Linkage control system with position estimator backup

• US 20090088931A1
• Filed: 09/26/2008
• Published: 04/02/2009
• Est. Priority Date: 09/28/2007
• Status: Active Grant

• Current Assignee: Caterpillar Incorporated
• Original Assignee: Caterpillar Incorporated
• Inventors: Kumar, Rajeev, Budde, Steven Conrad
• Granted Patent: US 8,135,518 B2
• Time in Patent Office: Days
• US Class Current: 701/50
• CPC Class Codes: E02F 9/265 with follow-up actions (e.g. control signals sent to actuate the work tool)

Abstract

A linkage control system for a machine having a linkage and a work implement is disclosed. The linkage control system has an operator input device configured to control the movement of the linkage, at least one actuator configured to respond to the operator input device to control the movement of the linkage, and at least one sensor configured to generate a signal indicative of sensor data on at least one actuator. The linkage control system has a controller in communication with at least one actuator, at least one sensor, and the operator input device. The controller is configured to calculate the position of the linkage, to detect anomalous sensor data from at least one sensor, and to predict the position of the linkage and work implement based on a last known accurate position, a last known accurate sensor data, and the operator input device.

Claims

1. A linkage control system for a machine having a linkage and a work implement, comprising:

an operator input device configured to control the movement of the linkage;

at least one actuator configured to respond to the operator input device to control the movement of the linkage;

at least one sensor configured to generate a signal indicative of a sensor data on the at least one actuator; and

a controller in communication with the at least one actuator, the at least one sensor, and the operator input device, the controller configured to calculate the position of the linkage, detect an anomalous sensor data from the at least one sensor, predict the position of the linkage and work implement based on a last known accurate position, a last known accurate sensor data, and the operator input device.

2. The linkage control system of claim 1, further including a predefined suspect sensor data zone.

3. The linkage control system of claim 2, wherein the controller is configured to enter a predictive mode while the linkage and work implement are in the predefined suspect sensor data zone.

4. The linkage control system of claim 1, wherein the sensor data includes a velocity and/or acceleration of the linkage.

5. The linkage control system of claim 1, wherein the controller is configured to calculate a velocity and/or acceleration of the linkage and work implement from the sensor data.

6. The linkage control system of claim 1, wherein the controller includes a memory having at least one table stored therein, the table including a predefined suspect sensor data zone.

7. The linkage control system of claim 1, wherein the at least one sensor measures a hydraulic fluid flow rate of hydraulic cylinders used to control the linkage and work implement.

8. The linkage control system of claim 1, wherein the linkage is a boom and stick and the work implement is a bucket.

9. A method of operating a machine having a linkage and a work implement, the method comprising:

tracking the position of the linkage and the work implement;

monitoring sensor data for anomalous sensor data;

upon detection of anomalous sensor data, entering a predictive mode to predict the position of the linkage and work implement based on a last known accurate position, a last known accurate sensor data, and an operator input device; and

detecting when the sensor data is accurate, and calculating the position of the linkage and work implement based on the sensor data.

10. The method of claim 9, further including a predefined suspect sensor data zone.

11. The method of claim 10, further including initiating the predictive mode when in the predefined suspect sensor data zone.

12. The method of claim 9, wherein the sensor data include a velocity and/or acceleration of the linkage.

13. The method of claim 9, further including calculating the velocity and/or acceleration of the linkage and work implement from the sensor data.

14. The method of claim 9, including storing at least one table having a predefined suspect sensor data zone in a memory.

15. The method of claim 9, further including measuring a hydraulic fluid flow rate of hydraulic cylinders used to control the linkage and work implement with the at least one sensor.

16. The method of claim 9, wherein tracking the position of the linkage and work implement includes tracking the position of a boom, a stick, and a bucket.

17. A machine, comprising:

a power source configured to produce a power output;

a linkage and a work implement powered by the power output; and

a linkage control system to control the linkage and work implement, the system including;

at least one actuator configured to move the linkage and work implement;

at least one sensor configured to generate sensor data signals indicative of the status of at least one actuator;

an operator input device configured to generate a desired velocity signal indicative of a desired velocity of the actuator; and

a controller in communication with the at least one actuator, the at least one sensor, and the operator input device, the controller configured to determine a position of the linkage and the work implement, detect anomalous sensor data, and predict a position of the linkage and work implement based on a last known accurate position, last known accurate sensor data, and the operator input device.

18. The machine of claim 17, wherein the controller configured to detect anomalous sensor data includes the controller configured to detect when the linkage and work implement enter or are in a predefined suspect sensor data zone.

19. A method of operating a machine having a linkage and a work implement, the method comprising:

tracking the position of the linkage and the work implement using at least one sensor and generating data including;

detecting when the sensor data is accurate, and calculating the position of the linkage and work implement based on the sensor data;

monitoring the sensor data for anomalous sensor data;

entering a predictive mode in response to detection of anomalous sensor data, to predict the position of the linkage and work implement based on a last known accurate position, a last known accurate sensor data, and an operator input device; and

if in predictive mode, returning to actual mode when the sensor data is not anomalous;

operating the linkage and work implement using the operator input device to perform tasks during predictive mode.

20. The method of claim 19, wherein monitoring the sensor data for anomalous sensor data includes monitoring the sensor data to detect when the linkage and work implement enter or are in a predefined suspect sensor data zone.