MOTION CONTROL SYSTEM WITH DIGITAL PROCESSING LINK

• US 20110208361A1
• Filed: 09/04/2009
• Published: 08/25/2011
• Est. Priority Date: 09/06/2008
• Status: Abandoned Application

• Current Assignee: Lord Corporation (Parker-Hannifin Corporation)
• Original Assignee: Lord Corporation (Parker-Hannifin Corporation)
• Inventors: Hildebrand, Stephen F., Smith, Matthew A., Swanson, Douglas, Ferguson, Matthew
• Application Number:
  US13/062,526
• Publication Number:
  US 20110208361A1
• Time in Patent Office: Days
• US Class Current: 700/280
• CPC Class Codes: G05B 19/404 characterised by control arrangements for compensation, e.g. for backlash, overshoot, tool offset, tool wear, temperature, machine construction errors, load, inertia G05B19/19, G05B19/41 take precedence
• CPC Class Codes: G05B 2219/25135 On data line multiplex data and control words

Abstract

A digital processing link for a vibration control system collects sensor signals at a transfer station and combines the sensor signals into a collective signal that is transmitted under a digital communications protocol to a base station. The sensor signals are separated at the base station and individually processed to produce one or more output control signals to actuators for counteracting the measured vibration.

Claims

1. A motion control system for regulating vibrations comprising

a plurality of sensors for acquiring information about the vibrations,

an actuator for counteracting the vibrations,

a controller for processing the information acquired from the sensors and for controlling the actuator to counteract the vibrations,

a digital processing link between the plurality of sensors and the controller comprising

a transfer station including a multiplexer/demultiplexer for combining signals from the sensors into a collective signal and a communication node for transmitting the collective signal under a communications protocol,

a base station including another communication node for receiving the collective signal under the communications protocol and a demultiplexer/multiplexer for dividing the collective signal into a plurality of separately processable digital signals, and

data transmit and receive lines interconnecting the transfer and base stations, and

the controller being arranged for processing the digital signals from the base station and outputting a control signal for controlling the actuator for regulating vibrations.

2. The motion control system of claim 1 in which the communication node of the base station transmits the control signal for the actuator under the communications protocol.

3. The motion control system of claim 2 in which the communication node of the base station transmits the control signal for the actuator over the data transmit and receive lines to the communication node of the transfer station.

4. The motion control system of claim 3 in which (a) the actuator is one of a plurality of actuators, (b) the controller outputs multiple control signals, (c) the demultiplexer/multiplexer of the base station combines the multiple control signals into a collective control signal for transmission over the data transmit and receive lines, and (d) the multiplexer/demultiplexer of the transfer station divides the collective control signal into a plurality of control signals that are directed to the plurality of actuators.

5. The motion control system of claim 1 in which the actuator is one of a plurality of actuators and further comprising a second digital processing link between the base station and a second transfer station interconnecting the plurality of actuators with the base station.

6. The motion control system of claim 5 in which the demultiplexer/multiplexer of the base station combines output control signals for the actuators into a collective output control signal, and the communication node of the base station transmits the collective output control signal under the communications protocol to the second transfer station.

7. The motion control system of claim 6 in which a communication node of the second transfer station receives the collective output control signal and a multiplexer/demultiplexer of the second transfer station divides the collective output control signal into a plurality of control signals to the actuators.

8. The motion control system of claim 1 further comprising

a power supply associated with the base station for transmitting electrical power over the data transmit and receive lines, and

a transformer associated with the transfer station for receiving electrical power over the data transmit and receive lines and for conditioning the electrical power for delivery to one or more of the sensors

9. The motion control system of claim 1 in which the communication node of the transfer station provides for converting the collective signal into a series of frames having a prescribed format for monitoring and resending errant transmissions.

10. The motion control system of claim 9 in which the communication node of the transfer station provides for temporally spreading energy content of the collective signal over the data transmit lines to reduce interference.

11. The motion control system of claim 10 in which the communication node of the transfer station includes a disconnect to avoid transmitting a lightning surge.

12. The motion control system of claim 1 in which the transfer station includes an analog to digital converter to convert analog signals from the sensors into digital signals.

