Crane monitoring and data retrieval systems and method

• US 6,496,766 B1
• Filed: 04/04/2002
• Issued: 12/17/2002
• Est. Priority Date: 03/01/1999
• Status: Expired due to Fees

• Current Assignee: North Carolina State University (University of North Carolina System)
• Original Assignee: North Carolina State University (University of North Carolina System)
• Inventors: Elliott, Scott D., Cobb, Michael S., Green, Anders R., Bernold, Leonhard E., Lorenc, Steven J.
• Primary Examiner(s): Cuchlinski, Jr., William A.
• Assistant Examiner(s): Hernandez, Olga
• Application Number:
  US09/914,173
• Time in Patent Office: 257 Days
• Field of Search: 701/50, 340/685, 340/684, 212/276, 212/277, 212/280
• US Class Current: 701/50
• CPC Class Codes: B66C 15/065 electrical
• CPC Class Codes: G05B 2219/24055 Trace, store a working, operation history
• CPC Class Codes: G05B 2219/2667 Crane
• CPC Class Codes: G05B 23/0264 Control of logging system, e.g. decision on which data to store; time-stamping measurements
• CPC Class Codes: G07C 5/085 using electronic data carriers

Abstract

A crane monitoring system and method is characterized by a plurality of sensors mounted to a crane which communicate data to an on-board control unit. The control unit is characterized by having “black box” functionality. A tip switch is mounted in parallel relation to the vertical portion of a hoist cable below the boom tip. The control unit processes and stores input data from the sensors which will indicate unsafe crane conditions, defined as alarm events such as dragging and extrication events. Each stored event has a time and date stamp. Upon detection of an alarm event, the control unit logs data from the sensors into a non-volatile memory, along with the data from a period of time prior to the alarm event. Data is stored continuously until the alarm event clears. Additional data is stored for a period of time after the conclusion of the alarm event. This results in a discrete event log residing on the non-volatile memory which can subsequently be accessed by authorized personnel for analysis and identification of the crane operator who caused the alarm event.

Claims

1. A method for monitoring critical operations of a crane, and for safely and automatically storing records of alarm events arising from such operations, comprising the steps of:

(a) providing a plurality of input channels over which crane condition signals can be transferred from a plurality of sensors mounted to a crane, each crane condition signal generated by one of the sensors and including a value representative of a specific measurement or condition of the crane during operation thereof;

(b) continuously sampling a data set at a predetermined sampling rate during operation of the crane by communicating with the input channels, each sampled data set including the value detected for each crane condition signal at the time of sampling and also including time and date information corresponding to the respective time and date of sampling, wherein the time of sampling substantially corresponds to the time at which the crane condition occurred;

(c) storing each data set sampled into a non-volatile memory device;

(d) for each data set sampled, comparing the values of the crane condition signals to a set of predetermined safe operating parameters to determine whether an alarm event has occurred, the alarm event defined when one or more of the values of the sampled crane condition signals falls outside a corresponding one or more of the safe operating parameters;

(e) if an alarm event has occurred, comparing the values of the crane condition signals to the safe operating parameters to determine whether the alarm event has ceased, the cessation of the alarm event defined when one or more of the values of the sampled crane condition signals falls back inside a corresponding one or more of the safe operating parameters; and

(f) if an alarm event has occurred, generating an event log for the alarm event by storing, into a separately addressed location of the non-volatile memory device, all data sets sampled over a period of event history, the period of event history defined as starting at a predetermined number of seconds prior to the occurrence of the alarm event and ending at a predetermined number of seconds after the cessation of the alarm event.

2. The method according to claim 1 wherein the data set is sampled at a sampling rate equal to or less than 10 seconds per sample.

3. The method according to claim 1 further comprising the step of defining the event history as a period of time starting at 10 seconds prior to the occurrence of the alarm event and ending at 10 to 30 seconds after the cessation of the alarm event.

4. The method according to claim 1 further comprising the step of activating an audible alarm output to indicate the occurrence of the alarm event.

