Power steering system update

In our project, the primary concern is related to the articulated steering structure. Articulated steering is actually rotating the whole front frame which requires a significant steering torque. However, The steering wheel is connected to the proportional rotary valve directly. That means considerable energy loss will occur at the valve.

In order to reduce the energy consumption, we will implement the DC system. However, haptic feedback won’t be available in this case, because the steering wheel no longer has a direct linkage with the steering cylinder. So we will use a sensor to measure the steering wheel position and a torque feedback device to replicate the road feel. A controller will be used to communicate the hydraulic pump and steering interface. 

In general, we will have improvements in 3 aspects: efficiency, safety and productivity

A lot of work has demonstrated the improved efficiency of the displacement controlled actuation by getting rid of the throttling loss across the valve. Next, stability is normally an issue for articulated steering vehicle, like jackknifing or snaking. However, with the new system, the active steering assistance can modify the driver’s input to stabilize the vehicle. We will also use progressive steering to help driver be more productive. That means in low speed situation, driver will experience faster and easier steering than that in high speed, in which case the resistive force will increase for better stability.