Steering wheel helps the driver to control and operate the vehicle. The earlier steering systems were effective but very hard to operate as compared to power steering system. Today with easy in operation and controllability, power steering mechanism is enabled with hydraulic or electric actuators. They are used with less physical efforts and increased the command of the driver over the vehicle.
In older steering system, the mechanical system including the steering shaft in conjunction with the pitman arm lever and shaft were responsible for the movement of the front wheels.
This system makes it hard for the driver to easily control the vehicle. But nowadays the power steering is hydraulic or electric operated, they are well constructed in the steering system and decreases the efforts of the driver while operation.