Add starting point for figures in Mechanics.Rotational.

[maltelenz]

These originate from figures created for Wolfram System Modeler, and are likely to need cleanup and improvement.

Our one existing figure in MSL is probably a good style to follow:

ModelicaStandardLibrary/Modelica/Blocks/package.mo

Lines 159 to 180 in 3f72865

	figures = {
	Figure(
	title = "Anti-windup compensation",
	identifier = "anti-windup",
	preferred = true,
	plots = {
	Plot(
	title = "Reference tracking",
	identifier = "tracking",
	curves = {
	Curve(y = integrator.y, legend = "Reference speed"),
	Curve(y = inertia1.w, legend = "Actual speed")}),
	Plot(
	title = "Anti-windup limiter",
	identifier = "limiter",
	curves = {
	Curve(y = PI.limiter.u, legend = "Input to the anti-windup limiter"),
	Curve(y = PI.y, legend = "Controller output")})},
	caption = "%(plot:tracking) Reference speed (%(variable:integrator.y)) and the actual speed (%(variable:inertia1.w)). The system initializes in steady state, since no transients are present. The inertia follows the reference speed quite good until the end of the constant speed phase. Then there is a deviation.
	%(plot:limiter) Here the reason for the deviation can be seen: The output of the controller (%(variable:PI.y)) is in its limits. The anti-windup compensation works reasonably, since the input to the limiter (%(variable:PI.limiter.u)) is forced back to its limit after a transient phase.
	")}));

Creating as Draft to indicate that library officer(s) probably want/should improve them before merging.

[tobolar]

@maltelenz First of all, thanks for reaching out and opening this and related "mechanical" issues.

Generally, I would prefer to reduce the usage of titles.
IMO the people use to understand texts like "inertial.w" or "torque.tau", so my preference is to reduce the usage of legend in Curve where possible. Where curves of the same quantity are ploted in one diagram, something like Plot.title="Angular velocities" could be sufficient.

I will review your PRs regarding "mechnical" examples having abovementioned in mind. Starting probably end of September due to vacations.

[henrikt-ma]

Generally, I would prefer to reduce the usage of titles. IMO the people use to understand texts like "inertial.w" or "torque.tau", so my preference is to reduce the usage of legend in Curve where possible. Where curves of the same quantity are ploted in one diagram, something like Plot.title="Angular velocities" could be sufficient.

I think most of these figures were created before we even had support for captions in System Modeler, which much also have contributed to titles trying to convey too much information. Now that a figure can have captions, I am also strongly in favor of having concise titles (but not to leave empty and for the tool to decide), and then make use of captions whenever this is needed to make the figure speak for itself.