Vision System With Deterministic Low-Latency Communication

• US 20090027509A1
• Filed: 07/25/2007
• Published: 01/29/2009
• Est. Priority Date: 07/25/2007
• Status: Active Grant

• Current Assignee: National Instruments Corporation (Emerson Electric Company)
• Original Assignee: National Instruments Corporation (Emerson Electric Company)
• Inventors: Giesen, Robert J. B.
• Granted Patent: US 7,760,238 B2
• Time in Patent Office: Days
• US Class Current: 348/211.300
• CPC Class Codes: H04N 23/661 Transmitting camera control signals through networks, e.g. control via the Internet
• CPC Class Codes: H04N 23/90 Arrangement of cameras or camera modules, e.g. multiple cameras in TV studios or sports stadiums

Abstract

Vision system and method. The system includes a vision system, including: a camera, a processor and memory, coupled to the camera, and an EtherCAT interface, coupled to the processor and memory, possibly contained in a chassis, and operable to couple to an EtherCAT network that provides for deterministic low-latency communication between the vision system and devices coupled to the EtherCAT network. The vision system may be configurable to operate as any of: an EtherCAT master device, an EtherCAT slave device, or a TCP/IP Ethernet device. One or more additional vision systems may couple to the EtherCAT network. The vision systems may be synchronized using an EtherCAT distributed clock technique, time-based triggered, and/or event triggered, via the EtherCAT network, e.g., in a multi-view vision, collaborative processing, control, I/O, or video servoing application, e.g., using an EtherCAT deterministic low latency closed loop feedback system, including processing, control, or I/O devices.

Claims

1. A system, comprising:

a vision system, comprising;

a camera;

a processor and memory, coupled to the camera; and

an EtherCAT interface, coupled to the processor and memory, and operable to couple to an EtherCAT network;

wherein the EtherCAT network provides for deterministic low-latency communication between the vision system and devices coupled to the EtherCAT network.

2. The system of claim 1, wherein the vision system is an EtherCAT slave device.

3. The system of claim 1, wherein the vision system is an EtherCAT master device.

4. The system of claim 1, wherein the vision system is configurable to operate as any of:

an EtherCAT master device;

an EtherCAT slave device;

or

a TCP/IP Ethernet device.

5. The system of claim 1, further comprising:

one or more additional vision systems, coupled to the EtherCAT network;

wherein the vision system and the one or more additional vision systems compose a plurality of vision systems, and wherein the plurality of vision systems are synchronized using an EtherCAT distributed clock technique.

6. The system of claim 5, wherein the plurality of vision systems are operable to be time-based triggered via the EtherCAT network.

7. The system of claim 6, further comprising:

wherein the vision system comprises an EtherCAT master device, and each of the one or more additional vision systems comprises a respective EtherCAT slave device, and wherein the plurality of vision systems implement a multi-view vision application with respect to a target object, wherein each of the one or more additional vision systems is operable to send vision data to the EtherCAT master device via the EtherCAT network.

8. The system of claim 6, further comprising:

wherein the vision system comprises an EtherCAT master device, and each of the one or more additional vision systems comprises a respective EtherCAT slave device, and wherein the plurality of vision systems are operable to perform collaborative processing with respect to a target object, wherein each of the one or more additional vision systems is operable to send vision data to the EtherCAT master device via the EtherCAT network.

9. The system of claim 1, further comprising:

one or more additional vision systems, coupled to the EtherCAT network;

wherein the vision system and the one or more additional vision systems compose a plurality of vision systems, and wherein the plurality of vision systems are operable to be event triggered via the EtherCAT network.

10. The system of claim 9, further comprising:

wherein the vision system comprises an EtherCAT master device, and each of the one or more additional vision systems comprises a respective EtherCAT slave device, and wherein the plurality of vision systems implement a multi-view vision application with respect to a target object, wherein each of the one or more additional vision systems is operable to send vision data to the EtherCAT master device via the EtherCAT network.

11. The system of claim 9, further comprising:

wherein the vision system comprises an EtherCAT master device, and each of the one or more additional vision systems comprises a respective EtherCAT slave device, and wherein the plurality of vision systems is operable to perform collaborative processing with respect to a target object, wherein each of the one or more additional vision systems is operable to send vision data to the EtherCAT master device via the EtherCAT network.

12. The system of claim 1, further comprising:

at least one EtherCAT device, coupled to the vision system via the EtherCAT network;

wherein the vision system is operable to send data on the EtherCAT network for use by the at least one EtherCAT device to perform a control function.

