To fabricate a four wheel vehicle having steering system with four modes being operated mechanically. The four modes facilitate the following capabilities: 1) To ensure tight turns in heavy traffic and tight spaces.2) To let the vehicle to turn around its central axis which will help in turning at tight spaces.3)To make use of mechanical approach for these different modes. In this process the vehicle has been designed and fabricated in such a way that driver is able to steer the wheels for attaining different modes easily. These four modes uses a screw & nut mechanism and split axle mechanism for working of different modes, which will facilitate the driver to make use of it at different driving conditions. These all modes are mechanically operated and these modes have different adjustment for changing modes.
The vehicle has been observed in full lock position for short turning radius mode in which the rear wheels were steer opposite to that of front wheels. The vehicle is then allowed to form two circles i.e. one for short turning radius mode and other one for Normal mode (front steer) as shown below. The turning radius formed by short turning radius mode is of small radius as compared to normal mode turning circle. By normal mode, the radius of the circle is found to be of 4.4m whereas in case of Short turning mode it is 2.85m, which shows the difference in the turning radius obtained by different modes. Hence there is reduction in the turning radius by 35%.
In this case, the vehicle is allowed to move diagonally by aligning all wheels in same direction. By this mode, the vehicle’s ergonomics is observed suitable for the parking purposes, where the following case arises for parking. The parking maneuver is observe to be more easy in this mode (Crab steer) as compare to normal mode.
The vehicle is also observed to be suitable for high speed lane change purposes, in which there is reduction of path followed by the vehicle as compare with normal mode. hence the crab steer mode is found to be beneficial for these two purposes. Hence, the crab steer mode can be used in two ways, that are parking purposes and high speed lane change purposes.
3. Zero Turning Radius Mode:
As from the working of the zero turn radius mode , it has been clarified that by changing the orientation of the tires and giving the torque to one of the wheel results in movement of the vehicle about its own axis. So it will be beneficial in various fields.