haydenproject/MEMORY.md

AI Agent Memory — HaydenProject

AI agents working in this repo: read this file first for context, then update it when you make significant changes.

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Project Identity

• Repo: https://git.molloyhome.net/mmolloy/haydenproject.git
• Branch: main
• Owner: Michael Molloy (dad) assisting Hayden Molloy (student)
• Course: AERO3220 — Aerospace Engineering, undergraduate
• Assignment: HW4, due 18 Feb 2026

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What This Project Contains

File	Description
AERO3220_HW4.m	Hayden's MATLAB script — solves a coupled two-mass spring-damper system across 5 parameter cases using ode45 and plots results
AERO3220_HW4.pdf	Professor's original assignment PDF (image-compressed, not OCR-extractable)
AERO3220_HW4_block_diagram.md	Block diagram document created by AI agent — see section breakdown below
.gitignore	MATLAB + macOS ignores: .DS_Store, *.pdf.png, *.asv, *.m~, slprj/, *.mex*, profile_results/

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Physics Summary (AERO3220 HW4)

Two-mass spring-damper system. State vector: x = [z1, z1dot, z2, z2dot].

Equations of motion:

• Mass 1 (top, unforced): m1*z1ddot + k1*(z1-z2) = 0
• Mass 2 (bottom, forced): m2*z2ddot + b*z2dot + (k1+k2)*z2 - k1*z1 = u(t)

Parameters:

• k1 = 100 N/m, k2 = 50 N/m, m1 = 500 kg, m2 = 250 kg
• Time: t = 0 to 200 s, dt = 0.01 s
• Initial conditions: all zero

Five simulation cases varying damping b and forcing F:

Case	b (N·s/m)	Force u(t)
1	100	100 N constant
2	100	100 sin(0.25t) N
3	0	100 sin(0.25t) N
4	100	100 sin(0.50t) N
5	0	100 sin(0.50t) N

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Block Diagram File Sections

AERO3220_HW4_block_diagram.md contains:

1. Program Flow Block Diagram — Mermaid flowchart of the MATLAB script execution (setup → 5 cases → 5 plots)
2. ODE Model — LaTeX equations for z1ddot and z2ddot
3. System Equations Block Diagram — Mermaid diagram of coupled dynamics signal flow (not a flowchart)
4. Transfer Function Block Diagram Form — Mermaid diagram with explicit gain blocks, integrator 1/s blocks, and summation nodes. Includes Laplace-domain relations Z1(s) and Z2(s).
5. Coupled State Space Form — LaTeX xdot = Ax + Bu with full A and B matrices
6. Assignment-Style Block Diagram — Mermaid flowchart with a loop over cases (submission-oriented)
7. Solver Subsystem — Mermaid diagram zoomed into eom_two_mass internals

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Known Mermaid Rendering Constraints

The repo viewer (Gitea at git.molloyhome.net) uses a strict Mermaid parser. These constructs break rendering:

• Square brackets [...] inside node labels (e.g. vector notation) — use plain text or parentheses-free descriptions
• Parentheses (...) inside [...] node labels — replace with plain text equivalents
• Math superscripts like ^T inside labels — write out in words

Always test Mermaid node labels with plain alphanumeric text and spaces only inside [...] blocks.

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Conversation History Summary

1. Michael shared the PDF (assignment) and .m file (Hayden's code).
2. AI read the MATLAB file and created AERO3220_HW4_block_diagram.md as a Mermaid flowchart of program flow.
3. Repo repointed to https://git.molloyhome.net/mmolloy/haydenproject.git (no prior remote existed), committed and pushed.
4. .gitignore added for MATLAB/macOS artifacts, committed and pushed.
5. Several Mermaid parse errors fixed iteratively (square brackets, parentheses in labels).
6. Hayden clarified: he wanted a system equations block diagram, not a program flowchart.
7. Added system-equations diagram, state-space form, and transfer-function block diagram with 1/s integrator blocks and gain blocks.
8. This MEMORY.md and README.md created and pushed.

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Agent Update Instructions

• After any meaningful change (new diagram, physics correction, new file), update the Conversation History Summary and Block Diagram File Sections tables above.
• If Mermaid parse errors are encountered, add the pattern to Known Mermaid Rendering Constraints.
• Do not remove prior history entries — append new ones.