13. The motion control system of claim 1 in which the actuator includes two or more eccentric masses that are relatively angularly positionable about a rotational axis under the influence of an electric coil.

14. The motion control system of claim 13 in which the plurality of sensors include accelerometers for measuring vibration and other sensors for measuring the relative angular positions of the eccentric masses.

15. The motion control system of claim 1 in which the actuator amplifies force at one or more tuned frequencies.

16. The motion control system of claim 15 in which the actuator includes one or more eccentric masses that are rotatable about a rotation axis.

17. The motion control system of claim 15 in which the actuator includes a translatable mass that is reciprocable along a linear axis.

18. The motion control system of claim 1 in which the plurality of sensors include accelerometers used for sensing vibration.

19. The motion control system of claim 18 in which the transfer station is positioned for reducing an average distance between the transfer station and the plurality of sensors.

20. An active balancer for a rotatable shaft comprising

one or more eccentric masses positionable with respect to a rotational axis of the rotatable shaft,

a driver for repositioning the one or more eccentric masses with respect to the rotational axis of the rotatable shaft,

a plurality of sensors including one or more rotation sensors together with one or more vibration sensors for monitoring performance characteristics of the rotatable shaft,

a controller for processing the information acquired from the sensors and for controlling the operation of the driver to reduce vibrations in the rotatable shaft,

a transfer station collecting information from the sensors and a base station connected to the controller, and

a communications protocol for sending and receiving data between the transfer and base stations in a prescribed format for monitoring and resending errant transmissions.

21. The active balancer of claim 20 in which the driver is formed as a part of a coil block within which one or more of the plurality of sensors are embedded.

22. The active balancer of claim 21 in which the plurality of sensors include one or more sensors within the coil block for monitoring the position of the one or more eccentric masses.

23. The active balancer of claim 20 in which the transfer station includes a multiplexer/demultiplexer for combining signals from the sensors into a collective signal and a communication node for transmitting the collective signal under the communications protocol.

24. The active balancer of claim 23 in which the base station includes another communication node for receiving the collective signal under the communications protocol and a demultiplexer/multiplexer for dividing the collective signal into a plurality of separately processable digital signals.

25. The active balancer of claim 20 further comprising data transmit and receive lines connecting the transfer and base stations for exchanging information under the communications protocol, and a power supply associated with the base station for transmitting electrical power over the data transmit and receive lines to the transfer station.

26. The active balancer of claim 25 further comprising one or more power transmission pathways from the transfer station to one or more of the plurality of sensors.

27. An active vibration control system for minimizing vibrations in a structure that supports a member for rotation comprising

a plurality of sensors mounted with the structure for monitoring vibration,

one or more actuators that drive a movable mass at tuned frequencies,

a controller that receives information from the plurality of sensors and controls operation of the one or more actuators for cancelling sensed vibrations within the structure,

a transfer station collecting information from the sensors and a base station connected to the controller and

a communications protocol for sending and receiving data between the transfer and base stations in a prescribed format for monitoring and resending errant transmissions.

28. The active vibration control system of claim 27 in which the transfer station is located centrally among the sensors for reducing an average distance between the sensors and the transfer station.

29. The active vibration control system of claim 27 further comprising data transmit and receive lines connecting the transfer and base stations for transferring information under the communications protocol, and a power supply associated with the base station for transmitting electrical power in addition to data over the data transmit and receive lines to the transfer station.

30. The active vibration control system of claim 29 further comprising one or more power transmission pathways from the transfer station to one or more of the plurality of sensors.

31. The active vibration control system of claim 27 in which the transfer station includes a multiplexer/demultiplexer for combining signals from the sensors into a collective signal and a first communication node for transmitting the collective signal under the communications protocol.

32. The active vibration control system of claim 31 in which the base station includes a second communication node for receiving the collective signal under the communications protocol and a demultiplexer/multiplexer for dividing the collective signal into a plurality of separately processable digital signals.

