Data processing: vehicles – navigation – and relative location – Vehicle control – guidance – operation – or indication – Automatic route guidance vehicle
Reexamination Certificate
2000-03-14
2001-05-22
Zanelli, Michael J. (Department: 3661)
Data processing: vehicles, navigation, and relative location
Vehicle control, guidance, operation, or indication
Automatic route guidance vehicle
C701S023000, C701S094000
Reexamination Certificate
active
06236915
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an autonomous traveling vehicle, and more particularly to an autonomous traveling vehicle which autonomously travels within a traffic lane by utilizing positional information from magnetic information sources which are mounted on a road.
2. Description of the Prior Art
Such an autonomous traveling vehicle has already been proposed by the assignee of the present application (refer to Japanese Patent Application No. 7-283973). With the prior art vehicle, the position and speed of the vehicle after a predetermined time period as estimated on the basis of the detection of magnetic nails, are compared with a control plan concerning the position and speed of the vehicle as set on the basis of information received from a leakage coaxial cable, whereby the vehicle is driven in accordance with the control plan by controlling a throttle and a brake so as to diminish the deviations of the comparison. The controlled amounts of the throttle and the brake which are determined on the basis of the magnitudes of the deviations, are set assuming that the road is flat. Therefore, when the road is sloping, it becomes difficult to drive the vehicle in accordance with the control plan. By way of example, in the case where the vehicle falls behind the control plan, the throttle is opened to increase the vehicle speed. Since, however, the quantity of opening of the throttle on that occasion is set assuming a flat road, the vehicle speed does not increase as expected, on a road of an ascending slope, so that the deviations cannot be diminished.
SUMMARY OF THE INVENTION
The present invention has been made in view of the above circumstances, and it has for its object to eliminate the influence of the inclination of a road and realize precise control for driving a motor vehicle in accordance with a control plan.
In order to accomplish the above object, an autonomous traveling vehicle having acceleration/deceleration actuators comprises a vehicle position detection means for detecting the position of the vehicle on the basis of information received from information sources disposed on a road. A control plan processing means creates a control plan formed of correlation data of speed and distance, on the basis of at least one of the information received from a preceding vehicle and the information received from information transmission means disposed on or near the road. A deviation calculation means calculates at least one of a distance deviation and a speed deviation at an anticipated arrival point of the vehicle after a predetermined time period, on the basis of the control plan and the vehicle position. A vehicle-speed control means controls the accelerating/decelerating actuators, on the basis of at least one of the distance deviation and the speed deviation. Correction means corrects at least one of the distance deviation and the speed deviation in order to compensate for any deviation due to a gradient of the road, on the basis of information about the road gradient as received from the information transmission means.
In the prior art, when any gradient exists in a road, the vehicle speed increases or decreases as compared with that in the case of traveling on a flat road, and hence, vehicle speed control conforming to a control plan becomes impossible. In contrast, according to the present invention, the distance deviation or the speed deviation at the anticipated arrival point of the vehicle after the predetermined time period is corrected on the basis of the road gradient, whereby the influence of the road gradient is compensated for, and control conforming to the control plan can be realized.
The predetermined time period is set at 1.5 seconds in one embodiment, but it is appropriately alterable in accordance with the capability of the arithmetic unit of the system or the required precision of the control.
The anticipated arrival point is calculated on the basis of the vehicle position, a first-order differential value of the vehicle position and a second-order differential value of the vehicle position. The anticipated arrival point can thus be accurately calculated merely by executing simple operations.
The information from the information transmission means is speed directive information relative to positions on the road. Thus, the vehicle can be driven at a preset speed along the road.
The deviation calculation means calculates the distance deviation and the speed deviation by comparing the information on the position and speed as received from the information transmission means, with the position and speed of the vehicle at the anticipated arrival point. The deviation between the target traveling state of the vehicle conforming to the control plan, and the actual traveling state of the vehicle, can thus be appropriately calculated.
The deviation calculation means calculates the distance deviation and the speed deviation by comparing the position and speed of the preceding vehicle after the predetermined time period as calculated on the basis of the positional information received from the preceding vehicle, with the position and speed of the vehicle at the anticipated arrival point. Thus, the vehicle can be driven following the preceding vehicle.
The position and speed of the preceding vehicle after the predetermined time period, are calculated on the basis of a first-order differential value and second-order differential value of the positional information received from the preceding vehicle. The position and speed of the preceding vehicle after the predetermined time period, can thus be accurately calculated merely by executing simple operations.
REFERENCES:
patent: 5853846 (1998-12-01), Clark et al.
patent: 5887268 (1999-03-01), Furukawa
patent: 7476977 A1 (1974-12-01), None
patent: 4-328009 (1992-11-01), None
patent: 7-283973 (1995-10-01), None
*Abstract of Japanese Patent No. JP4328009, by Higashihara Yoshiaki, dated Nov. 17, 1992.
Furukawa Yoshimi
Kobayashi Sachio
Arent Fox Kintner & Plotkin & Kahn, PLLC
Gibson Eric M
Honda Giken Kogyo Kabushiki Kaisha
Zanelli Michael J.
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