JP2503534Y2 - 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 and the like of an unmanned vehicle.

B. Outline of the Invention In the present invention, the deviation of the unmanned vehicle from the planned trajectory can be easily performed according to the geometrical conditions based on the arrangement of the light receiving points of the laser irradiated on the two optical position detectors mounted on the unmanned vehicle. And can be accurately determined. For this reason, operation control for returning to the planned orbit becomes easy.

C. Conventional technology Conventionally, in the method of guiding an unmanned guided vehicle, a cable is embedded in the floor surface, and electromagnetic waves generated by passing an electric current through it are detected by two pickup coils mounted on the vehicle body. There are an electromagnetic induction system and an optical tape induction system in which a reflective tape is attached to the surface of the traveling path and the reflected light is detected by an unmanned guided vehicle to perform control. However, these methods have the following drawbacks.

(1) In the case of the electromagnetic induction method, a large construction cost is required for burying the electric wire, and it is difficult to change the erasure of the route.

(2) The optical reflection tape may be contaminated, which causes malfunction of the automated guided vehicle. Therefore, maintenance is always required so that there is no stain.

In view of the above points, many self-supporting automated guided vehicles have recently been proposed that do not use these guide wires or reflective tapes. For example, a method of detecting the current position and direction of the vehicle body using a gyro, a method of controlling the deviation from the course stored by detecting the vehicle body angle from an encoder attached to the wheel, and a spatial filter There is a method of detecting the position of the carrier by looking at the uneven pattern on the road surface. However, it is necessary to perform fixed point correction at appropriate intervals for long-distance running due to wheel unevenness due to unevenness of the road surface, wear of wheels due to external force, gyro error, and the like.

Since so high accuracy is required for position information for fixed point correction, some so-called laser lighthouse methods using a laser with good directivity have been proposed.

D. Problems to be Solved by the Invention However, no conventional laser lighthouse system satisfies 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) Limit the range that the laser beam reaches for safety.

An object of the present invention is to provide a vehicle body position / speed detection device that can satisfy the above conditions.

E. Means and Actions for Solving the Problem First, in order to solve the above problem (1), a laser for irradiating a laser beam is fixed with a downward depression angle with respect to the horizontal direction from a direction perpendicular to the planned orbit. I installed it.

Next, in order to solve the above problem (2), two one-dimensional optical position detection elements were attached to the unmanned vehicle at an angle oblique to the traveling direction.

Further, in order to solve the above-mentioned problem (3), the rotating mechanism such as a mirror, which was necessary in the laser lighthouse method, was deleted.

Further, in order to solve the above-mentioned problem (4) and improve safety, a mechanism for scanning light left and right, which is required in the laser lighthouse method, is deleted, and laser light is emitted downward with respect to the horizontal direction at a depression angle. I did it.

Thus, in response to the above problems (1), (3) and (4), the laser for irradiating the laser beam is fixed from the direction perpendicular to the planned trajectory A to the horizontal direction downward at the depression angle. Since it is attached, the rotating mechanism such as a mirror, which is necessary in the conventional laser light system, can be omitted, and the optical system can be simplified. In addition, the laser lighthouse method needs to scan the laser from side to side, and the range of light that reaches it is wide and dangerous.However, in the present invention, laser light is emitted downward at an angle of depression θ with respect to the horizontal direction. Therefore, the reach of light is limited and it is safe.

Further, in response to the above-mentioned problem (2), two one-dimensional optical position detecting elements are attached to the unmanned vehicle at an angle oblique to the traveling direction, so that the two optical position detecting elements are irradiated with laser light. By analyzing the arrangement of the light receiving points according to the geometric conditions, the unmanned vehicle can detect the position and speed information by itself.

In the conventional laser lighthouse method, the unmanned vehicle only moves by being guided by the laser light, and therefore cannot know its own position and cannot autonomously travel.

On the other hand, since the unmanned vehicle equipped with the vehicle body position / speed detection device of the present invention constantly acquires the vehicle body position / speed information by itself, by performing fixed point correction based on the information, Autonomous driving becomes possible.

Further, the fixed point correction has a function of detecting position information and a function of controlling the vehicle body to a correct position from the information, but in order to perform these vehicle body controls, not only the vehicle body position,
It is necessary to detect the inclination and speed.

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

As shown in FIG. 2, a planned track A is set in the center of the passage 1, and the operation of the unmanned vehicle 2 is controlled based on speed and position information by a gyro so that the unmanned vehicle 2 can travel along the planned track A. . That is, the unmanned vehicle 2 is a self-propelled type. However, in the case of the self-sustaining traveling type, there may be a deviation from the planned trajectory A due to an error such as a gyro. Therefore, as shown in FIGS. 2 and 3, the unmanned vehicle 2 is mounted as an optical position detector with a one-dimensional semiconductor position detecting element (hereinafter referred to as PSD) 3, 4 having an inclination ρ and an interval L. . The inclination ρ is with respect to the traveling direction of the unmanned vehicle, and the interval L is a horizontal distance. Each of PSDs 3 and 4 is formed by forming a P layer on the front surface of a rectangular silicon, an N layer on the back surface, and an I layer on the intermediate layer as shown in FIGS. 4 and 5, and its short side. Are equipped with electrodes 5 and 6. Therefore, the incident light is photoelectrically converted, separated and output from each of the electrodes 5 and 6 as a photocurrent, and the one-dimensional position of the incident point (light receiving point) is obtained from the ratio of the values. Each PSD
Is mounted vertically in FIG. 6, the position of the light receiving point in the vertical direction can be obtained. Here, for convenience, the center of the PSDs 3 and 4 is the origin and the vertical direction is the y-axis.

