Automatic steering system and method
First Claim
1. An automatic steering control system for a vehicle, which comprises:
- a GPS receiver;
a guidance controller connected to the GPS receiver;
a vehicle steering system including a steering actuator and a steering power source connected to the steering actuator;
a steering input device connected to the steering power source and the steering actuator;
the guidance controller being operably connected to the steering input device;
a loop for feeding back an operating parameter to the guidance controller, said operating parameter corresponding to a GPS-derived actual turning rate for comparison to a desired turning rate and automatic correction to a desired guide pat initiated automatically by said guidance controller in response to a discrepancy between said desired turning rate and said actual turning rate determined utilizing GPS-derived vehicle position, around speed, steering rate and course information item said GPS receiver and said guidance controller, and said correction to said desired guide path occurring automatically in response to said actual turning rate parameter based on GPS-derived vehicle position, ground speed, steering rate and course information without operator intervention.
1 Assignment
0 Petitions
Accused Products
Abstract
An automatic steering system and method are provided for a vehicle including an hydraulic primary steering system. The automatic steering system includes a guidance module with a GPS receiver and a microprocessor adapted to process and store GPS data defining travel paths, which can be associated with a cultivated field in an agricultural vehicle application. An automatic steering module is connected to the guidance module and to a steering valve control block, which provides pressurized hydraulic fluid in parallel with the vehicle'"'"'s primary hydrostatic steering system. The automatic steering system utilizes a constant factor, such as steering rate, for predictability and simplicity in the operation of the automatic steering system. A feedback loop from the vehicle hydrostatic steering system uses the vehicle'"'"'s actual turning rate for comparison with a desired turning rate. The system is adapted for original equipment installation and retrofitting on vehicles, such as farm tractors, with various primary hydrostatic steering system configurations. An automatic steering method includes the steps of: initializing the system; adjusting the steering with an hydraulic valve to provide a constant steering rate; providing feedback corresponding to the vehicle'"'"'s actual turning rate and combining the feedback with other input signals to provide automatic steering.
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Citations
33 Claims
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1. An automatic steering control system for a vehicle, which comprises:
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a GPS receiver;
a guidance controller connected to the GPS receiver;
a vehicle steering system including a steering actuator and a steering power source connected to the steering actuator;
a steering input device connected to the steering power source and the steering actuator;
the guidance controller being operably connected to the steering input device;
a loop for feeding back an operating parameter to the guidance controller, said operating parameter corresponding to a GPS-derived actual turning rate for comparison to a desired turning rate and automatic correction to a desired guide pat initiated automatically by said guidance controller in response to a discrepancy between said desired turning rate and said actual turning rate determined utilizing GPS-derived vehicle position, around speed, steering rate and course information item said GPS receiver and said guidance controller, and said correction to said desired guide path occurring automatically in response to said actual turning rate parameter based on GPS-derived vehicle position, ground speed, steering rate and course information without operator intervention. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19)
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20. An automatic steering control system for an agricultural vehicle, which system comprises:
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a GPS receiver;
a guidance controller connected to the GPS receiver;
a primary vehicle hydrostatic steering system including an hydraulic steering actuator, an hydraulic power source connected to the steering actuator and a primary steering input device directing hydraulic power from said power source to said steering actuator;
an auxiliary steering input device connected to said guidance controller, said steering power source and said steering actuator, said auxiliary steering input device including an hydraulic steering valve control and providing a constant steering rate;
said guidance controller providing a steering input signal to said auxiliary steering input device from among the input signal set consisting of left, right and none;
a feedback loop from the vehicle steering system to the guidance controller;
an inertial based yaw rate gyro sensor in said feedback loop correcting said feedback signal by smoothing the effects of course deviations associated with vehicle yaw;
a proportional integral derivative (PID) compensator with an input connected to said guidance controller and an output;
adjustable gain inputs to said PID compensator corresponding to a computed error, an integral of said error and a time derivative of said error corresponding to an error rate;
said guidance controller including a path planner;
a position/speed signal output from said GPS receiver and input to said guidance controller;
a yaw rate filter including a first input connected to and receiving a differential heading signal from said GPS receiver and an output connected to and providing a smooth heading signal to said guidance controller;
said yaw rate filter including a second input connected to said yaw rate gyro sensor and receiving a signal corresponding to the gyroscopically-corrected actual turning rate;
a low pass noise filter with an adjustable time constant and including an input connected to said yaw rate gyro sensor output and receiving a corrected actual turning rate signal therefrom and an output providing an observed turning rate output signal;
a summer with an observed turning rate input connected to said noise filter output and a desired turning rate input connected to said guidance controller and adapted to receive a desired turning rate signal therefrom;
said summer providing an output signal corresponding to a differential between said desired and observed turning rate signals to said PID compensator;
said steering actuator comprising an hydraulic piston-and-cylinder steering unit connected to said vehicle steering;
said steering input device including a steering valve control block with left and right solenoid-actuated steering valves each having an hydraulic output connected to said steering unit, an hydraulic input and an electrical input connected to said guidance controller and receiving an on-off input signal therefrom whereby each said valve is selectively movable between respective on and off positions;
said steering valve control block including a steering rate control comprising an adjustable hydraulic flow valve with an input connected to said hydraulic power source and an output connected to said steering valve hydraulic inputs;
a straight-line (A-B) operating mode;
a contour operating mode for guidance along curved lines;
said guidance controller having a memory adapted for storing multiple straight-line and contour guide paths;
said guidance controller automatically steering said vehicle along straight and contour guide paths in said straight-line and contour operating modes respectively;
said guidance controller including a switching function adapted for switching between said straight-line and contour operating modes while said automatic steering system is automatically steering said vehicle; and
said guidance controller including an auto-disengage feature activated by one or more predetermined auto-disengage conditions and an auto-engage feature activated by one or more predetermined auto-engage conditions.
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21. An automatic steering method for a vehicle, which comprises the steps of:
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defining a guide pat pattern wit GPS locations;
storing said guide path pattern electronically in a guidance controller computer memory;
defining a desired turning rate;
storing said desired turning rate in said guidance controller computer memory;
operating said vehicle in proximity to said guide path pattern receiving GPS signals corresponding to current vehicle locations;
comparing said stored guide path GPS locations with current GPS locations;
steering said vehicle to said guide path;
deriving with GPS a vehicle operating parameter comprising an actual turning rate for said vehicle utilizing GPS-derived vehicle position, ground speed, steering rate and course information from said GPS receiver and guidance controller;
providing a feedback signal corresponding to said actual turning rate vehicle operating parameter to said guidance controller;
comparing said desired turning rate to said actual turning rate; and
automatically without operator intervention correcting the course of said vehicle to said guide pat pattern in response to said feedback signal indicating a discrepancy between said desired turning rate by said guidance controller in response to said actual turning rate parameter based on GPS-derived vehicle position, ground speed, steering rate and course information. - View Dependent Claims (22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33)
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Specification