add default constructor and multi example

examples/Multi/Multi.ino

@@ -0,0 +1,46 @@
+/*
+    This example demonstrates the use of multiple instances of DerivsLimiter.
+    Each one calulates an independent motion profile.
+    This example uses arrays to avoid duplicating code
+    Tested on an Arduino Uno but should work on anything.
+    Requires Derivs_Limiter version 3.1.0 or greater
+
+    v1.0 by joshua-8 2022-11-16
+*/
+#include <Arduino.h>
+#include <Derivs_Limiter.h> // https://github.com/joshua-8/Derivs_Limiter
+// detailed documentation of Derivs_Limiter can be found here: https://joshua-8.github.io/Derivs_Limiter/class_derivs___limiter.html
+
+const int NUM_DLs = 4; // limited only by the Arduino's memory and the time it takes to compute each Derivs_Limiter
+
+Derivs_Limiter DL[NUM_DLs];
+
+// random settings just as an example of each Derivs_Limiter getting unique settings
+float velLimit[NUM_DLs] = { 150, 222.2, 122, 160 };
+float accLimit[NUM_DLs] = { 270, 245.5, 250, 340 };
+
+void setup()
+{
+    Serial.begin(115200);
+    for (int i = 0; i < NUM_DLs; i++) {
+        DL[i] = Derivs_Limiter(velLimit[i], accLimit[i]); // https://joshua-8.github.io/Derivs_Limiter/class_derivs___limiter.html#a674339d1db4ca3a2358e1d25b9eb6cf4
+        // now is a good place to set other settings for each DL
+    }
+}
+
+void loop()
+{
+    for (int i = 0; i < NUM_DLs; i++) {
+
+        float targ = ((millis() % (500 + 100 * i)) < (500 + 100 * i) / 2) ? -(i + 1) : (i + 1); // targets are set to be -(i+1) or (i+1) on an interval that is unique for each DL
+        DL[i].setTarget(targ); // you could give each DL any target you want it to go to
+
+        DL[i].calc();
+
+        Serial.print(DL[i].getPosition()); // DL[i].getPosition() is the value that could be sent to the i numbered servo
+        if (i < NUM_DLs - 1) // add commas between numbers, a newline at the end
+            Serial.print(", ");
+        else
+            Serial.println();
+    }
+}

library.properties

@@ -1,5 +1,5 @@
 name=Derivs_Limiter
-version=3.0.2
+version=3.1.0
 author=Joshua Phelps <[email protected]>
 maintainer=Joshua Phelps <[email protected]>
 sentence=This library can be used to limit the first and second derivative of a variable as it approaches a target value.

src/Derivs_Limiter.h

@@ -43,7 +43,7 @@ class Derivs_Limiter {
      * @param  _preventGoingWrongWay: (bool) default=false, stop immediately if velocity is going away from target
      * @param  _preventGoingTooFast: (bool) default=false, constrain velocity to within velLimit
      * @param  _posLimitLow: (float) default=-INFINITY, lower bound for position
-     * @param  _posLimitHigh: (float) default=INFINITY, upper bound for position
+     * @param  _posLimitHigh: (float) default=INFINITY, upper bound for position, will be set to _posLimitLow if below _posLimitLow
      * @param  _maxStoppingDecel: (float) default=2, how many times accelLimit can be used to stop in time for target position (can be 1 through INFINITY)
      * @param  _posPointer: set pointer to an external variable that will be read and modified during calc as position.  use &var
      * @param  _velPointer: set pointer to an external variable that will be read and modified during calc as velocity.  use &var
@@ -84,6 +84,37 @@ class Derivs_Limiter {
         velocityTarget = 0;
     }
 
+    /**
+     * @brief  default constructor for Derivs_Limiter
+     * @note  make sure to use the normal constructor after this, this constructor is only to allow arrays of Derivs_Limiters
+     */
+    Derivs_Limiter()
+    {
+        accel = 0;
+        lastTime = 0;
+        velLimit = 0;
+        originalVelLimit = 0;
+        accelLimit = 0;
+        setDecelLimit(NAN);
+        target = 0;
+        posMode = true;
+        lastTarget = 0;
+        targetDelta = 0;
+        position = 0;
+        lastPos = 0;
+        posDelta = 0;
+        velocity = 0;
+        time = 0;
+        preventGoingWrongWay = false;
+        preventGoingTooFast = false;
+        posLimitLow = 0;
+        posLimitHigh = 0;
+        maxStoppingDecel = 1;
+        positionPointer = NULL;
+        velocityPointer = NULL;
+        velocityTarget = 0;
+    }
+
     /**
      * @brief  set position and velocity
      * @param  pos: (float) default: 0, ignored if NAN