JP3024902U - Vehicle guidance device - Google Patents

Abstract

(57) [Summary] (Modified) [Purpose] The tracking system becomes invisible under normal ambient illumination and becomes visible only when stimulated by invisible radiation (ultraviolet radiation) generated by the guidance system itself. It is possible to follow the route. A vehicle guidance device for guiding a vehicle along a surface, the vehicle guidance device including a fluorescent substance that emits radiation in the visible frequency region in response to stimulation by radiation in the invisible frequency region, and also under normal ambient lighting conditions. A guide line that is substantially invisible below, a radiation device that is provided in the vehicle and emits radiation in the visible frequency range, and detects radiation in the visible frequency range emitted by the guide line, and detects the position of the vehicle. A sensor device that generates an error output signal that represents a deviation from a predetermined lateral position with respect to the guide route, and that responds to the error output signal so that the vehicle moves along the guide line at the predetermined lateral position. Control.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a route tracking system for automatically guiding a vehicle along a predetermined route, and more specifically to a route tracking system capable of tracking an invisible guide route.

[0002]

[Prior art]

 Traditionally, there have been vehicle guidance devices that use buried wires and do not use reflected light or steering radiation. For example, U.S. Pat. No. 3,147,817, U.S. Pat. No. 2,317,400, and U.S. Pat. No. 3,411,603.

[0003]

[Issues to be solved by the device]

 When the buried wire is used as in the prior art, there is a problem that it is expensive.

The present invention allows a tracking system to follow a line that is invisible under normal ambient illumination and is only visible when stimulated by invisible radiation (ultraviolet radiation) generated by the guidance system itself. The aim is to be possible, thus achieving the flexibility and low cost of the reflected beam system, while at the same time eliminating the difficulties previously associated with the visibility of reflected lines.

[0005]

[Means for solving the problem]

 The present invention includes a vehicle guidance device for guiding a vehicle along a surface using a guide line that includes a material that emits radiation in a first frequency region in response to stimulation by radiation in a second frequency region.

The vehicle guidance system includes a radiation source adapted to direct radiation in the second frequency region to the guide line, whereby the guide line thereby emits radiation in the first frequency region.

A sensor circuit in the vehicle detects the first frequency radiation emitted by the guide line and produces an error signal proportional to the vehicle's variation from its intended position relative to the guide line.

A controller within the vehicle is adapted to steer the vehicle along a guide line in response to an error signal generated by the sensor mechanism.

It is desirable that the guide line includes a fluorescent material that emits visible radiation in the first frequency region in response to stimulation by invisible (ultraviolet) radiation in the second frequency region. The sensor mechanism is appropriately filtered so that it responds to visible light emitted by the guideway but essentially does not respond to ultraviolet radiation. Similarly, the radiation source is filtered to emit only ultraviolet radiation.

[0010]

[Action]

 This system significantly reduces the detrimental effects caused by the reflection of the radiation source from the background surface, since the radiation source produces exciting radiation in the invisible spectrum and the sensor device responds primarily to radiation in the visible region.

In order to improve the effectiveness and reliability of the inductive system, signal modulation circuits minimize static background illumination. In addition, a closed loop contrast or gain control circuit keeps the ratio between the error output voltage and vehicle displacement from the center of the guideway line constant regardless of the level of background illumination.

In addition, the filtering network localizes the guided response to the radiation emanating from the guide line, and the improved line detection circuit prevents the tracking system from working in the absence of a valid guide line.

For the purpose of providing a suitable mechanical feedback from the control mechanism to the sensor mechanism, the sensor circuit is mounted for pivoting movement with the vehicle's turnable control wheels, whereby the vehicle is maneuverable Even if it is not immediately returned to its original position, the sensor circuit is moved to the “error-free” position by the original turning of the control wheels. In a forward steered vehicle, the sensor mechanism is mounted in front of the front wheel (s) to turn with the wheels. In rear-floor vehicles, where the steering is performed by the rear wheel (s) capable of turning, a suitable mechanical link is used to move the sensor circuit in the opposite direction of the turning movement of the rear wheel. This is because the rear steering wheel is turned in the direction opposite to the desired direction of the vehicle.

