CN104567787B - Method for calibrating measurement accuracy of dynamic angle measuring system - Google Patents

Abstract

The invention belongs to the technical field of measurement and control, and specifically relates to a method for calibrating the measurement accuracy of a dynamic angle measurement system, and aims to provide a method capable of calibrating a high-speed dynamic angle acquisition system based on a turntable. It includes, test preparation, installation of calibration device, dynamic angle reference determination and angle calibration steps. The method adopts the step of installing a calibration device, and installs the calibration device coaxially with the angle sensor of the turntable, provides a static reference angle for the dynamic angle, and eliminates system errors. After calibrating the dynamic angle measurement system, it is shown that the dispersion of the measured value is less than 0.1″ at low speed (less than 1°/s), indicating that the angle sensor and the coaxially installed pulse signal generator in the calibration system are The zero position difference of the angle encoder has good repeatability, and the relative angular displacement is very small, which meets the needs of high-precision calibration.

Description

Calibration Method of Measuring Accuracy of Dynamic Angle Measuring System

technical field

The invention belongs to the technical field of measurement and control, and in particular relates to a method for calibrating the measurement accuracy of a dynamic angle measurement system.

Background technique

The high-precision turntable is mainly used for the calibration of inertial navigation products, star sensors and other products and the motion simulation of some parts on the missile. The index accuracy that the turntable can achieve also reflects the development level of the defense industry to a certain extent. With the improvement of the dynamic performance of various tested products, the dynamic angular position measurement capability of the turntable, as an important indicator, is required in more and more projects. Therefore, special research has been started on the dynamic angle measurement system in China, and the research and development of the corresponding accuracy calibration method is imminent.

Dynamic angular position, that is, the actual angular position of a rotating body in motion at a specified moment. As the constituent elements of the concept, time value and position are indispensable. Dynamic angle measurement generally refers to the process that the angle measurement system of the moving body in rotation receives a time pulse, and then measures the angular position of the rotating body at that moment, so the dynamic angle measurement system generally has a pulse trigger function. The calibration method of the accuracy of the dynamic angle measurement system is dedicated to finding a standard with an order of magnitude higher accuracy than the dynamic angle measurement system to evaluate the accuracy of the dynamic angular position.

Errors in dynamic goniometric systems are generally caused by various delays in the processing circuitry. Taking the turntable as an example, the position sensor of the turntable is generally a photoelectric encoder or an inductive synchronizer. Both of them emit sine waves that can identify the position during the rotation process. The process of generating sine waves is a photoelectric conversion process, and the time consumption is basically negligible. To obtain the angular position of the turntable, it is necessary to process and convert the sine waves. For a turntable in motion, the position sensor is still moving while emitting a sine wave. When the sine wave is processed and converted into a position value, the turntable is already in another angular position, which is not the current dynamic angular position. The measurement error of the dynamic angle is mainly caused by the product of the angular rate of the turntable and the delay of the angle measurement system, referred to as "rate-induced error", and there are also error sources such as "acceleration-induced error". In any dynamic angle measurement system, the work of electronic components will inevitably lead to delay, and this delay will cause dynamic angle measurement error.

At present, domestic calibration methods for dynamic angle measurement products are in their infancy. This is mainly because the research on dynamic angle measuring products has just started. At present, dynamic angle measurement focuses on the method of taking pictures: that is, imaging through high-speed cameras or other CCD products, and obtaining dynamic angular positions through background analysis. It obtains the standard template graphics projected from the goniometric system through imaging, and combines the image evaluation software to qualitatively give the comprehensive performance of the goniometric system, and assists in the calibration of the goniometric system. This calibration method relies on imaging, which has high cost, troublesome background processing and is not ideal for high-speed dynamic angle measurement. In addition, there are also attempts to use a target running at a certain angular velocity or angular acceleration as a standard to control the movement of the system to be calibrated in this way, and compare the difference between the two movement methods to achieve dynamic precision calibration. In fact, in this method, the target is used as a calibration reference, and its own dynamic angle measurement error magnitude is much higher than that of arc seconds (″), which can only be used for low-precision dynamic precision calibration, and cannot meet the needs of high-precision calibration .

