Apparatus and method for a machine stability system for an articulated work machine

• US 6,437,701 B1
• Filed: 12/18/2000
• Issued: 08/20/2002
• Est. Priority Date: 12/18/2000
• Status: Expired due to Fees

• Current Assignee: Caterpillar Incorporated
• Original Assignee: Caterpillar Incorporated
• Inventors: Muller, Thomas P.
• Primary Examiner(s): Wu, Daniel J.
• Application Number:
  US09/740,283
• Publication Number:
  US 20020075157A1
• Time in Patent Office: 610 Days
• Field of Search: 340/679, 340/684, 340/686.1, 340/689, 340/440, 340/685, 701/124
• US Class Current: 340/679
• CPC Class Codes: E02F 9/24 Safety devices , e.g. for preventing overload E02F9/226 takes precedence
• CPC Class Codes: E02F 9/26 Indicating devices E02F5/145 takes precedence

Abstract

In the present invention, the distance from a predetermined point to the center of gravity of the load and a first portion of a work machine and the distance from that predetermined point to the center of gravity of the second portion of the work machine are compared, either singly or in a combination, to a predetermined value. Optionally, the articulation angle of the machine and weight and position of the load are combined with a vehicle weight value into a stability value and the stability value is compared to an alarm value. Should an instability condition be detected, an output signal is sent to an output device to alert the operator and/or affect the movement of the machine to prevent instability of the work machine.

Claims

1. A machine stability system, comprising:

a machine adapted to carry a load;

a front sensor system adapted to produce a front signal indicative of the location of the center of gravity of the combination of the load and a predetermined portion of the machine relative to a predetermined point;

a rear sensor system adapted to produce a rear signal indicative of the location of the center of gravity of a second predetermined portion of the machine relative to the predetermined point; and

a controller adapted to receive the front signal and the rear signal, compare the front signal and the rear signal to predetermined values from at least one of a table, a formula, an algorithm, and a combination thereof, and responsively produce an output signal.

2. The machine stability system of claim 1, wherein the controller calculates a combined signal based on the front signal and the rear signal which indicates the position of the center of gravity of the combination of the load and machine relative to a predetermined point, compares the combined signal to at least one predetermined value, and responsively produces an output signal.

3. A method of measuring machine stability, comprising the steps of:

sensing a front weight and front position, determining the center of gravity, relative to a predetermined point, of a load combined with a predetermined portion of a machine, and responsively producing a front signal;

sensing a rear weight and rear position, determining the center of gravity, relative to the predetermined point, of a second predetermined portion of the machine, and responsively producing a rear signal;

receiving the front signal and the rear signal;

comparing the front signal and the rear signal to predetermined values from at least one of a table, a formula, an algorithm, and a combination thereof; and

responsively producing an output signal.

4. The method of claim 3, further comprising the steps of:

calculating a combined signal, indicative of the position of the center of gravity of the load and the machine relative to a predetermined point, based on the front signal and the rear signal; and

comparing the combined signal to a predetermined value from at least one of a table, a formula, an algorithm, and a combination thereof.

5. The method of claim 3, including the steps of:

reading an articulation angle signal;

reading a weight signal;

reading a position signal;

determining a stability value from the articulation angle, weight, and position signals;

comparing the stability value to a predetermined alarm value; and

responsively sending an output signal to an output device.

6. A machine stability system, comprising:

a first frame;

a second frame;

an articulation joint connecting the first frame and the second frame and having an articulation angle indicating the positional relationship between the first frame and the second frame;

an articulation sensor adapted to sense the articulation angle and responsively produce an articulation angle signal;

a weight sensor adapted to sense the weight of a load carried by one of the first frame and the second frame and responsively produce a weight signal;

a position sensor adapted to sense the position of a load carried by the one of the first frame and the second frame and responsively produce a position signal;

a controller adapted to receive the articulation angle signal, the weight signal, and the position signal and responsively provide an output signal; and

an output device for receiving the output signal.

7. The machine stability system of claim 6, wherein the output device is at least one of a visible device, an audible device, a tactile device, and a machine control device.

8. The machine stability system of claim 7, wherein the controller is further adapted to determine a stability value, based on the weight signal, the position signal, the articulation signal, and a machine weight value, from at least one of a table, a formula, an algorithm, and a combination thereof.

9. The machine stability system of claim 8, wherein the controller compares the stability value to at least one of a predetermined alarm value and a predetermined range of alarm values, each alarm value provided by at least one of a table, a formula, an algorithm, and a combination thereof, and responsively produces the output signal.

10. The machine stability system of claim 9, wherein the controller determines the output device responsive to the comparison of the stability value and the alarm value and responsively sends the output signal to the chosen output device.