Dynamic stabilization and control of an earthmoving machine

• US 7,317,977 B2
• Filed: 08/23/2004
• Issued: 01/08/2008
• Est. Priority Date: 08/23/2004
• Status: Active Grant

• Current Assignee: Topcon Positioning Systems Incorporated (Topcon Corporation)
• Original Assignee: Topcon Positioning Systems Incorporated (Topcon Corporation)
• Inventors: Matrosov, Ivan
• Primary Examiner(s): Camby; Richard M.
• Application Number:
  US10/924,018
• Publication Number:
  US 20060041361A1
• Time in Patent Office: 1,233 Days
• Field of Search: 701/1, 701/36, 701/50, 701/215, 701/213, 701/216, 379/07, 172/4.5
• US Class Current: 701/50
• CPC Class Codes: E02F 3/842 using electromagnetic, optical or photoelectric beams, e.g. laser beams
• CPC Class Codes: E02F 3/847 using electromagnetic, optical or acoustic beams to determine the blade position, e.g. laser beams
• CPC Class Codes: E02F 9/2045 Guiding machines along a predetermined path for graders E02F3/841; machines for construction of roads E01C19/004
• CPC Class Codes: G05D 1/0278 using satellite positioning signals, e.g. GPS

Abstract

An earthmoving machine including a control system is disclosed. The machine comprises first and second satellite navigation antennas mounted in a longitudinal direction on the earthmoving machine. A third satellite navigation antenna is mounted on a pole attached to an operational element of the earthmoving machine. In one embodiment, the earthmoving machine is a bulldozer and the operational element is a blade of the bulldozer. The machine further comprises a gravity reference sensor and a plurality of gyroscopes mounted on the machine. A computer processor generates control signals based on sensor data received from the various components. The disclosed system and method allows for dynamically stable operation of the earthmoving machine at relatively fast speeds without the development of unwanted oscillations.

Claims

1. A machine comprising:

a first and second satellite antenna mounted in a longitudinal direction on said machine and connected to a satellite receiver;

a third satellite antenna attached to an operational element of said machine and connected to a satellite receiver;

a gravity reference sensor mounted on said machine;

a plurality of gyroscopes mounted on said machine; and

a computer processor for generating control signals based on sensor data received from said satellite receivers, gravity reference sensor; and

said plurality of gyroscopes.

2. The machine of claim 1 wherein said computer processor is configured to:

determine a current state of the machine using said sensor data;

predict a future state of the machine using said current state and position information from a prior epoch;

calculate a reduced error state utilizing said determined state and said predicted state;

calculate a delay compensated state of the machine;

calculate control signals for said operational element; and

apply said control signals to said operational element.

3. The machine of claim 2 wherein the state of the machine comprises one or more of:

the position of the machine mainframe, the orientation of the machine mainframe, the position of said operational element, the position of a control mechanism of said operational element.

4. A method for operating a machine comprising the steps of:

determining a current state of the machine using data from sensors mounted on said machine;

predicting a future state of the machine using said current state and filtered position information from a prior epoch;

calculating a reduced error state using said determined state and said predicted state;

calculating a delay compensated state of the machine using said reduced error state;

calculating control signals for at least one operational element of said machine using said delay compensated state; and

applying said control signals to said at least one operational element.

5. The method of claim 4 further wherein said step of predicting further comprises the step of Kalman filtering.

6. The method of claim 4 wherein said machine is a bulldozer and said at least one operational element is a blade, and wherein said step of calculating control signals further comprises the step of calculating control signals for elevation and slope of said blade.

7. The method of claim 4 wherein said step of predicting further comprises the steps of:

calculating a generalized velocity of the machine;

calculating a time interval since a previous epoch;

interpolating the generalized velocity between the current and previous epochs; and

adding the generalized velocity integrated for time interval since the previous epoch and the previous machine state estimation.

8. The method of claim 7 wherein said step of calculating a delay compensated state of the machine further comprises the step of:

extrapolating said generalized velocity forward for an interval of said delay.

9. The method of claim 4 wherein said step of calculating control signals for at least one operational element of said machine further comprises the steps of:

calculating a target manifold within a state space of said machine using design surface data;

calculating a control signal dependent vector field in said state space; and

generating a control signal which orients the vector field within the state space to minimize the time which is needed for the machine state to reach a tolerance neighborhood of the target manifold.

