Optical torque sensors and steering systems for vehicles incorporating them
First Claim
1. A torque sensor comprising:
- an input member;
an output member;
emitter means;
first receiver means for receiving a first signal, said first receiver means comprising means to output a first output signal dependent upon the first signal;
second receiver means for receiving a second signal, said second receiver means comprising means to output a second output signal dependent upon the second signal; and
signal processing means for dividing the difference between the first and second output signals by the sum of the first and second output signals so as to produce a modified output signal which is directly proportional to relative angular displacement between, or torque applied between, said input and output members.
1 Assignment
0 Petitions
Accused Products
Abstract
A torque sensor, or a relative angular movement sensor, comprises an LED light source mounted in a fixed position relative to a housing which shines light through an associated fixed collimator plate, the light being detected by a pair of detectors also mounted fixed relative to the housing. Two masks pass between the source and the detector, one of the masks being fixed to an input shaft of the steering system and the other being connected to the output shaft. Each of the masks has a first and second aperture, and the amount of light which is received by detectors depends upon the degree of overlap between associated pairs of apertures in the input and output masks. Signals from each of the detectors is fed to a control microprocessor which provides a signal indicative of differential torque between the input and output shafts. This signal is substantially independent of the intensity of the light source which allows it to compensate for ageing effects in the light source. The signal also shows a positive value for turning of the input shaft in one direction and a negative value for turning the input shaft in the opposite direction. The torque sensor can be used to obtain the torque, relative change of steering angle, and steering angle itself, which can all be passed to a vehicle ride or braking control system.
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Citations
16 Claims
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1. A torque sensor comprising:
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an input member; an output member; emitter means; first receiver means for receiving a first signal, said first receiver means comprising means to output a first output signal dependent upon the first signal; second receiver means for receiving a second signal, said second receiver means comprising means to output a second output signal dependent upon the second signal; and signal processing means for dividing the difference between the first and second output signals by the sum of the first and second output signals so as to produce a modified output signal which is directly proportional to relative angular displacement between, or torque applied between, said input and output members. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A power-assisted steering system having a torque sensor comprising:
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an input member; an output member; emitter means; first receiver means for receiving a first signal, said first receiver means comprising means to output a first output signal dependent upon the first signal; second receiver means for receiving a second signal, said second receiver means comprising means to output a second output signal dependent upon the second signal; signal processing means for dividing the difference between the first and second output signals by the sum of the first and second output signals so as to produce a modified output signal which is directly proportional to relative angular displacement between, or torque applied between, said input and output members; an input column transmitting torque from steering wheel to said input member of said torque sensor; and an output column transferring torque to a steering mechanism adapted to steer road wheels of the system. - View Dependent Claims (13, 14, 15, 16)
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Specification