ME 10: System Dynamics and Control

Proof required

Link the public repo with 2.004 problem sets 1–5 written up (a typeset PDF, LaTeX source or notebook), and show the self-check: which answers matched and how you fixed the ones that did not.

What gets checked

• Each model lists its elements, the through and across variables, and the energy stores.
• Each model is written as an ODE and as a transfer function, with units checked.
• Answers match the published solutions, and misses are reworked.

Common mistakes

• Answers copied from a solution with no working.
• Missing units, or a free-body diagram or sign convention left out.

Powstik Guide

A public write-up of 2.004 problem sets 1–5, with the self-check shown.

Steps

1. Study the linked course material.
2. Solve the problems on your own first.
3. Check them against the self-check and rework the misses.
4. Typeset the write-up (LaTeX or a notebook) in a public repo.
5. Ask someone who knows the subject to check it.

README
ME 10: System Dynamics and Control, unit 1: Lumped models of electrical and mechanical systems
Problems:
Self-check result (matched / reworked):
What I got wrong first and why:

What gets sent back

• No working shown.
• The self-check result is missing.

Resources

What a verifier looks for

• Each model lists its elements, the through and across variables, and the energy stores.
• Each model is written as an ODE and as a transfer function, with units checked.
• Answers match the published solutions, and misses are reworked.
• Is the engineering right, not just the final number?

You'll sign in first, then come straight back here.

Proof required

Link the public repo with 2.004 problem sets 6, 7 and 10 written up (a typeset PDF, LaTeX source or notebook), and show the self-check: which answers matched and how you fixed the ones that did not.

What gets checked

• Poles, natural frequency and damping ratio are read from each transfer function.
• Bode plots are sketched by hand, then checked in code.
• Answers match the published solutions, and misses are reworked.

Common mistakes

• Answers copied from a solution with no working.
• Missing units, or a free-body diagram or sign convention left out.

Powstik Guide

A public write-up of 2.004 problem sets 6, 7 and 10, with the self-check shown.

Steps

1. Study the linked course material.
2. Solve the problems on your own first.
3. Check them against the self-check and rework the misses.
4. Typeset the write-up (LaTeX or a notebook) in a public repo.
5. Ask someone who knows the subject to check it.

README
ME 10: System Dynamics and Control, unit 2: Transfer functions, time response and frequency response
Problems:
Self-check result (matched / reworked):
What I got wrong first and why:

What gets sent back

• No working shown.
• The self-check result is missing.

Resources

What a verifier looks for

• Poles, natural frequency and damping ratio are read from each transfer function.
• Bode plots are sketched by hand, then checked in code.
• Answers match the published solutions, and misses are reworked.
• Is the engineering right, not just the final number?

You'll sign in first, then come straight back here.

Proof required

Link the public repo with the code or model files, the one command that reruns it, the convergence (mesh or step-size) study and the hand-calculation check, and a README that says how to rerun it and what limits the result.

What gets checked

• The hand transfer function and the simulation agree within 2% on the key numbers, shown in a table.
• The solver study shows the result does not depend on the solver step or tolerance.
• The model files rerun from the repo and reproduce every plot.

Common mistakes

• A result that nobody else can rerun from the repo.
• A table with no explanation of the gaps.

Powstik Guide

A model of a DC motor driving an inertia through a belt (or a mass–spring–damper), built in OpenModelica or Python, with a hand-calculated step response to check it, in a public repo.

Steps

1. Write down what you expect before you start.
2. Write the equations of motion and the transfer function by hand. Predict the time constant (or natural frequency and damping ratio), rise time and steady-state value. Build the same model in OpenModelica or python-control, run a solver study (fix the step or tighten the tolerance, and show the answer does not change), and compare the simulated and hand values in a table. Then add a proportional controller and show how the response changes. Check the closed-loop steady-state error against 1/(1 + K·G(0)).
3. Fill the predicted-vs-measured (or hand-vs-simulated) table.
4. Explain every gap with a cause someone can check.
5. Write the README and ask someone who knows the subject to check it.

README
ME 10: System Dynamics and Control — Model a motor-driven load and match its step response
What I expected:
How to rerun it:
Predicted vs measured:
Why they differ:
Safety: hand tools and eye protection only

What gets sent back

• No convergence study, or no hand calculation that checks it.
• Machine tools, welding, pressure vessels, combustion, or springs and flywheels storing dangerous energy without a trained supervisor.

Resources

What a verifier looks for

• The hand transfer function and the simulation agree within 2% on the key numbers, shown in a table.
• The solver study shows the result does not depend on the solver step or tolerance.
• The model files rerun from the repo and reproduce every plot.
• Check the engineering and the numbers, not just that it exists: do the units, the hand calculation and the table agree?
• Build photos show hand tools only and eye protection worn: no machine tools, welding, pressure vessels, combustion, or springs and flywheels storing dangerous energy (unless a trained supervisor and a proper workshop are shown).

You'll sign in first, then come straight back here.