METHOD FOR OPERATING A HYDROSTATICALLY DRIVEN VEHICLE
First Claim
1. A method of operating a hydrostatically driven vehicle, the vehicle having a prime mover operating a variable displacement propel pump, a displacement of the pump varied based on an angle of a rotating swashplate included in the pump, a fluid flow impelled by the pump operating to transfer power to at least one propel motor, the propel motor operably connected to at least one wheel of the vehicle, the propel motor adapted to operate at a rotation speed and direction, motion of the vehicle being controlled by a control operated by a user, the method comprising:
- sensing at least one of the angle of the rotating swashplate and the direction and speed of the propel motor with a sensor to yield an actual signal;
relaying the actual signal to an electronic controller;
generating a control signal based on input from the control operated by the user;
determining a desired signal for the rotating swashplate based on the control signal;
comparing the actual signal with the desired signal in the electronic controller; and
stalling motion of the at least one wheel of the vehicle when the actual signal differs from the desired signal by a predetermined extent and for a predetermined period.
1 Assignment
0 Petitions
Accused Products
Abstract
A hydrostatically driven vehicle has an engine operating a variable displacement propel pump, a displacement of which can vary based on an angle of a rotating swashplate, such that a fluid flow impelled by the pump transfers power to at least one propel motor rotating a wheel of the vehicle. An electronic controller of the vehicle senses an operating parameter of the system, for example, the angle of the rotating swashplate or the direction and speed of rotation of the propel motor with a sensor to yield an actual signal, and relays the actual signal to an electronic controller. The controller determines a desired angle for the rotating swashplate based on the control signal, and compares it to the actual signal from the sensor. Motion of the vehicle is stalled when the angle signal differs from the desired angle by a predetermined extent and for a predetermined period.
55 Citations
19 Claims
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1. A method of operating a hydrostatically driven vehicle, the vehicle having a prime mover operating a variable displacement propel pump, a displacement of the pump varied based on an angle of a rotating swashplate included in the pump, a fluid flow impelled by the pump operating to transfer power to at least one propel motor, the propel motor operably connected to at least one wheel of the vehicle, the propel motor adapted to operate at a rotation speed and direction, motion of the vehicle being controlled by a control operated by a user, the method comprising:
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sensing at least one of the angle of the rotating swashplate and the direction and speed of the propel motor with a sensor to yield an actual signal; relaying the actual signal to an electronic controller; generating a control signal based on input from the control operated by the user; determining a desired signal for the rotating swashplate based on the control signal; comparing the actual signal with the desired signal in the electronic controller; and stalling motion of the at least one wheel of the vehicle when the actual signal differs from the desired signal by a predetermined extent and for a predetermined period. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A hydrostatically driven vehicle comprising:
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at least one wheel; at least one propel motor connected to said at least one wheel, said at least one propel motor operating at a motor speed and along a motor direction; a variable displacement pump, said pump being adapted to circulate a flow of propel fluid at a flow rate through said motor, the pump including a rotating swashplate having an axis of rotation, said swashplate being adapted to operate at selective angles with respect to said axis of rotation, said angle of the swashplate dictating said flow rate of the propel fluid, the flow rate of the propel fluid propelling the vehicle at a travel speed; a control device adapted to change said angle of the swashplate; an electronic controller; a system sensor disposed to measure at least one of said angle at which the swashplate operates and said motor speed and direction, the system sensor operably connected to said electronic controller and adapted to relay an actual signal to said controller during operation of the vehicle; a control sensor disposed to measure a displacement of said control device, said control sensor operably connected to the electronic controller and adapted to relay a desired signal to said controller during operation of the vehicle; the electronic controller adapted to receive said actual signal and said desired signal, said electronic controller being adapted to; calculate a difference between the actual signal and the desired signal; compare the difference with a threshold value; initiate a timer when the difference exceeds the threshold value; increment a time with the timer while the difference exceeds the threshold value; compare the time with a predetermined time limit; and arrest motion of the vehicle when the time is at least equal to the predetermined time limit and the difference exceeds the threshold value. - View Dependent Claims (9, 10, 11, 12, 13, 14)
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15. A method for operating a hydrostatically driven vehicle having a variable displacement pump operably associated with a propel motor driving at least one wheel, the method comprising:
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receiving a command from an operator within an electronic controller associated with the vehicle; correlating the command to a desired angle of operation for a swashplate included in the variable displacement pump; measuring at least one of the angle of operation of the swashplate and a speed and direction of rotation of the propel motor with a sensor yielding a measurement; relaying the measurement to the electronic controller; comparing the measurement to the desired angle to yield a difference; comparing the difference to a threshold; when the difference is above the threshold, initiating a timer counting a time value; incrementing the time value while the difference is above the threshold; determining whether the time value exceeds a time limit; arresting motion of the vehicle when the time value exceeds the time limit. - View Dependent Claims (16, 17, 18, 19)
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Specification