Lesson-8-Journal-2.markdown

@@ -111,6 +111,48 @@ Each turn is hard coded by imposing a certain power to each motor in a fixed amo
 
 The hardware setup is identical to previously. 
 
+The PlateauPilot performs an action every time a plateau is reached. This is sensed using the gyroscope. In the code snippet below the run function of the PlateauPilot is shown. This function sets the boolean ´isPlatueaReached´, which triggers the Arbiter to perform the next action, as described by the state machine above.
+
+```java
+public void run() {
+	while(true)
+	{
+		int gyroVal = gyro.readValue();
+		double filteredVal = oldFilteredVal*alpha + gyroVal*(1-alpha);
+		oldFilteredVal = filteredVal;
+		
+		switch (state) {
+		case idle: //starting in idle
+			if (filteredVal > gyroOffset + 40 && isAscending)
+			{
+				if(System.currentTimeMillis() > timePlateauReached + 2000) {
+					state = State.plateauReached;
+					isPlateauReached = true;
+				}
+			}
+			else if (gyroVal < gyroOffset - 40 && !isAscending)
+			{
+				if(System.currentTimeMillis() > timePlateauReached + 2000) {
+					state = State.plateauReached;
+					isPlateauReached = true;
+				}
+			}
+			break;
+		case plateauReached:
+			if (!isPlateauReached) {
+				state = State.idle;
+				timePlateauReached = System.currentTimeMillis();
+			}
+			break;
+		default:
+			break;
+		}
+	}
+}
+```
+The gyro values are filtered with an exponential filter to remove unwanted spikes. If the filtered value is 40 degress/second above or below the offset, a plateau is either entered or left. In order not to trigger the next action when leaving a plateau a timing threshold is inserted. This ensures that at least two seconds passes between actions.
+
+
 ### Results
 
 With the current setup the car is able to follow the black line on the first inclined path. However a problem arises in the plateau detection which is illustrated in the following figure.