JPH03220460A - Scale factor measuring apparatus - Google Patents

Abstract

PURPOSE:To enable measurement of a scale factor of an angular velocity sensor handily and simply by rotating the angular velocity sensor by a specified angle at a proper speed. CONSTITUTION:An angular velocity sensor 1 is an object to be measured and outputs a voltage (angular velocity omega) proportional to an angular velocity as output. An A/D converter 2 converts an output of the angular velocity sensor into digital from analog and a digital integrator 3 integrates an A/D value hourly. Before the rotating of the angular velocity sensor 1 by a specified angle, a start pulse is generated with a start button 6 and after the rotation thereof, a stop pulse is generated with a stop button 7. Then, the pulses are inputted into an input section 5 from the start button 6 and the stop button 7 to be outputted to an arithmetic device 4. Then, the arithmetic device 4 brings in an output data of the digital integrator 3 by the start and stop pulses from the input section 5 to calculate a scale factor.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a scale factor measuring device for measuring a scale factor of an angular velocity sensor.

[Prior Art] A navigation device mounted on a moving body such as a vehicle to detect the traveling trajectory of the moving body is usually equipped with an angular velocity sensor such as a vibrating gyro, and the output of this angular velocity sensor (proportional to the angular velocity of the moving body) is The yawing angle of the moving body is determined by performing an integral calculation on the yaw angle of the moving body.

Each of these angular velocity sensors has a different unique scale factor, and there is some error between the actual rotation angle and the output of the angular velocity sensor. The scale factor is the slope of the least squares approximation straight line of the gyro output voltage against the input angular velocity, and its unit is [mV/(deg/bu)].If this scale factor changes, the output of the angular velocity sensor with respect to the angular velocity will change. , the accuracy will deteriorate.

However, this scale factor gradually changes over time, so if the accuracy of the navigation system decreases, the scale factor must be measured anew and the navigation system's scale factor adjustment volume adjusted. Or, it is necessary to substitute a new scale factor value in the software process that calculates the yaw angle.

Conventionally, the method of measuring the scale factor of an acceleration sensor is to place the angular velocity sensor on a rotary table that rotates stably with accurate rotational angular velocity, and to calculate the scale factor by dividing the output of the angular velocity sensor by the rotational angular velocity. was measuring.

[Problem to be solved by the invention] However, the conventional method using a rotary table,
A high-performance rotary table with accurate and stable rotation is required, and a high-performance rotary table is heavy and large, making it difficult to carry. Therefore, it has been extremely difficult for service personnel or users to easily measure the scale factor of, for example, an angular velocity sensor attached to a vehicle.

The present invention has been made to solve the above-mentioned conventional drawbacks, and provides a scale factor measuring device that can easily and easily measure the scale factor of an angular velocity sensor.

[Means for Solving the Problems] In order to solve the above problems, the present invention provides an integrator that integrates the output of an angular velocity sensor, and an arithmetic device that inputs the integral value of this integrator and calculates a scale factor of the angular velocity sensor. The scale factor of the angular velocity sensor is calculated by rotating the angular velocity sensor by a predetermined angle.

Furthermore, the arithmetic device divides the output when the integrator is rotated by a predetermined angle by a coefficient obtained by multiplying the output per unit time when a constant voltage is applied to the integrator by the rotation angle of the angular velocity sensor. The configuration is such that the scale factor of the angular velocity sensor is calculated.

[Operation] According to the present invention, the angular velocity sensor is rotated by a predetermined angle,
The output at this time is integrated by an integrator, and this integrated value is input to an arithmetic circuit. This arithmetic device calculates the output by multiplying the output per unit time when a constant voltage is applied to the integrator by the rotation angle of the angular velocity sensor. The scale factor of the angular velocity sensor is calculated by dividing the output of the integrator at a predetermined angle of rotation by the coefficient.

[Example] An example of the present invention will be described with reference to the drawings. 1st
The figure is a circuit configuration diagram showing one embodiment of the present invention, and FIG. 2 is a relationship diagram among the input pulse signal, the angular velocity sensor output signal, and the integrator output. FIG. 3 is a flowchart of operations in the embodiment.

In FIG. 1, the angular velocity sensor 1 is the object to be measured in the present invention, and the output is a voltage proportional to the angular velocity (angular velocity ω).
Output.

The scale factor measuring device 11 converts the angular velocity sensor output into A
An A/D converter 2 that performs /D conversion, a digital integrator 3 that integrates the A/D value over time, and a start button 6 that generates a start pulse before rotating the angular velocity sensor 1 by a predetermined angle. A stop button 7 that generates a stop pulse after rotation, a start button 6, and a stop button 7
an input section 5 that inputs pulses from and outputs them to the arithmetic device 4;
and an arithmetic unit 4 which takes in the output data of the digital integrator 3 in response to start and stop pulses from the input unit 5 and calculates a scale factor.