5. The method according to claim 1 further comprising the step of downloading the generated event log into a remote storage medium.

6. The method according to claim 5 further comprising the step of transporting the remote storage medium containing the stored event log away from the crane.

7. A method for monitoring critical operations of a crane, and for safely and automatically storing records of alarm events arising from such operations, comprising:

(a) mounting a plurality of sensors to a crane, each sensor adapted to measure or detect a specific operating condition of the crane, and each sensor adapted to generate an electrical crane condition signal including a value representative of the operating condition measured or detected by that sensor;

(b) mounting a control unit to the crane;

(c) providing control circuitry within the control unit and a plurality of input channels to establish communication from the sensors to the control circuitry; and

(d) programming the control circuitry to perform the following functions;

(i) during operation of the crane, monitoring the input channels by continuously sampling a data set at a predetermined sampling rate during operation of the crane by communicating with the input channels, each sampled data set including the value detected for each crane condition signal at the time of sampling and also including time and date information corresponding to the respective time and date of sampling, wherein the time of sampling substantially corresponds to the time at which the crane condition occurred;

(ii) storing each data set sampled into a non-volatile memory device;

(iii) for each data set sampled, comparing the values of the crane condition signals to a set of predetermined safe operating parameters to determine whether an alarm event has occurred, the alarm event defined when one or more of the values of the sampled crane condition signals falls outside a corresponding one or more of the safe operating parameters;

(iv) if an alarm event has occurred, comparing the values of the crane condition signals to the safe operating parameters to determine whether the alarm event has ceased, the cessation of the alarm event defined when one or more of the values of the sampled crane condition signals falls back inside a corresponding one or more of the safe operating parameters; and

(v) if an alarm event has occurred, generating an event log for the alarm event by storing, into a separately addressed location of the non-volatile memory device, all data sets sampled over a period of event history, the period of event history defined as starting at a predetermined number of seconds prior to the occurrence of the alarm event and ending at a predetermined number of seconds after the cessation of the alarm event.

8. The method according to claim 7 further comprising the step of defining the event history as a period of time starting a 10 seconds prior to the occurrence of the alarm event and ending at 30 seconds after the cessation of the alarm event.

9. The method according to claim 7 further comprising the steps of establishing a communication link between the control unit and a computer disposed externally with respect to the control unit, and downloading the generated event log from non-volatile memory of control unit to the computer.

10. The method according to claim 7 further comprising the steps of establishing a communication link between the control unit and a computer disposed externally with respect to the control unit, and using the computer to assist in calibrating the control unit and sensors.

11. A crane monitoring system comprising:

(a) a plurality of sensors operatively mounted to a crane and adapted to monitor a plurality of operating conditions of the crane, each sensor operative to generate an electrical crane condition signal representative of one of the monitored crane operating conditions and to send the crane condition signal over a communication line;

(b) a crane monitoring control unit mounted to the crane;

(c) a non-volatile memory unit operatively disposed within the control unit; and

(d) digital processing circuitry operatively disposed within the control unit and communicating with the non-volatile memory unit, the digital processing circuitry adapted to execute a set of crane monitoring instructions, the crane monitoring instructions including;

(i) continuously sampling a data set at a predetermined sample rate and writing the sampled data set into the non-volatile memory, the data set including the respective crane condition signals generated by the sensors and sent over the respective communication lines associated with the sensors, the data set also including time and date information provided by the control unit and corresponding to the respective time and date of receipt of the crane condition signals by the digital processing circuitry;

(ii) for each data set sampled, comparing the crane condition signals to a set of predetermined safe operating parameters and detecting the occurrence and subsequent cessation of an alarm event, the alarm event defined when one or more of the sampled crane condition signals exceeds a corresponding one or more of the safe operating parameters; and

(ii) upon detection of an alarm event, generating a discrete event log and writing the event log into the non-volatile memory, the event log including a series of data sets sampled over a period of event history, the period of event history defined as starting at a predetermined number of seconds prior to the occurrence of the alarm event and ending at a predetermined number of seconds after the cessation of the alarm event.

