I spent quite some time to improve the air pouch so that a higher pressure can be achieved.
Air Pouch Design
Before that, I used some plastic material to make the air pouch which is not good enough. The air leaks from the joint between the plastic material and the black tube.
Plastic Air Pouches
Another type of rubber material which used to make the air pouch in pressure monitor is used to make the air pouch. For this type of material, the air-tightness is better, but still there is a minor air leakage. Plastic glue is used to seal the remaining air leakage spots.
Plastic Glue Applied to the Air Pouch
The air pouch is then wrapped with black tapes to make it tighter.
Final Product for Air Pouch
Here are some updates for my control system.
Minimum output pressure: 0.13 kPa
Maximum output pressure: 10 kPa
Sampling frequency: 100Hz
Sensor sensitivity: 450mV/kPa
I changed to a new sensor which has higher sensitivity so that the control system can perform better. I still have not gotten the time to plot the graphs. The graphs should be up in the next 2 days.