Work today was split between two tasks. Using a large DC power supply, we took measurements of the acutators motion versus the resistance on its potentiometer. Based off this data, we now have a simulink model of the actuator which can be used in the design of the closed loop feedback controller for positioning the wing in the wind tunnel chamber and also for the positioning of the wind speed probe.
We also tested and verified our interface for the microcontroller to the solid-state relay. Once we were sure that the switch worked on a simulated microcontroller input we hooked it up to the Si Labs board and managed to switch the wind tunnel on and off.
Click here to see it in action:The new actuator arrived in the last week and we will be testing it today to try to find some of its characteristics. We will use these to design the controllers for both actuators since this one is nearly identical to the one currently installed on the wind tunnel. The only difference is that this one has a longer arm on it.
In addition we will be working on the serial communication between the embedded system and the computer with the goal of turning the wind tunnel on and off through a GUI.
One other consideration for today is the design of the interface between the microcontroller and the relay.
Today was spent tracing and learning about the motor which controls the damper on the wind tunnel. Our initial thought was that it was a 3-phase appliance motor, but it turned out to be a Universal Motor.
The motor is very old and so we could not find a datasheet or any information on it initially. Mr. Mattus however had a nearly duplicate motor in a storage room here so we have a similar peice we can test to determine the functionality.
Today we installed a relay and replaced the existing on/off switch on the wind tunnel.
It is now possible to easily start and stop the wind tunnel with a 5V signal. Not only does this mean we are nearly ready to begin switching it with a microcontroller, but also that the physical switch is now safer than the original 220V switching mechanism.
Click here to see it in action:Today we split our focus between two tasks.
In preparation for beginning the development for the embedded system, Mike spent part of the day examining sample Java applications which use the serial port and doing some founational work on the wind tunnel control application.
Ben continued the research on the modeling of linear actuators. We hope to be able to come up with a model of the actuator used in the wind tunnel so we can develop the controller for it more effectively.