Four wheel steering control system for vehicles
First Claim
Patent Images
1. A four wheel steering control system comprising:
- front actuator means for steering the front wheels of a vehicle in response to a front control signal representing a controlled front wheel steer angle;
rear actuator means for steering the rear wheels of said vehicle in response to a rear control signal representing a controlled rear wheel steer angle;
first sensor means for sensing a steering wheel angle of said vehicle;
second sensor means for sensing the speed of said vehicle; and
controller means connected with said first and second sensor means for producing said front and rear control signals in accordance with a first and a second transfer function which are expressed as;
##EQU12## where δ
f (s) is the Laplace transform of said controlled front wheel steer angle δ
f, δ
f (s) is the Laplace transform of said controlled rear wheel steer angle δ
f, Θ
(s) is the Laplace transform of said steering wheel angle Θ
, δ
o (s) is the Laplace transform of a basic front wheel steer angle that is proportional to said steering wheel angle s is a Laplace transform variable, Kf, Kf, Tf and Tf are parameters whose values are fixed by said vehicle speed, and φ
(s)/Θ
(s) is a predetermined yaw rate characteristic.
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Abstract
A four wheel steering control system for a vehicle includes a steering wheel angle sensor, a vehicle speed sensor, and a controller for determining auxiliary front and rear wheel steer angles δf and δr with respect to a basic front wheel steer angle δo proportional to a steering wheel angle θ in accordance with the following transfer functions: ##EQU1## where s is a Laplace transform variable, and Kf, Kr, Tf and Tr are constant determined by the vehicle speed and the specifications of the vehicle.
16 Citations
6 Claims
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1. A four wheel steering control system comprising:
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front actuator means for steering the front wheels of a vehicle in response to a front control signal representing a controlled front wheel steer angle; rear actuator means for steering the rear wheels of said vehicle in response to a rear control signal representing a controlled rear wheel steer angle; first sensor means for sensing a steering wheel angle of said vehicle; second sensor means for sensing the speed of said vehicle; and controller means connected with said first and second sensor means for producing said front and rear control signals in accordance with a first and a second transfer function which are expressed as;
##EQU12## where δ
f (s) is the Laplace transform of said controlled front wheel steer angle δ
f, δ
f (s) is the Laplace transform of said controlled rear wheel steer angle δ
f, Θ
(s) is the Laplace transform of said steering wheel angle Θ
, δ
o (s) is the Laplace transform of a basic front wheel steer angle that is proportional to said steering wheel angle s is a Laplace transform variable, Kf, Kf, Tf and Tf are parameters whose values are fixed by said vehicle speed, and φ
(s)/Θ
(s) is a predetermined yaw rate characteristic. - View Dependent Claims (2, 3)
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4. A four wheel steering control system comprising:
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front actuator means for steering the front wheels of a vehicle in response to a front control signal representing a controlled front wheel steer angle; rear actuator means for steering the rear wheels of said vehicle in response to a rear control signal representing a controlled rear wheel steer angle; first sensor means for sensing a steering wheel angle of said vehicle; second sensor means for sensing the speed of said vehicle; and controller means connected with said first and second sensor means for producing said front and rear control signals and comprising first controlling means for determining said controlled front wheel steer angle in accordance with a first transfer function and rear controlling means for determining said controlled rear wheel steer angle in accordance with a second transfer function, said first and second transfer functions being expressed as ##EQU13## where δ
f (s) is the Laplace transform of said controlled front wheel steer angle δ
f,δ
f (s) is the Laplace transform of said controlled rear wheel steer angle δ
f,Θ
(s) is the Laplace transform of said steering wheel angle Θ
,δ
o (s) is the Laplace transform of a basic front wheel steer angle of said vehicle,s is a Laplace transform variable, φ
(s)/Θ
(s) is a predetermined yaw rate characteristic,M is the mass of said vehicle, I is the yawing moment of inertia of said vehicle, l0 is the wheelbase of said vehicle, a is the distance between the center of gravity of said vehicle and the position of said front wheels, b is the distance between said center of gravity and the position of said rear wheels, l3 is a quantity representing the distance between said center of gravity and a zero side slip angle position at which a vehicle side slip angle is zero, C1 is a front wheel cornering power, C2 is a rear wheel concerning power, and V is said vehicle speed, and N is a steering ratio. - View Dependent Claims (5, 6)
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Specification
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Current AssigneeNissan Motor Co., Ltd.
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Original AssigneeNissan Motor Co., Ltd.
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InventorsMori, Kazunori
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Primary Examiner(s)Black, Thomas G.
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Application NumberUS07/314,874Time in Patent Office739 DaysField of Search364/424.05, 280/91, 180/140-142US Class Current701/42CPC Class CodesB62D 7/1572 provided with electro-hydra...B62D 7/159 characterised by computing ...Y02T 10/72 Electric energy management ...
