REAR WHEEL STEERING SYSTEM

1. SUBMITTED BY
NASH DHAQUCIR

3.  INTRODUCTION
 STEERING SYSTEM & ITS TYPES
 WORKING PRINCIPLE
 BASIC GEOMETRY
 MODES IN 4WS SYSTEM
 FEATURES & APPLICATIONS OF 4WS MODEL
 CONCLUSIONS & SCOPE OF FUTURE WORK

4.  Rear wheel steering system is also called as “Four
wheel steering system” (or) “All wheel steering
system”.
 To improve stability, most cars nowadays are
designed to exhibit under steer characteristic when
driven at high speed.
 Although under-steer condition improves stability
of the vehicle, it increases the driver’s steering
effort.

5.  Also since a vehicle handling changes with the road
speed movement, both in time & direction, is
difficult to predict.
 These disadvantages can be overcome to greater
extent by using Four wheel steering.

7.  Steering is the term applied to the collection
of components,linkages, etc. Which will allow
a vehicle to follow the desired course.
 An exception is the case of rail transport by
which rail tracks combined together with
railroad swithches.

8.  Types of steering system:
 (i) Front wheel steering
 (ii) Rear wheel steering
 (iii) Four wheel steering

10.  Rear-wheel steering (or Four-wheel steering
or all-wheel steering) is a system employed
by some vehicles to improve steering
response, increase vehicle stability while
maneuvering at high speed, or to decrease
the ‘turning radius’ at low speed.

11.  The basic aim of steering is to ensure that
the wheels are pointing in the desired
directions. This is typically achieved by a
series of linkages, rods, pivots, & gears.

13.  (1) Mechanical 4WS
 (2) Hydraulic 4WS
 (3) Electro/Hydraulic 4WS

14.  The mechanical 4WS uses two separate
steering gears to control the front & rear
wheels.
 The hydraulic 4WS uses a two-way hydraulic
cylinder to turn both the wheels in the same
direction. It is not possible to turn them in
the opposite direction.
 The electro/hydraulic 4WS combine computer
electronic controls with hydraulics to make
the system sensitive to both steering angle
and road speeds.

15.  In conjugation with rear steer mode, four
wheel steering can significantly improve the
vehicle handling at both high & low speeds.
 Due to the better handling & easier steering
capability, driver fatigue can be reduced even
over long drives.
 Stability of the vehicle increases.
 Turning radius of the vehicle can be
decreased to a greater extent by ‘rear steer
mode’.

17.  An innovative feature of this steering linkage
design and its ability to drive all four (or two)
Wheels using a single steering actuator.
 Its successful implementation will allow for
the development of a four-wheel, steered
power base with maximum maneuveraility,
uncompromised static stability, front & rear
wheel tracking, & optimum obstacle climbing
capability.

19. THANK YOU