/// <summary>
/// Tests this class and throws an exception if a test fails.
/// </summary>
public static void Test()
{
void AssertIntAreEqual(int expected, int actual)
{
if (actual != expected)
{
throw new Exception(
"Assertion error: Expected: " + expected.ToString() + "; actual: " + actual.ToString());
}
}
void AssertDoubleAreEqual(double expected, double actual)
{
if (actual != expected)
{
throw new Exception(
"Assertion error: Expected: " + expected.ToString() + "; actual: " + actual.ToString());
}
}
RunningAverageCalculator c;
// Run tests with capacity 1:
c = new RunningAverageCalculator(1);
AssertIntAreEqual(1, c.Capacity);
AssertIntAreEqual(0, c.Count);
c.Add(1.0);
AssertIntAreEqual(1, c.Count);
AssertDoubleAreEqual(1.0, c.Average);
c.Add(2.0);
AssertIntAreEqual(1, c.Count);
AssertDoubleAreEqual(2.0, c.Average);
// Run tests with capacity 2:
c = new RunningAverageCalculator(2);
AssertIntAreEqual(2, c.Capacity);
AssertIntAreEqual(0, c.Count);
c.Add(1.0);
AssertIntAreEqual(1, c.Count);
AssertDoubleAreEqual(1.0, c.Average);
c.Add(2.0);
AssertIntAreEqual(2, c.Count);
AssertDoubleAreEqual((1.0 + 2.0) / 2, c.Average);
c.Add(3.0);
AssertIntAreEqual(2, c.Count);
AssertDoubleAreEqual((3.0 + 2.0) / 2, c.Average);
c.Add(4.0);
AssertIntAreEqual(2, c.Count);
AssertDoubleAreEqual((3.0 + 4.0) / 2, c.Average);
c.Add(5.0);
AssertIntAreEqual(2, c.Count);
AssertDoubleAreEqual((5.0 + 4.0) / 2, c.Average);
// Run tests with capacity 3:
c = new RunningAverageCalculator(3);
AssertIntAreEqual(3, c.Capacity);
AssertIntAreEqual(0, c.Count);
c.Add(1.0);
AssertIntAreEqual(1, c.Count);
AssertDoubleAreEqual(1.0, c.Average);
c.Add(2.0);
AssertIntAreEqual(2, c.Count);
AssertDoubleAreEqual((1.0 + 2.0) / 2, c.Average);
c.Add(3.0);
AssertIntAreEqual(3, c.Count);
AssertDoubleAreEqual((1.0 + 2.0 + 3.0) / 3, c.Average);
c.Add(4.0);
AssertIntAreEqual(3, c.Count);
AssertDoubleAreEqual((4.0 + 2.0 + 3.0) / 3, c.Average);
c.Add(5.0);
AssertIntAreEqual(3, c.Count);
AssertDoubleAreEqual((4.0 + 5.0 + 3.0) / 3, c.Average);
c.Add(6.0);
AssertIntAreEqual(3, c.Count);
AssertDoubleAreEqual((4.0 + 5.0 + 6.0) / 3, c.Average);
c.Add(7.0);
AssertIntAreEqual(3, c.Count);
AssertDoubleAreEqual((7.0 + 5.0 + 6.0) / 3, c.Average);
}
/// <summary>
/// Runs a clock driven by a simple DC motor.
/// </summary>
/// <param name="motor">The motor to drive continuously.</param>
/// <param name="minimumMotorSpeed">The minimum speed setting that causes the motor to turn. Speeds below this
/// threshold may cause the motor to not turn at all.</param>
/// <param name="initialSpeedGuess">A rough initial guess for a speed to try to reach the first cycle in time.
/// </param>
/// <param name="pulse">The input which pulses to measure the motor speed.</param>
/// <param name="pulseDebounceMillisecondsAtFullSpeed">The time, in milliseconds, that shall be used as the
/// debounce time for the <paramref name="pulse"/> input when the <paramref name="motor"/> runs at full speed.
/// </param>
/// <param name="pulseMonitor">An output to show the monitored pulse input.</param>
/// <param name="idealSecondsPerCycle">The number of seconds for one pulse cycle which would give a perfectly
/// accurate operation of the clock.</param>
/// <remarks>The motor speed is constantly adapted to the measurement given by the pulse to realize the needed
/// pulse times without cumulative errors, even if the motor changes its behaviour during the operation.
