JPH06149355A - Body bearing detector - Google Patents

Abstract

PURPOSE:To prevent the precision of a bearing detection with a geomagnetic direction sensor provided on a body from being deteriorated due to the change of the loading state of a metallic load. CONSTITUTION:A geomagnetic direction sensor 13 which detects a direction based on a geomagnetism is provided on the body, and this device is equipped with a processing means 5c which searches the direction of the body based on the detected value of the geomagnetic direction sensor 13, and a stoppage detecting means 5d which detects whether or not a rotary wheel which is rotated while being brought into contact with a ground according to the traveling of the body is stopped. Then, when the detected value of the geomagnetic direction sensor 13 is changed while the rotary wheel is stopped, the processing means 5c stores the changing amount as a correction value, and corrects the detected value of the geomagnetic dierection sensor 13 by the correction value. Also, the device is equipped with a rotary wheel rotating amount detecting means 12 which detects the rotating amount of the rotary wheel, and measures the traveling distance of the body, and the stoppage detecting means 5d detects whether or not the rotary wheel is stopped based on the detected information of the rotary wheel rotating amount detecting means 12.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is provided with a geomagnetic direction sensor for detecting a direction based on the geomagnetism, and a processing means for determining the direction of the vehicle body based on the detected value of the geomagnetic direction sensor. The present invention relates to a vehicle body direction detection device.

[0002]

2. Description of the Related Art As one of means for detecting the orientation of a vehicle body such as a work vehicle or a transport vehicle outdoors, there is one using a geomagnetic orientation sensor. This geomagnetic direction sensor
The azimuth is obtained from the ratio by separately detecting the longitudinal component of the vehicle body and the orthogonal component thereof in a plane parallel to the ground. Therefore, if there is an external magnetic field other than the earth's magnetic field in the vicinity, it is easily affected, and even if an object having a high magnetic permeability such as a metal approaches, the detected value fluctuates and the direction detection accuracy deteriorates.

Therefore, conventionally, when attaching the geomagnetic direction sensor to the vehicle body, it has been devised to keep it away from the metal frame as much as possible, and to shield the motor when a motor or the like which generates magnetism is present nearby. . or,
The offset of the detection value of the geomagnetic direction sensor is corrected while it is actually attached to the vehicle body.

[0004]

However, for example, when a geomagnetic direction sensor is attached to a golf cart to detect the direction, even if the offset correction described above is carried out without the club being loaded, the direction of the club can be increased by stacking the club. It was found that the accuracy of detection deteriorates. This is because the club adversely affects the geomagnetism applied to the geomagnetic direction sensor. Such a problem can generally occur not only in the golf cart but also in the direction detection of a small-sized carrier for loading and unloading metal luggage.

The present invention has been made in view of the above circumstances, and an object thereof is to prevent deterioration of the direction detection accuracy by the geomagnetic direction sensor when the loading state of metal luggage changes as described above. To do.

[0006]

In a vehicle body direction detecting device according to the present invention, a geomagnetic direction sensor for detecting the direction based on the geomagnetism is attached to the vehicle body, and the direction of the vehicle body is detected based on the detection value of the geomagnetic direction sensor. A vehicle body direction detection apparatus provided with a processing unit for obtaining the first characteristic configuration, wherein the first characteristic configuration determines whether or not a rolling wheel rolling on the vehicle body while being in contact with the ground as the vehicle body travels is stopped. Stop detection means for detecting is provided, and when the detection value of the geomagnetic direction sensor changes in the stopped state of the rolling wheels, the processing means stores the changed amount as a correction value, and the geomagnetic direction sensor thereafter. It is configured so that the detected value of 1 is corrected by the correction value.

The second characteristic configuration specifies a preferable specific configuration for implementing the first characteristic configuration, and detects the rotation amount of the rolling wheels in order to measure the traveling distance of the vehicle body. Rolling wheel rotation amount detection means is provided, the stop detection means, based on the detection information of the rolling wheel rotation amount detection means,
It is configured to determine whether or not the wheel is stopped.

[0008]

In the first and second characteristic configurations, the rolling wheels that roll while being in contact with the ground as the vehicle body travels may be driving wheels for driving or driven wheels, and are provided separately from them. It may be a wheel for measuring the traveled distance. If the wheels are stopped, the vehicle body is stationary and the detected value of the geomagnetic direction sensor should not change normally.