13. The system of claim 12, further comprising:

an EtherCAT master device, coupled to the EtherCAT network; and

one or more additional vision systems, coupled to the EtherCAT network;

wherein the vision system and the one or more additional vision systems compose a plurality of vision systems, and wherein each of the plurality of vision systems is operable to send vision data to the EtherCAT master device, wherein the EtherCAT master device is operable to generate control data based on the received vision data, and send the control data to the at least one EtherCAT device to perform a control function.

14. The system of claim 1, further comprising:

at least one EtherCAT device, coupled to the vision system via the EtherCAT network;

wherein the vision system is operable to send data on the EtherCAT network for use by the at least one EtherCAT device to perform an I/O function.

15. The system of claim 1, further comprising:

at least one EtherCAT motion control device, coupled to the vision system via the EtherCAT network, wherein the vision system is operable to;

acquire images;

determine motion control data based on information in the acquired images;

deterministically send the motion control data to the at least one EtherCAT motion control device via the EtherCAT network to control the at least one EtherCAT motion control device to perform a portion of a motion control task; and

repeat said acquiring, said determining, and said sending in an iterative manner to perform successive portions of the motion control task based on the information, thereby performing a visual servoing control loop with a frequency of 1 KHz or higher.

16. The system of claim 1,

wherein the a vision system comprises a smart camera, comprising:

the camera;

the processor and memory;

the EtherCAT interface; and

a chassis, containing the camera, the processor and memory, and the EtherCAT interface.

17. A system, comprising:

a plurality of vision systems, each comprising;

a camera;

a processor and memory, coupled to the camera; and

a network interface, coupled to the processor and memory, and operable to couple to a network;

wherein a first vision system of the plurality of vision systems comprises a master device, and wherein others of the plurality of vision systems comprise slave devices;

wherein the master device is operable to place a frame on the network, wherein the frame includes data addressed to each of one or more of the slave devices; and

wherein each slave device is operable to read the data addressed to the slave device and write data to the frame while the frame passes through the slave device.

18. The system of claim 17, wherein the network comprises an EtherCAT network.

19. A method, comprising:

providing an EtherCAT master device;

providing one or more vision systems, each comprising a camera, a processor, memory, and an EtherCAT interface, coupled to the processor and memory, wherein the EtherCAT master device and the one or more vision systems are each coupled to an EtherCAT network, wherein the EtherCAT network provides for deterministic low-latency communication between the EtherCAT master device and the one or more vision systems, and wherein each of the vision systems is configured as an EtherCAT slave device; and

the EtherCAT master device triggering the one or more vision systems via the EtherCAT network.

20. The method of claim 19, wherein the EtherCAT master device is a vision system, comprising a camera, a processor and memory, and an EtherCAT interface.

21. A method, comprising:

providing one or more vision systems, each comprising a camera, a processor, and memory, wherein each of the one or more vision systems is configured as an EtherCAT device, and wherein the one or more vision systems are coupled to an EtherCAT network; and

synchronizing the one or more vision systems using an EtherCAT distributed clock technique.

22. A method, comprising:

providing one or more EtherCAT motion control systems, each comprising an EtherCAT interface;

providing one or more EtherCAT vision systems, each comprising a camera, a processor and memory, and EtherCAT interface, wherein the one or more EtherCAT motion control systems and the one or more EtherCAT vision systems are coupled to an EtherCAT network, composing a deterministic low latency closed loop feedback system, wherein the latency is less than or equal to 1 millisecond;

the one or more EtherCAT vision systems acquiring images of a target object, and generating visual information based on the images;

the one or more EtherCAT vision systems sending the visual information to a master EtherCAT device coupled to the EtherCAT network;

the master EtherCAT device computing motion control information based on the visual information, and sending the motion control information to the one or more EtherCAT motion control systems; and

the one or more EtherCAT motion control systems operating according to the motion control information;

wherein said one or more EtherCAT vision systems acquiring images, said one or more EtherCAT vision systems sending the visual information, said master EtherCAT device sending the motion control information, and said one or more EtherCAT motion control systems operating implement a high frequency visual servoing control loop with an operating frequency greater than or equal to 1 Khz; and

repeating said one or more EtherCAT vision systems acquiring images, said one or more EtherCAT vision systems sending the visual information, said master EtherCAT device sending the motion control information, and said one or more EtherCAT motion control systems operating in an iterative manner, to perform a visual servoing task.