Diff: StateMachine.cpp

Revision:

1:08ca9b208045

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/StateMachine.cpp	Fri Mar 31 11:00:19 2017 +0000
@@ -0,0 +1,142 @@
+/*
+ * StateMachine.cpp
+ * Copyright (c) 2017, ZHAW
+ * All rights reserved.
+ */
+
+#include <cmath>
+#include <algorithm>
+#include "StateMachine.h"
+
+using namespace std;
+
+const float StateMachine::PERIOD = 0.01f;                   // period of task in [s]
+const float StateMachine::DISTANCE_THRESHOLD = 0.25f;        // minimum allowed distance to obstacle in [m]
+const float StateMachine::TRANSLATIONAL_VELOCITY = 0.8f;    // translational velocity in [m/s]
+const float StateMachine::ROTATIONAL_VELOCITY = 4.0f;       // rotational velocity in [rad/s]
+
+/**
+ * Creates and initializes a state machine object.
+ */
+StateMachine::StateMachine(Controller& controller, DigitalOut& enableMotorDriver, DigitalOut& led0, DigitalOut& led1, DigitalOut& led2, DigitalOut& led3, DigitalOut& led4, DigitalOut& led5, DigitalIn& button, IRSensor& irSensor0, IRSensor& irSensor1, IRSensor& irSensor2, IRSensor& irSensor3, IRSensor& irSensor4, IRSensor& irSensor5) : controller(controller), enableMotorDriver(enableMotorDriver), led0(led0), led1(led1), led2(led2), led3(led3), led4(led4), led5(led5), button(button), irSensor0(irSensor0), irSensor1(irSensor1), irSensor2(irSensor2), irSensor3(irSensor3), irSensor4(irSensor4), irSensor5(irSensor5) {
+    
+    enableMotorDriver = 0;
+    state = ROBOT_OFF;
+    buttonNow = button;
+    buttonBefore = buttonNow;
+    
+    ticker.attach(callback(this, &StateMachine::run), PERIOD);
+}
+
+/**
+ * Deletes the state machine object and releases all allocated resources.
+ */
+StateMachine::~StateMachine() {
+    
+    ticker.detach();
+}
+
+/**
+ * Gets the actual state of this state machine.
+ * @return the actual state as an int constant.
+ */
+int StateMachine::getState() {
+    
+    return state;
+}
+
+/**
+ * This method is called periodically by the ticker object and contains the
+ * implementation of the state machine.
+ */
+void StateMachine::run() {
+    
+    // control leds based on distance measurements
+    
+    led0 = irSensor0 < DISTANCE_THRESHOLD;
+    led1 = irSensor1 < DISTANCE_THRESHOLD;
+    led2 = irSensor2 < DISTANCE_THRESHOLD;
+    led3 = irSensor3 < DISTANCE_THRESHOLD;
+    led4 = irSensor4 < DISTANCE_THRESHOLD;
+    led5 = irSensor5 < DISTANCE_THRESHOLD;
+    
+    // implementation of the state machine
+    
+    switch (state) {
+        
+        case ROBOT_OFF:
+            
+            buttonNow = button;
+            if (buttonNow && !buttonBefore) {   // detect button rising edge
+                enableMotorDriver = 1;
+                controller.setTranslationalVelocity(TRANSLATIONAL_VELOCITY);
+                state = MOVE_FORWARD;
+            }
+            buttonBefore = buttonNow;
+            
+            break;
+            
+        case MOVE_FORWARD:
+            
+            buttonNow = button;
+            if (buttonNow && !buttonBefore) {   // detect button rising edge
+                controller.setTranslationalVelocity(0.0f);
+                state = SLOWING_DOWN;
+            } else if ((irSensor0 < DISTANCE_THRESHOLD) || (irSensor1 < DISTANCE_THRESHOLD)) {
+                controller.setTranslationalVelocity(0.0f);
+                controller.setRotationalVelocity(ROTATIONAL_VELOCITY);
+                state = TURN_LEFT;
+            } else if (irSensor5.read() < DISTANCE_THRESHOLD) {
+                controller.setTranslationalVelocity(0.0f);
+                controller.setRotationalVelocity(-ROTATIONAL_VELOCITY);
+                state = TURN_RIGHT;
+            }
+            buttonBefore = buttonNow;
+            
+            break;
+            
+        case TURN_LEFT:
+            
+            buttonNow = button;
+            if (buttonNow && !buttonBefore) {   // detect button rising edge
+                controller.setRotationalVelocity(0.0f);
+                state = SLOWING_DOWN;
+            } else if ((irSensor0 > DISTANCE_THRESHOLD) && (irSensor1 > DISTANCE_THRESHOLD) && (irSensor5 > DISTANCE_THRESHOLD)) {
+                controller.setTranslationalVelocity(TRANSLATIONAL_VELOCITY);
+                controller.setRotationalVelocity(0.0f);
+                state = MOVE_FORWARD;
+            }
+            buttonBefore = buttonNow;
+            
+            break;
+            
+        case TURN_RIGHT:
+            
+            buttonNow = button;
+            if (buttonNow && !buttonBefore) {   // detect button rising edge
+                controller.setRotationalVelocity(0.0f);
+                state = SLOWING_DOWN;
+            } else if ((irSensor0 > DISTANCE_THRESHOLD) && (irSensor1 > DISTANCE_THRESHOLD) && (irSensor5 > DISTANCE_THRESHOLD)) {
+                controller.setTranslationalVelocity(TRANSLATIONAL_VELOCITY);
+                controller.setRotationalVelocity(0.0f);
+                state = MOVE_FORWARD;
+            }
+            buttonBefore = buttonNow;
+            
+            break;
+            
+        case SLOWING_DOWN:
+            
+            if ((fabs(controller.getActualTranslationalVelocity()) < 0.01f) && (fabs(controller.getActualRotationalVelocity()) < 0.01f)) {
+                enableMotorDriver = 0;
+                state = ROBOT_OFF;
+            }
+            
+            break;
+            
+        default:
+            
+            state = ROBOT_OFF;
+    }
+}
+