linear motor position and speed detection system, so that the motor control system can obtain accurate and fast speed measurement feedback information within the entire range of the mover movement, so that the high-speed linear motor can generate stable electromagnetic thrust; avoid the speed fluctuation caused by the absolute position error of the sensor, and reduce the tracking delay of the tracking differentiator to the speed.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG1 is a schematic diagram of a position and speed detection system for a high-speed linear motor provided in an embodiment of the present invention.

FIG. 2 is a schematic diagram of the structure of a grating scale of a position and speed detection system for a high-speed linear motor provided by an embodiment of the present invention.

FIG. 3 is a flow chart of a method for detecting the speed of a high-speed linear motor provided in an embodiment of the present invention.

FIG. 4 is a comparison of measurement results of a position signal and an intermediate variable position tracking signal x ₁ (k) before and after initialization during a speed detection method for a high-speed linear motor provided by an embodiment of the present invention.

FIG. 5 is a comparison of the reference speed and the speed signal x ₂ (k) measured speed results before and after the initialization in a method for detecting the position and speed of a high-speed linear motor provided by an embodiment of the present invention.

FIG6 is a comparison of measurement results of multiple receiving sensor output pulses using the tracking differentiator of the present invention and the traditional tracking differentiator method during an embodiment of a method for detecting the position and speed of a high-speed linear motor provided by an embodiment of the present invention.

Detailed ways

The following will describe in detail specific real-time examples of the present invention in conjunction with the accompanying drawings, and set forth specific details to help fully explain the present invention.

As shown in FIG1 , the present invention provides a position and speed detection system for a high-speed linear motor, which includes a grating ruler 0, multiple laser generators 1, a receiving device 2, a receiving sensor 21, a signal processor 22 and a controller 3.

Grating ruler 0 is a device with fixed grid holes of equal width and spacing, used to block and transmit laser light to generate optical pulse signals;

A plurality of laser generators 1 are arranged at fixed intervals on the high-speed linear motor, and are used to emit lasers and keep them in a constant light state;

The receiving device 2 includes a receiving sensor 21 and a signal processor 22, which is used to receive the optical pulse signal and perform calculations. The receiving device 2 can receive multiple pulse signals from the receiving sensor 21. In this embodiment, the receiving device 2 can receive 16 pulse signals from the receiving sensor 21. The signal processor 22 includes a photoelectric conversion module, a filtering circuit, a high-speed digital processor and a communication module. The receiving sensor 21 is arranged in parallel with the laser generator 1 and is used to receive the optical pulse signal. The high-speed digital processor calculates the speed and position based on the electrical pulse signal and the grid hole spacing of the grating ruler 0, and then transmits the speed and position signals to the controller 3 through the communication module.

The controller 3 is used to receive the speed signals calculated by each receiving device 2 .

The present invention provides a method for detecting the position and speed of a high-speed linear motor, the method comprising:

The receiving device 2 determines the real-time position of the mover of the high-speed linear motor according to the pulse number of the pulse signal, the grid hole spacing of the grating ruler 0 and the absolute position of the receiving sensor 21, including:

The real-time position of the mover = the absolute position of the receiving sensor + the number of signal pulses × the grid hole spacing of the grating ruler.

As shown in Figure 2, the present invention provides a schematic diagram of the grating scale structure of a high-speed linear motor position and speed detection system, wherein the grating scale 0 has a grating hole spacing w=10 mm, and a total length of the grating scale L=2.2 m. The movement of the mover will drive the grating scale 0 to move in the array of the multiple laser generators 1, driving the receiving sensor 21 to receive pulse signals one by one in the direction of movement.

It should be noted that the length of the grating ruler needs to be a certain length. In this embodiment, the length of the grating ruler is L=2.2m, which is slightly longer than 2 times the interval of the laser generator 1, that is, at least two pairs of the receiving sensors 21 generate pulse signals at any time. When the system is operating normally, the high-speed digital processing device uses the latest pulse signal of the receiving sensor 21 for processing. When the receiving sensor 21 fails, the signal processor 22 can use the previous signal of the receiving sensor 21. More details about fault detection and processing will not be elaborated in detail in this invention.