33. A method of counteracting vibration comprising steps of

monitoring vibrations using a plurality of sensors,

outputting signals from the plurality of sensors for conveying information about the vibrations,

combining the signals from the sensors at a transfer station into a collective signal,

transmitting the collective signal over data transmit and receive lines under a communications protocol in a prescribed format for monitoring and resending errant transmissions,

receiving the collective signal under the communications protocol at a base station associated with a controller,

transmitting power from a power source associated with the base station over the data transmit and receive lines to the transfer station,

distributing the power from the transfer station to one or more of the sensors,

dividing the collective signal received at the base station into a plurality of processable digital signals, and

processing the digital signals within the controller, and

outputting a signal from the controller to an actuator for counteracting the monitored vibrations.

34. The method of claim 33 including a step of distributing the sensors according to results from an optimization study.

35. The method of claim 33 including a step of locating the transfer station among the sensors for reducing an average distance between the sensors and the transfer station.

36. The method of claim 33 in which the step of transmitting the collective signal includes converting the collective signal into a series of frames having a prescribed format for monitoring and resending errant transmissions.

37. The method of claim 33 in which the step of transmitting the collective signal includes temporally spreading energy content of the collective signal over the data transmit lines to reduce interference.

38. The method of claim 33 including a step of converting analog signals from the sensors into digital signals.

39. A method of making a vibration control system for regulating vibrations, said method comprising steps of

arranging a plurality of sensors for acquiring information about the vibrations,

providing an actuator for counteracting the vibrations,

providing a controller for processing the information acquired from the sensors and for controlling the actuator to counteract the vibrations,

establishing a digital processing link between the plurality of sensors and the controller including the steps of

combining signals from the sensors into a collective signal at a transfer station and transmitting the collective signal from the transfer station under a communications protocol, and

receiving the collective signal at a base station under the communications protocol and dividing the collective signal into a plurality of separately processable digital signals, and

processing the digital signals from the base station with the controller and outputting a control signal for controlling the actuator to regulate the vibrations.

40. The method of claim 39 including a step of locating the transfer station among the sensors for reducing an average distance between the sensors and the transfer station.

41. The method of claim 39 including a step of establishing a digital processing link between the controller and the actuator.

42. The method of claim 41 in which the actuator is one of a plurality of actuators and the step of establishing a digital processing link between the controller and the actuators includes combining output control signals from the controller into a collective output control signal at the base station and transmitting the collective output control signal from the base station under the communications protocol.

43. The method of claim 42 in which the step of establishing a digital processing link between the controller and the actuators includes receiving the collective output control signal at the transfer station under the communications protocol and dividing the collective output control signal into a plurality of separate control signals to the actuators.

44. The method of claim 42 in which the step of establishing a digital processing link between the controller and the actuators includes receiving the collective output control signal at a second transfer station under the communications protocol and dividing the collective output control signal into a plurality of separate control signals to the actuators.

45. A method of controlling machine vibrations, said method comprising steps of

operating an active balancer for a machine rotatable shaft having one or more eccentric masses positionable with respect to a rotational axis of the machine rotatable shaft,

monitoring vibration characteristics of the machine rotatable shaft using a plurality of sensors including one or more rotation sensors together with one or more vibration sensors,

collecting information from the sensors at a transfer station and transmitting the collected information through a base station to a controller and

sending and receiving data under a communications protocol between the transfer and base stations in a prescribed format for monitoring and resending errant transmissions,

processing the information acquired from the sensors with the controller and for outputting from the controller a control signal for the active balancer, and

repositioning the one or more eccentric masses of the active balancer with respect to the rotational axis of the machine rotatable shaft in response to the control signal for reducing vibrations in the machine rotatable shaft.

46. A method of controlling a plurality of vibrations in an aircraft structure, said method including steps of

monitoring vibration in the aircraft structure using a plurality of sensors mounted with the structure, and

collecting information from the sensors at a transfer station and transmitting the collected information to a base station connected to a controller and

sending and receiving data under a communications protocol between the transfer and base stations in a prescribed format for monitoring and resending errant transmissions,

processing the information from the plurality of sensors with the controller and outputting a control signal to one or more actuators that drive a movable mass at tuned frequencies, and

operating the one or more actuators at the tuned frequencies for cancelling sensed vibrations within the structure, wherein the vibrations in the aircraft structure are regulated.