[0014]

【Example】

 Examples will be described with reference to the drawings. The principle of the guidance system of the present invention can be applied to any type of vehicle adapted for maneuvering along a path on the surface, but as an example, here, floor maintenance machines are more specific. Only the vacuum cleaner will be explained.

Floor cleaner 10 includes a typical three-wheeled platform 14 which is generally comprised of a pair of spaced apart rear wheels 16 and a pivotable front wheel 18. Each of these wheels may be a plurality of closely spaced wheels (as shown) instead of a single wheel. The vehicle is driven using a drive motor 20 which drives the wheels 18 by a suitable chain drive mechanism or the like.

Manual steering of the vehicle can be performed by a driver in the vehicle turning the wheel 18 with the control wheel and appropriate gears (not shown).

For the purpose of cleaning the floor, the floor cleaner 10 includes a solution supply mechanism 28 for supplying a solution containing a cleaning agent to the floor, a brush mechanism 30 for cleaning the floor with the solution, and a brush for cleaning the floor. Then, it includes a squeeze 32 for wiping the cleaning solution off the floor surface and a vacuum device 34 for sucking dirty water from the floor surface and delivering it to an appropriate container.

To provide a path for the automated guidance system 12 of the floor cleaner 10, a planned track, preferably 1 inch wide, is occupied by the guide line 36 on the floor area 17. For the purpose of providing a means for distinguishing the guide line from the floor surface, the guide line 36 contains a suitable amount of fluorescent material, so that when the guide line is illuminated by UV light, the fluorescent material will fluoresce and is predetermined. Emit visible light in the specified frequency range.

The desired phosphors emit visible light in the blue-green spectrum (approximately 450-500 nanometers) when stimulated by ultraviolet radiation of about 360 nanometers. This visible light is detected by the guidance system and provides effective control for maneuvering the vehicle along the guideway.

The automatic guidance mechanism 12 used in the floor cleaner 10 includes a position sensing unit 13, which is attached to the swivel mounting mechanism for the wheels 18 by means of an appropriate dwarf 38 or the like. The position-sensing unit 13 is capable of a swiveling movement with the wheel 18, so that if this unit is maintained in the center of the guide line, the wheel 18 is constantly oriented such that the wheels follow the guide line.

The position detection unit 13 detects the position of the guidance mechanism with respect to the guide route and generates an error signal proportional to the position variation of the detection unit with respect to the planned route relative to the guide route. . The detection unit produces an error output signal that is proportional to the deviation of the guideway from the center of the detection unit. The error output signal generated by the position sensing unit 13 is transmitted to the automatic control device 15 by the conductor 40, which drives the vehicle in response to the error output signal and along the guide route. The automatic controller 15 includes a servo amplifier 42 that amplifies the signal from the conductor 40, and the servo amplifier drives a reversible steering motor 22 for controlling the steering of the vehicle.

The servo amplifier 42 is connected to the steering motor 22 with separate conductors 44 and 46 for forward and backward operation of the steering motor 22. The steering motor is connected to the slewing wheel 18 with appropriate sprockets 24 and drive chains 26 for vehicle steering. Other drive train schemes can also be used. The position detection unit 13 is shown in FIG. 1 at a position just above the guide line 36. The radiation source 50 is mounted on the detection unit 13 so that the guide line 36 emits fluorescence immediately below the detection unit 13.

According to the invention, the mechanical feedback is provided not by the actual movement of the vehicle itself, but by the movement of the control wheel 18 into the original steering position, which can be turned. The error signal generated by the position detection unit 13 causes the car 18 to turn so as to keep the position detection unit on the guide line, thus causing the car to continuously follow the position detection unit along the guide line.

