Method and apparatus for collision avoidance

• US 8,346,468 B2
• Filed: 07/07/2009
• Issued: 01/01/2013
• Est. Priority Date: 07/08/2008
• Status: Active Grant

• Current Assignee: TotalTrax, Inc.
• Original Assignee: Sky-Trax Incorporated (TotalTrax, Inc.)
• Inventors: Emanuel, David C., Kunzig, Robert S., Taylor, Robert M.
• Primary Examiner(s): Nguyen, Cuong H
• Application Number:
  US12/459,728
• Publication Number:
  US 20110093134A1
• Time in Patent Office: 1,274 Days
• Field of Search: 701/23, 701/301, 701/41, 701/117, 701/119, 342/71, 235/462, 340/901
• US Class Current: 701/301
• CPC Class Codes: B66F 17/003 for fork-lift trucks
• CPC Class Codes: B66F 9/063 Automatically guided
• CPC Class Codes: G05D 1/0289 with means for avoiding collisions between vehicles vehicle fittings for automatically controlling speed including means for detecting potential obstacles B60K31/0008; avoiding obstacles by action on the steering system B62D; radar, sonar, lidar systems designed for anti-collision purposes G01S13/93, G01S15/93, G01S17/93
• CPC Class Codes: G05D 1/0297 by controlling means in a control room

Abstract

A method and apparatus for avoiding collisions of moving vehicles in an environment that utilizes a position and rotational orientation system to track vehicle locations within a preconfigured operational zone, the method comprising using position tracking data to calculate a predicted trajectory and safety zone of each vehicle for a predetermined prediction time period and determining potential areas of intersection with vehicles to predict collisions.

Claims

1. A method for avoiding collisions between manned vehicles and other manned vehicles or between manned vehicles and automatically guided vehicles within a defined operational environment, the method comprising:

a) receiving, by a server, information on the position and orientation of each vehicle within the defined operational environment at predetermined time intervals from an optical position and rotational orientation system;

b) determining, by a collision avoidance apparatus configured to communicate with the server, a predicted trajectory and a safety zone for each vehicle by calculating the velocity and direction of travel of each vehicle from the position and orientation information at successive time intervals;

c) determining, by the collision avoidance apparatus, any areas of intersection of the safety zone of a manned vehicle with the safety zones of other manned or automatically guided vehicles to predict a potential collision;

d) transmitting instructions by the collision avoidance apparatus to the server to an automatically guided vehicle whose predicted safety zone lies within an area of intersection of the safety zone of another vehicles to reduce the speed or to stop the automatically guided vehicle to prevent the predicted collision, the automatically guided vehicle reducing its speed or stopping in response to the instructions; and

e) transmitting a warning by the collision avoidance apparatus to the server to one or more manned vehicles whose predicted safety zone(s) lies within an area of intersection of the safety zone of another vehicle to cause a driver interface of the one or more manned vehicles to alert the one or more drivers of a predicted potential collision, so that the one or more drivers can take appropriate action to avoid the predicted collision.

2. The method of claim 1 wherein the steps a) through c) are repeated and if no areas of intersection of the safety zones between a manned and an automatically guided vehicle are subsequently determined then

transmitting instructions by the collision avoidance apparatus to the server to an automatically guided vehicle previously slowed or stopped to resume its previous velocity, the automatically guided vehicle resuming its previous velocity in response to the instructions;

and if no areas of intersection of the safety zones between a manned and another manned vehicle are subsequently determined, then

transmitting a signal by the collision avoidance apparatus to the server canceling the alarm to the one or more manned vehicles to cause the driver interface of the one or more manned vehicles to alert the one or more drivers that no potential collision is predicted so that the one or more drivers can take appropriate action.

3. The method of claim 1 wherein the defined operational environment is divided into operational zones that define areas within which the vehicles operate and barrier zones that define fixed obstacles within the defined operational environment, the method further comprising in step c):

the collision avoidance apparatus determining from the predicted trajectory and safety zones of the vehicles if a barrier zone masks any areas of intersection of the safety zone of a manned vehicle or an automatically guided vehicle with the other safety zone of the manned or automatically guided vehicles, and thus not predicting a potential collision.