However, as in the case of loading and unloading golf clubs in a golf cart, the magnetic field around the geomagnetic direction sensor may change due to changes in the loading state of metal luggage, and its output may change subtly. . In this case, according to the first characteristic configuration, the processing unit stores the change amount as a correction value, and corrects the subsequent detection value of the geomagnetic direction sensor by the correction value.

Further, in detecting the position of the vehicle body, it is necessary to detect the direction of movement of the vehicle body (distance traveled) as well as to detect the direction by a geomagnetic direction sensor. A rotation amount detecting means is often provided. Therefore, according to the second characteristic configuration, the stop detection unit determines whether or not the wheel is stopped based on the detection information of the wheel rotation amount detection unit.

[0011]

As described above, when there is a state change such as the loading and unloading of a golf club which gives a change in the magnetic field around the geomagnetic direction sensor when the vehicle body is stationary, the processing means causes the geomagnetic direction to follow the state change. Since the change amount of the detection value of the sensor is stored as a correction value and the subsequent detection value of the geomagnetic direction sensor is corrected by the correction value, the deterioration of the detection accuracy due to the change of the state can be prevented.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the present invention is applied to position detection of a golf cart will be described below with reference to the drawings. Figure 2
As shown in FIG. 1, the golf cart of the present embodiment (hereinafter referred to as a cart) is configured by attaching a steering handle 3, a club case 4, etc. to a three-wheel vehicle body including a pair of rear wheels 1 and front wheels 2. ing. The rear wheel 1 is a traveling wheel and is rotationally driven by a traveling motor. The front wheels 2 are idle wheels,
A steering wheel whose steering angle is changed by a steering motor.
Both motors are driven by the electric power of the battery installed in the cart.

The handle 3 is for operating the cart for running, stopping and the like. By rotating the grip 3a around the left and right axis P, it is possible to switch between forward, reverse and neutral. Further, with respect to forward movement, it is possible to switch between low speed traveling and high speed traveling. Each switching position is
Rotary switch 3 provided on the left side of the grip 3a
detected by b.

When the grip 3a is turned around the longitudinal axis Q, the steering motor changes the steering angle of the steering wheel 2. For example, if you turn the grip 3a clockwise when moving forward, the cart will turn right,
Turn counterclockwise and the cart will turn left. Also, the radius of gyration changes depending on the turning angle. In other words, a small turn will make a gentle curve, and a large turn will make a sharp curve.
The rotation direction and the rotation angle are detected by the potentiometer 3c. The grip 3a is urged to return to its original state (straightening state) when the hand holding the grip 3a is loosened.

The above-mentioned traveling / steering control is controlled by the controller 5 which is composed of a microcomputer mounted on the cart and its peripheral circuits. As shown in FIG. 1, the signals from the rotary switch 3b and the potentiometer 3c are input to the controller 5. Based on these signals, the controller 5 controls driving of the traveling motor 6 and the steering motor 7 via the motor drive circuits 6a and 7a, thereby performing traveling / steering control of the cart. A push-button type power switch 3d for instructing start and stop of the electric system by opening and closing a power supply circuit from the battery to the controller 5 and the like is provided on the right side of the grip 3a.

As shown in FIG. 2, L is provided in front of the handle 3.
A display device 8 including a CD module or the like is attached. This is mainly for displaying the hole information such as the shape of the hole for the convenience of the player. The display device 8 includes a graphic display 8a and a touch panel 8b for performing screen switching input, score input, and the like. Graphic display 8a consisting of LCD
A touch panel 8b made of a transparent electrode is superposed on the above, and both are integrated.

The graphic display 8a provides a display as shown in FIG. 3, for example. In the figure, a schematic diagram of the entire hole is displayed graphically in 9 and the current position of the cart obtained as described below is displayed in a mark as shown in 9a, and a message such as one-point advice is displayed in 10 To be done. In 11, the approximate distance to the pin calculated as described later is displayed.

On the right side of the screen, the effective key functions of the touch panel are displayed. For example, if the "next shot" is pressed, an enlarged view from the second hitting point to the green is displayed at 9. If you press "Enter score", the screen will change to the score entry screen, including the display of valid keys. "SO at the bottom right of the screen
“S” is a key for making an emergency call to the clubhouse by a communication function provided in the cart when some trouble occurs.

As shown in FIG. 1, the display device 8 is provided with a microprocessor 8d for executing screen control and key input processing and a removable memory card 8e. Display data for each hole of one golf course is stored in one memory card 8e. That is, a plurality of display data such as display data for the entire hole, zoom display data from the second shot point to the green, and zoom display data around the green are stored for each hole.