Contents of the invention

The purpose of the present invention is to provide a calibration method capable of calibrating the measurement accuracy of the dynamic angle measurement system of the high-speed dynamic angle acquisition system based on the turntable.

The present invention is achieved like this:

A method for calibrating measurement accuracy of a dynamic angle measurement system, comprising the steps of:

The first step: test preparation;

An angle sensor connecting the dynamic angle measuring device and the turntable;

The second step: install the calibration device;

Install the calibration device on the turntable, install the calibration device coaxially with the angle sensor of the turntable, the rotatable part of the calibration device is fixed on the rotating shaft of the turntable, the reading head circuit of the calibration device is fixed on the non-rotating shell of the turntable, and the reading The head circuit and the rotatable part are installed according to the installation requirements of the calibration device;

The third step: dynamic angle benchmark determination;

Power the turntable and the calibration device, drive the turntable to rotate at an angular velocity of ω ₀ =0.1°/s, drive the rotatable part of the calibration device to rotate, and collect the zero pulse signal of the calibration device for i times; the zero pulse signal is used as a synchronous pulse signal sent to the dynamic angle measuring device; the dynamic angle measuring system collects the angular position signal of the angle sensor of the turntable, and when the turntable passes through the _zero position of the calibration device at an angular velocity of ω0 for i times, the synchronous pulse signal triggers the measured value of the dynamic angle measuring device to be θ ₀₀ , θ ₀₁ , θ ₀₂ , θ ₀₃ ..... θ _0i , then the approximate static position θ ₀ is:

Step 4: Angle calibration;

Sequentially drive the turntable to rotate at the angular velocity of ω ₁ , ω ₂ , ..., ω _j , drive the rotatable part of the calibration device to rotate, and collect the zero pulse signal of the calibration device i times at each angular speed; the zero pulse signal is used as The synchronous pulse signal is sent to the dynamic angle measurement device; the dynamic angle measurement system collects the angular position signal of the angle sensor of the turntable, and obtains the digital angle signal θ _ij at the arrival time of the synchronous pulse signal, where j is the speed point serial number, j is a natural number, i is the i-th sampling point under the j-th rate point, and i is a natural number;

Then when the angular rate is _ωj , the dynamic angle measurement error of the dynamic angle measurement system is:

Δθ _jmax = Max|θ _nj -θ ₀ | (2)

In the formula, 1≤n≤i, n is a natural number.

In the above-mentioned test preparation step, the dynamic angle measurement device includes an angular position signal analog-to-digital conversion module, a synchronous pulse receiving device and a data processing center; wherein, the angular position signal analog-to-digital conversion module is connected to the synchronous pulse receiving device and the data processing center respectively , the angle position signal analog-to-digital conversion module performs analog-to-digital conversion on the angle sensor signal of the turntable to obtain a digital angle signal, and then sends the digital angle signal to the data processing center when the synchronous pulse receiving device receives the synchronous pulse signal; the synchronous pulse receiving device Receive the synchronous pulse signal and send the synchronous pulse signal to the angular position signal analog-to-digital conversion module; the data processing center receives the digital angle signal for subsequent analysis.

In the step of installing the calibration device as described above, the calibration device is a photoelectric encoder, a circular grating or a magnetic grating. For the photoelectric encoder, the moving disk is pressed tightly on the rotating shaft of the turntable, the fixed disk is fixed on the non-rotating shell of the turntable, and the gap between the reading head on the fixed disk and the moving disk is within the range of 0.5-1.5mm.

The beneficial effects of the present invention are:

The method adopts the step of installing a calibration device, and installs the calibration device coaxially with the angle sensor of the turntable, provides a static reference angle for the dynamic angle, and eliminates system errors. After calibrating the dynamic angle measurement system, it is shown that the dispersion of the measured value is less than 0.1″ at low speed (less than 1°/s), indicating that the angle sensor and the coaxially installed pulse signal generator in the calibration system are The zero position difference of the angle encoder has good repeatability, and the relative angular displacement is very small, which meets the needs of high-precision calibration.