As shown in FIG3 , the present invention provides a method for detecting the speed of a high-speed linear motor, the method comprising:

Step S1, determining that the grating scale hole spacing is 20 mm, the spacing between two adjacent receiving sensors is 1000 mm, and the multiple receiving sensors are defined in order as the first receiving sensor, the second receiving sensor, and so on, the mth receiving sensor;

Step S2, the receiving device receives the input pulse signals of each receiving sensor and performs photoelectric conversion; the receiving device first performs speed detection according to the output pulse of the first receiving sensor, and uses the method of grating scale grid spacing/rise edge time of two adjacent pulses to obtain 6 consecutive pulses, and the speed v _{1_1} , v _{1_2} ...v _{1_6} corresponding to each pulse;

Step S3, obtaining an average speed v _{T — 1} corresponding to the six pulses continuously output by the first receiving sensor, that is, v _{T — 1} =(v _{1 — 1} +v _{1 — 2} +…+v _{1 —} 6 )/6;

Step S4, taking the average speed v _{T_1} corresponding to the output pulse of the first receiving sensor as the initial value of the tracking differentiator, and performing the initial value assignment operation on the tracking differentiator; after the initial value assignment is completed, combining the grating scale grid spacing of 20mm and the number of output pulses of the first receiving sensor N ₁ , according to the relative displacement formula X ₁ =20mm×N ₁ , the relative displacement X ₁ of the mover plate detected by the first receiving sensor is obtained as the input of the tracking differentiator, and the tracking differentiator calculation program is started to obtain the speed v _{G_1} calculated by the tracking differentiator corresponding to the output pulse of the first receiving sensor;

Step S5, when the second receiving sensor continuously outputs 6 pulses, according to the method of the above steps S3 to S4, the average speed v _{T_2} corresponding to the 6 pulses continuously output by the second receiving sensor is obtained; when the third receiving sensor outputs a pulse, according to the method of the above steps S3 to S4, the average speed v _{T_3} corresponding to the 6 pulses output by the third receiving sensor is obtained; and so on, when the m-th receiving sensor outputs 6 pulses, the average speed v _{T_m} corresponding to the 6 pulses continuously output by the m-th sensor is obtained;

Step S6, when the second receiving sensor continuously outputs 6 pulses, according to the method of step S4, the speed v _{G_2} of the second sensor output pulse calculated by the tracking differentiator is obtained; when the third receiving sensor outputs 6 pulses, according to the method of step S4, the speed v _{G_3} of the third receiving sensor output pulse calculated by the tracking differentiator is obtained; and so on, when the m-th sensor outputs 6 pulses, according to the method of step S4, the speed v _{G_m} of the m-th receiving sensor output pulse calculated by the tracking differentiator is obtained;

Step S7, during the movement of the mover, when v _{G_1} tracks the actual speed and stabilizes, v _{G_1} is selected as the detection result v _f ; when v _{G_2} is stable, in the overlapping area of v _{G_1} and v _{G_2} , v _{G_2} is selected as the detection result v _f ; when v _{G_3} is stable, in the overlapping area of v _{G_2} and v _{G_3} , v _{G_3} is selected as the detection result v _f ; and so on. The receiving device transmits v _f to the controller, and the controller selects v _f uploaded by different receiving devices, and finally realizes speed detection within the entire range.