By providing a feedback connection in the vehicle, via the steering mechanism, opposite the vehicle position, the time response characteristics of the vehicle and thus the maneuverability and tracking ability are noticeably improved.

In the embodiment described herein, a three-wheeled vehicle having a single front control wheel 18 is shown. Even in a vehicle having two front control wheels, the same principle of operation allows the position detection unit to be suspended by a mechanical link mechanism between the mounting mechanisms of the two vehicles due to the lateral movement accompanied by the turning of the vehicle. It will be used, except that it should be done.

The same basic principle is applied to a rear-wheeled vehicle that is a three-wheeled vehicle in which a single turning wheel is mounted on the rear side and a pair of fixed wheels are mounted on the front side. Additional mechanical linkages or gears are required to compensate for the wheels turning in the opposite direction to the desired direction of the vehicle. One interconnection is shown in FIG. 4, where the guidance system is shown in a rear-steered tricycle with front wheels 16 'and pivotable rear wheels 18'.

The rear wheel 18 ′ is connected to a gear 19, which is drivingly connected to a gear 21. The gear 21 is connected by a frame 23 to the detection unit 13 '. As the sensing unit deviates from the guide line 36, the error deviation signal causes the rear wheel 18 'and gear 19 to pivot in one direction (eg, opposite to the hands of a clock), which in turn gear 21 and detection unit 13'. Move in the opposite direction (eg, toward the hands of a clock) until the sensing unit is properly placed on the guideway again. Other types of mechanical linking devices could be devised to serve similar purposes.

Radiation source 50 comprises a conventional ultraviolet lamp that emits radiation primarily in the ultraviolet frequency spectrum. Pure UV radiation is invisible to the eye, but the fluorescent material fluoresces and emits radiation at visible frequencies. If the UV lamp 50 emits some visible light in the blue spectrum outside the invisible UV radiation, a suitable filtering plate 52 is used to prevent the blue light from reflecting off the floor to the detector 13. (Fig. 2). Therefore, the lamp 50 emits only invisible radiation to the floor surface, and only invisible radiation is reflected from the floor surface. The only visible radiation produced as a result of the radiation emitted by the lamp 50 is the fluorescent radiation emitted by the fluorescent live guide line 36.

Fluorescent lamps are energized to blink at a different rate than the standard 100 or 120 Hz. This frequency is chosen so that the harmonic overlap between UV and normal background fluorescence illumination is minimized.

This character of the device offers important advantages over the prior art reflected radiation tracking system. In a reflected radiation system, the same radiation is reflected from both the background and the trailing track, and the radiation reflected from the background distinguishes between the guideline and the background. This is because it minimizes the contrast. This discrimination is especially troublesome when a light background surface is used. When a fluorescent system is used, the fluorescent substance need only be stimulated with invisible light in the second frequency range, and the fluorescent substance radiates visible light in the first frequency range to it. The sensor mechanism is selectively responsive to visible light in a specific frequency range radiated by the guideway, that is, the sensor is responsive only to visible radiation from the fluorescent guideway and not to invisible radiation reflected from the background surface. It need only be made non-responsive.

The contrast between the guideway and the background is thus maximized, which results in a significant improvement in reliability over the reflected ray tracing system. The detection unit 13 includes a left photovoltaic cell 56, a right photovoltaic cell 58, and a centerline photovoltaic cell 60 mounted above the guide route. The device is designed so that the centerline photovoltaics are located directly above the guideway 36 and the left and right photovoltaics are equidistant on either side of the guideway. Desirably, the left and right photovoltaic cells are each spaced about 2 inches from the centerline photovoltaic cell and are tilted 15 ° -18 ° from the horizontal position.

This ensures a wide and continuous view for tracking the guide route, and in addition provides the benefits associated with feedback control.

