#  Subsystem Design 

 



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  expand\_more  

 
  

 

## Team Vision for Subsystem-Level Design Phase

Our primary objective in this phase was to prototype and analyze our 3 subsystems which were the Control, Navigation, and Force Actuation. For each subsystem, we came up with different proof-of-concepts for different designs, which we then benchmarked and chose the best design to move forward with.

Control: H-bridge, Motor drivers, Solenoid drivers,

Navigation: Motors, Chassis, Wheels, Gearbox, BOM

Force Actuation: Solenoid valves, Flow loop design, Arm designs, Hand, BOM

## Sub-Subsystem Design & Engineering Requirements

[](https://edge.rit.edu/edge/P16227/public/Photo%20Gallery/Subsystems.jpg)

## Feasibility: Prototyping, Analysis, Simulation

### Control:

Micro-controller:

- considered PWM requirements
- [MSP430](https://docs.google.com/document/d/1kwxy8DEwyRQFFdyp2yZOhC424bq2rho6wW7SFoxennA/edit?usp=sharing)

Peripherals:

- [Drivers](https://docs.google.com/document/d/1aBTrXrclcvV0YWQJ16cH7UE9XlhnQ1Wxk6IY7GpogzE/edit?usp=sharing)
    - [](https://edge.rit.edu/edge/P16227/public/Subsystem%20Design%20Documents/Pictures/circuit1.JPG)
    - solenoid drivers
    - motor drivers
    - compressor driver

Power Regulators:

- [Power Supplies](https://docs.google.com/document/d/1BRjEuFaiRPqlMdE6zKra3bItZPla21omlvtbbAUZt18/edit?usp=sharing)
    - [](https://edge.rit.edu/edge/P16227/public/Subsystem%20Design%20Documents/Pictures/circuit2.JPG)

### Navigation:

Locomotion:

- motors
    - CIM
    - Pololu 100:1 gear motor
- wheels
    - Pololu wheels
- gearbox

Structural: [](https://edge.rit.edu/edge/P16227/public/Subsystem%20Design%20Documents/Pictures/CAD_assembly.JPG)

- frame (2ft x 2ft)

### Force Actuation:

Arm:

- 2 arm designs considered
    - 4 Channel Arm (4ChA)
    - Slinky Arm (SA)
- preliminary prototyping of 4 Channel Arm (4ChA)
    - mold being made
    - [](https://edge.rit.edu/edge/P16227/public/Subsystem%20Design%20Documents/Pictures/4channel_hand_mold.jpg)
    - material considerations: Smooth-On Ecoflex 0030, mold-star

Finger:

- 1 finger design considered
    - PneuNets Bending Actuator (PNBA)
- preliminary prototyping of PNBA has begun
    - prototype part made

Pressure Distribution:

- Flow loop designed (schematic below)

- Solenoid valves tested
    - [](https://edge.rit.edu/edge/P16227/public/Subsystem%20Design%20Documents/Pictures/solenoid_valve.jpg) [](https://edge.rit.edu/edge/P16227/public/Subsystem%20Design%20Documents/Pictures/solenoid_manifold.jpg)[](https://edge.rit.edu/edge/P16227/public/Subsystem%20Design%20Documents/Pictures/power_supply.jpg)[](https://edge.rit.edu/edge/P16227/public/Subsystem%20Design%20Documents/Pictures/solenoid_valve2.jpg)
- Pressure regulators tested
    - [](https://edge.rit.edu/edge/P16227/public/Subsystem%20Design%20Documents/Pictures/pressure_regulator.jpg)

### Inputs and Source

1. Engineering Requirements
2. Concept Selection
3. System Architecture

### Outputs and Destination

1. A list of Design Parameters, Quantified Targets, and acceptable tolerances
2. Sensitivity analysis
3. Concept Selection

## Drawings, Schematics, Flow Charts, etc.

**Air System Schematic**

- A, B, C, D, E - one-way solenoid valves
- F - two-way solenoid valve

[](https://edge.rit.edu/edge/P16227/public/Photo%20Gallery/Air_System_Schematic.PNG)

### **Valve Positioning:**

- 1 (power on - valve closed)
- 0 (power off - valve open)

Sort 

Valves

Task

A

B

C

D

E

F

Tank Fill

0

0

0

1

0

0

Arm Inflation

0

1

0

0

1

0

Finger Inflation

0

1

1

0

0

0

Finger Deflation

1

0

1

1

0

1

Arm Deflation

1

0

0

1

1

1

Pressure Release

0

0

0

1

0

0





## Bill of Materials (BOM)

**Navigation:**

SortQTY

Description

Supplier

Cost ($)

-----

------------Structural------------

------------

----------

6

30” Aluminum C-Channel

Andymark

$18/ea

8

C-Base Aluminum Corner

Andymark

$4/ea

42

¼” - 20 Hex Head Bolts

N/A

$14

-----

------------Locomotion------------

------------

----------

2

2.5” CIM Motor

Andymark

$28/ea

2

Toughbox 14.88:1 Gear Box

Andymark

$75/ea

4

4” Rubber Treaded Wheel

Andymark

$4/ea

2

½” x 4” Free Axle

N/A

N/A

2

Direct Drive Collar

N/A

N/A

2

3’ Drive Chain

N/A

N/A

2

Sprockets for Chain Drive

N/A

N/A





**Air System:**

SortQTY

Description

Supplier

Cost per Part($)

Link

1

Compressor

AndyMark

69.00

[Link](http://www.andymark.com/product-p/am-2005.htm)

1

Check Valve

McMaster

17.03

[Link](http://www.mcmaster.com/#4292k22/=zgw18f)

2

Air Tank

AndyMark

16.00

[Link](http://www.mcmaster.com/#4292k22/=zgw18f)

8

1-Way Solenoid Valve

RIT

0

N/A

1

2-way Soleniod Valve

RIT

0

N/A

17

Soleniod Valve Connector

RIT

0

N/A

2

Pressure Regulator

RIT

0

N/A

2

2-Outlet Manifold

McMaster

22.94

[Link](http://www.mcmaster.com/mv1444077061/#5975k31/=zgw7c7)

6

1/4" NPT Compression Fitting

McMaster

1.35

[Link](http://www.mcmaster.com/mv1444077061/#50775k329/=zgw8fr)

4

1/8" NPT Compression Fitting

McMaster

1.30

[Link](http://www.mcmaster.com/mv1444077061/#50775k327/=zgwr4s)

25 ft.

1/4" OD Polyethylene Tubing

McMaster

0.10 per foot

[Link](http://www.mcmaster.com/mv1444077061/#5181k39/=zgwt81)

25 ft.

1/8" OD Polyethylene Tubing

McMaster

0.05 per foot

[Link](http://www.mcmaster.com/mv1444077061/#5181k15/=zgwv0j)





## Risk Assessment

[Updated Risk Assessment](http://edge.rit.edu/edge/P16227/public/Planning%20&%20Execution#Risk_Assessment_and_Growth_Curves)