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            In a globalised world where container ships with several thousand containers call at the
            world's largest ports, the loading and unloading of ships is supported by fully automated
            systems. The containers are stacked by self-propelled lifting cranes, so-called Straddle
            Carriers, in an intermediate storage facility in the port area. The hydraulics and electronics
            installed in the Straddle Carrier are often in use 24 hours a day and a system failure would
            cause very high costs.

          Several Stradle Carriers are controlled from one control room.
          The dispatcher simply indicates the desired end position to
          the vehicle, everything else is managed independently by the
          vehicle.  Due  to  its  high  payload,  a  Straddle  Carrier  has  six
          to  eight  axes  that  are  individually  controlled,  regulated  and
          monitored  hydraulically via proportional  valves. For  safety
          reasons, similar to aircraft construction, the entire hydraulics,
          including  the  control  electronics  and  the  axes  control,  is
          kept redundant. In addition to increased security, the system
          thus gains in availability. System failures and the associated
          time delays in  24-hour  port operation are thus  practically

                       CAN 3
                       CAN 4        power supply 24VDC
                                    CAN 1
                   steering unit
                      8 x valves
                   A  B
               a       b
                   P  T  solenoid outputs  steering
                               controller  digital  vehicle
               8 x pressure  p  analog inputs  in / outputs
                           CAN 2
                   8 x rotary encoder wheel angle

          The heart of the system is the SIL2-capable steering controller.
          Via a redundant CANbus system, the steering unit transmits
          the values to the controller that compares and regulates the
          positions with robust angle sensors. Through the proportional
          amplifier  electronics,  the  proportional  spool  valves  and  the
          steering angle of the axes are then controlled. All components
          are adjusted to each other, allowing easy commissioning and
          controlled operation.

          •  Manual vehicle steering and various driving modes integrated
          •  Various safety functions additionally expandable
          •  Parameterisation software for commissioning and maintenance
          •  Completely aligned system. Hydraulics and electronics from one provider

          PAGE 4           |              WANDFLUH MOBILE     |       APPLICATION     |       STRADDLE CARRIER
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