Description of drawings

Fig. 1 is a flowchart of a method for calibrating measurement accuracy of a dynamic angle measurement system according to the present invention.

detailed description

A method for calibrating measurement accuracy of a dynamic angle measurement system of the present invention is introduced below in conjunction with the accompanying drawings and embodiments:

As shown in Figure 1, a method for calibrating the measurement accuracy of a dynamic angle measurement system includes the following steps:

The first step: test preparation;

Angle sensor for connecting the dynamic goniometer to the turntable. Generally, a dynamic angle measuring device includes an angular position signal analog-to-digital conversion module, a synchronous pulse receiving device and a data processing center. Wherein, the angular position signal analog-to-digital conversion module is respectively connected with the synchronous pulse receiving device and the data processing center, which performs analog-to-digital conversion on the angle sensor signal of the turntable to obtain a digital angle signal, and then when the synchronous pulse receiving device receives the synchronous pulse signal, Send the digital angle signal to the data processing center. The synchronous pulse receiving device receives the synchronous pulse signal, and sends the synchronous pulse signal to the angular position signal analog-to-digital conversion module. The data processing center receives the digital angle signal for subsequent analysis.

The second step: install the calibration device;

Install the calibration device on the existing turntable, install the calibration device coaxially with the angle sensor of the turntable, the rotatable part of the calibration device is fixed on the rotating shaft of the turntable, and the reading head circuit of the calibration device is fixed on the non-rotating shell of the turntable Above, the reading head circuit and the rotatable part are installed according to the installation requirements of the calibration device. In this embodiment, the calibration device is a photoelectric encoder, a circular grating or a magnetic grating. For photoelectric encoders, the moving disk is pressed tightly on the rotating shaft of the turntable, and the fixed disk is fixed on the non-rotating shell of the turntable. The gap between the reading head on the fixed disk and the moving disk is in the range of 0.5-1.5mm, such as 0.5mm , 1mm or 1.5mm.

The third step: dynamic angle benchmark determination;

Provide power to the turntable and the calibration device, drive the turntable to rotate at an angular velocity of ω ₀ =0.1°/s, drive the rotatable part of the calibration device to rotate, and collect the zero pulse signal of the calibration device i times. The zero pulse signal is sent to the dynamic angle measuring device as a synchronous pulse signal. The dynamic angle measurement system collects the angular position signal of the angle sensor of the turntable. Taking the reference angular velocity at this time as an approximate static state, the zero position of the calibration device relative to the position θ ₀ of the angle sensor of the turntable is an approximate static position. When the angular velocity of ₀ passes through the zero position of the calibration device, the synchronous pulse signal triggers the measurement value of the dynamic angle measuring device to be θ ₀₀ , θ ₀₁ , θ ₀₂ , θ ₀₃ ...... θ _0i , then the approximate static position θ ₀ is:

Step 4: Angle calibration;

Sequentially drive the turntable to rotate at the angular speed of ω ₁ , ω ₂ ,..., ω _j , and drive the rotatable part of the calibration device to rotate, and collect the zero pulse signal of the calibration device i times at each angular speed. The zero pulse signal is sent to the dynamic angle measuring device as a synchronous pulse signal. The dynamic angle measurement system collects the angular position signal of the angle sensor of the turntable, and obtains the digital angle signal θ _ij at the arrival time of the synchronous pulse signal, where j is the serial number of the speed point, j is a natural number, and i is the first speed point under the jth speed point i sampling points, i is a natural number.

Then when the angular rate is _ωj , the dynamic angle measurement error of the dynamic angle measurement system is:

Δθ _jmax = Max|θ _nj -θ ₀ | (2)

In the formula, 1≤n≤i, n is a natural number.

