Magnetorheological fluid brake and force-feedback system for a steering mechanism
First Claim
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1. A brake comprising:
- a positive displacement fluid pump having a rotating pump shaft, a pump housing, a first port, and a second port, the pump adapted to pump a magnetorheological fluid from one of the first and the second ports to the other of the first and the second ports when the pump shaft is rotated relative to the pump housing;
a viscosity regulator fluidly connected between the first port and second port, though which flows the magnetorheological fluid is pumped from the fluid pump, the viscosity regulator adapted to controllably vary the viscosity of the magnetorheological fluid passing there through, thereby varying pumping restriction against the fluid pump, resulting in variable resistance to pump shaft rotation relative to the pump housing.
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Abstract
A magnetorheological fluid brake utilizing a positive displacement fluid pump adapted to pump a magnetorheological fluid through a viscosity regulator. The viscosity regulator is adapted to controllably vary the viscosity of the magnetorheological fluid, altering the pumping restriction against the fluid pump, resulting in variable resistance to pump shaft rotation relative to the pump housing. An electronic steering system for a work vehicle utilizing the illustrated magnetorheological brake as a resistance device to provide tactile feedback as a function of steering shaft rotational position.
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Citations
28 Claims
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1. A brake comprising:
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a positive displacement fluid pump having a rotating pump shaft, a pump housing, a first port, and a second port, the pump adapted to pump a magnetorheological fluid from one of the first and the second ports to the other of the first and the second ports when the pump shaft is rotated relative to the pump housing;
a viscosity regulator fluidly connected between the first port and second port, though which flows the magnetorheological fluid is pumped from the fluid pump, the viscosity regulator adapted to controllably vary the viscosity of the magnetorheological fluid passing there through, thereby varying pumping restriction against the fluid pump, resulting in variable resistance to pump shaft rotation relative to the pump housing. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A brake comprising:
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a positive displacement fluid pump having a rotating pump shaft, a pump housing, a first port, and a second port, the pump adapted to pump a magnetorheological fluid from one of the first and the second ports to the other of the first and the second ports when the pump shaft is rotated relative to the pump housing;
a viscosity regulator fluidly connected between the first port and second port, the viscosity regulator comprising a flow orifice though which flows the magnetorheological fluid pumped from the fluid pump, and an electromagnet adjacent to the flow orifice, the electromagnet adapted to controllably impart a magnetic field upon the magnetorheological fluid flowing through the flow orifice, thereby varying the viscosity of the magnetorheological fluid, and thus varying the pumping restriction-against the fluid pump, resulting in variable resistance to pump shaft rotation relative to the pump housing. - View Dependent Claims (9, 10, 11, 12, 13)
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14. A steering mechanism for a vehicle having a frame, wheels, and an actuator to controllably vary vehicle steering angle, the mechanism comprising:
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a steering wheel adapted for rotation relative to the vehicle frame by a vehicle operator corresponding to a desired vehicle steering angle;
a steering shaft operatively coupled to the steering wheel;
an sensor operatively coupled to the steering shaft adapted sense rotational position of the steering shaft;
a brake comprising a positive displacement fluid pump having a pump shaft, a pump housing, a first port, and a second port, the pump adapted to pump a magnetorheological fluid from one of the first and the second ports to the other of the first and the second ports when the pump shaft is rotated relative to the pump housing, the brake further comprising a viscosity regulator fluidly connected between the first port and second port, the viscosity regulator comprising a flow orifice though which flows the magnetorheological fluid pumped from the fluid pump, and an electromagnet adjacent to the flow orifice, the electromagnet adapted to controllably impart a magnetic field upon the magnetorheological fluid flowing through the flow orifice, thereby varying the viscosity of the magnetorheological fluid, and thus varying the pumping restriction against the fluid pump, resulting in variable resistance to pump shaft rotation, and thus variable resistance to steering shaft rotation;
a controller in communication with the actuator, the sensor, and the viscosity regulator, the controller adapted command the actuator to controllably vary vehicle steering angle in response to rotational position of the steering shaft sensed by the sensor, and the controller further adapted to command the viscosity regulator to controllably vary the viscosity of the magnetorheological fluid passing through, resulting in variable resistance to steering shaft rotation as a function of steering shaft rotational position sensed by the sensor. - View Dependent Claims (15, 16, 17, 18, 19, 20, 21)
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22. A steering mechanism for a vehicle having a frame, wheels, and an actuator to controllably vary vehicle steering angle, the mechanism comprising:
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a steering wheel adapted for rotation relative to the vehicle frame by a vehicle operator corresponding to a desired vehicle steering angle;
a steering shaft operatively coupled to the steering wheel;
an sensor operatively coupled to the steering shaft adapted sense rotational position of the steering shaft;
a brake comprising a positive displacement fluid pump having a pump shaft, a pump housing, a first port, and a second port, the pump adapted to pump a magnetorheological fluid from one of the first and the second ports to the other of the first and the second ports when the pump shaft is rotated relative to the pump housing, the brake further comprising a viscosity regulator fluidly connected between the first port and second port, the viscosity regulator comprising a flow orifice though which flows the magnetorheological fluid pumped from the fluid pump, and an electromagnet adjacent to the flow orifice, the electromagnet adapted to controllably impart a magnetic field upon the magnetorheological fluid flowing through the flow orifice, thereby varying the viscosity of the magnetorheological fluid, and thus varying the pumping restriction against the fluid pump, resulting in variable resistance to pump shaft rotation relative to the pump housing;
a controller in communication with the actuator, the sensor, and the viscosity regulator, the controller adapted command the actuator to controllably vary vehicle steering angle in response to rotational position of the steering shaft sensed by the sensor, and the controller further adapted to command the viscosity regulator to controllably vary the viscosity of the magnetorheological fluid passing through, resulting in variable resistance to steering shaft rotation as a function of steering shaft rotational position sensed by the sensor. - View Dependent Claims (23, 24, 25, 26, 27, 28)
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Specification