This document discusses four wheel steering (4WS) systems. It begins by defining 4WS as a rear wheel steering system that improves stability at high speeds. It then explains the basic components and types of steering systems, including front wheel, rear wheel, and 4WS. The document outlines the different modes in a 4WS system, including mechanical, hydraulic, and electro/hydraulic. It describes how 4WS provides benefits like improved handling, reduced driver fatigue, and increased stability at both high and low speeds. Finally, it states that a successful 4WS system could allow for development of a highly maneuverable vehicle with stability and obstacle climbing capabilities.

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