Method for reproducing multiple dynamic speed values ​​by one measurement standard device

Abstract

The invention discloses a method for reproducing multiple speed values ​​such as rotation speed and rotation acceleration, linear speed and linear acceleration by a metrological standard device, comprising: using a quartz crystal oscillator with high frequency accuracy and stability to output electric pulses of fixed frequency as reference frequency, and controlling a stepping motor speed regulating and dragging system through an intelligent numerically controlled continuous linear scanning frequency converter, outputting frequency value and its rising and falling slope (frequency increment per unit time) corresponding to the rotation speed and rotation acceleration, linear speed and linear acceleration values ​​to be reproduced (occurred), dragging a speed measuring wheel, a gear box, a standard linear speed wheel or a drum to rotate, reproducing standard values ​​such as rotation speed and rotation acceleration, linear speed and linear acceleration, and verifying or calibrating the metrological performance of various speed measuring instruments, including universal rotation speed and linear speed measuring instruments, escalator comprehensive performance testers, sliding time testers, etc.

Description

Technical Field

[0001] The present invention relates to a method for reproducing the measurement values ​​of dynamic rotational speed and rotational acceleration, linear speed and linear acceleration, and more specifically, to a method for simultaneously or separately reproducing (occurring) the measurement values ​​of rotational speed and rotational acceleration, linear speed and linear acceleration that continuously increase (decrease) in a uniform acceleration (deceleration) manner on a measurement standard device. Background Art

[0002] Various power machines are widely used. Their rotational speed and rotational acceleration during speed increase or decrease, as well as the rotational speed and acceleration, linear speed and linear acceleration generated by the equipment driven by them, must be measured, tested and regulated. Various speed measurement and testing instruments must be verified or calibrated during design, manufacturing and use to determine whether they meet the relevant technical indicators and are within the qualified range. This requires the establishment of corresponding measurement standards for reproducing (occurring) these values. The measurement standards that have been established in my country can only reproduce (occur) the rotational speed or linear speed under steady-speed operation. There is no measurement standard that can uniformly increase (decelerate) the continuous dynamic speed increase or decrease, reproduce (occur) the rotational acceleration and linear acceleration values. The measurement standard device that reproduces (occurs) the rotational speed or linear speed value must be driven by a rotating motor. The traction motors used in the existing devices, including brushless DC servo motors using digital phase-locked speed regulation technology and AC servo motors using variable frequency speed regulation technology, are all motor traction systems that use speed sensors for speed measurement feedback and closed-loop speed control. Due to the constraints of various factors, their speed control range and dynamic performance are limited, and they are prone to loss of control and stalling. It is difficult to achieve wide-range, high-dynamic speed regulation requirements, and they are unable to meet the requirements of reproducing (generating) high-precision continuous dynamic speed increase and decrease, performing uniform acceleration (deceleration) rotational motion, and reproducing rotational acceleration and linear acceleration values. Summary of the invention

[0003] The purpose of the present invention is to provide a traction motor and a speed control method thereof used in a metrological standard device that can reproduce (generate) the values ​​of rotational speed and rotational acceleration, linear speed and linear acceleration. The traction motor is a stepper motor using open-loop control technology. A stepper motor is a special pulse motor, the rotation angle (or number of steps) of its rotor is strictly proportional to the number of speed regulating electric pulses input to the motor drive power supply, the rotational speed of the rotor is strictly synchronized with the frequency of the speed regulating electric pulse, and is proportional to the rotational acceleration and the increment of the speed regulating electric pulse frequency per unit time (i.e., the frequency rise and fall slope) are strictly proportional, and there is no continuous cumulative error. Stepper motors have been widely used in the fields of automatic control, intelligent manufacturing, etc., mainly used for position control, while speed control technology has not yet been fully developed, and the speed regulation range, subdivision, accuracy and function cannot meet the new requirements of metrological standard devices that can reproduce multiple speed values. For this reason, innovative development is needed. The present invention is based on the traditional stepper motor open-loop control technology, and adopts intelligent control technology to control the speed regulating pulse generator composed of a continuous linear scanning frequency converter (similar to a sweeping frequency signal generator) or a digital frequency signal synthesizer (similar to a standard frequency signal source). According to the method provided by the present invention, the speed regulating electric pulses with wide bandwidth, high precision, high subdivision, and frequency directly corresponding to the rotation speed and acceleration are output to supply the stepper motor driver, and the motor is controlled to reproduce (generate) the standard values ​​of the rotation speed and rotation acceleration. The motor is connected to the gear transmission through a coupling to expand the measuring range, and can also drag a standard linear speed wheel or drum to reproduce (generate) the corresponding standard linear speed and linear acceleration values, thereby realizing the new requirements of the measurement standard device.

