The essential difference between the Wandfluh steering system and - steering comprises three important factors:
- The progression of the Wandfluh steering system is based on an error, the gimbal error.
- The steering power input is deflected by ~90°, similar to a recirculating ball steering. This means that the steering feedback is suppressed (dead steering feel).
- The sinusoidal change of steering angle, together with the accumulating torque fluctuations, produces a disharmonic steering with a strong tendency to ‘hook in’ in tighter curves.
Since the construction of the Wandfluh steering only allows a steering angle of maximum approx. 110°, a second transmission must be installed for use in normal vehicles to spread the progression for a greater steering wheel angle. That means additional friction and play.
All drivers of vehicles with Wandfluh steering criticise that the steering wheel angle does not correlate to the steering angle of the wheels. The discrepancy can be so large that dangerous situations can result if the driver is not experienced.
- The progression of the PSS steering increases logarithmically.
- The steering power input takes place directly via the rack. The feedback is thus fed directly to the steering wheel with no external influences. (seismographic steering feel).
- The logarithmic change of steering angle, together with the evenly increasing torque, results in harmonious and dynamic steering corresponding to the human haptic.
Due to the even and harmonious increase in the steering angle, the driver always has a good driving feel, because the steering always reacts as the driver expects and steers.
The possible settings of the Wandfluh steering are visible on the original diagram from Wandfluh (white, light grey, grey and light blue lines). The fluctuation in the progression can be clearly seen. The ‘hook-in’ criticised above can be seen most clearly in the white line. The green line added by us represents the progression of the PSS steering; the dark blue line that of conventional steering.