Project
# | Title | Team Members | TA | Documents | Sponsor |
---|---|---|---|---|---|
7 | Waterproof Solenoid Valve |
Daniel Yoon Maitreya Mujumdar Theodore Lietz |
AJ Schroeder | design_document1.pdf final_paper1.pdf other2.pdf proposal1.pdf |
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Group: In-person: Daniel Yoon(dyyoon2), Maitreya Mujumdar(mam4) Online: Ted Lietz (tlietz2) Problem: Current control valves are primarily made using a servo or solenoid. A valve controlled by a servo offers high precision control but has a large size and a slower response time. Solenoid valves are faster, but they usually do not have precision control and just offer binary output: an “open” or “closed” state. The valves in circulation are also large, and if a valve relies on current or voltage control, additional hardware is needed in between the microcontroller and the valve which can make the device bulky to operate. These factors make it difficult for new robotic developments to reap the benefits of utilizing hydraulics because newer robots require both the precision control of servos and the fast response time of a solenoid valve. Additionally, a lot of these robots require waterproof valves; no solenoid valves today have that feature. More than that, the fact that a separate device needs to be attached to make the valve operate with current or voltage control makes it bulky, and difficult to waterproof. Solution: Our plan is to integrate the current control functionality with a solenoid valve on the same device. This would allow us to have the precision control that a servo valve has, with the speed that using a solenoid provides. Moreover, this would allow easier waterproofing of the entire device, and the device would be smaller than adding the additional device to control current. Our project will have a central control board that directs multiple solenoid valves via I2C protocol. For precision control, we will experiment with different ideas to come up with the fastest and most reliable method of current control controlling the flow rate through the valve. Physical Design: The physical design will be similar to a traditional solenoid valve. However, the valve will have an I2C connection that could be connected to the central processing unit to modulate multiple servos at the same time. Each solenoid valve will be waterproof so that it can be operational underwater. Circuitry: The internal solenoid of each valve will have circuit protection in place in case of a short due to leakage, it does not damage all hardware. The central processing unit of the project will be separate from the valves itself, having multiple ports to communicate with the valves and be able to control each valve separately. Each valve will have it’s own I2C connection with its own master on the central processing unit so that all of the valves can be controlled simultaneously. Software: The central processing unit will send a 7-bit binary number to the valve to be decoded by the valve. The decoding algorithm will be the following; the MSB will be the variable/non-variable control bit. If the MSB is 0, then the valve will operate as a traditional solenoid valve; if the LSB is 0, the valve will open, and if the LSB is 1, the valve will close. However, if the MSB is 1, the percentage of openness will be determined by the following 6 digits of the signal; 0 being completely open, and 63 being completely closed. Valve Design Proposition: Utilization of 3D printing for prototyping and general design review Hope to make the valve either stainless steel or Aluminum The solenoid will be responsible for opening and closing the plunger Wires will be built into the valve as to be waterproof Water proof with casing and gasket Theory of Operation: With different currents, the magnitude of the magnetic field produced by the solenoid will change. This will make it possible to enact varying forces on the plunger inside the valve, which will allow the precision control that is desired. Confounding variables involved with the valve will have to be taken into account. These include friction between the plunger and body, water pressure inside the valve, and orientation of the valve. Testing: The testing will require a potentiometer to document and test the magnetic properties of the device. A microcontroller will be programmed to connect to our valve and test the variable control of the valve. The flow rate will be determined by setting our device up to different degrees of openness, then we will measure the time it takes to fill a container of known volume. This process will be repeated multiple times to get an accurate average of flow rate so that we can compare it to the flow rate of no valve attached at all to verify if our device is working correctly. If that method of testing proves to be imprecise, we will use an ultrasonic flow meter available at Texas Instruments. Flow rate testing will be done using water. Criterion for Success: Waterproof design that can withstand pressure up to 1 meter underwater No leaks between the valve and the water tube (size to be determined) Predictable flow rate based on the signal sent to the solenoid valve via its I2C connection Up to three valves being able to be controlled simultaneously If our project is able to satisfy all of the requirements stated above, it will be considered a success. Covid Contingency Plan: In the event that everybody needs to go online, we should have the 3D printed body by that time. All wire connections and soldering can be done at home using a soldering iron that we will buy. The testing can be done using at home supplies since it requires only water, a bucket or an ultrasonic flow sensor, a computer, and our microcontroller. We will create a video to demo our project. |