[0004] Method principle and technical route of the present invention

[0005] The low accuracy of the speed regulating electric pulse frequency generated by the traditional stepping motor speed regulation control technology, and the insufficient bandwidth and adjustment subdivision of the electric pulse frequency are the main reasons for the low upper speed limit, the inability to achieve wide range, uniform acceleration (deceleration) of the rotation speed and acceleration, and the failure of the accuracy and stability of the rotation speed to meet the requirements. The present invention uses the electric pulse output by a temperature compensated or constant temperature controlled quartz crystal oscillator with high frequency accuracy and stability as the reference frequency signal source, and adopts the intelligent control technology of a numerically controlled continuous linear scanning frequency converter or frequency synthesizer. According to the method provided by the present invention, the reference frequency signal electric pulse with a fixed frequency is converted into a speed regulating electric pulse corresponding to the value of the rotation speed or linear speed that is continuously increased or decreased, and the slope of the frequency increase or decrease (or the increment per unit time) corresponds to the value of the rotation acceleration or linear acceleration, and is input into the stepping motor driving power supply to control the operation of the stepping motor. According to the mechanical angular displacement (i.e., step angle β) of the selected stepping motor and the electric subdivision number (N) of the driver, the number of electric pulse equivalents (C) required for the motor rotor to rotate 360° is obtained. pk ),

[0006]

[0007] After selecting and determining the step angle (β) of the motor and the micro-step number of the drive power supply, calculate C according to formula (1-1) pk It is a constant. The equivalent speed pulse frequency (Fk) when the motor speed is 1r / min can be calculated by the following formula:

[0008]

[0009] This F k is also a constant. According to the selected speed regulation subdivision (Δn), the speed regulation electric pulse frequency subdivision ΔF can be obtained. n =F k ×Δn; and the speed regulating electric pulse frequency value corresponding to each rotation speed (F n ) can be calculated according to formula (1-3):

[0010] F n =F k ×n (1-3)

[0011] After setting the target rotation speed n, the speed regulating electric pulse frequency is n / Δn=m ΔF n The beat increases step by step to F n , reaching a rotation speed of n. By adjusting the increment of m per unit time, the rotation acceleration α of the stepper motor can be adjusted. This is also equivalent to setting the electric pulse frequency from F = 0 to F n The frequency sweep time length (t) is set at 1000. The motor is started and accelerated to a rotational acceleration n with a uniform speed of n. a =n / t. The corresponding increment of the speed regulating electric pulse per unit time (Δf na ), can be calculated as follows:

[0012] Δf na =F K / t (1-4)

[0013] As long as the motor's rotation speed and the corresponding speed regulating electric pulse frequency adjustment subdivision are small enough, the smoother the stepper motor runs, the higher the upper speed limit (necessary measures to eliminate oscillation should be taken to ensure this). Under a certain load inertia, the higher the speed regulation subdivision and the corresponding speed regulating electric pulse frequency subdivision and the increment per unit time, the higher the motor's reproducible rotation acceleration value. On the basis of the above, an appropriate standard linear speed wheel (or drum) is matched and dragged by a stepper motor to reproduce (generate) the corresponding linear speed and linear acceleration standard values ​​on the outer circumference. The product of the rotation speed and the outer circumference is the linear speed value (V n ). Rotational acceleration (na ) multiplied by the circumference of the outer circle is the linear acceleration (V a ). This requires designing and processing a standard linear speed wheel (or drum) with appropriate circumference and structural dimensions according to the range of values ​​to be reproduced and the bearing capacity of the motor load inertia. Taking into account the needs of friction transmission, the outer circumference of the wheel should have an anti-slip design (such as knurling). The coaxiality of the wheel and the machining accuracy of its diameter or circumference are the key factors that restrict the accuracy of the linear speed and linear acceleration values ​​it reproduces (generates). In order to meet the needs of different linear speed and linear acceleration ranges, several standard linear speed wheels with different diameters or circumferences can be designed. The structural block diagram of the measurement standard device that reproduces (generates) the values ​​of rotational speed and rotational acceleration, linear speed and linear acceleration according to the above method is shown in the attached figure. Figure 1 Attached Figure 2 The schematic diagram of the scanning frequency conversion speed regulation principle of the intelligent open-loop control stepper motor speed regulation and dragging system is shown in the figure. The open-loop control stepper motor speed regulation and dragging system is composed of a host computer and a slave computer. The host computer is a computer with special software installed. The slave computer is a numerically controlled continuous linear scanning frequency conversion pulse generator (similar to a sweep signal generator) or a digital frequency signal synthesizer (similar to a decimal standard frequency signal source) controlled by the program instructions of the host computer. The host computer and the slave computer communicate bidirectionally, and the speed standard value and related parameters of each detection point are set and stored in the host computer, which is controlled by a special software program, downloads instruction data to the slave computer, and controls the operation of the stepper motor. During the operation, the computer screen of the host computer displays real-time operation data. The intelligent stepping motor speed control system composed of the lower and upper machines generates a number of speed control electric pulses corresponding to the frequency values ​​and the speed values ​​according to the above invention method and the quantitative relationship shown in the formulas (1-1) to (1-4), and drives the stepping motor drive system to reproduce (generate) the required standard rotation speed and rotation acceleration, linear speed and linear acceleration values, which are used to calibrate the corresponding speed measuring instruments. The patents for the intelligent stepping motor speed control technology and the computer software copyright will be applied separately and will not be described in detail here. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a schematic diagram of the structure of a metrological standard device for reproducing (generating) standard values ​​of rotational speed and rotational acceleration, linear speed and linear acceleration.

