Data processing: vehicles – navigation – and relative location – Vehicle control – guidance – operation – or indication
Reexamination Certificate
1999-11-26
2001-11-06
Cuchlinski, Jr., William A. (Department: 3661)
Data processing: vehicles, navigation, and relative location
Vehicle control, guidance, operation, or indication
C701S002000, C701S004000, C701S005000, C700S001000, C700S245000, C700S251000, C700S254000, C700S258000, C700S262000, C700S275000, C318S139000, C318S489000, C318S587000, C180S167000, C180S168000, C180S169000
Reexamination Certificate
active
06314341
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention pertains to a vehicle, specifically to computing and storing its trajectory data and sensor data for a manually-driven vehicle. This invention falls into the Classification Definitions of 701/002 and 701/025.
Wheeled unmanned vehicles are widely adopted in manufacturing, services, and other industries. For instance, in manufacturing factories, they are used for unmanned material handling tasks. In semiconductor clean rooms, unmanned vehicles with articulated manipulators are widely used for silicon cassette handling to eliminate human operators who may produce unwelcome dust. Some hospitals use meal-delivering vehicles for cost-saving measures.
Heretofore, two methods have been known to navigate unmanned vehicles: an electrical/optical method and a programming method. The electrical/optical navigation method uses inductive wires or optical tapes pasted on the floor that are tracked by a vehicle. Another method is navigating a vehicle by computer programming.
U.S. Pat. No. 4,816,998 described a method for a self-pivoting vehicle of computing a steering angle signal by dead reckoning from a predetermined desired trajectory for the vehicle.
U.S. Pat. No. 5,109,340 describes a method for an autonomous vehicle of planning smooth paths by using Clothoid curves that has the feature of curvature continuity.
U.S. Pat. No. 5,170,352 describes a method for an autonomous vehicle of detecting obstacles and detecting the target areas of which the vehicle to be directed. The vehicle is supposed to operate within a predetermined physical area such as on the deck of an aircraft carrier.
U.S. Pat. No. 5,219,036 describes a method for an unmanned industrial trucks of guiding themselves using reference points embedded in the floor and a path-tracking algorithm.
U.S. Pat. No. 5,233,526 describes a method for a driverless vehicle of relocking on a theoretical trajectory during the passage of the vehicle by modifying its curvature. This method guarantees that the curve has the curvature-continuity.
U.S. Pat. No. 5,621,291 describes a method for a self-propelled robotic vacuum cleaner of controlling its motion by ultrasonic sensors.
U.S. Pat. No. 6,134,486 describes a method for a vehicle of tracking a path consisting of directed lines and circles.
U.S. Pat. No. 6,138,064 describes a method for a vehicle of branching from a main line and of merging into the main line again.
These just described navigation methods, however, suffer from a number of disadvantages: (A) As to the electrical/optical method, it is time consuming and costly to implement the wires or optical tapes in the working environment. The cost increases proportionally with its total travelling distance. Furthermore, it is also time consuming and costly to change a once implemented wire/tape because of environmental or mission modifications. In clean room applications, using wires/tapes themselves is not desirable because they may become a source of dust. (B) The programming method has problems also. Measurement of a path in the vehicle's operating environment is needed to program the vehicle. This is a time-consuming task. In some situations, an ideal path for the task cannot be defined easily by programming.
There is another problem where an unmanned vehicle is used for practical applications. A geometrical map of the vehicle environment is necessary for the vehicle's precise motion. Heretofore, there is no economical and simple method known to do this task.
BRIEF SUMMARY OF THE INVENTION
The prior art made of record cited in the previous section describe methods of controlling an autonomous vehicle by computer programs. However, this invention states a manual-controlling method of a non-autonomous vehicle.
One objective of the invention is to provide a method of recording trajectory data for a manually-driven vehicle. More specifically, the trajectory data contains the trajectory length traveled by the vehicle, vehicle frame (position and orientation), and trajectory curvature computed at each motion execution interval. This is a method of manually teaching trajectories to vehicles. Another objective of the invention is, in case a sensor is mounted on the vehicle, to provide a method of storing trajectory sensor data taken along the vehicle's manual motion at each sensor execution interval. The sensor data contains the trajectory length, vehicle frame, sensor frame, and information collected by the sensor.
An advantage of the invention is that the trajectory data contains the necessary and sufficient geometrical information (the length, position, orientation, curvature of each section of the trajectory) needed to reproduce the manually generated trajectory. The curvature is essential information to obtain better control of vehicles. Approximating each trajectory section by a circular arc or by a straight line is the best known method for vehicle odometry.
Another advantage is that any trajectory that is hard to define mathematically can be generated by the method since the vehicle trajectory is generated manually. Thus the invention solves one of the problems stated earlier that an ideal path for some task is difficult to define by a computer program.
Still further advantage of the invention is that it provides a timesaving and economical method of defining and modifying trajectories to a vehicle. For a vehicle equipped with a program implementing the invention, teaching a new trajectory can be done in a single manual driving session. Thus the invention solves another problem stated earlier that implementing and changing inductive wires or optical tapes is time consuming and costly.
Still further advantage of the invention is that it provides only spatial information of the vehicle trajectory without any timing information. This method allows more general playing back of the recorded motion, because a user can select any speed profile for a play-back motion independent of the speed profile at the teaching mode.
Still further advantage of the invention is to provide a hardware-independent method of handling the trajectory information. The invention can be applied to different vehicles with an arbitrary size and with an arbitrary wheel architecture such as differential-drive, tricycle, or car-like.
Still further advantage of this invention is to provide a straightforward method of recording on-board sensor information about the external world while the vehicle is manually-driven. This information helps the vehicle later when it reproduces the same motion for positional identification (or localization) and other purposes.
Still further advantage of this invention is to provide a straightforward method of creating a map of the world by a vehicle using an appropriate range sensor, such as a sonar. The range sensor data is an envelope of objects in the world that is scanned by the sensor. The envelope can be edited manually or by a computer program to generate a geometrical map. This method is far easier than the method of physically measuring the world by hand to generate a map. If the vehicle is operated by a person who has the knowledge of the physical characteristics of the sensor, he/she can drive the vehicle to maximize the sensor information.
Still further advantage of this invention is that the world map taken by a sensor during the teaching mode and the sensor data obtained in the play-back mode are consistent, since the sensor used in both modes are the same used at similar positions and orientations. Therefore, a localization task (or vehicle's positional error resetting) becomes easier and meaningful. If the world map had been manually made without the sensor, inherent differences between the hand-made map and the sensor data would degrade the localization task.
In this invention, an odometry method of computing the trajectory information (the trajectory length, coordinates, orientation, and curvature) for recording is stated. The method apparently is parallel to the one of computing the trajectory information of a computer-controlled vehicle as a part of the posit
Cuchlinski Jr. William A.
Mancho Ronnie
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