What is used in air-assist steering to help the driver with steering effort?

In air-assist steering systems, the power cylinder plays a crucial role in reducing the driver's effort when steering the vehicle. This system utilizes pressurized air to assist in turning the steering mechanism, which makes maneuvering the vehicle easier, especially in larger or heavier vehicles where steering can become cumbersome. The power cylinder amplifies the steering effort exerted by the driver, enabling smoother and more controlled turns, particularly at lower speeds or during parking maneuvers.

The other components mentioned do not serve the same function. The steering column primarily transmits the driver's input from the steering wheel to the rest of the steering system. The steering rack is part of the mechanism that converts rotational motion into linear motion for the wheels, but it does not provide additional assistance in effort. Control arms are components of the suspension that help to connect the vehicle's chassis to the wheels, and while they are vital for wheel movement and alignment, they are not involved in steering assistance. Hence, the power cylinder is the appropriate component that directly assists the driver in reducing steering effort in an air-assist steering system.