[0015] Figure 2 It is a schematic diagram of the scanning frequency conversion speed regulation principle of the intelligent open-loop control stepper motor speed regulation and dragging system. DETAILED DESCRIPTION

[0016] A temperature-compensated or thermostatically controlled quartz crystal oscillator with a frequency of 10MHz and an accuracy and stability better than 0.0001% is selected to output electric pulses as the reference frequency signal source. A hybrid stepper motor with a step angle of 1.8° and a 10-division drive power supply is selected to form an open-loop control stepper motor speed control system with the above-mentioned intelligent speed control system. The relevant parameters are calculated according to formulas (1-1) to (1-4): The electric pulse equivalent (C PK ) is 2000, the speed regulating electric pulse frequency equivalent at 1r / min is 33.3333Hz; the speed regulating electric pulse frequency (F n ) is 333.333kHz; speed regulation subdivision Δn = 0.01r / min, corresponding to speed regulation electric pulse frequency subdivision ΔF n 0.33333Hz; Select the motor's rotation acceleration adjustment subdivision Δn a =0.01r / s 2 , corresponding to the speed regulating electric pulse frequency s 2 Increment Δf na = 0.33333Hz; when the frequency value increases by 1 step per second (0.33333Hz / s 2 ) increases, the motor will increase by 0.01r / s 2 The rotation acceleration increases the rotation speed, and the time length to reach 10000r / min is 16666.666s; when the frequency is increased by 100 steps (100×0.33333Hz), the motor increases at 1r / s 2 The rotational acceleration is uniformly accelerated, and the time to reach 10000r / min is 166.666s (and so on). If there are higher requirements for the resolution, smoothness and accuracy of the low-speed range, a drive power supply with a higher electrical subdivision can be selected for component speed control. In order to expand the upper limit range of rotational speed and rotational acceleration, a gear transmission with a 5-fold speed increase transmission is used, which can expand the upper limit of the rotational speed to more than 40000r / min, and the upper limit range of rotational acceleration is also expanded accordingly. In order to reproduce (occur) the required linear speed and linear acceleration values, three types of standard rollers made of 304 stainless steel with outer circumference knurling are designed and processed with circumferences of 300mm, 200mm and 100mm respectively. The accuracy of the wheel diameter is ±0.01mm, and the linear acceleration is within the range of 1mm / s to 50m / s. 2 ~20m / s 2Within the measuring range, the corresponding standard value can be reproduced (generated) in sections. The measurement standard device designed and manufactured according to the above scheme can reproduce the relative expanded uncertainty of the rotation speed of (1~40000)r / min within 0.0005%; the rotation acceleration is (0.01~10)r / s 2 The accuracy within the range is better than ±0.05r / s 2 ; 10r / s 2 Above ±0.05%. Linear velocity error is no more than ±1mm / s within the range of (0.05~2)m / s, and ±0.05% within the range of (2~50)m / s. Linear acceleration is within the range of (0.05~1)m / s 2 ±2m / s 2 ; (1~20)m / s 2 The range is ±0.2%. Due to the restrictions of speed sensors and measurement methods, it is difficult to further improve the measurement accuracy of rotational acceleration, linear velocity and its acceleration). The above technical route can also be used to design and manufacture special calibration devices for calibrating escalator comprehensive performance testers and sliding time testers.