The photovoltaic cells used in the practice of the proposed invention are photoconductive with a relatively slow time constant and with a cusp, head response frequency region that coincides with or at least overlaps the fluorescent guide line. It is a tube. Since such photovoltaic cells are typically slightly sensitive to UV radiation, a filter plate 61 is used to filter the UV radiation reflected from the background surface. Desirably, the photovoltaic cell is selected to have a peak response in the frequency domain of the light rays emitted from the fluorescent guideline, in order to enhance the system's ability to distinguish lines.

Next, FIG. 3 will be described. This is a schematic representation of the control circuit for the guidance system. The photocell signal is the visible light received by the photocells 58, 56 and 60 from the floor as a voltage across the gain adjustment resistors 55, 57 and 59, which provide a means of compensating for the gain variation of the photocells. It is detected by the voltage signal corresponding to the strength of.

The photocell signals from photocells 58 and 60 are applied to a modulating differential amplifier circuit 70 via leads 66 and 68, respectively. The photovoltaic signal is modulated in circuit 70 to cancel the effects of background radiation. To this end, the circuit is synchronized to the frequency of the fluorescent radiation source, so that the effects of background radiation are eliminated from the error signal.

The circuit 70 includes a differential amplifier, which subtracts one of the photovoltaic signals from the other to obtain the output error signal. The error signal is applied to servo amplifier 42 via conductor 40.

The signal from the photovoltaic cell 60 is obtained from the resistor 59 and applied to the control circuit 74 via conductor 76. The error signal from circuit 70 is also applied to control circuit 74. The output from control circuit 74 is applied to automatic gain control (AGC) circuit 78, which output is applied to photovoltaic cells 58, 56 and 60. An output stop signal is provided at the output 82 when the control circuit 74 determines that there is no guide line near the sensing unit 13 or when there are other conditions in which it is desirable to stop the vehicle. The outputs of photovoltaic cells 58 and 56 are also applied to control circuit 74 (FIG. 3). Automatic gain control enhances system stability by keeping the ratio between the error output voltage and the deviation from the guideline center constant.

In one implementation, the automatic gain control circuit is designed to maintain a constant sum of left and right photovoltaic output signals.

In another implementation, a feedback circuit keeps the difference between the centerline voltage and the average of the left and right photovoltaic output constant. When their positions are adjusted so that the photocells receive nearly the same background illuminance from the same field of view, the discriminant function eliminates the background illuminance component of the aggregate signal and depends only on the strength of the guideway signal. Leave the reference voltage.

In order to maintain a constant closed loop gain without reference to the background illuminance with the improved automatic gain control circuit, the centerline photocells should be arranged so that the background illuminance received by the centerline photocell is left when the guide line is aligned. And needs to be placed to be substantially the same as the background illumination received by the right photovoltaic cell. The intensity of the illuminance received by a photocell is a function of the field of view of the photocell from which the illuminance is received and the effective distance traveled by the time the illuminance is received by the photocell. The background illuminance received by the route can be equalized by placing these photovoltaics in the proper position and, if necessary, by placing a suitable shield over the photovoltaics.

The use of a feedback signal consisting of the difference between the centerline output and the average of the side outputs is effective in keeping a constant closed loop signal gain without interference from background illumination, but The signal gain remains constant only while the points of interest are close to each other and the effective background illumination received by each photovoltaic cell is equal. As the guideway deviates to either side of the center, the effective amount of background illumination received by each photovoltaic cell changes, thus allowing the background illumination component to enter the feedback signal. Also, the difference between the centerline voltage and the average of the lateral photocell outputs is small. The error introduced by the deviation of the guideway will, at least in part, make the time constant of the automatic gain control circuit sufficiently slow and the reaction time and accuracy of the servo control sufficiently high so that the vehicle will automatically gain. This can be avoided by allowing the control circuit to return the feedback signal due to the deviation to the zero error position before reacting to it.

In order to avoid the deviation of the closed-loop gain due to the difference between the centerline output and the average of the lateral photovoltaic cell outputs decreasing with increasing deviation from the centerline, the absolute value of the error output signal is Can be added to the centerline voltage before subtracting the average of the left and right photovoltaic cells. By moderating the centerline signal in this manner, the automatic gain control circuit voltage can remain relatively constant, even for significant excursions from the centerline of the proposed route.

