[DESIGN] - Shutter Mechanism

[JLefebvre55]

@UofTAgritech/mechanical

This is a sub-issue of #1

Design Scope

Design an airflow control mechanism made of servo-actuated airtight shutters.

Purpose

The purpose of the shutter mechanism is to prevent unwanted airflow and allow airflow on demand.

Function

Inputs:

• Servo control

Outputs:

• Airflow regulation

It interfaces with/depends on the following systems:

• Power delivery
• Automation control

System operation assumes:

• TBD

Method

Setup:

1. TBD

Process:

1. Servos rotate to close the air passageway, forming a nearly-airtight seal
2. Servos rotate to open the air passageway, allowing for free movement of air

Shutdown:

1. TBD

Features

Each feature should be added to relevant BoMs and CADs where applicable. Design decisions should be well-supported using relevant research and calculations, and should be documented in the Solution Overview. If a feature is complex enough, create a new issue for it using this template, and tag it here.

• [ ] Servo Motor: Must deliver enough force to hold shutters sealed
• [ ] Shutter blade: Must overlap with other shutter blades to seal
• [ ] Force delivery mechanism: Rack and pinion?

Requirements and Validation

What does this design need to accomplish? How do we know it has accomplished this?

List any applicable metrics with criteria/constraints, applicable to purpose, function, method, and each feature, as well as how to test them.

1. Nominal airflow when sealed ~0CFM
2. Maximum airflow when opened ~100% of fan throughput Note (19/11/21): this means near-perpendicular range of motion
3. Time to open and close the mechanism <2 seconds

Verification

Each test should be performed and documented, and the testing documentation attached to the PR. The testing suite should address the full scope of the function (i.e. ensure inputs are met and outputs work), method (all steps execute correctly), and features (each feature performs as expected) with respect to the purpose and requirements.

How does this design achieve its method effectively, safely, and reliably? How do we test this?

Specific testing procedure:

1. Servos can actuate the full shutter operation range
2. Shutters seal when closed

Additional context

Add any other context about the design scope or additional deliverables here.

[KHash22]

https://user-images.githubusercontent.com/91762267/142577874-e24e0a3b-615b-4f1a-83bb-2f6caaf8ca8f.mp4

Example of fins + shutter mechanism. Improvements needed:

• [x] lever moved to one side
• [x] lever moves only in vertical axis (slider+rotation joint)
• [x] fins have 90 degrees of movement
• [ ] rack for pinion mounting
• [ ] increase to 8 fins

Possible additions:

• Introduce wedge or mounting for rubber piece for better seal?

[JLefebvre55]

Example of fins + shutter mechanism.

Looks fantastic @KHash22. Some notes:

• Can we move the lever to one side? (that way we can have it be servo-controlled)
• Can we make the fins smaller? Like rather than 4 big ones, maybe 8 ones half as big (that way they stick out less)

[KHash22]

https://user-images.githubusercontent.com/91762267/142696959-97aac105-d4e3-449f-ba16-92f0cb09748e.mp4

Second example of fins+shutter