Claims

1. A method for reproducing multiple speed values ​​by a measurement standard device, comprising a traction motor for driving a device to perform rotational motion and a variable frequency speed regulation pulse generation method, characterized in that: The measurement standard device is driven by an open-loop controlled stepper motor, and an intelligent numerically controlled continuous linear variable frequency speed regulating pulse generator is used. According to the quantitative calculation relationship between the given speed regulating electric pulse frequency and the speed value, the electric pulse with a fixed frequency output by the reference frequency source is automatically converted into the corresponding continuously linearly changing speed regulating electric pulse, and the hybrid stepper motor is controlled to increase or decrease the rotation speed in a uniform acceleration or deceleration manner, reproduce or generate the set rotation acceleration value, and the rotation speed is moved at a steady speed at each set point, and the corresponding rotation speed value is reproduced or generated; when the motor drags the standard linear speed wheel or drum, the corresponding linear speed and linear acceleration values ​​are reproduced or generated on its outer circumference; The intelligent numerically controlled continuous linear variable frequency speed regulating pulse generator adopts a digital frequency synthesizer, which is characterized in that the speed regulating electric pulse frequency equivalent F at 1 r / min is calculated according to the selected step angle of the stepping motor and the micro-step subdivision number of the driving power supply. k And speed regulation electric pulse frequency subdivision ΔF n , set the rotation speed and acceleration of the calibration point, calculate the corresponding m value, and use m ΔF per unit time n The beat rate increases or decreases the speed regulating electric pulse frequency to F n , control the digital frequency synthesizer to output speed regulating electric pulses of corresponding frequency in a continuous linear frequency conversion mode, control the rotation speed and rotation acceleration of the stepping motor through the driving power supply, and drive the measurement standard device to reproduce or generate the corresponding standard values ​​of rotation speed and rotation acceleration; The speed regulating electric pulse frequency equivalent F at 1r / min calculated by the selected stepping motor step angle and the micro-stepping number of the driving power supply k And speed regulation electric pulse frequency subdivision ΔF n， The specific calculation method is: N is the number of micro-steps of the driving power supply, β is the step angle, C pk is the number of electrical pulse equivalents; F k ΔF is the speed regulating electric pulse frequency equivalent; n =F k ×Δn,ΔF n is the speed regulation electric pulse frequency subdivision; Δn is the speed regulation subdivision.

2. The method for reproducing multiple speed values ​​by a measurement standard device as claimed in claim 1, wherein the intelligent numerically controlled continuous linear variable frequency speed modulation pulse generator can also be a numerically controlled scanning signal generator, characterized in that: The speed regulating electric pulse frequency equivalent F is calculated based on the step angle of the stepping motor and the micro-step subdivision number of the driving power supply k And speed regulation electric pulse frequency subdivision ΔF n , set the calibration point rotation speed and rotation acceleration, calculate the time length of frequency increase and decrease, and use this to set the scanning time length of the scanner between two frequency points, control the CNC scanning signal generator to continuously output speed regulation electric pulses of the corresponding frequency, control the rotation movement of the stepper motor through the driving power supply, and drive the measurement standard device to reproduce or generate the corresponding rotation speed and rotation acceleration standard values.

3. The method for reproducing multiple speed values ​​by a measurement standard device as claimed in claim 1, wherein the intelligent numerically controlled continuous linear variable frequency speed modulation pulse generator outputs speed modulation electric pulses, controls the stepping motor to rotate through the driving power supply, drags the standard linear speed wheel or roller to rotate synchronously, and reproduces or generates corresponding linear speed and linear acceleration standard values ​​on the outer circumference, characterized in that: According to the size of its measuring range, a wheel or roller with corresponding diameter or outer circumference is matched to reproduce or generate the linear speed and linear acceleration measuring range of the corresponding measuring range in sections; when the speed sensor of the speed measuring instrument being tested or calibrated needs to be directly coupled and dragged with the stepper motor and a linear speed wheel or roller cannot be used, the speed pulse generator sets the virtual diameter or outer circumference of the wheel or roller, outputs the corresponding speed regulating electric pulse to control the rotational motion of the stepper motor, and reproduces or generates the corresponding linear speed and linear acceleration values.

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