Video locked, pivot arm automation for a trade fair exhibit.

Videosynchrone Schwenkarm-Automation

Position and speed regulation using a digital radial piston pump and 4/3 directional valves combined with the Beckhoff SPC.

This is how the trade fair stand of the future could look.

Rädlinger is one of the leading manufacturers of excavator slew drives and buckets located in Cham in Bavaria. On behalf of the Upper Palatinate company, we produced an automated trade fair stand for carrying out realistic movements of a pivot arm. The goal: to enthuse new customers with the performance of the company.

The customer requirements included hydraulic equipment that was reliable and designed for permanent operation, positional control for the slew drive and bucket cylinder and the selection of suitable position measurement systems for the rotary drive and the bucket cylinder. Alongside simple operation, there had to be the possibility to play video sequences in synchronization with the movements of the excavator arm.

How we solved the problem:

In order to achieve a harmonious slewing process, a digital variable displacement pump and radial piston pump with analog SPC connection were used. In addition, the hydraulic unit is equipped with a special oil/air cooler. In the process, the special container was made with the smallest possible dimensions so that it could be integrated in the space available in the trade fair display cabinet. Further key features of the automation concept are a contactless, increment position measurement system with magnetic belt for the slew drive, and a cable sensor analog output for the bucket cylinder. For the Beckhoff control solution and presentation of the video sequence, an embedded PC, series CX51, was used.

Thanks to the automatic movement sequence of the stand exhibit, no monitoring measures or interventions into the control process by the trade fair personnel were necessary. The synchronization of the video sequences with the movement process internally to the SPC made the cost intensive acquisition of further hardware and software unnecessary.

The most important points about the project:

  • Implementation time: from October 2015 until April 2016.
  • Customer requirements: Slew arm automation via a hydraulic system, simple handling, movement processes synchronized with video.
  • Basic data: System pressure: 210 bar, Volume flow: 27 l/min.
  • Special features: High precision position and speed control, digital radial piston pump with analog SPC connection, all actuators (cylinder, slew drive) are supplied by a pump.


Martin Ruckdeschel

Manager of the technical back office ET
+49 9208 657439-15
Martin Ruckdeschel