The method adopts the step of installing a calibration device, and installs the calibration device coaxially with the angle sensor of the turntable, provides a static reference angle for the dynamic angle, and eliminates system errors. After calibrating the dynamic angle measurement system, it is shown that the dispersion of the measured value is less than 0.1″ at low speed (less than 1°/s), indicating that the angle sensor and the coaxially installed pulse signal generator in the calibration system are The zero position difference of the angle encoder has good repeatability, and the relative angular displacement is very small, which meets the needs of high-precision calibration.

Claims (4)

1. a kind of scaling method of dynamic angular measuring system certainty of measurement, comprises the steps：The first step：Test prepares；Connection is dynamic The angular transducer of state angle measuring system and turntable；Second step：Caliberating device is installed；Caliberating device is installed on turntable, will be demarcated Device is co-axially mounted with the angular transducer of turntable, and the rotatable portion of caliberating device is fixedly mounted in the rotating shaft of turntable, mark The read head circuit for determining device is fixed on the nonrotational housing of turntable, and read head circuit is with rotatable portion according to caliberating device Installation requirement is installed；3rd step：Dynamic angular benchmark is determined；It is that turntable and caliberating device are powered, drives turntable with ω₀=0.1 °/s Angular speed rotate, drive caliberating device the rotatable portion component of rotation, i time gather caliberating device zero pulse signal；This zero Digit pulse signal is sent to dynamic angular measuring system as synchronization pulse；Dynamic angular measuring system enters to the angular transducer of turntable Row angle position signal is gathered, and turntable i time is with ω₀Angular speed when the zero-bit of caliberating device, synchronization pulse triggering is dynamic The measured value of state angle measuring system is θ₀₀, θ₀₁, θ₀₂, θ₀₃……..θ_0i, then less stationary position θ₀For：

4th step：Angle calibration；Turntable is driven successively with ω₁, ω₂... ..., ω_jAngular speed rotate, drive caliberating device The rotatable portion component of rotation, the zero pulse signal of i collection caliberating device under each angular speed；The zero pulse signal conduct Synchronization pulse is sent to dynamic angular measuring system；Dynamic angular measuring system carries out angle position signal and adopts to the angular transducer of turntable Collection, obtains the digital angle signal θ of synchronization pulse due in_ij, wherein, j is speed point sequence number, and j is natural number, and i is Ith sample point under j-th speed point, i is natural number；It is then ω in angular speed_jWhen dynamic angular measuring system dynamic measuring angle Error is：

Δθ_jmax=Max | θ_nj-θ₀| ... in (2) formula, 1≤n≤i, n is natural number.

2. the scaling method of a kind of dynamic angular measuring system certainty of measurement according to claim 1, it is characterised in that：Described Test preparation process, dynamic angular measuring system is included at angle position signal analog-to-digital conversion module, lock-out pulse reception device and data Reason center；Wherein, angle position signal analog-to-digital conversion module is connected respectively with lock-out pulse reception device and data processing centre, angle Position signalling analog-to-digital conversion module carries out analog-to-digital conversion and obtains digital angle signal, Ran Hou to the angular transducer signal of turntable When lock-out pulse reception device receives synchronization pulse, digital angle signal is sent to into data processing centre；Synchronous arteries and veins Rush reception device and receive synchronization pulse, and the synchronization pulse is sent to into angle position signal analog-to-digital conversion module；Number Digital angle signal is received according to processing center, in case subsequent analysis are used.

3. the scaling method of a kind of dynamic angular measuring system certainty of measurement according to claim 1, it is characterised in that：Described In installing caliberating device step, caliberating device is photoelectric encoder, Circular gratings or magnetic grid.

4. the scaling method of a kind of dynamic angular measuring system certainty of measurement according to claim 3, it is characterised in that：Described The Moving plate of photoelectric encoder is pressed in the rotating shaft of turntable, and price fixing is fixed on the nonrotational housing of turntable, the reading on price fixing Head is with the gap of Moving plate in the range of 0.5~1.5mm.