In the embodiment, a start button and a stop button are provided separately, but a single button may be used to output start and stop signals.

The operation of the scale factor measuring device having such a configuration will be explained with reference to the flowchart shown in FIG. First, when the start button 6 is pressed, a start pulse S0 is output from the input section 5 to the arithmetic device 4. The arithmetic device 4 detects that the start button has been pressed in step 101, and moves to step 102. In step 102, the integrator 3
The time integral value of the output of the angular velocity sensor when the start pulse is input from After the rotation is complete, press the stop button 7. Note that the rotation speed (rotation angular velocity) does not have to be constant like a conventional rotary table.

When the stop button 7 is pressed, a stop pulse S2 is input from the input section 5 to the arithmetic unit 4.
When it is detected in step 3 that the stop button 7 has been pressed, the process moves to step 104, and in step 104, the time integral value y=fω2d t t2) of the output of the angular velocity sensor 1 is taken from the integrator 3 into the arithmetic unit ri4 and stored. FIG. 2 shows the relationship among the input pulse signal, angular velocity sensor output, and integrator output in these processes.

Subsequently, in step 105, the time integral value of the output of the angular velocity sensor 1 when the angular velocity sensor 1 is rotated by a predetermined angle at an appropriate speed is determined from z=/ω2dt−/ωtdt (31).

In the subsequent step 106, the scale factor SF is obtained as in equation (4) by dividing the angular velocity integral value Z obtained in equation (3) by the number of threads determined from the integrator coefficient and the rotation angle.

S F = z / k (41 The above coefficient is determined as follows. First, 1 mV
The output of the integrator when the input of is applied for 1 second is measured and designated as S. Since the integral value of angular velocity is proportional to the angle, S is a scale factor of 1 [mV/(d e g/
s )] is equal to the integral value when the angular velocity sensor is rotated once. This S is multiplied by the rotation angle θ of the angular velocity sensor described above to obtain a coefficient. This value is equal to the integral value when an angular velocity sensor with a scale factor of 1 [mV/(deg/s)] is rotated by a predetermined angle of 0.

Based on the new scale factor obtained in this way, the yawing angle can be calibrated by adjusting the scale factor adjustment volume of the navigation system or by substituting the new scale factor into software processing for calculating the yawing angle.

In the above embodiment, the start pulse and stop pulse were input manually, but as shown in FIG. It is also possible to provide a detection means 9 for detecting a rotation start position and a rotation stop position, and use the signals from this detection means 9 as a start pulse and a stop pulse. In this way, simply by placing the angular velocity sensor on the rotary table 8 and rotating the rotary table 8 by a predetermined angle, a start pulse and a stop pulse are automatically generated, making it possible to measure the scale factor more easily.

Note that if the scale factor measuring device according to the present invention is built into a navigation system or other equipment that uses an angular velocity sensor, maintenance of the angular velocity sensor can be performed without using an external measuring device.

[Effects of the Invention] As explained above, according to the scale factor measuring device according to the present invention, the scale factor can be easily measured by simply rotating the angular velocity sensor by a predetermined angle at an appropriate speed, compared to conventional measuring devices. I can do it. Further, since the scale factor measuring device according to the present invention does not require a large and expensive rotary table unlike the conventional ones, service personnel and users can easily measure the scale factor.

Further, by incorporating the scale factor measuring device according to the present invention into a device such as a navigation system, it is possible to easily calibrate the scale factor on the spot where the device is being used.

[Brief explanation of drawings]

FIG. 1 is a block diagram of the scale factor measuring device according to the present invention, FIG. 2 is a relationship diagram of the input pulse signal, angular velocity sensor output signal, and integrator output, and FIG. 3 is a diagram showing the operation of the scale factor measuring device according to the present invention. Flowchart, 4th
The figure is a block diagram of another embodiment according to the present invention.

Claims (2)

[Claims] (1) It has an integrator that integrates the output of the angular velocity sensor, and an arithmetic device that inputs the integral value of the integrator and calculates a scale factor of the angular velocity sensor, and rotates the angular velocity sensor by a predetermined angle. A scale factor measuring device characterized by having a configuration for calculating a scale factor of an angular velocity sensor. (2) The arithmetic device calculates the output of the integrator when the integrator is rotated by a predetermined angle using a coefficient k obtained by multiplying the output per unit time when a constant voltage is applied to the integrator by the rotation angle of the angular velocity sensor. 2. The scale factor measuring device according to claim 1, wherein the scale factor of the angular velocity sensor is calculated by dividing the scale factor of the angular velocity sensor.