Automatic steering means for a driverless carriage

• US 4,344,498 A
• Filed: 12/27/1979
• Issued: 08/17/1982
• Est. Priority Date: 01/02/1979
• Status: Expired due to Term

• Current Assignee: Olof H. Lindfors
• Original Assignee: Olof H. Lindfors
• Inventors: Lindfors, Olof H.
• Primary Examiner(s): Mitchell, David M.
• Application Number:
  US06/107,601
• Time in Patent Office: 964 Days
• Field of Search: 180/168, 180/167, 180/131, 180/197, 180/79, 180/6.5, 180/216, 318/587, 414/273, 46/261
• US Class Current: 180/168
• CPC Class Codes: B62D 1/28 non-mechanical , e.g. following a line or other known markers
• CPC Class Codes: G05D 1/0272 comprising means for registering the travel distance, e.g. revolutions of wheels measuring distance traversed on the ground by vehicles, e.g. using odometers G01C22/00

Abstract

A driverless carriage with automatic steering rendering the carriage capable of travelling in a straight line as well as performing a rotation about a vertical axis. To improve the precision of the turning movement, the carriage monitors during said movement the position, with reference to the surface on which the carriage moves, of the axis of rotation of the carriage. At least one measuring wheel engages the surface to detect a deviation of said vertical axis from a stationary position to produce a correction signal used for adjusting the steering of the carriage so as to eliminate the deviation of said vertical axis from the proper position.

Claims

1. In a driverless carriage comprising

a carriage chassis,

at least three wheels for supporting said chassis,

motor means and transmission means for driving at least one of said wheels,

first bearing means for not more than two of said wheels, said first bearing means being arranged to define a single geometrical axis of said wheel or wheels which extends in a fixed horizontal direction with respect to the chassis,

second bearing means for the remaining at least one supporting wheel, said second bearing means being pivotably connected to the chassis to allow adjustment of the direction of said at least one supporting wheel with respect to the chassis and thus to enable the carriage to turn about a vertical slewing axis intersecting said single geometrical axis, and,

steering means for adjusting the position of said slewing axis with respect to the chassis,

the improvement comprising

means for monitoring the position of said slewing axis including

at least one non-driven measuring wheel arranged to engage the surface supporting the carriage, said measuring wheel having a horizontal geometrical axis extending in the same vertical plane as said single geometrical axis, and,

signal generating means arranged to be operated by said at least one measuring wheel for generating a signal representing the rate of rotation of the measuring wheel,

said monitoring means being arranged to provide an output signal derived from the signal generated by said signal generating means so as to have a sign representing forward and backward movement respectively and a magnitude representing the rate of speed, with respect to the surface supporting the carriage, of a predetermined point of said single geometrical axis, said point defining a desired position of said slewing axis, and,

means controlled by said output signal for operating said steering means in such a way as to cause said steering means to adjust the slewing axis into said desired position.

2. In a carriage as claimed in claim 1 provided with two measuring wheels, the further improvement comprising

a registering meter arranged to receive the signals transmitted during a turning operation by the signal generating means operatively connected with at least one of said measuring wheels and to compute therefrom a quantity representing the angle of rotation of the carriage resulting from said turning operation, and,

means for comparing said computed quantity with a preset quantity representing a predetermined change of direction of the chassis.

3. In a carriage as claimed in claim 1, the further improvement comprising,

a registering meter arranged to receive the signals transmitted during the passage of the carriage from one location to another by said signal generating means and to compute therefrom a quantity representing the distance travelled by the carriage during said passage, and,

means for comparing said computed quantity with a preset quantity representing a predetermined distance.

4. In a carriage as claimed in claim 2, the further improvement comprising,

a registering meter arranged to receive the signals transmitted during the passage of the carriage from one location to another by the signal generating means operatively connected with at least one of said measuring wheels and to compute therefrom a quantity representing the distance travelled by the carriage during said passage, and,

means for comparing said computed quantity with a preset quantity representing a predetermined distance.

5. A carriage as claimed in claim 2 in which said non-driven measuring wheels also constitute two of said at least three supporting wheels.

6. In a driverless carriage comprising

a carriage chassis,

at least three wheels for supporting said chassis,

motor means and transmission means for driving at least one of said wheels,

first bearing means for not more than two of said wheels, said first bearing means being arranged to define a single geometrical axis of said wheel or wheels which extends in a fixed horizontal direction with respect to the chassis,

second bearing means for the remaining at least one supporting wheel, said second bearing means being pivotably connected to the chassis to allow adjustment of the direction of said at least one supporting wheel with respect to the chassis and thus to enable the chassis to turn about a vertical slewing axis intersecting said single geometrical axis, and, steering means for adjusting the position of said slewing axis with respect to the chassis,

the improvement comprising two non-driven measuring wheels of equal diameters having a common horizontal geometrical axis extending in the vertical plane through said single geometrical axis,

two signal generators each of which is operated by one of said measuring wheels to provide a signal representing the rate of rotation of the measuring wheel,

means for comparing said signals and for producing an output signal representing the difference between the rates of rotation of said measuring wheels, and

means controlled by said output signal for adjusting said steering means towards a setting rendering the rates of rotation of the measuring means equal.