private void timerChart_Tick(object sender, EventArgs e)
{
// sample states for plotting
SampleStates(Plant);
// draw chart
UpdateChart(dataChart, states);
UpdateChart(perturbationChart, perturbations);
// update time axis minimum and maximum
Charting.UpdateChartAxes(dataChart, time_chart_window);
Charting.UpdateChartAxes(perturbationChart, time_chart_window);
// draw animation
Animation.DrawTanks(this);
// update labels
UpdatePerturbationLabels(Disturbance);
}