Travel control device for unmanned conveyance vehicle
An unmanned conveyance vehicle ( 11 ) includes a detecting device ( 23 ) that has a plurality of sensing elements ( 25 ), first to fourth marker sensors ( 31 - 34 ) arranged on both sides of the sensing elements 25 , and a magnetic member ( 35 ). The sensing elements ( 25 ) detect positions of guide tapes ( 12, 13 ) laid down along a road travel surface. The marker sensors ( 31 - 34 ) detect magnetic markers ( 14 A- 14 D) laid down along the road travel surface. The magnetic member ( 35 ) is arranged above the sensing elements ( 25 ) and the marker sensors ( 31 - 34 ). When a left end ( 35 a ) of the magnetic member ( 35 ) moves to a position above the branch guide tape ( 13 ), the first marker sensor ( 31 ) operates, and the left end ( 35 a ) is magnetized to the north pole by the magnetic flux of the branch guide tape ( 13 ). A right end ( 35 b ) of the magnetic member ( 35 ) is magnetized to the south pole to operate the third marker sensor ( 33 ). As a result, ON signals are output from the first and third marker sensors ( 31, 33 ) to an erroneous determination preventing section ( 52 ) of a control unit ( 22 ). The erroneous determination preventing section ( 52 ) determines the ON signals to be invalid.
1. A travel control device for an unmanned conveyance vehicle, comprising:
a first magnetic sensor that is arranged in an unmanned conveyance vehicle to detect a guide tape laid down along a road travel surface;
a plurality of second magnetic sensors that are arranged on left and right sides of the first magnetic sensor to detect magnetic markers laid down along the road travel surface on the sides of the guide tape;
a magnetic member that is arranged above the first and second magnetic sensors to improve detection sensitivities of the magnetic sensors; and
a control unit that performs guided travel and various operation controls of the unmanned conveyance vehicle on the basis of detection signals from the first and second magnetic sensors,
wherein the control unit includes erroneous determination preventing means, wherein, when a plurality of detection signals output from the second magnetic sensors include only one ON signal, the erroneous determination preventing means determines the ON signal to be valid, and when the detection signals include a plurality of ON signals, the erroneous determination preventing means determines all the ON signals to be invalid.
2. The travel control device for an unmanned conveyance vehicle according to claim 1 , wherein the erroneous determination preventing means includes a software filter that determines whether the detection signals include only one ON signal or a plurality of ON signals.
3. The travel control device for an unmanned conveyance vehicle according to claim 1 , wherein the second magnetic sensors include a pair of left second magnetic sensors arranged on the left side of the first magnetic sensor and a pair of right second magnetic sensors arranged on the right side of the first magnetic sensor, the left second magnetic sensors detecting a magnetic marker having the south pole on the upper surface thereof and a magnetic marker having the north pole on the upper surface thereof, and the right second magnetic sensors detecting a magnetic marker having the south pole on the upper surface thereof and a magnetic marker having the north pole on the upper surface thereof.
4. The travel control device for an unmanned conveyance vehicle according to claim 1 , wherein the second magnetic sensors include a left second magnetic sensor arranged on the left side of the first magnetic sensor and a right second magnetic sensor arranged on the right side of the first magnetic sensor, the left second magnetic sensor detecting a magnetic marker that is laid down along a road travel surface and has the south pole or the north pole on the upper surface thereof, and the right second magnetic sensor detecting a magnetic marker that is laid down along the road travel surface and has the north pole or the south pole on the upper surface thereof in order to detect a magnetic polarity different from that detected by the left second magnetic sensor.
5. The travel control device for an unmanned conveyance vehicle according to claim 1 , wherein the first magnetic sensor is configured by a plurality of sensing elements arranged in a line at predetermined intervals along the widthwise direction of the vehicle body of the unmanned conveyance vehicle, the sensing elements being turned ON when the sensing elements are located above the guide tape, and the control unit including guide control means that calculates a deviation between an arrangement center in the widthwise direction of the vehicle body of a predetermined number of sensing elements that have been turned ON by the guide tape and a center position of the vehicle body, thereby causing the vehicle body to travel unmanned along the guide tape in such a manner as to cancel the deviation.