The main purpose of the feedback signal is to prevent changes in line brightness or contrast or fluctuations in the level of UV radiation from affecting the output gain. Thus, if the signal level goes down, the automatic gain control circuit reduces the gain. By making the feedback circuit independent of background illumination, the gain control will only respond to condition changes in the excursion error signal calculated at the photovoltaic output in response to the guideway excursion. Another important feature of the device is the inclusion of a line detection circuit to prevent the vehicle and vehicle guidance system from operating unless it is on a valid guide line.

In one implementation of the invention, the active line is first displayed when the centerline photovoltaic output is greater than the output on both the left and right cells. To this end, the difference between the centerline output and the left output is calculated in control circuit 74, and the difference between the centerline output and the right photovoltaic output is calculated in control circuit 74. This voltage difference is compared with an appropriate reference voltage. To acquire the line first, the centerline power must be greater than both the left and right channels and the signal strength must be strong enough to approve the acquisition. If the intensity of the right or left channel is greater than the centerline, the control circuit 74 produces an output signal at 82 to stop the vehicle. The fact that the programmed lines are bright and of adequate width guarantees this control quality. This control feature also prevents false line markings, such as those that might create strips of paper or black and white grid tile patterns.

Once the route is captured, the logical condition reverts to the requirement that the centerline output be greater than either the left or right channel. If this condition cannot be found, the control circuit 74 will generate a stop signal to stop the vehicle.

In order to exclude the operation of the vehicle when the route is too weak, in the control circuit 74, the difference between the centerline photocell output signal and the left and right photocell output signals are respectively set to predetermined values. Devices can be used until the vehicle is reached, except for activation.

The purpose of having a separate logical condition for first capturing a route and then displaying the effective route after the route is captured is to increase the effective field of view if the route is captured. This avoids generating a lineless signal in situations such as when vehicles are traveling at high speeds and turning sharp radii on obscure lines.

Alternatively, the input or output of the automatic gain control circuit can be used for the purpose of effective route determination. In this implementation, the input or output of the automatic gain control circuit is compared to the reference voltage at the level detector. The reference voltage is adjusted so that the level detector emits a negative line indication when the automatic gain control circuit amplifier reaches saturation. If the effective line to be detected is not there, the automatic gain control circuit amplifier cannot maintain a constant voltage differential and the amplifier will quickly saturate. As such, the saturation between the centerline output of the automatic gain control circuit and the side sensor level can be used to detect a deadline condition. It is desirable to incorporate a deviation limiting device in the control circuit 74 to prevent violent capture reactions. This excursion limiting mechanism utilizes the absolute difference between the right and left photovoltaic cell outputs and compares this difference in control circuit 74 to an appropriate reference voltage (eg, 1 volt). A stop signal is generated at the output 82 as soon as the difference between the right and left photovoltaic cell outputs exceeds this predetermined reference voltage.

[0049]

[Effect of device]

 The guidance device of the present invention can be advantageously used on almost any type of vehicle, either on hard or rugged surfaces that can be equipped with planned routes or tracks. The present invention is particularly applicable to a wide variety of industrial supply vehicles for which a command signal is given to the vehicle, or to an industrial vehicle that is a floor cleaner, a floor wiper, or a vacuum cleaner. It is possible to adapt to those used for maintaining the floor surface such as.

[Brief description of drawings]

FIG. 1 is a schematic plan view of a floor cleaner showing the guiding system block form of the present invention.

FIG. 2 is a schematic diagram showing the relative positions of the excitation lamp and the photovoltaic sensor used in the guidance system of the present invention.

FIG. 3 is a schematic block diagram of the control system of the present invention.

FIG. 4 is a schematic block diagram showing interconnection between sensor circuits and steering control mechanisms in a rear-wheeled tricycle.

