Method for automatic recovery of lost communications for unmanned ground robots

• US 9,246,749 B1
• Filed: 11/29/2012
• Issued: 01/26/2016
• Est. Priority Date: 11/29/2012
• Status: Active Grant

• Current Assignee: the united states of america as represented by the secretary of the navy
• Original Assignee: The United States of America As Represented By The Secretary of Agriculture
• Inventors: Nguyen, Hoa Gia
• Primary Examiner(s): Tran, Khoi
• Assistant Examiner(s): Rink, Ryan
• Application Number:
  US13/689,545
• Time in Patent Office: 1,153 Days
• US Class Current: 1/1
• CPC Class Codes: G05D 1/0022 characterised by the communication link data switching networks in general H04L12/00
• CPC Class Codes: G05D 1/028 using a RF signal
• CPC Class Codes: H04L 41/0654 using network fault recovery ring fault isolation or reconfiguration in loop networks without recovery actions by a network management system H04L12/437
• CPC Class Codes: H04L 43/0811 by checking connectivity

Abstract

A lost communications link recovery method for a remotely-operated robot comprising the following steps: monitoring command and control (C2) signals transmitted over a wireless network from an operator control unit (OCU) to the robot; storing the C2 signals in a sliding window buffer; monitoring the wireless network for communication link breaks between the OCU and the robot; and creating, and issuing to the robot, reverse C2 commands based on the stored C2 signals upon detecting a communication link break.

Claims

1. A lost communications link recovery method for a remotely-operated robot comprising the following steps:

receiving command and control (C2) signals transmitted over a wireless network from an operator control unit (OCU) to the robot, wherein the C2 signals comprise movement instructions for the robot;

issuing received C2 signals to the robot;

storing past C2 signals in a sliding window buffer;

monitoring the wireless network for communication link breaks between the OCU and the robot;

creating, and issuing to the robot, reverse C2 commands based on the stored C2 signals upon detecting a communication link break, wherein the reverse C2 commands are opposites of the stored C2 signals that are issued to the robot on a last-in-first-out basis until the communication link is restored or the sliding window buffer is empty; and

wherein the above steps are performed by a radio processor inside a radio receiver without the aid of external environmental characteristic sensors, and wherein the radio receiver is mounted to the robot and is electronically connected to an internal processor inside the robot.

2. The method of claim 1, further comprising the steps of:

waiting a predefined period of time after detecting a communication link break;

resuming normal operations if the communication link is reestablished before the end of the predefined period; and

creating the reverse C2 commands only if the communication link has not been reestablished by the end of the predefined time period.

3. The method of claim 2, wherein the predefined time period is greater than two seconds and less than 20 seconds.

4. The method of claim 1, wherein the steps performed by the radio processor are performed without modifying software residing on the robot'"'"'s internal processor.

5. The method of claim 4, wherein the steps performed by the radio processor are performed without modifying software residing on the OCU.

6. The method of claim 1, wherein the reverse C2 commands are based solely on the past C2 signals.

7. The method of claim 1, wherein no optical imaging or space-based-satellite-navigation-system sensors are used to reestablish the communication link.

8. The method of claim 1, wherein no way-point navigation is used to reestablish the communication link.

9. The method of claim 1, wherein no maps are used to reestablish the communication link.

10. The method of claim 1, further comprising the steps of

determining if the robot is right-side up after detecting a communication link break;

and

if the robot is determined not to be right-side up, performing the following steps before issuing reverse C2 commands;

performing self-righting maneuvers by the robot, and

positioning the robot such that its orientation is substantially equal to its orientation just before the communication link break.

11. A method for restoring wireless network connectivity between a remotely-operated robot and an operator control unit (OCU) comprising the following steps performed by a radio processor inside a radio receiver without the aid of external environmental characteristic sensors:

receiving command and control (C2) signals transmitted to the robot over the wireless network from the OCU, wherein the C2 signals comprise movement instructions for the robot;

issuing the received C2 signals to the robot to execute;

storing the received C2 signals in a sliding window buffer such that when a new C2 signal is received and stored the oldest stored C2 signal is purged from the buffer;

monitoring the wireless network for communication link breaks between the OCU and the robot; and

performing the following steps upon detecting a communication link break;

resuming normal operations if the communication link is reestablished before the end of a predefined period,

creating reverse C2 commands based on the stored C2 signals if the communication link is not reestablished before the end of the predefined period, wherein the reverse C2 commands comprise opposite movement instructions to the stored C2 signals, and

issuing the reverse C2 commands to the robot to execute on a last-in-first-out basis, such that the reverse C2 command corresponding to the newest stored C2 signal is issued to the robot first, until the communication link is restored or the sliding window buffer is empty.

12. The method of claim 11, wherein no optical imaging or space-based-satellite-navigation-system sensors are used to reestablish the communication link.

13. The method of claim 11, further comprising the steps of:

determining if the robot is right-side up after the robot detects a break in the communication link; and

if the robot is determined not to be right-side up, performing the following steps before issuing reverse C2 commands;

performing self-righting maneuvers by the robot, and

positioning the robot such that its orientation is substantially equal to its orientation just before the communication link break was detected.

14. A lost communications link recovery method for a remotely-operated robot comprising the following steps:

1.) receiving wirelessly-transmitted command and control (C2) signals from an operator control unit (OCU) with a radio receiver mounted to the robot, wherein the C2 signals comprise movement instructions for the robot, and wherein the radio receiver performs the following steps;

a.) relaying the received C2 signals to an internal processor inside the robot such that the robot executes the movement instructions;

b.) storing the received C2 signals in a sliding window buffer;

c.) monitoring a wireless network for communication link breaks between the OCU and the robot;

d.) upon detecting a communication link break, creating a reverse C2 command that comprises a movement instruction that is opposite of the last-received C2 signal in the sliding window buffer;

e.) issuing the reverse C2 command to the robot as if the reverse C2 command came from the OCU such that the robot executes the reverse C2 command;

f.) removing the last-received C2 signal from the sliding window buffer after its corresponding reverse C2 command is issued to the robot; and

g.) repeating steps (d) through (f) until the communication link is restored or the sliding window buffer is empty.

15. The method of claim 14, further comprising the steps of:

determining if the robot is right-side up after detecting a break in the communication link; and

if the robot is determined not to be right-side up, performing the following steps before issuing reverse C2 commands;

performing self-righting maneuvers by the robot, and

positioning the robot such that its orientation is substantially equal to its orientation just before the communication link break was detected.

16. The method of claim 15 wherein the reverse C2 commands are created based solely on the stored C2 signals in the sliding window buffer without the aid of external environmental characteristic sensors.