JPH04204006A - Apparatus for detecting position of moving body - Google Patents

Abstract

PURPOSE:To prevent the deterioration of the measuring accuracy of the position of a vehicle body resulting from the change of the running condition and to control the position with high accuracy by detecting the diameter of ground contact of the right and left wheels and operating the running position by using the diameter of ground contact. CONSTITUTION:The effective diameter of the right and left tyres is obtained by right and left sensors 70 and a diameter operating means 62A contained in a CPU 62. The running distance of each of the right and left wheels 12a, 12b is obtained from the effective diameter. At the same time, the slight directional change is detected by a sensor 84 and a position operating means 62B which operates the position where the tyre is in contact with the ground. The CPU 62 runs the vehicle along a planning route while correcting the running direction and the position of the vehicle based on the operating result.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a position detection device for a moving body that determines the running position by separately detecting the rotational speed of left and right wheels.

(Prior art) In mobile objects such as golf carts and on-site transportation vehicles, it is considered that the moving object measures the rotational speed of the left and right wheels separately, determines the running position by sequential calculation, and follows the planned running route. ing.

In such a moving body, there is a limit to position detection accuracy because the tires of the wheels deform due to changes in road conditions such as inclination angle, and driving conditions such as acceleration/deceleration and cornering.

(Problem to be Solved by the Invention) The problem to be solved by the present invention is to ensure that position detection accuracy does not decrease even if the left and right wheels are deformed, and that highly accurate position detection is always possible. .

(Means for Solving the Problem) According to the present invention, this problem is solved by detecting the diameter of the ground contact diameter of the left and right wheels in a moving body that determines the running position by separately detecting the rotational speed of the left and right wheels. This is achieved by a position detecting device for a moving body, characterized by comprising: a means for detecting the position of a moving body; and a calculation means for determining the running position using the determined ground contact diameter.

Furthermore, instead of determining the ground contact diameter described above, the tread may be detected. That is, this can also be achieved by a position detection device for a moving body characterized by comprising a ground contact position detection means for detecting the ground contact positions of the left and right wheels, and an arithmetic means for calculating the running position using the tread determined from the ground contact positions. The purpose is achieved.

(Example) Fig. 1 is a control system diagram of a golf cart which is an embodiment of the present invention, Fig. 2 is a side view of this golf cart, and Fig. 3A, 3
B, Figure 30 is a principle diagram of the ground diameter detection means, 4A, 4B,
FIG. 4C is a diagram explaining the principle of the grounding position detection means.

In this embodiment, the position of the golf cart is determined from the rotation distance of the wheels, and the exact position is corrected as appropriate. That is, the angles between the golf cart and the reflector, whose three positions are known, are detected, and the position is corrected based on changes in travel distance and travel direction.

In FIG. 2, reference numeral 10 indicates a vehicle body frame, 12 (12a
, 12b) are a pair of left and right rear wheels, and 14 is one steering front wheel. The vehicle body frame 10 has an upper frame 10a that stands up from between the rear wheels 12 and whose upper end extends horizontally forward. The rotation of the electric drive motor 16 connects the rear wheel 12 to the chain 1.
8.20, transmitted via the differential 22. The amount of rotation of the left and right rear wheels 12a, 12b is determined by a pair of left and right encoders 24.
(24a, 24b) are detected separately. front wheel 1
4 is attached to the lower end of the steering shaft 28 held in the steering shaft cylinder 26. A clutch 30 is attached to the upper end of this steering shaft 28.
The steering motor 32 is connected via the link 3.
4 allows the rotation of the handle shaft 36 to be transmitted. That is, the front wheels 14 are steered by either the motor 32 or the handlebar 38 by engaging and disengaging the clutch 3o.

4o is a controller, which has a circuit for controlling the electric power of each of the motors 16 and 32 for driving and steering, an interface, and the like. 42 is a lead-acid battery mounted at the bottom near the center of the vehicle body.

A step 46 is provided protruding from the rear of the vehicle body frame 10 so that the driver can stand on it. The driver stands at this step 46 as necessary and presses the input device 48 and main switch 5.
0. The handle 38 etc. can be operated.

52 (52a, b) is a laser projector/receiver, which is attached to the front end of the upper frame 10a. These light emitters and receivers 52 main scan the laser in an almost vertical direction using a polygonal mirror that rotates at high speed around a horizontal axis.
The entire image is rotated around a vertical axis and sub-scanned independently in the circumferential direction. The light emitter/receiver 52 is rotated in the sub-scanning direction by a motor, and this rotation angle is detected by an encoder. Further, a light-receiving element is attached to these light emitting/receiving devices 52 for detecting the emitted laser beam reflected by the flapper, and detects the laser beam being fixed at a predetermined position or the light reflected by the flapper and returning.

Next, the control device 60 will be explained. This device 60 includes a CPU 62 consisting of a digital computer, a semiconductor memory (storage device) 64, a pulse counter 66 (66a, 66b), and the like. The pulse counter 66 separately counts the pulses output by the encoder 24 as the left and right rear wheels 12 rotate. The count value of the counter 66 is the controller 40
CPU via an interface (not shown) provided in
62. In addition to the operating program of the CPU 62, the memory 64 stores data such as the coordinates of a glue flaper serving as a light reflecting means, a planned travel route, and the like.

