JPH0716164Y2 - Vehicle position / speed detector - Google Patents

Description

[Detailed Description of the Invention] A. Field of Industrial Application The present invention relates to a device capable of detecting the position, speed, etc. of an unmanned vehicle.

B. Outline of the Invention In the present invention, it is possible to easily and easily deviate from the planned orbit according to geometric conditions from the trajectory of the light receiving point of the laser irradiated at a certain elevation angle onto the optical position detector mounted on the front of the unmanned vehicle. Can be accurately determined. For this reason, operation control for returning to the planned orbit becomes easy.

C. Conventional technology As an induction system for an unmanned vehicle, for example, an induction wire is placed on the floor surface, an electric current is passed through this, an electromagnetic field is detected by a pickup coil, and the unmanned vehicle is driven along the induction wire. There is a guidance system. In addition, there is an optical system in which a light reflection tape is attached to the floor surface, illuminated by a floodlight, detected by an optical sensor, and an unmanned vehicle is run along the light reflection tape.

However, when a guide wire, a light reflecting tape, or the like is laid on the road surface, detection becomes uncertain due to dirt and the like, and therefore regular maintenance is required. In addition, there is a drawback that laying work is required for each course change.

As a method for solving these drawbacks, a gyro system capable of autonomous traveling and a spatial filter method are used.

The gyro system detects the rotation speed of the wheel with an encoder,
The change of the traveling direction is measured by the gyro at the same time as the moving distance is calculated, and the guide wire and the light reflection tape are not necessary. However, wheel slips and gyro accumulation errors occur. On the other hand, the spatial filter method can detect the speed and the moving distance in a non-contact manner, but a calculation error occurs.

Therefore, in order to realize precise traveling, it is necessary to perform fixed point correction and speed correction with extremely high speed and position.

D. Problems to be Solved by the Invention Conventionally, light, ultrasonic waves, electromagnetic waves, lasers, etc. have been used in fixed point correction and speed correction. However, since it is necessary for the positional relationship between the oscillator and the receiver, it takes a long time to install and the device is complicated. Moreover, the calculation is complicated, and there is a calculation error.
The cost of the correction device was also high.

Further, in the so-called laser lighthouse system using a laser having a good directivity, conventionally, there has been no one satisfying the following conditions.

(1) The rotation of the mirror or the like is avoided so that the laser light is not shaken.

(2) Information about the vehicle body such as position and speed is detected by the automated guided vehicle itself.

(3) The optical system is simple.

(4) For safety, the range that the laser beam reaches is limited.

It is an object of the present invention to provide a vehicle body position / speed detection device capable of accurately obtaining the position, speed, etc. of an unmanned vehicle by a simple calculation.

E. Means for solving the problem A laser emitted from a laser oscillator installed on the road surface at a certain elevation angle enters an optical position detector mounted on the front surface of the unmanned vehicle and receives light as the unmanned vehicle advances. Draw a locus with dots. This locus is peculiar to the traveling direction of the unmanned vehicle and the like. Therefore, if this trajectory is analyzed under geometric conditions, the deviation from the planned trajectory can be accurately and easily obtained.

F. Embodiment Hereinafter, one embodiment of the present invention will be described in detail with reference to the drawings.

1 to 5 show one embodiment of the present invention. As shown in the figure, a semiconductor position detector (hereinafter abbreviated as PSD) 3 is attached as an optical position detector to the front surface of the unmanned vehicle 2 traveling on the road surface 1. Although the unmanned vehicle 2 is an autonomous traveling type that travels based on speed / position information from a gyro or the like, it is necessary to remove accumulated errors and the like, and this PSD3 is used to perform fixed point correction. As shown in FIGS. 3 and 4, PSD3 has a P layer on the front surface of the flat silicon and an N layer on the back surface.
It is formed by forming three layers, i.e., an I layer in the middle, and electrodes 4, 5, 6, 7 are attached to each side. The incident light is photoelectrically converted and, as shown in FIG. 4 showing a one-dimensional state thereof, is divided and output from each of the electrodes 4 and 5 as a photocurrent, and 2 of the incident points (light receiving points) depending on the ratio of the values. Dimensional position is required.

On the other hand, in order to perform fixed point correction, a semiconductor laser 8 is installed at a fixed point on the road surface 1. The emission direction of this semiconductor laser is an angle θ with respect to the horizontal direction in the vertical plane, and is in the horizontal plane along a predetermined track set for the unmanned vehicle in advance. The light emitted from the semiconductor laser 8 is incident on the PSD 3 of the traveling unmanned vehicle 2 and the light receiving point thereof is the unmanned vehicle 2
Draw a trajectory as you run. This locus is peculiar to the traveling position and direction of the unmanned vehicle 2, and in order to analyze this, the two-dimensional position signals detected by the PSD3 are analyzed by the A / D converter 9 as shown in FIG. , 10, buffer 11,12
It is input to the central processing circuit (hereinafter abbreviated as CPU) 13 via. The CPU 13 processes the input position signal according to geometric conditions as follows.