Furthermore, the discrete form of the tracking differentiator is expressed as:

in: fhan(x ₁ ,x ₂ ,u,r,h) is the discrete fastest control comprehensive function, and its algorithm formula is as follows:

In order to concisely represent fhan(x ₁ ,x ₂ ,u,r,h), d, d ₀ , y, a ₀ , a are introduced as intermediate variables; is a sign function, where x is y or a; u is the position input signal, _x1 is the position tracking signal, which is an intermediate variable, _x2 is the speed output signal, r is the speed factor, and h is the filter factor. The two are adaptive functions of the speed output signal _x2 and the parameters _γ1 and _γ2 . r increases rapidly with the increase of _x2 , and h decreases rapidly with the increase of _x2 . _γ1 and _γ2 are adjustable parameters. Adjusting their sizes can change the change rates of r and h respectively. At the same time, _γ1 and _γ2 control the range of the tracking differentiator passband. Therefore, it is necessary to adjust according to the spectrum of the input signal u so that the differentiator has a good differential effect on the input signal u and can filter out the high-frequency noise of the input signal u. A is the range of r, T is the discretization step size, and k is the discrete time (k=0, 1, 2, 3...); the tracking differentiator adopts the form of parameter adaptation and can output a fully accurate speed signal. In this embodiment, T=0.0001s. According to the spectrum analysis of the input signal u, γ ₁ =10, γ ₂ =40, A =2500.

Based on the required initial velocity value v _{T — 1} , the receiving device performs an operation of assigning an initial value to the tracking differentiator, which is specifically implemented as follows:

Step S40: the receiving device assigns an initial value to the speed signal of the tracking differentiator, that is, the initial value of the speed signal x ₂ (k). In this embodiment, when the speed after the first sensor outputs 6 pulses is an average speed of 100 m/s, x ₂ (0) = v _{T — 1} = 100 m/s;

Step S41: the receiving device assigns an initial value to the position input initial value of the tracking differentiator, that is, the initial value of u is u(0)=0;

Step S42: The initial value of the intermediate variable position tracking signal x ₁ (k) of the receiving device is:

Wherein, y=x ₁ (0)-u(0)+hx ₂ (0). In this embodiment, x ₁ (0)=-0.2 is calculated to satisfy the constraint condition.

Step S43, after assigning initial values, the tracking differentiator calculation program is started to track the actual mover speed. When the tracking differentiator tracks the actual speed, the calculation result of the tracking differentiator can be selected as the speed detection result output.

As shown in FIG4 , according to the process of the speed detection method of the present invention, the relative position curve of the mover detected by the first receiving sensor is calculated. In FIG4 , the stepped line segment is the relative displacement signal _X1 curve, which increases in a period of 0.0001s; _x1 (k) and _x1 (k)' are the curves of the intermediate variable position tracking signal of the tracking differentiator with and without initialization values, respectively. It can be seen that when the speed is initialized, the intermediate variable position tracking signal needs to be initialized so that it can start tracking from _x1 (0) in advance instead of starting from zero.

As shown in FIG5 , according to the process of the speed detection method of the present invention, the mover speed curve is calculated based on the output pulse of the first receiving sensor. In FIG5 , v _ref is a reference speed curve, whose value is equal to the initial speed value v _ref =100 m/s, and x ₂ (k) and x ₂ (k)' are the curves of the output speed signal of the tracking differentiator with initial value assigned by the method of the present invention and the traditional one without initial value assigned, respectively. It can be seen that the speed of x ₂ (k)' can quickly track the actual speed, effectively reducing the tracking time of the step signal of the tracking differentiator with no initial value assigned by the traditional one.

As shown in FIG6 , when the mover moves, the first receiving sensor, the second receiving sensor, and the third receiving sensor output pulses in sequence. FIG6 shows the speed measurement results corresponding to the output pulses of each sensor obtained by using the traditional tracking differentiator without initialization and the tracking differentiator calculation results. Among them, v _{p_1} , v _{p_2} , and v _{p_3} are the calculation results of the traditional tracking differentiator without initialization, and v _{G_1} , v _{G_2} , and v _{G_3} are the calculation results of the tracking differentiator with initialization. It can be seen from the figure that the calculation result of the tracking differentiator without initialization has a large tracking delay. In order to output the smooth speed throughout the whole process, the overlapping area of the output speeds of two adjacent sensors is required for speed switching. However, the switching area of v _{p_1} and v _{p_2} is very small, and untimely switching may cause speed fluctuations. The tracking differentiator algorithm with initialization can effectively reduce the tracking time of the tracking differentiator for the step speed signal, reduce the tracking delay, thereby expanding the switching area and improving the reliability of the system.