4. The method of claim 1 further comprising, before step b), assigning predetermined probability factors to account for operational capabilities of each vehicle, thus establishing an uncertainty band for the predicted trajectory and safety zone for each vehicle.

9. The method of claim 4 wherein determining a predicted trajectory and a safety zone is performed by:

choosing a look ahead period t1, the time period t1 used for prediction analysis;

choosing a probability threshold for reporting a predicted collision;

calculating a trajectory for each vehicle based upon a current direction of travel, a current orientation, and a speed of the vehicle to predict the vehicle'"'"'s position at time t1;

using an uncertainty band for the calculated trajectory, calculating a positional probability area of each vehicle at time t1;

calculating an area of intersection between the positional probability areas of pairs of safety zones of non-stationary vehicles V1 and V2;

comparing the area of intersection of the positional probability areas with the reporting threshold;

if the positional probability exceeds the reporting threshold, determining if the area of intersection lies beyond a barrier zone;

if the area of intersection of the positional probability areas lies beyond a barrier, canceling the predicted collision;

if the area of intersection of the positional probability areas does not lie beyond a barrier, transmitting a warning of the predicted collision to each vehicle, the warned vehicles able to take appropriate action to avoid collision.

5. A collision avoidance apparatus for avoiding collisions between vehicles, the apparatus comprising a computing device having a central processing unit, a memory for storing operating instructions and data related to manned and automatically guided vehicles, a communications interface and an operator console;

the apparatus communicating with at least one server that utilizes an optical position and rotational orientation system to track the location and rotational orientation of the vehicles within a preconfigured operational zone by receiving vehicle location and rotational orientation data at predetermined time intervals from the at least one server;

the apparatus calculating the current predicted trajectory and safety zone of each manned vehicle and each automatically guided vehicle at each predetermined time interval to determine any areas of intersection of safety zones of other manned or automatically guided vehicles;

the apparatus calculating a probability of collision of each manned vehicle and each automatically guided vehicle with other manned or automatically guided vehicles;

the apparatus comparing each probability of collision with a predetermined threshold;

the apparatus communicating each predicted collision with a probability above the threshold to the at least one server, the server issuing a command or a warning to the vehicles predicted to collide, the warned vehicles able to take appropriate action to avoid collision.

6. The apparatus of claim 5 wherein, after the warned vehicles take appropriate action to avoid collision:

the collision avoidance apparatus continuing to track the vehicles and continuing to determine any areas of intersection of safety zones, and if no areas of intersection of the safety zones between a manned and an automatically guided vehicle are subsequently determined, then

the collision avoidance apparatus transmitting instructions to the at least one server to an automatically guided vehicle previously slowed or stopped to resume its previous velocity, the automatically guided vehicle resuming travel in response to the instructions;

and if no areas of intersection of the safety zones between a manned and another manned vehicle are subsequently determined, then

the collision avoidance apparatus transmitting a signal to the at least one server to the one or more manned vehicles canceling the alarm to cause a driver interface of the one or more manned vehicles to alert the one or more drivers that no potential collision is predicted so that the one or more drivers can take appropriate action.

7. A method for avoiding collisions between manned vehicles and other manned vehicles or between manned vehicles and automatically guided vehicles within a defined operational environment, the method being implemented by a collision avoidance system that communicates with a manned vehicle server and with an automatically guided vehicle server, each server having an associated optical position and rotational orientation system, each manned vehicle having a driver interface, the method comprising:

a) optically determining the position and orientation of each vehicle within the defined operational environment relative to one or more of a plurality of position markers in known locations at predetermined time intervals;

b) the collision avoidance system receiving information from the associated optical position and rotational orientation systems on the position and orientation of each vehicle within the defined operational environment at the predetermined time intervals;

c) the collision avoidance system determining a predicted trajectory and a predicted safety zone for each vehicle by calculating a velocity and a direction of travel of each vehicle from the position and orientation information at successive time intervals;

