Day 10: (Thu Sep 26, Week 5) Machine Design¶
Notes for 2024-09-26.
New Assignments¶
New assignment, due Tue Oct 1: detailed fabrication-ready design of an subsystem to be assigned individually.
Administrative¶
Who does not have laser cutter access?
Agenda¶
Discuss project plan and design considerations in detail for each proposed machine.
Assign subsystems.
Brainstorm design solutions.
ZYY ARM¶
Main subsystems:
rotary base for Z axis
common shoulder and elbow design for two Y axes
arm link structures
pneumatic actuators, plumbing, and valve system
joint feedback sensors and microcontroller electronics
end effector
Design Considerations
building at scale
structural fabrication: laser-cut 6mm plywood vs 15mm aluminum extrusion
aesthetics: joinery vs fasteners
base joint: thin-section bearing pair or turntable (e.g. VXB Kit12879)
base platform: pneumatic actuator anchor, anchor weights (e.g. sandbags)
range of motion
weight minimization
joint sensing: precision potentiometers (previously: https://www.mouser.com/datasheet/2/54/6630_obsolete-777205.pdf)
current joint prototype: modular-joint, modular-joint.zip
pneumatic component models: Clippard, Clippard.zip
pneumatic clevis components
Boom Motor¶
Main subsystems:
base: fixed (or sliding)
passive boom universal joint (yaw and roll)
boom structure or tube
wheel actuator
wheel
DC motor driver and power supply, microcontroller electronics
passive terrain elements
Design Considerations
building at scale
passive boom bearings: thin-section bearing pair or turntable
wheel size and boom length
range of motion, limit stops
motor selection
motor vs joint angle sensing
slip rings vs tether
boom joint sensing
motor rotation sensing
Hinged Box¶
Main subsystems:
lightweight lid and hinge system.
actuation (electric or pneumatic)
lightweight panel structure (solid or fabric?)
Design Considerations
sizing depends on arm size
position control vs bang bang operation
minimizing weight
hinge component selection
structural rigidity for hinge mounts
Machine Vision¶
Main subsystems:
camera
camera mounting (placement and support)
vision processing (e.g. OpenCV), prototype: Theater Vision System
Resources¶
PhysComp Visual Part Guides (from my other Fall course)
uxcell 6810ZZ via Amazon (65x50x7 mm ball bearings)
SolidWorks Component Models (sample parts, from my other Fall course)
Vendors¶
McMaster-Carr (industrial supplier, our favorite sources for common parts)
MiSUMi (automation and mechanical components)
Pololu (smaller robot parts, kits, components)
The Robot MarketPlace (inexpensive powerful 12V motors)
RobotShop (large variety of robot parts and systems)