PoleExploration

A simple GUI for playing around with poles and zeros and visualize how step/impulse/bode/nyquist plots change.

Installation

julia> ] add https://github.com/albheim/PoleExploration.jl

Usage

Start

Either start it from a running julia REPL like

julia> import PoleExploration

julia> PoleExploration.run()

or from the command line like

julia -e "import PoleExploration; PoleExploration.run()"

Additionally there is a run_sysimage.{sh/bat} for linux/windows which compiles a system-image and runs the program through this. This will take quite some time the first run, but reduce the startup for consecutive runs.

Interactive controls

Running it you will get a GUI where you can interact with poles/zeros.

Double left click will add a pole in the pole-zero diagram. Left click will select a root (pole/zero), when selected you can:

• Move it to a new location with right click.
• Switch between pole/zero with space.
• Remove it with delete.

Zooming is done with scroll or left click drag, panning is done with right click drag. Holding x or y while doing these actions will constrain them to only x or y axis.

Problems

There is some problem with GLFW.jl on some computers resulting in an error along the lines of libGL error: MESA-LOADER: failed to open iris: ..., this can be worked around by telling julia to use the local libstdc++ version instead of its own

export LD_PRELOAD=/usr/lib64/libstdc++.so.6 julia --project -e "using PoleExploration; start()"

This is currently the default in the run_sysimage.sh file.

TODO

• Using unit static gain tfs, 1/(sT+1) and w^2/(s^2+2zw*s+w^2), though displaying the full tf could be improved.
• Add sliders for currently selected root(s) parameters, i.e. T or w/z. Needs to be linked with roots in both directions.
• Maybe add textfield for each slider to allow more precise control?
• Skip sliders and have textfield which is scrollable or something similar?
• Allow selecting a freq in bode/nyquist and reflect the point in the other.
• Impulse or not, need to fix delay problems.
• Allow setting timespan and freqspan by zooming step plot and bode plot respectively.
• Improve instructions with tooltips and color, tooltip!(Point2f(0), "This is a tooltip pointing at x")
• Allow for multiple tfs, one is "active" and can be interacted with, the other are just for comparison in different color?
• Improve precompile as well as packagecompiler.
• Fix tests, could maybe be used for precompile/packagecompiler.
• Use https://docs.makie.org/stable/documentation/events/#point_picking instead of home rolled