The CPU 62 sequentially and repeatedly performs predetermined calculations according to a program stored in the memory 64. First, the CPU 62 sends a signal to the controller 40 to drive the steering motor 32 and the travel motor 16 according to the planned travel route stored in the memory 64 . As a result, the front wheels 14 are steered, the rear wheels 12 are driven, and the vehicle travels on its own approximately along the planned travel route.

The CPU 62 rotates the light projector/receiver 52 that detects the laser around a vertical axis while performing vertical main scanning, and detects the direction of the reflector by receiving the light reflected by the reflector. While the moving body is running, the two light emitters and receivers 52 continue to determine the direction of the lifter at three locations, and the position of the vehicle body is accurately determined by calculation from the relationship between the amount of travel and the direction of movement during this time.

This calculation method is disclosed in Japanese Patent Application Laid-Open No. 59-67476, Japanese Patent Application No. 63
315172, so the explanation will not be repeated.

In this manner, the vehicle body sequentially detects the direction of each reflector while traveling, and during that time, the vehicle travels along the planned travel route while detecting the travel direction and travel distance using the rotational speed of both rear wheels 12. For example, the left and right wheels 12a, 12
Let the travel distance of b be LL and LR, and the distance (tread) between both rear wheels 12 and a straight line passing through the center of gravity of the vehicle in the longitudinal direction be TL,
If TR, then the minute travel distance of the vehicle body Δ℃ and minute change in direction are Δg= (LL+LF+)/2 △θ” (LL Lll) / (TL +TR)
It is determined by While performing this calculation, the CPU 62 drives the steering motor 32 so that the vehicle body follows the travel route.

Here, the travel distances LL and L- of both wheels 12A and 12b are determined by N (rotation speed) x D (tire diameter) x π. However, this tire diameter changes depending on driving conditions. Furthermore, since the grounding point of the tire changes depending on the driving conditions, the treads TL and T8 also change. Therefore, the accuracy of Δθ and Δρ decreases.

Therefore, in the present invention, these are detected in real time and Δθ and Δθ are detected in real time.
This is to obtain β with high accuracy.

The diameter detection means for determining the effective diameter of the tire is formed by the sensor 70 (70A-C) shown in FIGS. 3A-C and the diameter calculation means 62A (FIG. 1), which is one of the functions of the CPU 62. .

The sensor 70A shown in FIG. 3A is formed by a distance sensor that measures the distance a from the back surface of the ground contact portion of the airless elastic tire 12A. Here, the sensor 70A is held on the frame 10 side so as to be directed from the inner diameter side of the rim 72 to the back surface of the tire ground contact area. The sensor 70A measures the distance to the back surface of the tire's ground contact area through a plurality of windows 74 that open along the circumference of the rim 72. In this case, the tire thickness is t, the distance from the rotation axis to the sensor 70A is i, and the inclination of the sensor 70A is α.
Then, the effective radius at the time of ground contact is D=2 (n+t+a
cos θ).

In the embodiment shown in FIG. 3B, the distance from the sensor 70B held on the frame 10 side to the protrusion 76 formed in an annular shape on the side portion of the tire 12B is determined.

Since the position of this protrusion 76 changes up and down corresponding to the amount of deformation of the tire 12B, the diameter calculation means 6
The effective radius can be determined using 2A.

In the embodiment shown in FIG. 3C, the optical fiber 78 is embedded in the crown portion of the tire 12C in the circumferential direction for n circumferences. Tire 12
A sensor 70C consisting of a light wave range finder is disposed on the axis of C, and a laser beam emitted from this sensor in the axial direction of the tire 12C is guided to one end of an optical fiber 78 by a prism 80 fixed to the tire 12C side. (The laser beam emitted from the other end of the optical fiber 78 is transmitted to the tire 12 by a prism 80.
It is reflected by the corner cube 82 fixed on the C side and returns to the sensor 70C following the outward path in the opposite direction. The sensor 70C determines the optical path length k from the phase change of this returned laser light. The diameter calculating means 62A calculates the effective diameter by: =2H+2 (nπ+1)D.

Tire 12 obtained by the above method or other appropriate method
The travel distance of the wheels 12a and 12b is calculated using the effective diameter of L.
, ,Lll are determined as described above.

Next, the tread T required to find the minute direction change Δθ
A grounding position detection means for detecting changes in L and T in real time will be explained. This means includes a sensor 84 shown in FIGS. 4A and 4B.
(84A, B) and a ground contact position calculation means 62B (FIG. 1), which is one function of the CPU 62.

The sensor 84A of the embodiment shown in FIG. 4A is connected to the tire 12D.
It is formed by a pair of short-range sensors 84Aa and 84Ab facing each other on both sides near the grounding part.

The distance χ from one sensor 84Aa to the grounding point is χ=(H-(I2.+J2a)'t/2+1
2°=(H(I2a 121))/2. Here, H is the distance between both sensors, I21 and β2
is the distance between each sensor and the side portion of the tire 12D.

