Subsystem Design

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

border|Subsystem Archetecture

Feasibility: Prototyping, Analysis, Simulation

Control:

Micro-controller:

  • considered PWM requirements
  • MSP430

Peripherals:

  • Drivers
    • border|Circuit 1
    • solenoid drivers
    • motor drivers
    • compressor driver

Power Regulators:

Navigation:

Locomotion:

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

Structural: border|CAD

  • 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
    • border|4 Channel Hand
    • 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
    • border|solenoid valve border|solenoid manifoldborder|power supplyborder|solenoid valve 2
  • Pressure regulators tested
    • border|pressure regulator

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

public/Photo Gallery/Air_System_Schematic.PNG

Valve Positioning:

  • 1 (power on - valve closed)
  • 0 (power off - valve open)
 Valves
TaskABCDEF
Tank Fill000100
Arm Inflation010010
Finger Inflation011000
Finger Deflation101101
Arm Deflation100111
Pressure Release000100

Bill of Materials (BOM)

Navigation:

QTYDescriptionSupplierCost ($)
-----------------Structural----------------------------------
630” Aluminum C-ChannelAndymark$18/ea
8C-Base Aluminum CornerAndymark$4/ea
42¼” - 20 Hex Head BoltsN/A$14
-----------------Locomotion----------------------------------
22.5” CIM MotorAndymark$28/ea
2Toughbox 14.88:1 Gear BoxAndymark$75/ea
44” Rubber Treaded WheelAndymark$4/ea
2½” x 4” Free AxleN/AN/A
2Direct Drive CollarN/AN/A
23’ Drive ChainN/AN/A
2Sprockets for Chain DriveN/AN/A

Air System:

QTYDescriptionSupplierCost per Part($)Link
1CompressorAndyMark69.00Link
1Check ValveMcMaster17.03Link
2Air TankAndyMark16.00Link
81-Way Solenoid ValveRIT0N/A
12-way Soleniod ValveRIT0N/A
17Soleniod Valve ConnectorRIT0N/A
2Pressure RegulatorRIT0N/A
22-Outlet ManifoldMcMaster22.94Link
61/4" NPT Compression FittingMcMaster1.35Link
41/8" NPT Compression FittingMcMaster1.30Link
25 ft.1/4" OD Polyethylene TubingMcMaster0.10 per footLink
25 ft.1/8" OD Polyethylene TubingMcMaster0.05 per footLink

Risk Assessment

Updated Risk Assessment