The score entry data is stored in the memory card 8e.
Written in. After the play is completed, the memory card 8e is removed from the display device 8 and connected to the computer installed in the club house. Then, the score entry data is read and aggregated. In addition, writing or changing the display data of the hall information is also performed by connecting to the computer of the club house.

The display data for each hole is switched by the microprocessor 8d based on the switching input from the touch panel 8b. The display within one hall can be switched by input from the touch panel 8b, but the microprocessor 8d automatically executes it based on the current position of the cart obtained as described below. In other words, for example, if you move the cart near the position of the second shot after finishing the tee shot,
Automatically switch from a schematic view of the entire hole to an enlarged view from the second shot to the green.

The cart is provided with a rotary encoder 12 for detecting the traveling distance and a geomagnetic direction sensor 13 for detecting the direction (direction) of the vehicle body, and output signals of these are input to the controller 5. (See FIG. 1). The rotary encoder 12 corresponds to a rolling wheel rotation amount detection unit that detects a rotation amount of the traveling wheel 1 that is a rolling wheel that rolls in contact with the ground, and has a pulse number proportional to the rotation amount (rotational speed) of the traveling wheel 1. The signal of is output. Then, the distance counter 5a provided in the controller 5 integrates the number of pulses to obtain a value corresponding to the traveling distance.

The geomagnetic direction sensor 13 separately detects a vehicle front-rear direction (Y direction) component and a perpendicular direction (X direction) component of the geomagnetism on a plane parallel to the ground, and detects the direction of the vehicle body from the ratio. And is configured as shown in FIG. High magnetic permeability toroidal core 14
It is a flux-gate type in which an exciting coil 15 is wound around and a pair of output coils 16 and 17 wound in the diametrical directions orthogonal to each other are provided from above, and the axis P is in the vertical direction. Attached to.

When an object having a high magnetic permeability such as metal approaches the geomagnetic direction sensor 13, it becomes impossible to accurately detect the X-direction component and the Y-direction component of the geomagnetism. Also, if there is a magnetism generating object in the vicinity, it is easily affected. Therefore, as shown in FIG.
In order to keep away from the metal frame as much as possible, a resin case 13b supported by a column 13a made of a non-magnetic material is provided in the front part of the cart, and the geomagnetic direction sensor 13 is housed in this case. Further, the steering motor 7 arranged above the front wheels 2 is housed in the shield case 7b.

As shown in FIG. 4, the geomagnetic direction sensor 13
An alternating current having a sufficiently large amplitude is supplied from the oscillator 18 to the exciting coil 15 via the driver 19. As a result, in the toroidal core 14, an alternating magnetic field having a positive / negative symmetrical waveform in which the peaks and valleys of the sine wave are clamped due to the saturation characteristic is generated. Therefore, no voltage is induced in the output coils 16 and 17. This is because the electromotive force generated on each end side of each output coil in the diametrical direction of the toroidal core 14 has the opposite direction and the same magnitude.

However, for example, when an external DC magnetic field (geomagnetism) is applied to the output coil 16 from a direction (X direction) at right angles,
The balance of the magnitude of electromotive force generated at both ends of the output coil 16 is lost. If the direction of the AC magnetic field by the exciting coil 15 and the direction of the earth's magnetism match at one end side, the direction becomes opposite at the other end side, so the clamp amount of the electromotive force due to the saturation characteristic of the toroidal core 14 becomes large at the one end side, and This is because the clamp amount becomes smaller on the side. As a result, an AC voltage is induced in the output coil 16.

On the other hand, since no influence of the earth magnetism appears on the output coil 17 provided in the direction perpendicular to the output coil 16, no voltage is induced. When the geomagnetism is applied to the output coil 17 from the direction perpendicular to the output coil (Y direction), an AC voltage is induced in the output coil 17 and no voltage is induced in the output coil 16, contrary to the above. Generally, when the geomagnetism H is applied from an arbitrary direction forming an azimuth angle θ with the output coil 16, the orthogonal components H _X and H _{Y with} respect to the output coils 16 and 17 are H _X = H sin θ and H _Y = H cos θ. An AC voltage proportional to H _X and H _Y is induced in 16 and 17. The induced AC voltage is extracted as DC voltages Vx and Vy through the respective filter amplifiers 20 and detectors 21.

Output voltages Vx, V of the geomagnetic direction sensor 13
y is input to the controller 5 as shown in FIG.
It is sampled by the A / D converter 5b in the controller 5 and converted into a digital value. In the following description, the values converted into digital values are detected values Vx and Vy.
Say. Then, the processing means 5c in the controller 5
The orientation of the vehicle body is obtained based on the detected values Vx and Vy of the geomagnetic orientation sensor 13.

