Mobile unit support system

• US 6,016,109 A
• Filed: 03/30/1998
• Issued: 01/18/2000
• Est. Priority Date: 03/28/1997
• Status: Expired due to Fees

• Current Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Original Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Inventors: Nomura, Noboru, Kane, Joji, Yosida, Takasi
• Primary Examiner(s): Hofsass, Jeffery A.
• Assistant Examiner(s): TRIEU, VAN THANH
• Application Number:
  US09/049,998
• Time in Patent Office: 659 Days
• Field of Search: 340/941, 340/933, 340/935, 340/854.6, 340/854.8, 340/936, 340/939, 340/905
• US Class Current: 340/941
• CPC Class Codes: G08G 1/042 using inductive or magnetic detectors

Abstract

A mobile unit support system comprises at least one magnetic member for forming a magnetic field in said vicinity of a movement path of a mobile unit which is made of a dielectromagnetic material; and at least one magnetic sensor which, when said mobile unit passes over, detects a change of said magnetic field and which transmits a result of said detection to an external, and said mobile unit comprises receiving means for receiving said transmitted signal, and a processing section which processes a signal from said receiving means.

Claims

1. A mobile unit support system comprising at least one magnetic sensor including

an impedance circuit employing a magnetic impedance element having an impedance that is changed by a variation of a surrounding magnetic field,

a power source which supplies a current to the impedance circuit,

a detector which detects a change in an output of the impedance circuit caused by a change of impedance of the magnetic impedance element;

and

a transmitter for transmitting a signal indicating detection of a change in the output of the impedance circuit caused by a change of impedance of the magnetic impedance element; and

at least one mobile unit having;

a plurality of magnetic members arranged in a substantially linear manner, polarities of the plurality of magnetic members being alternately inverted on a side of the at least one mobile unit facing the impedance circuit,

a receiver for receiving signals transmitted by the transmitter of the at least one magnetic sensor, and

a processor which processes signals received by the receiver and informs a driver of the at least one mobile unit of information obtained by processing the signals received by the receiver, or which processes signals received by the receiver and controls movement of the at least one mobile unit on the basis of the processing, wherein a number of the plurality of magnetic members disposed in the at least one mobile unit corresponds to one of a length of the at least one mobile unit, a weight of the at least one mobile unit, and a width of the at least one mobile unit.

2. A mobile unit support system, comprising:

at least one mobile unit formed with a dielectromagnetic material and having a radio wave generator;

a magnetic member for forming a magnetic field in a vicinity of a movement path of the at least one mobile unit; and

at least one oscillation magnetic sensor separated from the magnetic member by a predetermined distance, the magnetic sensor including;

a Colpitts oscillating circuit which includes

at least one magnetic impedance element having an impedance that is changed by a variation of the magnetic field when the at least one mobile unit moves through the magnetic field, and

a transistor and which is operated by a DC current,

whereby an oscillation frequency of the Colpitts oscillating circuit changes when the impedance of the magnetic impedance element changes,

an external power source which produces a DC voltage by performing diode detection on a radio wave transmitted from the radio wave generator of the at least one mobile unit when the at least one mobile unit approaches, and supplies the DC voltage to a point between a collector and a ground of the transistor to thereby cause the Colpitts oscillating circuit to oscillate when the at least one mobile unit approaches,

an oscillation voltage detector that detects a change in the oscillation frequency of the Colpitts oscillating circuit, and

a transmitter that transmits a signal when the oscillation voltage detector detects a change in the oscillation frequency of the Colpitts oscillating circuit.

3. A mobile unit support system, comprising:

at least one mobile unit formed with a dielectromagnetic material and having a radio wave generator;

a magnetic member for forming a magnetic field in a vicinity of a movement path of the at least one mobile unit; and

at least one magnetic sensor separated from the magnetic member by a predetermined distance, the magnetic sensor including;

a Colpitts oscillating circuit having;

at least one magnetic impedance element having an impedance that is changed by a variation of the magnetic field when the at least one mobile unit moves through the magnetic field, and

a transistor and which is operated by a DC current,

whereby an output oscillation frequency and amplitude of the Colpitts oscillating circuit changes when the impedance of the magnetic impedance element changes,

an internal excitation power source which applies a predetermined voltage between a base and an emitter of the transistor so that the Colpitts oscillating circuit enters an oscillation excitation state;

an antenna that, in response to an input of a radio wave from said radio wave generator when the at least one mobile unit approaches, causes the internal excitation power source to apply the predetermined voltage so that the Colpitts oscillating circuit enters the oscillation state;

an oscillation voltage detector that detects a change of an oscillation voltage output of the Colpitts oscillating circuit, and

a transmitter for transmits a signal indicating detection of a change in the oscillation voltage output of the Colpitts oscillating circuit.

4. A mobile unit support system, comprising:

at least one oscillation sensor disposed in a vicinity of a movement path of a mobile unit, the at least one oscillation sensor including;

a receiving antenna for receiving radio waves and producing a high-frequency signal in response thereto,

an impedance circuit employing an input for receiving the high-frequency signal from the receiving antenna, a magnetic impedance element having an impedance that is changed by a variation of a surrounding magnetic field, and an output for providing an output signal, the impedance circuit changing the high-frequency signal present at the input from the receiving antenna according to variations in the surrounding magnetic field to provide an output signal,

an amplifier for amplifying the output signal from the impedance circuit, and

a transmitting antenna for transmitting the amplified output signal from the amplifier; and

at least one mobile unit including;

a radio wave generator,

a receiver for receiving a signal from the transmitting antenna, and

a processor which processes signals received by the receiver and informs a driver of the at least one mobile unit of information obtained by processing the signals received by the receiver, or which processes signals received by the receiver and controls movement of the at least one mobile unit on the basis of the processing.