Those skilled in the art can clearly understand that, for the convenience and brevity of description, the specific working process and related instructions of the system described above can refer to the corresponding process in the aforementioned method real-time example, and will not be repeated here.

So far, the present invention has been described in conjunction with the preferred embodiments shown in the accompanying drawings, but it is easy for those skilled in the art to understand that the protection scope of the present invention is obviously not limited to these specific embodiments. Without departing from the principle of the present invention, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will fall within the protection scope of the present invention.

Claims (5)

1. A detection method for a position and speed detection system of a high-speed linear motor, characterized in that: The position and speed detection system includes a grating ruler, a plurality of laser generators, a receiving device and a controller; The plurality of laser generators are arranged at fixed intervals on the high-speed linear motor and are used to emit lasers and keep them in a constant light state; The grating ruler has grating holes of fixed equal width and equal spacing, which are used to block and transmit the laser to generate an optical pulse signal; The receiving device includes a receiving sensor and a signal processor, which are used to receive and calculate the optical pulse signals of multiple laser generators; the signal processor includes a photoelectric conversion, a filtering circuit, a high-speed digital processor and a communication module; the receiving sensor is arranged in parallel with the laser generator, and is used to receive the optical pulse signal; the high-speed digital processor calculates the speed and position according to the electrical pulse signal and the grid hole spacing of the grating ruler, and then transmits the speed and position signals to the controller through the communication module; A controller, for receiving speed and position signals calculated from a receiving device; The position detection method is: the receiving device determines the real-time position of the mover of the high-speed linear motor according to the number of pulses of the optical pulse signal, the grid hole spacing of the grating ruler and the absolute position of the receiving sensor, including: The real-time position of the mover = the absolute position of the receiving sensor + the number of signal pulses × the grid hole spacing of the grating ruler; The speed detection method comprises: Step S1, determining that the grating hole spacing of the grating ruler is w, the spacing between two adjacent receiving sensors is l ₁ , and the multiple receiving sensors are defined in order as a first receiving sensor, a second receiving sensor, to an mth receiving sensor; Step S2, the receiving device receives the input pulse signals of each receiving sensor and performs photoelectric conversion; the receiving device first performs speed detection according to the output pulse of the first receiving sensor, and uses the grating scale grid spacing and the rising edge time of two adjacent pulses to obtain the speed v _{1_1} , v _{1_2} ... v _{1_n} corresponding to each pulse in the continuous n pulses; Step S3, obtaining an average speed v _{T — 1} corresponding to n pulses continuously output by the first receiving sensor, wherein v _{T — 1} =(v _{1 — 1} +v _{1 — 2} +… +v _{1 — n} )/n; Step S4, taking the average speed v _{T_1} corresponding to the output pulse of the first receiving sensor as the initial value of the tracking differentiator, and performing the initial value assignment operation on the tracking differentiator; after the initial value assignment is completed, combining the grating scale grid spacing w and the number of output pulses N ₁ of the first receiving sensor, according to the relative displacement formula w×N ₁ , the relative displacement X ₁ of the mover plate detected by the first receiving sensor is obtained as the input of the tracking differentiator, and the tracking differentiator calculation program is started to obtain the speed v _{G_1} calculated by the tracking differentiator corresponding to the output pulse of the first receiving sensor; Step S5, when the second receiving sensor continuously outputs n pulses, according to the method of the above step S3, the average speed v _{T_2} corresponding to the n pulses continuously output by the second receiving sensor is obtained; when the