As described above, the strengths of the X-direction component and the Y-direction component of the geomagnetism change according to the azimuth of the vehicle body, so the detected values Vx, V when the azimuth θ of the vehicle body is changed by 360 degrees.
As shown in FIG. 5A, the change of y draws a circle centered on the offset voltages (hereinafter, referred to as offset values) Vx ₀ and Vy ₀ . Therefore, the azimuth angle θ of the vehicle body can be obtained from the following equation. θ = tan ⁻¹ ((Vy−Vy ₀ ) / (Vx−Vx ₀ ))

The offset values Vx ₀ and Vy ₀ are generated by the influence of the vehicle body frame or the like when the geomagnetic direction sensor 13 is attached to the cart, and are obtained as follows. That is, when the cart is stopped at the time of start-up (after stabilization), the motor M shown in FIG. 4 is rotationally driven to drive the main body (core 14, coils 15, 16, 1) of the geomagnetic direction sensor 13.
7) is rotated 360 degrees around the axis P together with the bracket B. Then, the detection values Vx and Vy are detected for each predetermined angle detected by the potentiometer PM, and the average value of each of them is obtained and set as the offset values Vx ₀ and Vy ₀ .

However, even if the above offset correction is performed,
The offset voltage changes as the clubs are loaded and unloaded. For example, as shown in FIG. 5B, assuming that the offset values Vx ₀ and Vy ₀ in the state where the clubs are not loaded are obtained, when the clubs are loaded, the offset values are (Vx ₀ + Vx ₁ , Vy Assuming that ₀ + Vy ₁ ), the _{equation for} obtaining the azimuth angle θ of the vehicle body at this time is as follows. θ = tan ⁻¹ ((Vy−Vy ₀ −Vy ₁ ) / (Vx−Vx ₀ −Vy ₁ ))

That is, since the offset value changes as the clubs are loaded and unloaded, the accuracy of detecting the azimuth angle θ of the vehicle body deteriorates. In order to prevent this, the processing means 5c
When the detected values Vx and Vy change while the cart is stopped, it is determined that the club has been unloaded, and the changes ΔVx and ΔVy are stored as correction values, and the detected values Vx and Vy after that are stored as correction values ΔVx. , ΔVy. That is, the sum of the correction values ΔVx and ΔVy corresponds to Vx ₁ and Vy ₁ in the above equation.

Whether the cart is stopped or not depends on the traveling wheel 1
Is determined by whether or not is stopped. That is, the stop detection means 5d in the controller 5 is based on the detection information of the rotary encoder, in other words, the distance counter 5
It is determined based on whether or not the value of a has changed. The above distance counter 5a, processing means 5c, stop detection means 5d
Etc. are actually constituted by the program of the microcomputer of the controller 5. The position calculation processing executed by the microcomputer including these means will be described below with reference to the flowchart of FIG.

FIG. 6 shows the current value (X, K) of the cart with respect to a reference point (for example, a tee shot point) in the hole.
The position calculation processing for calculating Y) is shown. First, in the process (a), it is checked whether or not the distance counter 5a has changed. Specifically, the value of the distance counter 5a is temporarily stored, and the previous value and the current value are compared. If there is a change, the process moves to (B) and thereafter such as calculation of the azimuth of the vehicle body. If there is no change, the process moves to (C) and subsequent processes for obtaining the correction value. Thirteen
It is checked whether the detected values Vx and Vy of No. have changed.

That is, when the distance counter 5a does not change, the cart is stopped, so normally the detected values Vx and Vy of the geomagnetic direction sensor 13 should not change.
If a change still occurs, it is determined that there is a load / unload change of the club as described above, and the changes ΔVx and ΔVy are calculated and stored as correction values (process (d)). Specifically, the detected values Vx and Vy are temporarily stored, and the previous value and the current value are compared. However, FIG.
Although omitted, the changed value is valid when it becomes stable for a predetermined time (predetermined number of times). Further, in reality, Vx ₁ and Vy ₁ obtained by integrating the correction values ΔVx and ΔVy are effective correction values. (Processing (e)).

In the process (b), the distance counter 5a
It is checked whether or not the change of the value of has reached the change corresponding to the predetermined distance L (for example, 1 m), and if it has reached, the processing from (f) onward is executed, and if it has not reached, the process returns to the original routine. That is, the processing after (f) is executed for each predetermined distance L.

