Line tracking data over Ethernet

• US 9,046,890 B2
• Filed: 09/05/2008
• Issued: 06/02/2015
• Est. Priority Date: 09/05/2008
• Status: Active Grant

• Current Assignee: Fanuc Robotics America Incorporated (Fanuc Corporation)
• Original Assignee: Fanuc Robotics America Incorporated (Fanuc Corporation)
• Inventors: Krause, Kenneth W., Huber, Jim, Wong, Ho Cheung, Graca, Randy, Clifford, Scott J.
• Primary Examiner(s): Nguyen, Bao Long T
• Application Number:
  US12/205,165
• Publication Number:
  US 20100063625A1
• Time in Patent Office: 2,461 Days
• US Class Current: 1/1
• CPC Class Codes: G05B 19/4182 manipulators and conveyor only
• CPC Class Codes: G05B 2219/31432 Keep track of conveyed workpiece, batch, tool, conditions of stations, cells
• CPC Class Codes: Y02P 90/02 Total factory control, e.g. smart factories, flexible manufacturing systems [FMS] or integrated manufacturing systems [IMS]

Abstract

A robot control system includes a line tracking encoder that measures a reference position of a conveyor line and transmits a tracking signal representing tracking data including the reference position of the conveyor line. A master controller is in communication with the encoder to receive the tracking signal, process the tracking data represented by the tracking signal, and generate a data packet in response to processing of the tracking data. A slave controller is in communication with the master controller and at least one robot for receiving the data packet and controlling the movement of the at least one robot in response to the data packet. A communications network directly interconnects the master controller and the slave controller and transmits the data packet from the master controller to the slave controller.

Claims

1. A control system, comprising:

a line tracking encoder adapted to measure a reference position of a conveyor line and transmit a tracking signal representing tracking data including the reference position of the conveyor line as a plurality of reference position values;

a master controller in communication with and not including said line tracking encoder, said master controller adapted to receive said tracking signal, said tracking data represented by said tracking signal, said master controller adapted to record the plurality of the received reference position values included in said tracking signal and calculate a velocity value of the conveyor line from the reference position values, and said master controller adapted to generate a data packet in response to processing of said tracking data, said data packet including one of the reference position values, the velocity value of the conveyor line and a tick time value for the one reference position value, said master controller being in electrical communication with an at least one robot for controlling movement of said at least one robot in response to the reference position values and the velocity value;

a slave controller in communication with said master controller and in electrical communication with at least another robot, said slave controller adapted to receive said data packet and control movement of said at least another robot in response to said data packet; and

a communications network directly interconnecting said master controller and said slave controller, wherein said communications network is adapted to transmit said data packet from said master controller to said slave controller, wherein said slave controller predicts a future position of the conveyor line from said data packet previously received and compares the predicted future position with the one reference position value, and when the predicted future position differs from the one reference position value by more than a predetermined tolerance range, said slave controller modifies a command function for moving said at least another robot.

2. The control system according to claim 1 wherein said master controller includes a synchronization system to time tag said tracking data.

3. The control system according to claim 1 wherein said communications network is an Ethernet network.

4. A control system, comprising:

a line tracking encoder adapted to measure a reference position of a conveyor line and transmit a tracking signal representing tracking data including the reference position of the conveyor line;

a master controller in communication with said encoder, said master controller adapted to receive said tracking signal, process said tracking data represented by said tracking signal, and generate a data packet in response to processing of said tracking data, said master controller being in electrical communication with an at least one robot for controlling movement of said at least one robot;

a slave controller in communication with said master controller and in electrical communication with at least another robot, said slave controller adapted to receive said data packet and control movement of said at least another robot in response to said data packet; and

a communications network directly interconnecting said master controller and said slave controller,

wherein said communications network is adapted to transmit said data packet from said master controller to said slave controller,

wherein processing of said tracking data comprises the steps of;

determining the reference position of the conveyor line;

determining a tick time value for the reference position; and

determining a velocity value of the conveyor line,

wherein said master controller is adapted to predict a future position of the conveyor line in response to processing of said tracking data,

wherein said master controller is adapted to compare the predicted future position of the conveyor line with the reference position within a pre-determined tolerance range, and

wherein said data packet is an updated data packet and said updated data packet is transmitted only when the reference position value is not in within the tolerance range of the predicted future position calculated by said master controller.

5. A method for controlling movements of a plurality of robots, the method comprising the steps of:

measuring a reference position of a conveyor line;

transmitting a tracking signal representing tracking data including a plurality of reference position values of the reference position of the conveyor line to a master controller controlling movement of at least one robot, the master controller not including a line tracking encoder, and the master controller adapted to record a plurality of the received reference position values included in the tracking signal;

processing the tracking data represented by the tracking signal with the master controller to calculate a velocity value of the conveyor line from the reference position values;

generating a data packet with the master controller in response to the processing of the tracking data, the data packet including one of the reference position values, the velocity value and a tick time value for the one reference position value;

transmitting the data packet over a communications network from the master controller to a slave controller;

processing the data packet with the slave controller; and

controlling a movement of at least another robot with the slave controller in response to the processing of the data packet, wherein the slave controller predicts a future position of the conveyor line from the data packet previously received and compares the predicted future position with the one reference position value, and when the predicted future position differs from the one reference position value by more than a predetermined tolerance range, said slave controller modifies a command function for moving the at least another robot.

6. The method according to claim 5 wherein the communications network is an Ethernet network.

7. A method for controlling movements of a plurality of robots, the method comprising the steps of:

providing a control system including,

a line tracking encoder adapted to measure a reference position of a conveyor line and transmit a tracking signal representing tracking data including a plurality of reference position values for the reference position of the conveyor line, and

a master controller in communication with the encoder, the master controller not including the line tracking encoder, the master controller adapted to receive the tracking signal, process the tracking data represented by the tracking signal, the master controller adapted to record the plurality of the received reference position values included in said tracking signal and calculate a velocity value of the conveyor line from the reference position values, and the master controller adapted to generate a data packet in response to processing of the tracking data, the data packet including one of the reference position values, the velocity value of the conveyor line and a tick time value for the one reference position value, the master controller being in electrical communication with at least one robot for controlling movement of the at least one robot in response to the reference position values and the velocity value;

providing a slave controller in communication with the master controller and in electrical communication with at least another robot; and

a communications network directly interconnecting the master controller and the slave controller;

transmitting the data packet over the communications network to the slave controller; and

controlling a movement of the at least another robot in response to the data packet, wherein the slave controller predicts a future position of the conveyor line based upon the one reference position value and the velocity value included in the data packet previously received and compares the predicted future position of the conveyor line with a reference position within a pre-determined tolerance range, and when the predicted future position differs from the one reference position value by more than a predetermined tolerance range, the slave controller modifies a command function for moving the at least another robot.

8. The control system according to claim 7 wherein the master controller includes a synchronization system to time tag the tracking data.

9. The method according to claim 7 wherein the communications network is an Ethernet network.