[Explanation of symbols]

 10 Floor Cleaner 12 Automatic Guidance Mechanism 13 Position Detection Unit 13 'Position Detection Unit 14 Frames 15 Automatic Control Device 16 Front Wheel 16' Front Wheel 17 Floor Area 18 Drive Wheel (Control Wheel) 18 'Rear Wheel 19 Gear 20 Drive motor 21 Gear 22 Steering motor 24 Sprocket 26 Drive chain 28 Solution supply mechanism 30 Brush mechanism 32 Squeezing 34 Vacuum device 36 Guide line 38 Frame 40 Conductor 42 Servo amplifier 44 Conductor 46 Conductor 50 Radiation source 52 Filter plate 55 Gain adjustment register 56 Photocell 57 Gain control register 58 Photocell 59 Gain control register 60 Photocell 61 Filter plate 66 Conductor 68 Conductor 70 Differential amplifier circuit 72 Conductor 74 Control circuit 76 Conductor 78 Automatic gain limiting circuit 80 Conductor (from 78) 82 Output end (stop output) Signal)

Claims (4)

[Scope of utility model registration request] 1. A vehicle guidance device for guiding a vehicle along a surface, comprising a fluorescent substance that emits radiation in the visible frequency region in response to stimulation by radiation in the invisible frequency region,
Moreover, a guide line that is substantially invisible under normal ambient lighting conditions; a radiation provided in the vehicle, which emits radiation in the invisible frequency range toward the guide line, and forms the guide line in the visible frequency range. A radiation device for emitting radiation in the vehicle; detecting radiation in the visible frequency range radiated by the guide line in response to the radiation device; and in response thereto, a predetermined lateral position of the vehicle position with respect to the guide line. A sensor device adjusted to generate an error output signal representative of a deviation from the vehicle; the vehicle moving along the guide line in response to the error output signal provided by the vehicle and generated by the sensor device And a control device for maintaining the predetermined lateral position when the vehicle guidance device is included. 2. The radiating device according to claim 1, wherein the radiating device substantially does not emit visible light, and the sensor device is responsive to radiation in the visible frequency range emitted from the guide line. A vehicle guidance device which has a property of being non-responsive to reflection of radiation in the invisible frequency range generated by the radiation device. 3. The fluorescent substance included in the guide line according to claim 2, wherein the fluorescent substance emits radiation in the visible frequency region in response to a stimulus due to invisible ultraviolet radiation. The sensor device includes an ultraviolet lamp that emits the ultraviolet radiation in the invisible frequency range, the ultraviolet lamp being filtered to an extent sufficient to block visible light from the lamp, and the sensor device A photovoltaic device capable of producing an output signal substantially comparable to the intensity of visible light, the photovoltaic device responding to visible light in the visible frequency range emitted by the guide line containing the fluorescent material. The sensor device also includes a light filtering device such that the photovoltaic device has a frequency substantially different from the ultraviolet and visible frequency ranges. A vehicle guidance device characterized in that it is adapted to illuminate light rays to an extent sufficient to have substantially non-responsiveness to background radiation having. 4. The vehicle of claim 1, wherein the vehicle is a rear-operated vehicle that rides on a rotatable vehicle for steering by turning at least one of the wheels. And at least one non-turnable rear wheel and at least one non-turnable front wheel, wherein the control device is adapted to turn the wheels to steer the vehicle. When the controller turns the rear wheels sufficiently to steer the vehicle along, the turning causes the sensor device to return the vehicle to the predetermined lateral position with respect to the guideway. At least, the sensor device can be moved to a position where a zero error output signal is generated, and the sensor device can be moved by a mounting device. When mounted on a vehicle, the mounting device has a direction opposite to the direction of movement of the rear wheel that can turn, even if steering by turning the rear wheel is performed in a direction opposite to the desired direction of the vehicle. A vehicle guidance device, wherein the sensor device is moved in a direction so that the sensor device follows the guide route in response to the operation of the vehicle.