Method and apparatus for lane sensing for automatic vehicle steering

A vehicle control system for controlling a vehicle operable to travel over a surface, the system comprising:

• a transmitter on the vehicle operable to illuminate a first predetermined area of the surface beneath the vehicle;
• a first receiver on the vehicle operable to receive reflections from a second predetermined area of the surface beneath the vehicle;
• a second receiver on the vehicle operable to receive reflections from a third predetermined area of the surface beneath the vehicle, said second and third predetermined areas disposed substantially adjacent one another and each comprising portions of said first predetermined area;
• a processor coupled to said first and second receiver and operable to determine the difference in the amplitudes of the reflections received by said first and second receivers and generate a steering control signal responsive to said difference, said first and second receivers receiving reflections from a reflective areas disposed on the surface and illuminated by the transmitter resulting in said difference when said stripe is not disposed equally in said second and third predetermined areas, said reflections received by said first and second receivers varying in response to said intervals, said processor comprising circuitry for counting said intervals to yield a value proportional to the speed of the vehicle, said processor circuitry further operable to generate a speed signal indicating the speed of the vehicle;
• a speed control system operable to receive said speed signal and adjust the speed of the vehicle so as to keep the speed of the vehicle constant.

A method for controlling a vehicle operable to travel over a surface, the method comprising the steps of:

• illuminating a first predetermined area of the surface beneath the vehicle using a transmitter on the vehicle;
• receiving reflections from a second predetermined area of the surface beneath the vehicle using a first receiver on the vehicle;
• receiving reflections from a third predetermined area of the surface beneath the vehicle using a second receiver on the vehicle, the second and third predetermined areas disposed substantially adjacent one another and each comprising portions of the first predetermined area;
• determining the difference in the amplitudes of the reflections received by the first and second receivers using a processor coupled to the first and second receiver;
• and
• generating a steering control signal responsive to the difference using the processor, the reflections being received from a stripe broken in predetermined intervals of unmarked and reflective areas disposed on the surface and illuminated by the transmitter resulting in the difference in the amplitudes when the stripe is not disposed equally in the second and third predetermined areas.