JPH0329697Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a gyro calibration device that can be applied to a gyro used to realize a guidance system for mobile robots such as automatic guided vehicles and unmanned forks.

[Conventional technology]

For example, an inertial guidance method is one of the guidance methods for mobile robots such as automatic guided vehicles. This allows the mobile robot to determine its own position, without installing guiding media such as electric wires or reflective tape on the running course.
This method measures the direction (attitude angle) from moment to moment, and steers and moves the robot to follow a course that is stored in advance by the mobile robot's control device.

A gyroscope is essential to realize this method. There are various types of gyroscopes, such as mechanical gyroscopes that use gimbals and rotors, rate gyroscopes, and gas rate gyroscopes that use He gas flow and hot wire anemometers, but here we will standardize on gas rate gyroscopes.

In the case of the inertial guidance method, the accuracy of detecting its own position and direction depends largely on the accuracy of this gyro.
In particular, gas rate gyroscopes have poor temperature stability and temporal stability. Therefore, it is necessary to calibrate the gyro from time to time to maintain a certain level of accuracy. In other words, in the case of a gas rate gyro, an output voltage proportional to the angular velocity of the gas rate gyro body applied to it is obtained, but the value of the conversion coefficient (hereinafter referred to as a scale factor) between the angular velocity and the output voltage varies depending on the temperature and the output voltage. Change over time. This value is used when calculating the robot's position and direction, but if it changes significantly from the value stored in advance in the control device, errors will accumulate, so in order to minimize the change, it is necessary to wait for a certain period of time. It is necessary to calibrate the scale factor every time.

[Problem that the invention attempts to solve]

However, this calibration, or measurement of scale factors, requires rotating the gas rate gyroscope.
Currently, the gas rate gyroscope output is integrated while the mobile robot is turned by an appropriate angle, and the scale factor is calibrated from the resulting value and the turning angle. However, the angle at which the robot body has turned needs to be measured externally by some method, and currently we have no choice but to rely on humans. Furthermore, if an attempt is made to improve the accuracy of the gyroscope, it may become necessary to perform this calibration every hour, which is extremely inconvenient and poses the problem of not being able to fully utilize the original capabilities of the mobile robot.

The object of the present invention is to eliminate such problems and provide a gyro calibration device that can automatically calibrate the scale factor of a gas rate gyro.

[Means for solving problems]

The gyro calibration device according to the present invention includes a gas rate gyro installed on a turntable, an A/D converter that inputs the output voltage of the gas rate gyro and digitizes it, and an output signal of the A/D converter. a mobile robot controller that calculates the trajectory of the mobile robot by inputting the rotation angle of the gas rate gyroscope; and means that controls the rotation of the turntable by being controlled by an output signal output from the mobile robot controller. It is characterized by comprising the following.

[Effect]

According to the present invention, by providing a turntable in the mobile robot that rotates only the gas rate gyro and a mechanism that accurately detects the rotation angle, the gas rate gyro can be calibrated by rotating the robot body. The above-mentioned problems of the conventional art can be solved by making it possible to perform the process automatically and without having to do so.

〔Example〕

An embodiment of the present invention will be described in detail based on the drawings.

FIG. 1 is a block diagram showing the configuration of an embodiment of the present invention, FIG. 2 is a diagram showing changes in the output voltage of the gas rate gyroscope in FIG. 1, and FIGS. 3A and B are turn diagrams in FIG. FIG. 3A is a plan view and FIG. 3B is a side view of a specific example of the table.

In Figs. 1 to 3 A and B, 1 is a gas rate gyroscope, 2 is an A/D converter, 3 is a mobile robot controller, 4 is a turntable, 5 is a motor driver, 6 is a rotating table, and 7 is a Stepping motor, 8 is a coupling, 9 is a solenoid,
Normally, the output voltage of gas rate gyro 1 is A/D.
The converter 2 digitizes the data and sends it to the mobile robot controller 3, where it is integrated (added).
Then, the rotation angle θ is determined and the trajectory of the mobile robot is calculated (in this case, the turntable 4 and the gyro 1 are stationary with respect to the robot body). Then when calibrating,
A pulse is output from the mobile robot control device 3 to the motor driver 5 so as to keep the robot stationary and rotate the turntable 4 by a certain angle. That is, since the stepping motor 7 for driving the turntable 4 rotates by an angle proportional to the number of applied pulses, the rotation angle of the turntable 4 can be controlled. Since the turntable 4 and the gyro 1 rotate coaxially, the rotation is transmitted to the gyro 1.