d) the collision avoidance system determining any areas of intersection of the safety zone of a manned vehicle with the safety zones of other manned or automatically guided vehicles to predict a potential collision;

e) the collision avoidance system transmitting instructions to the automatically guided vehicle server to any automatically guided vehicle whose predicted safety zone falls within an area of intersection of safety zones to reduce the speed or to stop the automatically guided vehicle to prevent the predicted collision, the automatically guided vehicle reducing its speed or stopping in response to the instructions; and

f) the collision avoidance system transmitting a warning to the manned vehicle server to one or more manned vehicles whose predicted safety zone falls within an area of intersection to cause the one or more driver interfaces to alert the one or more drivers of a predicted potential collision, so that the one or more drivers can take appropriate action to avoid the predicted collision.

8. The method of claim 7 wherein the steps a) through d) are repeated and if no areas of intersection between the safety zone of a manned vehicle and the safety zone of an automatically guided vehicle are subsequently determined, then

the collision avoidance system transmitting instructions to the automatically guided vehicle server to any automatically guided vehicle previously slowed or stopped to resume its previous velocity, the automatically guided vehicle resuming its previous velocity in response to the instructions;

and if no areas of intersection between a manned and another manned vehicle are subsequently determined, then

transmitting a signal canceling the alarm to the manned vehicle server to the one or more manned vehicles to cause the one or more driver interfaces to alert the one or more drivers that no potential collision is predicted, so that the one or more drivers can take appropriate action.

10. A method, performed by a collision avoidance apparatus, for avoiding collisions between manned vehicles and other manned vehicles or between manned vehicles and automatically guided vehicles within a defined operational environment, the manned vehicles and the automatically guided vehicles each being equipped with an optical position and rotational orientation system for optically determining the position and orientation of each vehicle within the defined environment relative to position markers in known locations at predetermined time intervals, each optical position and rotational orientation system being in communication with a server, the method comprising:

a) the optical position and rotational orientation system on each vehicle transmitting information on the position and rotational orientation of each vehicle within the defined operational environment at predetermined time intervals to the server;

b) the server transmitting the position and rotational orientation information to the collision avoidance apparatus;

c) the collision avoidance apparatus assigning predetermined probability factors to account for operational capabilities of each vehicle, thus establishing an uncertainty band for the predicted trajectory and safety zone for each vehicle;

d) the collision avoidance apparatus determining a predicted trajectory and a safety zone for each vehicle by calculating a velocity and direction of travel of each vehicle from the position and rotational orientation information at successive time intervals;

e) the collision avoidance apparatus determining any areas of intersection of the safety zone of a manned vehicle with the safety zone of other manned or automatically guided vehicles to predict a potential collision by;

i) choosing a look ahead period t1, the time period t1 used for prediction analysis;

ii) choosing a probability threshold for reporting a predicted collision;

iii) calculating a trajectory for each vehicle based upon a current direction of travel, a current orientation, and a speed of the vehicle to predict the vehicle'"'"'s position at time t1;

iv) using the uncertainty band for the predicted trajectory, calculating a positional probability area of each vehicle at time t1;

v) calculating an area of intersection between the positional probability areas of pairs of safety zones of non-stationary vehicles;

vi) comparing the area of intersection of the positional probability areas with the reporting threshold;

vii) if the probability exceeds the threshold, determining if the area of intersection lies beyond a barrier;

viii) if the area of intersection of the positional probability areas lies beyond a barrier, generating a negative prediction of collision;

ix) if the area of intersection of the positional probability areas does not lie beyond a barrier, generating a positive prediction of collision;

f) the collision avoidance apparatus transmitting instructions to the server to an automatically guided vehicle within an area of intersection of the safety zones to reduce the speed or to stop the automatically guided vehicle to prevent the predicted collision, the automatically guided vehicle reducing its speed or stopping in response to the instructions;

g) the collision avoidance apparatus transmitting a warning to the server to one or more manned vehicles to cause the driver interface to alert the one or more drivers of a predicted collision, so that the one or more drivers can take appropriate action to avoid the predicted collision.