On the other hand, in order to perform fixed point correction, a laser oscillator 8 is attached to the fixed point of the passage 1. The laser B from the laser oscillator 8 is perpendicular to the planned trajectory A in the plan view shown in FIG. 2, and forms a depression angle θ with respect to the horizontal direction C as shown in FIG.

Here, when the unmanned vehicle 2 deviates from the planned track A, the position of the light receiving point of the laser B irradiated on the PSDs 3 and 4 is different from the normal position. Therefore, if this position is geometrically analyzed, the horizontal distance from the planned trajectory A, the inclination of the vehicle body, and the speed can be obtained.

First, the horizontal distance Z has the relationship shown in FIG. Here, the horizontal distance Z indicates how far from the planned trajectory A in the vertical direction, and is parallel to the horizontal direction C. The horizontal distance Z is calculated as follows from the relationship shown in FIG.

Z = y · tan (π / 2−θ) (1) Furthermore, at time t ₁ , the position of the point received by the PSD 3 is y ₁ ,
If the position of the point that the PSD 4 receives at time t ₂ is y ₂ ,
The change amount ΔZ of the horizontal distance between the times t ₁ and t ₂ is as follows.

ΔZ = (y ₂ −y ₁ ) tan (π / 2−θ) = Δy tan (π / 2−θ) (2) Next, regarding the inclination φ of the traveling direction D of the unmanned vehicle 2 with respect to the planned trajectory A, There is a relationship shown in FIGS. However, it is assumed that the slope φ and the vehicle speed V are constant and do not change during the time t ₂ to t ₁ when the laser B passes through the PSDs 3 and 4. When the sine theorem is applied to the triangle shown in FIG. 1 (b), which shows the positional relationship shown in FIG. 1 (a), the following equation is established. Incidentally, Δt = t ₂ −t ₁ .

This can be rewritten as the following two equations.

L · sin ρ = ΔZ · sin (π / 2 + φ) (4) V · Δt · sin ρ = ΔZ · sin (π / 2−ρ−φ) (5) Here, the slope φ is calculated from the equation (4). It becomes as follows, and by substituting the equation (2), it is further transformed as follows.

On the other hand, if the equation (5) is modified, the velocity V can be obtained as follows.

As described above, according to this embodiment, the horizontal distance Z from the planned trajectory A, the vehicle body inclination φ, and the vehicle body speed V can be calculated based on simple geometric conditions. By doing so, it is possible to return to the planned trajectory by correcting the operation control. The PSDs 3 and 4 are still fixed at a fixed angle, and there is no need to rotate the mirror as in the past, which simplifies the optical system. Furthermore, since the detector is attached to the vehicle body only and cannot be attached to the outside of the vehicle, the traveling direction can be corrected by itself without depending on the guidance from outside the vehicle. On the other hand, since the irradiation angle of the laser is a depression angle, the range that the laser can reach is limited and the safety is high. When the laser light is irradiated in the horizontal direction (θ = 0), the right side of the equation (1) becomes infinite and the horizontal distance z with respect to the planned track of the unmanned vehicle is z.
However, when the laser light is irradiated with a downward depression angle with respect to the horizontal direction (θ ≠ 0), the formula (1)
Thus, the horizontal distance z with respect to the planned track of the unmanned vehicle is obtained.

When the optical position detecting elements 3 and 4 are attached in parallel to the traveling direction of the vehicle body (ρ = 0),
Equations (2) and (3) cannot be derived because the triangle in FIG. (B) does not hold, but if the attachment is tilted with respect to the traveling direction (ρ ≠ 0), then Since the triangle in FIG. 1B is established, the equations (2) and (3) can be derived. The light position detecting elements 3 and 4 are attached only at an angle with respect to the traveling direction, and are attached vertically to the floor surface.

G. Effects of the Invention As described above in detail based on the embodiment, the position of the laser receiving point of the laser irradiated on the optical position detector mounted on the unmanned vehicle is compared with the planned trajectory according to the geometric conditions. You can easily and accurately find the deviation of an unmanned vehicle. Therefore, the control for returning to the planned orbit becomes easy.

[Brief description of drawings]

1 (a) and 1 (b) are explanatory views showing geometrical conditions in one embodiment of the present invention, FIG. 2 is a plan view showing a relationship between a planned trajectory and a laser, and FIG. 3 is an unmanned vehicle. Perspective view, 4th
Fig. 5, Fig. 5 and Fig. 6 are sectional view, perspective view, and
Arrangement drawings, FIG. 7 and FIG. 8 are explanatory views showing geometric conditions in one embodiment of the present invention. In the drawing, 2 is an unmanned vehicle, 3 and 4 are PSDs, 5 and 6 are electrodes, ρ is the mounting angle of PSD,
φ is the inclination of the unmanned vehicle with respect to the planned trajectory, and θ is the depression angle of the laser.

Claims (1)

(57) [Scope of utility model registration request] 1. An optical position detector (3, 4) capable of detecting a one-dimensional position of a received light is attached to a vehicle body of an unmanned vehicle (2) at an angle (ρ) oblique to the traveling direction. On the other hand, while mounting, a laser for irradiating a laser beam with a downward depression angle (θ) from a direction perpendicular to the planned track (A) of the unmanned vehicle (2) is fixed and attached, and each of the optical position detectors The arrangement of the light receiving points on (3, 4) is analyzed based on geometric conditions, and the horizontal distance (z), the inclination (φ) of the vehicle body and the vehicle body of the unmanned vehicle (2) with respect to the planned track (A) are analyzed. Position of the vehicle characterized by calculating the speed (V) of
Speed detection device.