In one embodiment of the present invention described above, the gas rate gyro output power υ _(V) is for an angular velocity of 1°/sec.
A voltage of F _(V) is generated. The A/D converter 2 digitizes the voltage while sampling it at a certain set time Δt. The mobile robot control device 3 adds N pieces of this digital data to determine the rotation angle θ.

θ=1/F _N 〓 ・υ・Δt (deg) (1) Here, E (V/1°/sec) is the scale factor, and if this value is inaccurate, the rotation angle θ can be calculated from equation (1). This will result in an error of Therefore, the accurate value of F is determined and the gyro is calibrated as follows.

First, the turntable 4 is rotated by an angle. If the turntable 4 is rotated by the stepping motor 7, the mobile robot control device 3 may calculate in advance how many pulses the angle corresponds to. Also, when calibrating this angle,
The number of pulses can be memorized in advance since it can always be the same value. In this way, turntable 4
When rotates by an angle, the output of the gas rate gyro 1 changes accordingly as shown in FIG.
This is A/D converted by the A/D converter 2 every Δt, and added by the mobile robot control device 3 until the rotation stops. The start and end of this rotation may be synchronized with the first and last timings of pulses sent from the mobile robot control device 3 to the motor driver 5. The added result corresponds to _N 〓 ・υ・Δt in equation (1),
The rotation angle of the turntable 4 corresponds to θ.
Therefore, the scale factor F can be calculated from these values.

Therefore, next time in the normal mode, the momentary position direction of the mobile robot can be calculated using equation (1) using the scale factor F obtained in the previous calibration mode.

Next, the details of a specific example of the turntable 4 will be explained with reference to FIGS. 3A and 3B. The gas rate gyroscope 1 is mounted on the rotary table 6, and the center thereof and the shaft of the stepping motor 7 are connected via the coupling 8. Connecting. The stepping motor 7 is fixed at a suitable location on the mobile robot.

Since the electric wire supply cable and the output cable are respectively connected to the gas rate gyroscope 1, it is necessary to keep the rotation angle within a range of approximately ±90°.
However, this limitation does not pose any problem when calibrating the gyro, and it is sufficient to limit the rotation of the turntable 4 to ±90°. (In other words, the rotation angle should be set to ±90° or less). Also, as a calibration method, if you calculate the value of the scale factor for clockwise rotation by rotating 90 degrees, and then calculate the value of the scale factor for counterclockwise rotation by rotating 90 degrees in the opposite direction, the position of gas rate dial 1 can be determined. is always in the same position except during calibration, eliminating the need to put strain on the cable.

Further, as shown in FIGS. 3A and 3B, in the normal mode, the rotary table 6 is fixed by a claw protruding from the solenoid 9. When calibrating the gyroscope, a solenoid 9 is energized from the mobile robot control device 3, and the protruding pawl is retracted so that the rotary table 6 can rotate freely.

In addition, a servo motor and a rotary encoder are provided in place of the stepping motor 7 in the embodiment of the present invention, and instead of determining the rotation angle by the number of pulses, the rotation angle is detected by the rotary encoder, and the value is fed back to the servo motor. However, it is also possible to rotate by an angle equal to the set angle.

According to the present invention, the calibration accuracy of the gas rate gyro 1 is determined by the rotation angle detection accuracy of the turntable 4. For example, if the stepping motor 7 is used, the scale factor can be determined with an accuracy of about 0.1° for a rotation of 90°. F can be calibrated.

[Effect of idea]

As described above, according to the present invention, by providing a rotation mechanism for only the gas rate gyro, the scale factor of the gas rate gyro can be calibrated automatically and in a short time without rotating the mobile robot body. It can be done. Furthermore, this calibration can be used to perform self-diagnosis of the gas rate gyro, resulting in excellent effects such as improved reliability.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the configuration of an embodiment of the present invention, FIG. 2 is a diagram showing changes in the output voltage of the gas rate gyroscope in FIG. 1, and FIGS. 3A and B are turn diagrams in FIG. FIG. 3A is a plan view and FIG. 3B is a side view of a specific example of the table. 1... Gas rate dial, 2... A/D converter, 3... Mobile robot control device, 4... Turntable, 5... Motor driver.

Claims (1)

[Scope of utility model registration request] A gas rate gyro installed on a turntable, an A/D converter that inputs the output voltage of this gas rate gyro and digitizes it,
A mobile robot controller inputs the output signal of this A/D converter and calculates the rotation angle of the gas rate gyroscope to calculate the trajectory of the mobile robot. A gyro calibration device comprising means for controlling rotation of a turntable.