/// </remarks>
public static void Run(ISingleOutput motor,
float minimumMotorSpeed,
float initialSpeedGuess,
IBooleanInput pulse,
double idealSecondsPerCycle,
IBooleanInput runAtFullSpeedSwitch)
{
// Check parameters:
if (motor == null)
{
throw new ArgumentNullException(nameof(motor));
}
if (minimumMotorSpeed <= 0f || minimumMotorSpeed >= 1f)
{
throw new ArgumentOutOfRangeException(nameof(minimumMotorSpeed));
}
if (initialSpeedGuess < minimumMotorSpeed || initialSpeedGuess > 1f)
{
throw new ArgumentOutOfRangeException(nameof(initialSpeedGuess));
}
if (pulse == null)
{
throw new ArgumentNullException(nameof(pulse));
}
if (idealSecondsPerCycle <= 0f)
{
throw new ArgumentOutOfRangeException(nameof(idealSecondsPerCycle));
}
// Run unit tests on the RunningAverageCalculator class:
Console.WriteLine("Testing RunningAverageCalculator");
RunningAverageCalculator.Test();
Console.WriteLine("RunningAverageCalculator successfully tested");
// An average calculator the motor output voltage (ranging from 0.0f to 1.0f) needed to read one cycle in
// idealSecondsPerCycle seconds:
var voltageForIdealCycleTime = new RunningAverageCalculator(10);
// Add the initial guess of that voltage:
voltageForIdealCycleTime.Add(initialSpeedGuess);
// Give a short full speed pulse to the motor to get it surely running:
motor.Value = 1.0f;
System.Threading.Thread.Sleep(10);
// Let the motor run until the pulse changes from false to true to initialize the position to a pulse
// boundary:
Console.WriteLine("Initializing to pulse position");
motor.Value = initialSpeedGuess;
pulse.WaitFor(true, true);
// This is our starting point:
var clockStartTime = DateTime.UtcNow;
int n = 0; // The number of cycles passed
DateTime t0 = clockStartTime; // Ideal start of the running cycle
DateTime a0 = t0; // Actual start of the running cycle
Console.WriteLine("Ideal seconds per cycle = " + idealSecondsPerCycle.ToString("N4"));
Console.WriteLine("Running the clock at initial v = " + initialSpeedGuess.ToString("N4"));
while (true)
{
if (runAtFullSpeedSwitch.Value)
{
Console.WriteLine("Manually adjusting clock by running at full speed");
// Let the motor run at full speed to adjust the clock's time on the user's request:
float lastSpeed = motor.Value;
motor.Value = 1f;
runAtFullSpeedSwitch.WaitFor(false);
// Reinitialize:
Console.WriteLine("Initializing to pulse position");
motor.Value = lastSpeed;
pulse.WaitFor(true, true);
Console.WriteLine("Pulse reached");
n = 0;
clockStartTime = DateTime.UtcNow;
t0 = clockStartTime;
a0 = t0;
}
// Calculate the end of the current (and the beginning of the next) cylce:
n++;
DateTime t1 = clockStartTime.AddSeconds(idealSecondsPerCycle * n);
double t1a0 = (t1 - a0).TotalSeconds;
// Wait for the next (debounced) pulse, telling us that we reached the end of the current cycle:
DateTime a1; // The actual end of the current cycle.
double a1a0; // a1 - a0: The number of seconds between a0 and a1.
int bounces = 0; // The number of bounces the pulse contacts made
do
{
pulse.WaitFor(true, true);
a1 = DateTime.UtcNow;
a1a0 = (a1 - a0).TotalSeconds;
bounces++;
} // Debounce by accepting the next pulse not earlier than at 70% of the wanted time interval:
while (a1a0 < 0.7 * t1a0);
// We may have missed one or more pulses due to mechanical errors in pulse detection.
// Estimate the number of real cyles, rounding by adding 0.5 and casting to int (which truncates):
int cycles = (int)((a1 - t1).TotalSeconds * motor.Value /
(voltageForIdealCycleTime.Average * idealSecondsPerCycle)
+ 0.5)
+ 1;
if (cycles > 1)
{
// We lost [cycles - 1] pulses. The worm turned multiple times until we got a contact.
// Adjust the counted pulses and the ideal target time for that number of pulses since the last
// contact:
n = n + cycles - 1;
t1 = clockStartTime.AddSeconds(idealSecondsPerCycle * n);
}
// Take note of the current measurement's insight:
voltageForIdealCycleTime.Add(motor.Value * a1a0 / (idealSecondsPerCycle * cycles));
// Calculate the motor voltage needed to reach the next cycle pulse right in time t1 and
// set the motor voltage to this value, taking the lower and upper bounds into account:
DateTime t2 = clockStartTime.AddSeconds(idealSecondsPerCycle * (n + 1));
motor.Value =
Math.Max(minimumMotorSpeed,
Math.Min(1.0f,
(float)(voltageForIdealCycleTime.Average * idealSecondsPerCycle
/ (t2 - a1).TotalSeconds)));
// Report to debugger:
double diff = (a1 - t1).TotalSeconds;
// Math.Abs(double) is not implemented on Netduiono 3:
double absDiff = diff < 0.0 ? -diff : diff;
Console.WriteLine(
"n = " + n.ToString("N0").PadLeft(8) +
" | bounces = " + bounces.ToString().PadLeft(3) +
" | cycles = " + cycles.ToString().PadLeft(2) +
" | vi = " + voltageForIdealCycleTime.Average.ToString("N4").PadLeft(6) +
" | t1 = " + t1.ToString("HH:mm:ss") +
" | a1 = " + a1.ToString("HH:mm:ss") +
" | " + (diff == 0.0 ? "exactly in time " :
((diff < 0.0 ? "early by " : " late by ") + absDiff.ToString("N4").PadLeft(7) + "s (" +
(absDiff * 100.0 / t1a0).ToString("N2").PadLeft(5) + "%)")) +
" | v = " + motor.Value.ToString("N4"));
// The current cycle gets the passed one:
t0 = t1;
a0 = a1;
}
}