Flectofold developed at ITKE (Institut für Tragkonstruktionen und Konstruktives Entwerfen, University of Stuttgart) is the name of a compliant façade shading system. In this bio-inspired material system, the mechanical hinges have been replaced by a simplified curved-line folding geometry with distinct flexible hinge-zones. [source: Flectofold – A biomimetic compliant shading device for complex free form facades]
Baubionik exhibition at Schloss Rosenstein/Stuttgart was an opportunity to display the advancement of Flectofold on a proto-architecture scale. Designed and fabricated by researcher Saman Saffarian, this demonstration depicted the possibilities of using this shading device in real-world architecture.
The demonstrator consisted of a frame holding 36 Flectofold panel in a 6 by 6 grid representing a curved surface. Each element was controlled by a pneumatic actuator to apply a distributed pressure to the middle part of the Flectofold panels.
To regulate the amount of air pressure in each pneumatic cushion (with a direct relation to the applied force), a control system was developed from scratch including digital pressure regulators, customized electrical circuit, and a graphical user interface.
The multi-layer control system starting from Festo pressure valves to high-level user interface was the area I had the chance to contribute the most.
The user interface consisted of a server-side software responsible for communication with embedded software and a client-side web application to change control-modes and visualize the current state of each panel.
The embedded software running on Arduino board was responsible for conversion from high-level commands coming from server software to low-level one-byte data and send them over SPI protocol to the targeted digital potentiometer.
Each digital potentiometer was designated to one Flectofold which was able to output a range of voltage indicating the goal pressure of Festo pressure valves.