Design and fabrication of an actuation module using integrated pneumatic technology

In this thesis, xurography techniques are used to create an integrated pneumatic card (IPC) by integrating fluidic channels inside the electronic circuitry of their control system. In the simplest design of an IPC, there are three main layers: the top layer made of printed circuit board (PCB), the middle layer made of double-sided tape with air channels xurographically cut in it, and a bottom layer of PCB. Flow enters through an opening in the top layer of PCB and is routed through valves and to outlets in the bottom PCB by the air channels in the tape. The surfacemount valves are attached pneumatically and electrically to the first layer of PCB. By using PCB as the substrate, the circuitry for controlling the device can be integrated directly onto the same material as the valves. A prototype was device created for testing purposes to verify that the device could be operated within specifications. It consists of an air inlet and eight three-way valves that route air to four bladders, three pinch points and one flow-through channel. The dimensions of the entire device measure 2.4 x 3.6 x 1 in excluding the protruding wire attachment. The modeling of this device was done using a one-dimensional flow assumption and was used to predict the time constant to inflate a bladder. Key calculations of this model include: an equation to calculate bladder pressure as a function of time and flow rate, and an equation for flow rate as a function of pressure. Also, equations to predict the acceleration of air in the channel were developed. Data for channel expansion due to expansion of the acrylic adhesive are used directly in the model. These calculations were made iteratively using a spreadsheet. The results were compared to experimental results and shown to be an adequate representation of reality.