third receiving sensor outputs a pulse, according to the method of the above step S3, the average speed v _{T_3} corresponding to the n pulses continuously output by the third receiving sensor is obtained; and so on, when the m-th receiving sensor outputs n pulses, the average speed v _{T_m} corresponding to the n pulses continuously output by the m-th sensor is obtained; Step S6, when the second receiving sensor continuously outputs n pulses, according to the method of step S4, the speed v _{G_2} of the second sensor output pulse calculated by the tracking differentiator is obtained; when the third receiving sensor outputs n pulses, according to the method of step S4, the speed v _{G_3} of the third receiving sensor output pulse calculated by the tracking differentiator is obtained; and so on, when the m-th sensor outputs n pulses, according to the method of step S4, the speed v _{G_m} of the m-th receiving sensor output pulse calculated by the tracking differentiator is obtained; Step S7, during the movement of the mover, when v _{G_1} tracks the actual speed and becomes stable, v _{G_1} is selected as the detection result v _f ; when v _{G_2} becomes stable, in the overlapping area of v _{G_1} and v _{G_2} , v _{G_2} is selected as the detection result v _f ; when v _{G_3} becomes stable, in the overlapping area of v _{G_2} and v _{G_3} , v _{G_3} is selected as the detection result v _f ; and so on, the receiving device transmits v _f to the controller; Step S8: The controller selects v _f uploaded by different receiving devices, and finally realizes speed detection in the whole range. 2. The detection method according to claim 1, characterized in that the discrete form of the tracking differentiator is expressed as: , in: ; fhan(x ₁ ,x ₂ ,u,r,h) is the discrete fastest control comprehensive function, and its algorithm formula is as follows: , In order to concisely represent fhan(x ₁ ,x ₂ ,u,r,h), d, d ₀ , y, a ₀ , a are introduced as intermediate variables; is a sign function, where x is y or a; u is the position input signal, _x1 is the position tracking signal, which is an intermediate variable, _x2 is the speed output signal, r is the speed factor, and h is the filter factor. The two are adaptive functions of the speed output signal _x2 and parameters _γ1 and _γ2 . r increases rapidly with the increase of _x2 , and h decreases rapidly with the increase of _x2 . _γ1 and _γ2 are adjustable parameters. Adjusting their sizes can change the change rates of r and h respectively. At the same time, _γ1 and _γ2 control the range of the tracking differentiator passband. Therefore, they need to be adjusted according to the frequency spectrum of the input signal u so that the differentiator has a good differential effect on the input signal u and can filter out the high-frequency noise of the input signal u. A is the range of r, T is the discretization step size, and k is the discrete moment, where k=0,1,2,3······; the tracking differentiator adopts the form of parameter adaptation and can output a fully accurate speed signal. 3. The detection method according to claim 2, characterized in that the operation of assigning an initial value to the tracking differentiator in step S4 comprises: Step S40: the average speed v _{T — 1} corresponding to the n pulses continuously output by the first receiving sensor calculated by the receiving device is used as the initial value v ₀ of the tracking differentiator speed signal, that is, the initial value of the tracking differentiator speed signal x ₂ (k) is x ₂ (0)=v _{T —} 1 ; Step S41: the receiving device assigns an initial value to the position input initial value of the tracking differentiator, that is, the initial value u(0) of u is 0; Step S42: The receiving device assigns an initial value to the position tracking signal of the tracking differentiator, that is, the initial value of the intermediate variable position tracking signal x ₁ (k) is: ; in, ; Calculate the values of x ₁ (0) for the above three cases, correspond to the respective conditional constraints, and select the value that satisfies the constraints. 4. The detection method according to claim 1 is characterized in that the pulse signals output by each receiving sensor are processed and calculated independently to avoid speed fluctuations caused by errors in the absolute position of the receiving sensor. 5. The detection method according to claim 1 is characterized in that the length of the grating ruler is greater than the spacing between adjacent receiving sensors to ensure that the detection result is continuous.