Technic & Comparison
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The essential difference between active steering (overlay steering) and  Pss-logo 14p - steering comprises three important factors:

Active steering:

  1. The transmission ratio is adapted to the speed. The slower you drive, the more direct the steering.
  2. The steering is electronic and requires significant expenditure for electronics and additional mechanical parts. Active steering places a high demand on functional reliability in the development of active chassis functions, i.e. chassis functions which are changeable by means of a controller unit. The functional reliability, the technical safety concept, the safety-orientated functional and software development process and the methods for securing the safety functions must be ensured by means of special processes with constant monitoring.
  3. The additional parts hinder the ‘feel’ of the steering.

The very direct steering, particularly when driving slowly, is very exhausting as it requires a constantly high degree of concentration. When driving fast, there is no feedback or resetting of the steering, so that the driver must continually check his direction visually and correct the steering.

Pss-logo 14p - steering

  1. The transmission ratio is adapted to the steering angle; the steering always has the same directness, independent of the driving speed.
  2. The transmission ratio is altered purely mechanically, no error-prone electronics.PSS ritzel
  3. The simple rack and pinion construction needs no additional mechanical parts which influence the feel of the steering.

When driving slowly, the indirect steering in the central position is relaxing, since each small movement of the steering wheel does not lead to an abrupt change of direction. When driving fast, feedback and resetting of the steering is always guaranteed due to the low-friction, no-backlash construction of the PSS steering. The driver feels every influence on the steering, just as with conventional rack and pinion steering.

Conclusion:
For heavy vehicles such as HGVs, delivery vans and SUVs, active-assisted steering is recommended for safety reasons. The combination of the progressive PSS steering with an overlay steering for emergencies results in an optimum combination of agile, tactile and comfortable driving with the advantages of active driving assistance functions.
 

 

The shaded area of the diagram illustrates the electronically-changeable zone (between ~30 and ~120km/h) of the active steering.  The green area is the safe steering zone of the PSS steering

 

 

 

 

 

 

 

 

 

                        

 

 

 

 

 

 

 

                       

 

    

 
 

Technic & Comparison / Active-Steering