12. The crane monitoring system according to claim 11 further comprising an audible alarm device adapted to receive an activating output signal from the digital processing circuitry upon detection of the alarm event.

13. The crane monitoring system according to claim 11 wherein the plurality of sensors includes a tip switch.

14. The crane monitoring system according to claim 11 wherein the plurality of sensors includes a pair of main lift cylinder pressure transducers.

15. The crane monitoring system according to claim 11 wherein the plurality of sensors includes a pair of turret drive pressure transducers.

16. The crane monitoring system according to claim 11 wherein the plurality of sensors includes a winch drive pressure transducer.

17. The crane monitoring system according to claim 11 wherein the plurality of sensors includes a winch drive pressure transducer.

18. The crane monitoring system according to claim 11 wherein the plurality of sensors includes an accelerometer.

19. The crane monitoring system according to claim 11 wherein the control unit includes a clock module adapted to provide the time and date information included in each data set.

20. The crane monitoring system according to claim 11 further comprising computer code embedded within a computer code storage device, the computer code storage device disposed within the control unit and communicating with the digital processing circuitry, the computer code providing the set of crane monitoring instructions executed by the digital processing circuitry.

21. The crane monitoring system according to claim 20 wherein the digital processing circuitry includes a microprocessor adapted for interfacing with the computer code storage device and for processing the set of crane monitoring instructions provided by the computer code.

22. The crane monitoring system according to claim 11 further comprising a portable computing device communicating with the control unit, the portable computing device including a portable computing device memory unit and interface code, the interface code adapted to provide access to the event log and downloading of the event log to the portable computing device memory.

23. The crane monitoring system according to claim 22 further comprising a user interface device mounted to the control unit and adapted to permit communication between the control unit and the portable computing device.

24. A crane equipped with a crane data acquisition system comprising:

(a) a crane support section including a plurality of operative crane components mounted thereto, the plurality of operative crane components including;

(i) a hydraulically actuated turret assembly rotatable about a vertical axis;

(ii) a boom assembly pivotably mounted to the turret assembly and rotatable about a horizontal axis, the boom assembly including a boom tip disposed at a distal end of the boom assembly;

(iii) a hydraulically actuated main lift cylinder pivotably interconnected between the crane support section and the boom assembly;

(iv) a winch assembly; and

(v) a cable windable about a drum within winch assembly, the cable extending along the length of the boom assembly and downwardly toward the ground below the boom tip;

(b) a crane operator section adapted for use by a crane operator;

(c) a plurality of sensors operatively mounted to a crane and adapted to monitor a plurality of operating conditions of the crane, each sensor operative to generate an electrical crane condition signal representative of one of the monitored crane operating conditions and to send the crane condition signal over a communication line, the plurality of sensors including;

(i) a tip switch mounted proximate to the boom tip and suspended therefrom in parallel relation to the cable, the tip switch adapted to detect whether the cable is operating at an excessive angle of inclination;

(ii) a pair of main lift cylinder pressure transducers operatively mounted to the main lift cylinder and adapted to measure hydraulic pressure variations experienced by the main lift cylinder;

(iii) a pair of turret drive pressure transducers operatively mounted to the turret assembly and adapted to measure hydraulic pressure developed by the turret assembly during respective left and right rotations of the turret assembly; and

(iv) an accelerometer operatively mounted to the boom assembly and adapted to measure accelerations and decelerations experienced by the boom assembly;

(d) a crane monitoring control unit mounted to the crane operator section and communicating with the plurality of sensors, the crane monitoring control unit including digital processing circuitry for sampling and processing the crane condition signals, identifying the occurrence of an unsafe crane condition based on a comparison of the crane condition signals against predetermined safe operating parameters, and generating and storing an event log indicative of crane operations causing the unsafe crane condition, the event log including all crane condition signals sampled over a period of time starting at a predetermined number of seconds preceding the occurrence of the unsafe crane condition and ending at a predetermined number of seconds after a conclusion of the unsafe crane condition.