Time-of-flight localization

Patent metadata

Field	Value
Publication number	US-9623558-B1
Application number	US-201414574084-A
Country	US
Kind code	B1
Filing date	Dec 17, 2014
Priority date	Dec 17, 2014
Publication date	Apr 18, 2017
Grant date	Apr 18, 2017

Abstract

Robotic units may operate in a workspace that is shared with human workers. In order to safeguard the workers, operation of a robotic unit may be inhibited when a worker is near the robotic unit. In order to determine the position of the worker and thereby determine the proximity of the worker and the robotic unit, a time-of-flight measurement is performed to determine the distance of the worker from each of multiple reference locations within or about the workspace. A circular bounding area is defined around each reference location based on the determined distances. A bounded position area is identified as the intersection of the circular bounding areas. The worker is then indicated as being within the bounded position area.

First claim

What is claimed is:

1. A system, comprising:
multiple reference radios at respective known locations;
a portable radio;
each reference radio being configured to communicate with the portable radio to determine a signal flight time between the portable radio and the reference radio; and
control logic configured to perform actions comprising:
calculating, at a first time, a maximum possible distance of the portable radio from the respective location of each reference radio based at least in part on the signal flight time between the portable radio and the reference radio;
determining multiple bounding areas, wherein each bounding area is centered on a corresponding one of the respective locations of the multiple reference radios and has a radius that is at least as great as the calculated maximum possible distance of the portable radio from the corresponding one of the respective locations;
determining an intersecting area of the multiple bounding areas; and
determining, at or near the first time, that the portable radio is located at any position within the intersecting area.

2. The system of claim 1 , wherein each signal flight time comprises a round-trip flight time.

3. The system of claim 1 , wherein each reference radio is configured to communicate with the portable radio using an ultra-wideband communications protocol or a Wi-Fi communications protocol to determine the signal flight time between the portable radio and the reference radio.

4. The system of claim 1 , the actions further comprising:
determining that a first reference radio of the reference radios is not able to determine the signal flight time between the portable radio and the first reference radio; and
wherein the multiple bounding areas correspond to the respective locations of one or more second reference radios other than the first reference radio.

5. The system of claim 1 , wherein:
the portable radio is carried by a person within a workspace;
the actions further comprising:
identifying equipment that is within a predetermined distance of the intersecting area or inside the intersecting area; and
providing instructions to inhibit operation of the identified equipment to safeguard the person.

6. The system of claim 1 , wherein the portable radio is configured to receive a first signal from one of the reference radios and to provide a second signal to said one of the reference radios after a predetermined response delay from receiving the first signal.

7. The system of claim 1 , wherein calculating the maximum possible distance of the portable radio from the location of each reference radio comprises multiplying the signal flight time by the propagation speed of electromagnetic waves.

8. A method, comprising:
receiving, by a portable radio, a first signal from multiple reference radios at respective locations;
transmitting a second signal from the portable radio to the multiple reference radios;
determining, with a control logic, a signal flight time between the portable radio and each of the multiple reference radios;
calculating, at a first time with the control logic, a distance of the portable radio from the respective location of each reference radio based at least in part on the signal flight time between the portable radio and the reference radio;
determining, with the control logic, one or more bounding areas, wherein each bounding area is centered on a corresponding one of the respective locations and has a radius that is at least as great as the calculated distance of the portable radio from the corresponding one of the respective locations;
determining, with the control logic, an intersecting area of the one or more bounding areas; and
determining, at substantially the first time with the control logic, that the portable radio is located at any position within the intersecting area.

9. The method of claim 8 , wherein determining the signal flight time with the control logic comprises communicating with the portable radio using an ultra-wideband communications protocol or a Wi-Fi communications protocol.

10. The method of claim 8 , further comprising:
determining, with the control logic, that a first reference radio of the multiple reference radios is not able to at least one of: (1) send the first signal to the portable radio or (2) receive the second signal from the portable radio; and
wherein the one or more bounding areas correspond to the respective locations of one or more second reference radios other than the first reference radio.

11. The method of claim 8 , further comprising:
identifying equipment, with the control logic, that is within a predetermined distance of the intersecting area or inside the intersecting area; and
providing instructions from the control logic to the identified equipment to inhibit operation of the identified equipment.

12. The method of claim 8 , wherein the portable radio is configured to receive the first signal from one of the reference radios and to transmit the second signal to said one of the reference radios after a predetermined response delay from receiving the first signal.

13. The method of claim 8 , wherein calculating the distance from the portable radio to the respective location of each reference radio comprises multiplying the signal flight time by the propagation speed of electromagnetic waves.

14. A method, comprising:
sending one or more first signals from multiple reference radios at multiple locations to a portable radio;
receiving one or more second signals from the portable radio at the multiple reference radios at multiple locations;
determining, with a control logic, a signal flight time between the portable radio and each of the multiple reference radios;
calculating, in real-time with the control logic, a distance from the portable radio to the respective location of each reference radio based at least in part on the signal flight time between the portable radio and the respective reference radio;
determining one or more bounding areas, with the control logic, wherein each bounding area is centered on a corresponding one of the respective locations for the reference radios and has a radius that is at least as great as the calculated distance of the portable radio from the corresponding one of the respective locations;
determining, with the control logic, an intersecting area of the one or more bounding areas;
determining, in real-time with the control logic, that the portable radio is located at any position inside the intersecting area;
identifying, with the control logic, equipment that is inside the intersecting area; and
sending instructions from the control logic to the identified equipment to inhibit operation of the identified equipment in response to determining that the portable radio is located inside the intersecting area.

15. The method of claim 14 , wherein providing instructions from the control logic to the identified equipment to inhibit operation of the identified equipment in response to determining that the portable radio is located inside the intersecting area comprises providing instructions to inhibit the operation of a robotic unit.

16. The method of claim 14 further comprising:
determining, with the control logic, that at least one reference radio of the multiple reference radios is not able to at least one of: (1) send the one or more first signals or (2) receive the one or more second signals; and
providing instructions from the control logic to the identified equipment to inhibit operation of the identified equipment in response to determining that the at least one reference rad

Assignees

• Amazon Tech Inc

Inventors

• Stubbs Andrew
• Cohn Jonathan Evan

Classifications

• G01S2205/01

  specially adapted for specific applications · CPC title

• B25J9/1666 Primary

  Avoiding collision or forbidden zones · CPC title

• B25J5/00

  Manipulators mounted on wheels or on carriages (B25J1/00 takes precedence; programme-controlled manipulators B25J9/00 {; vehicle aspects B60, B62, e.g. remote-controlled steering for motor vehicles B62D1/24; control of position of vehicles G05D1/00}) · CPC title

• Y10S901/01

  Mobile robot · CPC title

• B25J9/162

  Mobile manipulator, movable base with manipulator arm mounted on it · CPC title