Electrical power assisted steering system
First Claim
1. An electric power assisted steering system comprising:
- a steering mechanism for a vehicle having a steering wheel and a plurality of road wheels which operatively connects said steering wheel to at least one of said road wheels of said vehicle, a torque sensor arranged to produce a first output signal indicative of a torque carried by a portion of said steering mechanism, a velocity sensor for producing a second output signal indicative of an angular velocity of said steering wheel, a difference means for determining the difference in value of said torque carried by a portion of said column between two points in time to produce a third output signal, an electric motor operatively connected to said steering mechanism, a signal processing unit adapted to receive said first signal, said second signal and said third signal and to produce a torque demand signal representative of a torque to be applied to said steering mechanism by said motor, and a motor drive stage adapted to provide a drive current to said motor responsive to said torque demand signal, wherein said torque demand signal comprises a steering assistance component which is dependent upon said first signal and a damping component that is dependent upon both said first output signal, said second output signal and said third output signal.
1 Assignment
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Accused Products
Abstract
An electric power assisted steering system comprising a steering mechanism which operatively connects a steering wheel to the road wheels of the vehicle, a torque sensing means (6) adapted to produce a first output signal indicative of the torque carried by a portion of the steering mechanism (7), a means (6) for producing a second output signal indicative of the angular velocity of the steering wheel, a difference means (21) for determining the difference in value of the torque carried by a portion of the column between two points in time to produce a third output value, an electric motor (1) operatively connected to the steering mechanism, a signal processing unit (7) adapted to receive the two signals and to produce a torque demand signal representative of a torque to be applied to the steering mechanism by the motor (1), and a motor drive stage adapted to provide a drive current to the motor (1) responsive to the torque demand signal, and in which the torque demand signal (1) includes a damping component that is dependent upon both the first output signal, the second output signal and the third output signal.
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Citations
16 Claims
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1. An electric power assisted steering system comprising:
- a steering mechanism for a vehicle having a steering wheel and a plurality of road wheels which operatively connects said steering wheel to at least one of said road wheels of said vehicle, a torque sensor arranged to produce a first output signal indicative of a torque carried by a portion of said steering mechanism, a velocity sensor for producing a second output signal indicative of an angular velocity of said steering wheel, a difference means for determining the difference in value of said torque carried by a portion of said column between two points in time to produce a third output signal, an electric motor operatively connected to said steering mechanism, a signal processing unit adapted to receive said first signal, said second signal and said third signal and to produce a torque demand signal representative of a torque to be applied to said steering mechanism by said motor, and a motor drive stage adapted to provide a drive current to said motor responsive to said torque demand signal, wherein said torque demand signal comprises a steering assistance component which is dependent upon said first signal and a damping component that is dependent upon both said first output signal, said second output signal and said third output signal.
- View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16)
Specification