System and methods for avoiding data collisions over a data bus

• US 8,601,185 B2
• Filed: 12/30/2010
• Issued: 12/03/2013
• Est. Priority Date: 07/16/2010
• Status: Active Grant

• Current Assignee: St. Jude Medical, Atrial Fibrillation Division, Inc. (Abbott Laboratories)
• Original Assignee: St. Jude Medical (Abbott Laboratories)
• Inventors: Sandhu, Kulbir S., Amiri, Atila G., Gee, Samuel K.
• Primary Examiner(s): Tsai, Henry
• Assistant Examiner(s): Shyu, Jing-Yih
• Application Number:
  US12/982,441
• Publication Number:
  US 20120017013A1
• Time in Patent Office: 1,069 Days
• Field of Search: None
• US Class Current: 710/61
• CPC Class Codes: G16H 40/63 for local operation
• CPC Class Codes: G16Z 99/00 Subject matter not provided for in other main groups of this subclass

Abstract

The disclosed system and methods involve controlling the timing and order in which numerous motors and sensors exchange data over a data bus. The method can be used with, for example, motion control, automotive, industrial automation, and medical equipment applications using data buses. As an example of one possible medical equipment application, the method of exchanging data on a bus can be used with a remote catheter guidance system. The disclosed system and methods help optimize data exchange over a bus and avoid collisions by grouping the transmission of sensor readings, by grouping the transmission of motor commands, and by predetermining the order of these groups. Further, the method provides a way of ensuring that incomplete data sets are not exchanged over the bus. The method also provides a way of synchronizing motor actuation based on data transmitted to the data bus.

Claims

1. A method for scheduling operations on a data bus used to exchange data throughout a system having a plurality of motors and a plurality of sensors, the method comprising:

determining respective bus access frequencies for a plurality of motors and a plurality of sensors, each bus access frequency being indicative of a frequency with which a respective one of the plurality of motors or a respective one of the plurality of sensors requires access to a data bus;

providing a plurality of repeating input/output (IO) cycles, wherein at least one of the plurality of motors or at least one of the plurality of sensors accesses the data bus during each of the plurality of IO cycles;

defining a respective cycle period, for each of the plurality of IO cycles, between respective recurrences of each of the plurality of IO cycles; and

assigning at least one of the plurality of motors and at least one of the plurality of sensors to at least one of the plurality of IO cycles according to respective bus access frequencies determined for the at least one of the plurality of motors and the at least one of the plurality of sensors;

wherein access to the data bus by motors and sensors assigned to one of the plurality of IO cycles excludes access to the data bus by motors and sensors assigned to each other IO cycle of the plurality of IO cycles;

wherein a priority of each of the plurality of IO cycles is determined by the respective cycle periods of each of the plurality of IO cycles and an IO cycle having a lower priority is blocked from accessing the data bus while an IO cycle having a higher priority is accessing the data bus; and

wherein access is granted to an IO cycle with a higher priority when two or more IO cycles request access to the data bus at substantially the same time.

2. The method of claim 1 further comprising performing a plurality of motor operations before performing a plurality of sensor operations in an IO cycle having both motor operations and sensor operations.

3. The method of claim 2, wherein each of a plurality of motor commands are written to the data bus before any of the plurality of motor commands are read from the data bus and each of a plurality of sensor readings are written to the data bus before any of the plurality of sensor readings are read from the data bus.

4. The method of claim 1 further comprising actuating at least two of the plurality of motors quasi-simultaneously in response to a transmission of a synchronization signal.

5. The method of claim 1, wherein at least two of the plurality of motors that perform similar functions are assigned to a same IO cycle.

6. The method of claim 1, wherein at least two of the plurality of sensors that measure similar attributes are assigned to a same IO cycle.

7. The method of claim 1, wherein at least two of the plurality of motors control at least one steering wire, the at least one steering wire further controlling a tip of a catheter, wherein actuation of at least two of the plurality of motors controlling the steering wires is performed quasi-simultaneously.

8. A method for operating a system using a data bus to exchange data throughout a plurality of motors and a plurality of sensors, the method comprising:

receiving at least one motor command transmitted to a data bus, the at least one motor command used to control at least two of a plurality of motors;

distributing the at least one motor command to the at least two motors during one of a plurality of IO cycles, each IO cycle defining a repeating duration of time with a defined frequency during which one or more of at least one of the at least two motors and at least one of the plurality of sensors accesses said data bus;

actuating the at least two motors in response to a synchronization signal that is different from the at least one motor command, the synchronization signal received during the one IO cycle, the at least two motors actuating based on the at least one motor command; and

receiving at least one sensor reading from at least one of a plurality of sensors.

9. The method of claim 8, wherein at least one of the plurality of sensors transmits at least one sensor reading to the data bus cyclically and at least one of the plurality of sensors transmits at least one sensor reading to the data bus acyclically.

10. The method of claim 8 further comprising:

checking the at least one motor command transmitted to the data bus for completeness; and

discarding the at least one motor command if a portion of the at least one motor command is missing.

11. The method of claim 8 further comprising storing the at least one motor command in a buffer before actuating at least two of the plurality of motors in response to the synchronization signal.

12. The method of claim 8, wherein the motor commands are based at least in part on the at least one sensor reading received from the at least one of the plurality of sensors.

13. The method of claim 8, wherein at least two of the plurality of motors control at least one steering wire, the at least one steering wire further controlling a tip of a catheter, wherein actuation of at least two of the plurality of motors controlling the steering wires is performed quasi-simultaneously.

14. The method of claim 8, wherein the one IO cycle includes access to the data bus by both a sensor and a motor.

15. A system of sensors and motors using a data bus to exchange data throughout the system, the system comprising:

an electronic control system for computing at least one motor command;

a bus controller configured to allow the at least one motor command to be distributed during one of a plurality of IO cycles, each IO cycle defining a repeating duration of time with a defined frequency during which one or more of a sensor and a motor accesses said data bus;

a plurality of motors capable of actuating based on the at least one motor command;

a plurality of sensors for measuring at least one sensor reading from a system, wherein the electronic control system is configured to receive the at least one sensor reading; and

a data bus for exchanging data between the electronic control system, the plurality of motors, and the plurality of sensors, wherein the plurality of motors actuate based on the at least one motor command in response to a synchronization signal received during the one IO cycle that is different from the at least one motor command.

16. The system of claim 15, wherein at least one of the plurality of sensors transmits the at least one sensor reading to the data bus cyclically and at least one of the plurality of sensors transmits the at least one sensor reading to the data bus acyclically.

17. The system of claim 15, wherein the bus controller is configured to check the at least one motor command for completeness and to prevent at least one of the plurality of motors from actuating if a portion of the at least one motor command is missing.

18. The system of claim 15, wherein the electronic control system is configured to read at least one sensor reading from the data bus during a second subinterval of a sensor time interval, the at least one sensor reading having been written to the data bus during a first subinterval of the sensor time interval.

19. The system of claim 15, wherein at least two of the plurality of motors control at least one steering wire, the at least one steering wire further controlling a tip of a catheter, wherein actuation of at least two of the plurality of motors controlling the steering wires is performed quasi-simultaneously.

20. The system of claim 15, wherein the electronic control system computes the at least one motor command based at least in part on the at least one sensor reading from at least one of the plurality of sensors.

21. The system of claim 15, wherein the one IO cycle includes access to the data bus by both a sensor and a motor.

22. The system of claim 21, wherein the one IO cycle includes a sensor time interval for exchanging sensor readings on the data bus followed by a motor time interval for exchanging motor commands on the data bus.