Detected value V read in the process (f)
Offset value V obtained as described above from x and Vy
x₀, Vy₀And the correction value V obtained in processing (d) and (e)
x₁, Vy₁Is reduced and the ratio (Vy-Vy₀-V
y₁) / (Vx-Vx₀-Vx ₁) To the azimuth angle θ of the vehicle body
Is calculated (processing (g)). The above calculation is the detected value V
First, the correction value Vx is calculated from x and Vy.₁, Vy₁Subtract (correct
), And the offset value Vx₀, Vy₀To reduce
In other words, the ratio of can be obtained.

Once the azimuth angle θ is obtained, the movement amount Δ in the X direction and the movement amount Δ in the Y direction based on the predetermined distance L and the azimuth angle θ.
Y is calculated (process (h)). These movement amounts ΔX, Δ
The present position (X, Y) of the cart with respect to the reference point (0, 0) is obtained by accumulating Y separately (processing (ri)).

Once the current position (X, Y) is obtained, the distance from the current position (X, Y) to the pin position (X0, Y0) is further obtained. The current position and the distance to the pin thus obtained are given to the display device 8 and displayed as described above. The pin position (X0, Y0) is included in the hole information stored in the memory card 8e, and the controller 5 resets the current position (X, Y) when the hole is changed and the pin position. (X0, Y0) is obtained from the display device 8.

Other examples will be listed below. In the above-described embodiment, the rotation amount of the traveling wheel 1 is measured to measure the traveling distance, and the target to detect whether or not the traveling wheel 1 is stopped to correct the detected value of the geomagnetic direction sensor is used. , The steering wheel 2 may be the above target,
Alternatively, a dedicated wheel to be the target may be attached to the cart separately. Further, it is not always necessary to detect the rotation amount for measuring the traveling distance and the detection of whether or not the vehicle is stopped for the calibration of the reference value by using the same wheels (wheels).

The present invention is not limited to the one using the fluxgate type geomagnetic direction sensor as in the above-mentioned embodiment, but can be widely applied to those using various known geomagnetic direction sensors such as magnetic needles.

Further, the present invention is not limited to the golf cart as in the above embodiment, but can be applied to an unmanned work vehicle such as a lawn mower.

It should be noted that reference numerals are given in the claims for convenience of comparison with the drawings, but the present invention is not limited to the configurations of the accompanying drawings by the entry.

[Brief description of drawings]

FIG. 1 is a control block diagram of a golf cart with a vehicle body direction detection device according to an embodiment of the present invention.

FIG. 2 is a perspective view of a golf cart.

FIG. 3 is a diagram showing an example of displaying hall information on a display device.

FIG. 4 is a diagram showing a configuration of a geomagnetic direction sensor.

FIG. 5 is a diagram showing detection values and correction values of the geomagnetic direction sensor.

FIG. 6 is a flowchart of position calculation processing.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 wheel 5c processing means 5d stop detection means 12 wheel rotation amount detection means 13 geomagnetic direction sensor

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification number Reference number within the agency FI Technical indication location G01V 3/10 7256-2G (72) Inventor Nobumi Yamanaka No. 64 Ishizukitamachi, Sakai City, Osaka Prefecture Co., Ltd. Inside the Kubota Sakai Plant (72) Inventor, Yukio Yokoyama 64, Ishizukita-machi, Sakai City, Osaka Prefecture Inside the Kubota Sakai Plant

Claims (2)

[Claims] 1. A geomagnetic direction sensor (13) for detecting a direction based on geomagnetism is attached to a vehicle body, and a processing means (5c) for obtaining the direction of the vehicle body based on a detection value of the geomagnetic direction sensor (13). A vehicle body azimuth detecting device provided, wherein stop detection means (5d) detects whether or not a rolling wheel (1) rolling on the vehicle body while being in contact with the ground as the vehicle travels is stopped. And the processing means (5c)
However, when the detected value of the geomagnetic direction sensor (13) changes in the stopped state of the wheel (1), the changed value is stored as a correction value, and the detected value of the geomagnetic direction sensor (13) thereafter. The vehicle body azimuth detecting device configured to correct the value according to the correction value. 2. Rolling wheel rotation amount detecting means (1) for detecting a rotation amount of the rolling wheel (1) in order to measure a traveling distance of a vehicle body.
2) is provided so that the stop detection means (5d) determines whether or not the wheel (1) is stopped based on the detection information of the wheel rotation amount detection means (12). The vehicle body azimuth detecting device according to claim 1, which is configured.