Volume 2 Re-Outline

Now that Volume 1 is in its second printing and MRRF 2019 is over, I’m jumping back into Volume 2. Some of you may recall that I originally wrote one giant book, but split it into three volumes when I realized it was going to be about a thousand pages long. So Volumes 2 and 3 are already drafted, albeit as a series of chapters in a long book, not necessarily coherent standalone works.

At minimum, I have to write new introduction chapters for Vol 2 and Vol 3. Then illustrate, tech review, etc. But there’s quite a bit of editorial work I want to do now that I have Volume 1 published. Getting the first book through technical review, editing, and reader feedback has given me a better understanding of what people find useful as well as more of a vision for how to tie all the book content together into one big arc. So Volume 2 is getting a major re-org and a lot of new connecting matter to tie it all together. The basic “belts, screws, deltas” content won’t change though.

Here’s a stab at a new book outline that I put together on the plane flights to/from MRRF. It’s a draft more or less off the top of my head, don’t be surprised if the final book doesn’t follow this. Just sharing for people who find the writing process interesting.

  • Foreword
  • 1 – Intro
    • Purpose of book
    • Place in series
      • Systems approach — understanding design drivers and integrating parts
    • Overview of drivetrain design process
      • Option 1: pick something popular and empirically tune for performance
      • Pick drivetrain type (belt/screw/whatever) based on architecture
      • Option 2: Understand performance requirements
      • Select a target transmission ratio
      • Fit a drivetrain to the target
      • Preload out backlash
    • Refresher of key Vol1 concepts
      • Machine architecture, series, parallel hybrid series/parallel
      • Coordinates, axis vs joint?
      • Structural loop and structural stiffness?
      • DOF vs constraints?
    • Key drivetrain concepts
      • Terminology – drivetrain, transmission, direct-drive vs geared, gearbox
      • Resolution
      • Loads – friction, gravity, accel, jump
      • Power = force * speed etc
      • Power conversion – rotary-rotary, rotary-linear, linear-linear, linkage
      • Transmission ratio
      • Actuator stiffness
      • Backlash
    • How to change transmission ratio
      • In the rotary-linear conversion: pulley size, rack pinion tooth count, screw lead, crank arm length for linkages (sidebar why racks are not covered)
      • Gearboxes (rotary-rotary)
      • Compound pulleys (linear-linear)
      • Linkage (any input to non-linear)
  • 2 – Gearboxes
    • Gearbox basics (input shaft, output shaft, ratio calc)
    • Types
      • Simple
      • Compound
      • Planetary
      • worm drive
      • Spur
      • Helical
      • Harmonic
      • synchronous belt/chain
    • Spur gear design well-covered by other sources such as…
    • Ratio selection
      • power curve
      • inertia matching,
      • etc (check V3C05)
    • Conclusion
  • 3 – Line Drive Principles
    • Introduction – spinning shaft pulls a line, sometimes linear actuator pulls a line
    • Define “Line drives” and types: belts, cables, chains, rope. Why chain & v-belt isn’t popular
    • Traction types:
      • Friction / capstan
      • Anchored (sidebar: screw pulls line)
      • synchronous/toothed
    • Principles
      • Line pull, net force in loop
      • Line Path – line of action parallelism, deflection equation, pitch diameter
      • Preload / tensioning
      • Pulleys/spools – arc of contact, shaft loads
    • Rotary-rotary pulley / drive types (endless loop gearbox)
      • Simple
      • Compound
      • Differential
    • Linear Line Drive Types
      • Winch
      • Split-loop (as opposed to endless loop)
      • Half-loop / omega  (sidebar: servobelt belt)
      • Compound winch (block and tackle)
      • Compound loop
    • Special Line Drives
      • Rotated / hybrid – corexy
      • Coupled joint – rhombus, Helios SCARA
      • Multiplexed
    • Conclusion
  • 4 – Timing Belts
    • Introduction
    • Timing Belts
      • Construction
      • Types – tooth shapes, history
    • Timing belt simple & compound gearboxes
    • Practical engineering
      • End-terminations
      • Center-center distance & loop length
      • Tensioners
      • Back-bending, twisting
      • Toothed vs smooth idlers
      • noise
      • Teeth in mesh
      • Tooth jumping
  • 5 – Cables
    • Wire rope
      • Construction, torque balancing, dyform/compacted
      • Coatings, materials
      • Fatigue
    • Polymer fishing line
      • Materials – aramid, spectra, vectran
      • Creep / set
      • Anisotropic thermal expansion
    • Spool behavior
      • capstan effect
      • Tracking
      • Grooved spools
      • Multi-drum traction winches
    • Preload options (gravity pole etc)
    • End terminations (knots, crimps, clamps)
    • Conclusion
  • 6 – Screw Principles
    • Introduction
    • Terminology
      • Pitch, lead, flank angle, etc
    • Principles
      • Backlash
      • Whipping
      • Mounting, end fixity, tension vs compression
      • Efficiency / friction
      • Back-driving
      • Lead selection
    • Conclusion
  • 7 – Screw Drive Construction
    • Introduction
    • Types of screws (sidebar: cd drive junkstrap)
    • Coupling options
    • Screw drive configuration, arrangement options
    • Interesting stuff: rotating nut, slide nut on rod, screw as linear rod, differential screws, screw as helical DOF
    • Conclusion
  • 8 – Delta Principles
    • Introduction
    • terminology
    • Kinematics, virtual geometry
    • Dynamics, constraints, DOFs, transmission ratios
  • 9 – Delta Construction
    • Introduction
    • Arm/effector physical geometry
    • Joints
    • Sources of error
    • Calibration
    • Conclusion
  • Book closing — tie drivetrains to motors in Vol3

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