Method for updating in a wheeled vehicle steered by dead reckoning

• US 4,541,049 A
• Filed: 10/01/1981
• Issued: 09/10/1985
• Est. Priority Date: 10/02/1980
• Status: Expired due to Fees

• Current Assignee: AB Volvo
• Original Assignee: AB Volvo
• Inventors: Ahlbom, Sten H. N.
• Primary Examiner(s): Chin, Gary
• Application Number:
  US06/307,700
• Time in Patent Office: 1,440 Days
• Field of Search: 364/424, 364/436, 364/444, 364/449, 364/450, 364/559, 180/167-169, 318/587, 73/178 R
• US Class Current: 701/23
• CPC Class Codes: G05D 1/0231 using optical position detecting means position-fixing by using electromagnetic waves other than radio waves, e.g. optical position detecting means G01S5/16
• CPC Class Codes: G05D 1/0261 using magnetic plots
• 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

In a wheeled vehicle steered by dead reckoning, which calculates its own position on the basis of distances determined by rolling-off measurement, the error in position determination will increase gradually and necessitate updating. A floor is provided with markings which are observed by a linear detector mounted transversely in the vehicle, and linear images are obtained. At least two different measurements are carried out of the position of a marking in relation to the vehicle, and the distance travelled by the vehicle between the measurements is measured. From these three measured distances, the angle between the vehicle and the marking can be determined. An additional marking forming an angle with the first marking makes it possible to determine the position in the direction of movement of the vehicle as well.

Claims

1. In a wheeled vehicle steered by a method of dead reckoning whereby said vehicle computes a position and attitude from rolled off distance measurements, a method for determining said vehicle position and attitude for said dead reckoning method by sensing the vehicle position with respect to a linear marking having a known position in a coordinate system for said vehicle on a surface traversed by said vehicle comprising:

utilizing a linear detector attached to said vehicle in a direction transverse to the direction of movement of said vehicle to measure two consecutive positions of said vehicle with respect to said linear marking, said consecutive positions providing two consecutive intersections between said linear marking and said linear detector;

determining an undeviated rolled off first distance between said consecutive positions;

determining a second distance corresponding to the distance between the points of intersection of said linear detector and said linear marking at said two measured consecutive positions; and

,

determining from said first and second distances an angle between said linear marking and said vehicle, whereby said vehicle position with respect to said linear marking is known, indicating the vehicle position in said coordinate system.

2. In a vehicle steered by a method of dead reckoning whereby said vehicle computes a position and attitude from rolled off distance measurements, a method for determining said vehicle position and attitude for said dead reckoning method by sensing the vehicle position with respect to a linear marking having a known position in a coordinate system for said vehicle on a surface traversed by said vehicle comprising:

measuring the lateral deviation of said vehicle with respect to said linear marking with first and second linear detectors, said linear detectors being attached to said vehicle and spaced apart at a known distance and parallel to each other in a direction tranverse to said vehicle direction of movement, said lateral deviation being determined from the distance between the points of intersection of said linear marking and said linear detectors; and

determining the attitude of said vehicle from said lateral deviation and said known distance between said linear detectors.

3. In a wheeled vehicle steered by a method of dead reckoning, whereby said vehicle computes a position and attitude from rolled off distance measurements representing linear motion of said vehicle, a method for updating said vehicle position coordinates by detecting said vehicle position with respect to first and second linear markings which intersect each other on the surface supporting said vehicle comprising:

optically scanning said surface with a linear detector positioned on said vehicle to determine positional points on said detector intersected by said linear markings;

determining, at first and second positions of said vehicle, the intersection of each of said first and second linear markings with said linear detector, each of said intersections representing a lateral deviation of each of said linear markings with respect to said vehicle at said first and second positions;

determining the difference in lateral deviation between each of said markings and said vehicle at each of said positions whereby first and second differences in lateral deviation A30, A31, for each of said positions are determined;

measuring the rolled off distance S31 traversed by said vehicle between said first and second positions; and

,

determining the distance Y between one of said vehicle positions and the intersection of said first and second linear markings from said rolled off distance S31 and said differences in lateral deviation A30, A31, whereby said vehicle position with respect to said intersection of said linear markings is determined.