10. The method of claim 4 wherein the state of the machine comprises one or more of:

the position of the machine mainframe, the orientation of the machine mainframe, the position of a blade of said machine, the position of a control mechanism of said blade.

11. A method for controlling a machine comprising a first and second satellite antenna mounted in a longitudinal direction on said machine and connected to a satellite receiver, a third satellite antenna attached to an operational element of said machine and connected to a satellite receiver, a gravity reference sensor, a plurality of gyroscopes mounted to said machine, and a computer processor for processing data received from said satellite receivers, gravity reference sensor;

and said plurality of gyroscopes, said method comprising the steps of;

determining a current state of the machine;

predicting a future state of the machine using said current state and position information from a prior epoch;

calculating a reduced error state utilizing said determined state and said predicted state;

calculating a delay compensated state of the machine;

calculating control signals for said operational element of said machine; and

applying said control signals to said operational element.

12. The method of claim 11 further wherein said step of predicting further comprises the step of Kalman filtering.

13. The method of claim 11 wherein said machine is a bulldozer and said operational element is a blade, and wherein said step of calculating control signals further comprises the step of calculating control signals for elevation and slope of said blade.

14. The method of claim 11 wherein said step of predicting further comprises the steps of:

calculating a generalized velocity of the machine;

calculating a time interval since a previous epoch;

interpolating the generalized velocity between the current and previous epochs; and

adding the generalized velocity integrated for time interval since the previous epoch and the previous machine state estimation.

15. The method of claim 14 wherein said step of calculating a delay compensated state of the machine further comprises the step of:

extrapolating said generalized velocity forward for an interval of said delay.

16. The method of claim 11 wherein said step of calculating control signals for said operational element of said machine further comprises the steps of:

calculating a target manifold within a state space of said machine using design surface data;

calculating a control signal dependent vector field in said state space; and

generating a control signal which orients the vector field within the state space to minimize the time which is needed for the machine state to reach a tolerance neighborhood of the target manifold.

17. The method of claim 11 wherein the state of the machine comprises one or more of:

the position of the machine mainframe, the orientation of the machine mainframe, the position of a blade of said machine, the position of a control mechanism of said blade.

18. A computer readable medium storing computer program instructions which are executable on a computer processor for implementing a machine control system, said computer program instructions comprising instructions defining the steps of:

determining a current state of the machine using data from sensors mounted on said machine;

predicting a future state of the machine using said current state and filtered position information from a prior epoch;

calculating a reduced error state using said determined state and said predicted state;

calculating a delay compensated state of the machine using said reduced error state;

calculating control signals for at least one operational element of said machine using said delay compensated state; and

applying said control signals to said at least one operational element.

19. The computer readable medium of claim 18 further wherein said computer program instructions defining the step of predicting further comprise computer program instructions defining the step of Kalman filtering.

20. The computer readable medium of claim 18 wherein said machine is a bulldozer and said at least one operational element is a blade, and wherein said computer program instructions defining the step of calculating control signals further comprise computer program instructions defining the step of calculating control signals for elevation and slope of said blade.

21. The computer readable medium of claim 18 wherein said computer program instructions defining the step of predicting further comprise computer program instructions defining the steps of:

calculating a generalized velocity of the machine;

calculating a time interval since a previous epoch;

interpolating the generalized velocity between the current and previous epochs; and

adding the generalized velocity integrated for time interval since the previous epoch and the previous machine state estimation.

22. The computer readable medium of claim 21 wherein said computer program instructions defining the step of calculating a delay compensated state of the machine further comprise computer program instructions defining the step of:

extrapolating said generalized velocity forward for an interval of said delay.

23. The computer readable medium of claim 18 wherein said computer program instructions defining the step of calculating control signals for at least one operational element of said machine further comprise computer program instructions defining the steps of:

calculating a target manifold within a state space of said machine using design surface data;

calculating a control signal dependent vector field in said state space; and

generating a control signal which orients the vector field within the state space to minimize the time which is needed for the machine state to reach a tolerance neighborhood of the target manifold.

24. The computer readable medium of claim 18 wherein the state of the machine comprises one or more of:

the position of the machine mainframe, the orientation of the machine mainframe, the position of a blade of said machine, the position of a control mechanism of said blade.