That is, the light receiving point locus on the PSD 3 when the unmanned vehicle 2 travels along the planned track is vertical, and the light receiving point a at time t _{0 and} the light receiving point b at time t ₁ are as shown in FIG. Where PS
The xy coordinate axis on D3 has the origin at the center of PSD3, the horizontal direction is the x-axis, and the vertical direction is the y-axis. As shown in FIG. 6, when the locus when normally traveling on the planned trajectory is adjusted so as to overlap the y-axis, the x-axis coordinate values of the light receiving points a and b are both zero.

On the other hand, when the unmanned vehicle 2 runs parallel to the planned track, the locus of the light receiving point on the PSD 3 becomes parallel to the y axis as shown in FIG. Here, the x coordinate value x ₁₀ (= x _t1 ) of the light receiving points c and d at the times t ₀ and t ₁ of this locus indicates the horizontal distance between the unmanned vehicle 2 and the planned track.

Further, as shown in FIG. 8, when the unmanned vehicle 2 travels with the deviation angle 1 with respect to the planned track, the locus of the light receiving point on the PSD 3 becomes an inclined line as shown in FIG. In the plan view shown in FIG. 8, the planned orbit and the laser light overlap, so the planned orbit is omitted and only the laser light is shown.

As shown in FIGS. 8 and 9, when the distance traveled by the unmanned vehicle 2 between time t ₀ and t ₁ is X and the length along the planned track is m, the following formula is established.

X = m / cos (1) m = Δx / sin (2) However, it is assumed that the following relationships exist between the coordinate values of the light receiving points e and f at the times t ₀ and t ₁ .

y _t0 −y _t1 = 2 y _a (3) x _t0 −x _t1 = Δx (4) Therefore, the following formulas are derived from the formulas (1) and (2).

Next, assuming that the horizontal distance between the semiconductor laser 8 and the PSD3 at the time t ₀ is m _t0 and the horizontal distance between the PSD 3 at the time t ₁ is m _t1 , the following equation is established as shown in FIG.

However, the vertical distance from the road surface 1 to the center of PSD3 is h
And .

_{m t0 = (h + y a} ) / tanθ ... (6) m t1 (h-y a) / tanθ ... (7) where the horizontal distance m _t0, m _t1 length m along the planned trajectory the above Since there is a relation of the following equation between them, the relation with the deviation angle is as shown in FIG.

m = m _t0 −m _t1 (8) Therefore, from the relationship shown in FIG. 12, the distance X traveled by the unmanned vehicle 2 is expressed by the following equation, and by substituting the equations (6) and (7) into the following equation, To be guided.

Then, the deviation angle is obtained from the equations (5) and (9) as follows.

2y _a · sin = Δx · tan θ sin = Δx · tan θ / 2y _a = sin ⁻¹ (Δx · tan / 2y _a ) ... (11) On the other hand, the moving speed V of the unmanned vehicle 2 is expressed by the following equation. However, T
= T ₁ −t ₀ .

If the command speed is V ₀ , the deviation E from the moving speed V is expressed by the following equation.

As described above, according to the present embodiment, the horizontal distance from the planned trajectory, the deviation angle, and the moving speed can be easily calculated based on the geometrical conditions. It can be easily returned to the orbit.

G. Effect of the Invention As described above in detail based on the embodiments, the invention is based on the geometric condition from the locus of the light receiving point of the laser which is attached to the unmanned vehicle and is irradiated on the optical position detector. It is possible to easily and accurately find the deviation of the unmanned vehicle from the planned track. Therefore, the control for returning to the planned orbit becomes easy. Furthermore, the range of laser irradiation is limited, and safety is high. Further, since the optical position detector does not need to be rotated, there is an advantage that the structure is simple.

[Brief description of drawings]

1 and 2 are a side view and a front view showing an embodiment of the present invention, and FIGS. 3 and 4 are sectional views of a PSD, respectively.
FIG. 5 is a perspective view, FIG. 5 is a configuration diagram of an arithmetic processing circuit, FIGS.
Figures and 9 are explanatory views of the trajectory on the PSD respectively. Figure 8 is a plan view showing the geometric conditions, Figure 10 is a side view showing the geometric conditions, and Figure 11 is a front view of the unmanned vehicle. FIG. 12 is an explanatory diagram showing the relationship between the deviation angle and the horizontal distances m _t0 and m _t1 . In the drawing, 1 is a road surface, 2 is an unmanned vehicle, 3 is a PSD (semiconductor position detector), 4,5,6,7 are electrodes, 8 is a semiconductor laser, 9 and 10 are A / D converters, and 11 and 12. Is a buffer, and 13 is a CPU (central processing circuit).

Claims (1)

[Scope of utility model registration request] 1. An optical position detector capable of detecting a two-dimensional position of a received light is attached to a front surface of an unmanned vehicle, and a laser oscillator is installed on a road surface in a planned track of the unmanned vehicle. Irradiate the position detector at a certain elevation angle, further analyze the trajectory of the light receiving point on the optical position detector according to geometric conditions, the horizontal distance to the planned trajectory,
A vehicle body position / velocity detection device comprising a calculation circuit for calculating a deviation angle and a vehicle body speed.