In the embodiment shown in FIG. 4B, since it is considered that when turning, the inner wheel side of the tire 12E will be at a lower speed and the outer wheel side will be at a higher speed.
This detects the speed difference between both sides. That is, slits 86 or slit-like patterns are formed at equal intervals in the radial direction on both sides of the tire 12H, and the passing speeds of the slits 86 are detected separately. sensor 84 here
B includes a pair of laser light sources 88 facing each other on both sides near the ground contact part of the tire 12H, a polarizing prism 9.0, and a λ/
The laser beam emitted from the light source 88 passes through the prism 90 and the λ/4 plate and is guided to the slit 86, where the reflected light is
The light is further polarized at λ/4 and guided to a light receiving element 92 by a prism 90. Grounding position calculation means 62 of CPU 62
B is the slit detection frequency N, , N2 by each sensor
For example, χ = ((N-Nl) / (N2-N, ))
Find the ground contact position χ using XH. Here N is wheel 12
For example, a slit may be formed at the same period as the encoder 24 for determining the wheel rotation speed described above, and the frequency detected by this encoder 24 may be set to N.

Tread TL determined by these methods or other methods,
Using TR, minute changes in orientation Δθ can be detected with high precision.

The calculation means 62 uses these calculation results to correct the running direction and position of the vehicle while causing the vehicle to travel along the planned travel route.

In this embodiment, the position of the moving body is determined and corrected by using reflections from three lifters whose positions are known, but the present invention is also capable of correcting the position using other methods or correcting the position while moving. The correction may not be performed.

In addition, in the embodiment described above, not only the diameter of the wheel (but also changes in the tread are detected to determine minute changes in direction), so the detection of the traveling position becomes even more accurate. However, the present invention detects only the effective diameter of the wheel. Alternatively, the running position may be corrected by determining only the change in the tread.

In each of the above embodiments, the diameter or tread of the wheel 12 is directly detected by the sensors 70 and 84. However, the present invention may detect these indirectly. For example, it is possible to determine changes in pitching load on the vehicle body, detect changes in wheel load, determine changes in lateral load on the vehicle body, determine changes in load distribution between the left and right wheels from this, and use calculations to determine the diameter or tread. . Here, the change in pitching load can be determined by determining the load distribution in the longitudinal direction of the vehicle body, for example, using an inclinometer installed near the center of gravity of the vehicle. Further, the change in lateral load can be determined using a gyroscope provided above between the left and right wheels, an accelerometer provided at two locations on the left and right, or the like. Using the relationship between the load and tire effective diameter defined in advance in a table or calculation formula, the current correct tire contact diameter can be determined from the previously determined load applied to each wheel, and the contact diameter due to tire deformation can be determined. The treads TL and TFL can be similarly determined from the change in location.

Generally, when driving force or braking force is applied to the wheels 12, it is inevitable that slippage occurs between the wheels 12 and the road surface. This occurrence of slippage is undesirable because it causes a measurement error. Therefore, it is desirable to separate the drive wheel and the measurement wheel. For example, in the golf cart described above, position detection accuracy can be improved by providing a wheel motor or the like on the front wheel 14 and using this as a driving wheel, and using the left and right wheels 12 as measurement wheels.

(Effect of the invention) As described above, the invention as claimed in claim (1) detects the effective diameter of the left and right wheels and calculates the running position using this effective diameter, so it is possible to Even if the effective diameter of the wheel changes due to changes in various running conditions, such as changes in inclination or vehicle load, calculations can always be performed using accurate effective diameters. Therefore, highly accurate position control is possible without reducing the accuracy of detecting the position of the vehicle body due to changes in driving conditions.

According to the invention of claim (2), since the traveling position is corrected by detecting the change in the ground contact position of the wheel, the position control accuracy is improved. Note that in the present invention, the position may be determined while detecting both the effective diameter of the wheel and the ground contact position, and in this case, the accuracy is further improved.

[Brief explanation of the drawing]

Fig. 1 is a control system diagram of a golf cart according to an embodiment of the present invention, Fig. 2 is a side view of this golf cart, and Figs.
Figures B and 3C are principle diagrams of the ground diameter detection means, 4A and 4B,
FIG. 40 is a diagram explaining the principle of the grounding position detection means. , 12...Wheel, 62...CPU. 62A...diameter calculation means, 62B...ground contact position calculation means, 70...sensor of diameter detection means, 84...sensor of ground contact position detection means, D...tire effective diameter. Patent applicant Yamaha Motor Co., Ltd.

Claims (2)

[Claims] (1) In a moving object that determines the running position by separately detecting the rotational speed of the left and right wheels, a diameter detection means that detects the ground contact diameter of the left and right wheels, and a calculation that uses the determined ground contact diameter to determine the running position. A position detection device for a moving body, comprising: means. (2) In a moving object that determines the running position by separately detecting the rotational speed of the left and right wheels, a ground contact position detection means that detects the ground contact positions of the left and right wheels;
A position detecting device for a moving body, comprising a calculation means for determining a running position using a tread determined from the ground contact position.