Breaking the Surface -  Servo terminals move virtual ocean

By M Matuschke, Beckhoff

 

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Norwegian oil company, Lundin Norway, envisioned something rather unique to mark the 10th anniversary of the company. Five hundred and twenty nine Plexiglas tubes are moved continuously together in such a way that they simulate ocean waves, and at the same time symbolise the constant search for oil under water on the Norwegian continental shelf. A markedly complex and sophisticated project, both artistically and mechanically, as well as in terms of the control technology, it is also interactive. Complex control technology simulates well.

The application communicates with the four IPC platforms, which also control the servomotors via TwinCAT ADS. A great deal of openFrameworks add-ons were used for this application. In addition, three new add-ons for ‘Breaking the Surface’ for:

• Controlling the display and alignment of several Kinect point clouds in the same coordinate system
• Facilitating the transmission of data between openFrameworks and the control platform
• Directing the communication and visualisation of sensfloor data in openFrameworks

The set values of the motion diagram, which are programmed in C++, are imported into the automation software via the ADS interface. In connection with the ultra-fast bus system and the servo terminals, the point-to-point axis positioning software calculates the position for each individual tube in a cycle time of 1 ms. An interpolating motion results, which the viewer perceives visually as natural undulation. If the sensors signal a movement, i.e. a person entering the ‘ocean’, then the axis positions of the undulation are overwritten; the position of the pipes in close proximity is adjusted to form a protective dome around the person moving around in the space. A thin metal ring, attached on the inside of each tube, gives a reference signal every time it passes the capacitative sensor inside the drive unit. This makes it easy and safe to double check and control our adjustment positioning algorithm which gives us the exact position of the tube at any time.

 

Take note

  • Increasingly large amounts of data are being collected in industry
  • Data needs to be reliably managed and used in order to serve the needs of a controlled process or plant.
  • Using PCs and EtherCAT has been shown to provide a viable means of doing this.