Steering control systems for the automatic steering of industrial trucks
The steering control system produced by Keltronik is used for the automatic steering of industrial trucks. The line driver LDU generates an alternating current in the contact wire installed under the road surface, which the vehicle can follow.
This wire runs in a closed loop from the line driver over a maximum length of 1200m and back again. If a longer distance is required, an additional line driver with a separate contact wire must be installed. The electricity generates a magnetic field in the contact wire with which the industrial truck is controlled.
The magnetic field is detected by two or more antennas attached to the underside of the vehicle. These are connected to a control unit IFE, which controls the steering. The entire process is continuously monitored by the control unit and the truck is stopped when an error occurs.
The line driver LDU requires a supply voltage of 230V (LDU-22) or 110V (LDU-21). There is a voltage card in the device with which the mains voltage is converted into a lower operating voltage. A generator card with an output stage generates the required current for the contact wire at a specific frequency (standard 6.25 kHz). In the event of a power failure, a built-in battery continues to power the device. The current operating status of the line driver can be monitored via LEDs and a built-in buzzer.
The antennas are mounted on the center line (+/-) 3mm of the industrial truck. Each antenna consists of three coils that detect the magnetic field of the contact wire laid in the ground. The coils detect different vehicle movements to the contact wire vertically, sideways and the angle to the contact wire. The antennas are connected with a shielded 5-wire cable, with which the signals are transmitted to the control unit. The signals from the antennas are amplified by a pre-amplifier card for further processing in the control unit.
The control unit IFE controls the steering of the vehicle with signals from the antennas and other vehicle components, e.g. Steering angle sensor. A control unit can be used for various types of industrial trucks, the correct parameters are set via a programmer. The parameters are written to a RAM memory and stored in an EEPROM after completion.