Diff: StateMachine.cpp

Revision:

37:698d6b73b50c

Child:

38:8aae5cbcf25f

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/StateMachine.cpp	Tue May 10 10:04:51 2022 +0200
@@ -0,0 +1,179 @@
+/*
+ * StateMachine.cpp
+ * Copyright (c) 2022, ZHAW
+ * All rights reserved.
+ */
+
+#include <cmath>
+#include "StateMachine.h"
+
+using namespace std;
+
+const float StateMachine::PERIOD = 0.01f;                   // period of task, given in [s]
+const float StateMachine::DISTANCE_THRESHOLD = 0.4f;        // minimum allowed distance to obstacle in [m]
+const float StateMachine::TRANSLATIONAL_VELOCITY = 1.0f;    // translational velocity in [m/s]
+const float StateMachine::ROTATIONAL_VELOCITY = 1.0f;       // rotational velocity in [rad/s]
+const float StateMachine::VELOCITY_THRESHOLD = 0.01;        // velocity threshold before switching off, in [m/s] and [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), thread(osPriorityAboveNormal, STACK_SIZE) {
+    
+    enableMotorDriver = 0;
+    state = ROBOT_OFF;
+    buttonNow = button;
+    buttonBefore = buttonNow;
+    
+    // start thread and timer interrupt
+    
+    thread.start(callback(this, &StateMachine::run));
+    ticker.attach(callback(this, &StateMachine::sendThreadFlag), 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 by the ticker timer interrupt service routine.
+ * It sends a flag to the thread to make it run again.
+ */
+void StateMachine::sendThreadFlag() {
+    
+    thread.flags_set(threadFlag);
+}
+
+/**
+ * This is an internal method of the state machine that is running periodically.
+ */
+void StateMachine::run() {
+
+    int buttonPress;
+    
+    while (true) {
+        
+        // wait for the periodic thread flag
+        
+        ThisThread::flags_wait_any(threadFlag);
+        
+        // set the 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;
+
+        // read the button
+        buttonNow = button;
+        buttonPress = buttonNow > buttonBefore;
+        buttonBefore = buttonNow;
+        
+        // implementation of the state machine
+        
+        switch (state) {
+            
+            case ROBOT_OFF:
+                
+                if (buttonPress) {   // detect button rising edge
+                    
+                    enableMotorDriver = 1;
+                    
+                    controller.setTranslationalVelocity(TRANSLATIONAL_VELOCITY);
+                    controller.setRotationalVelocity(0.0f);
+                    
+                    state = MOVE_FORWARD;
+                }
+                
+                break;
+                
+            case MOVE_FORWARD:
+                if (buttonPress) {
+                    controller.setTranslationalVelocity(0);
+                    controller.setRotationalVelocity(0);
+                    state = SLOWING_DOWN;
+                    break;
+                }
+             
+                if (irSensor2 < DISTANCE_THRESHOLD && irSensor2 < DISTANCE_THRESHOLD) {
+                    controller.setTranslationalVelocity(-TRANSLATIONAL_VELOCITY/2);
+                    controller.setRotationalVelocity(-ROTATIONAL_VELOCITY);
+                    state = TURN_RIGHT;
+                    break;
+                } else if (irSensor4 < DISTANCE_THRESHOLD && irSensor4 < DISTANCE_THRESHOLD) {
+                    controller.setTranslationalVelocity(-TRANSLATIONAL_VELOCITY/2);
+                    controller.setRotationalVelocity(ROTATIONAL_VELOCITY);
+                    state = TURN_LEFT;
+                    break;
+                } else if (irSensor3 < DISTANCE_THRESHOLD/2) {
+                    controller.setTranslationalVelocity(-TRANSLATIONAL_VELOCITY);
+                    controller.setRotationalVelocity(-ROTATIONAL_VELOCITY);
+                    state = TURN_RIGHT;
+                    break;
+                }
+                
+                break;
+                
+            case TURN_LEFT:
+                if (buttonPress) {
+                    controller.setTranslationalVelocity(0);
+                    controller.setRotationalVelocity(0);
+                    state = SLOWING_DOWN;
+                    break;
+                }
+
+                if ( (irSensor2 > DISTANCE_THRESHOLD) && (irSensor3 > DISTANCE_THRESHOLD) && (irSensor4 > DISTANCE_THRESHOLD) ) {
+                    controller.setRotationalVelocity(0);
+                    controller.setTranslationalVelocity(TRANSLATIONAL_VELOCITY);
+                    state = MOVE_FORWARD;
+                    break;
+                }
+                break;
+                
+            case TURN_RIGHT:  
+                if (buttonPress) {
+                    controller.setTranslationalVelocity(0);
+                    controller.setRotationalVelocity(0);
+                    state = SLOWING_DOWN;
+                    break;
+                }   
+
+                if ( (irSensor2 > DISTANCE_THRESHOLD) && (irSensor3 > DISTANCE_THRESHOLD) && (irSensor4 > DISTANCE_THRESHOLD) ) {
+                    controller.setRotationalVelocity(0);
+                    controller.setTranslationalVelocity(TRANSLATIONAL_VELOCITY);
+                    state = MOVE_FORWARD;
+                    break;
+                }
+                break;
+                
+            case SLOWING_DOWN:
+                if (abs(controller.getActualTranslationalVelocity()) < VELOCITY_THRESHOLD 
+                    && abs(controller.getActualRotationalVelocity()) > VELOCITY_THRESHOLD) {
+                    state = ROBOT_OFF;
+                    enableMotorDriver = 0;
+                    state = ROBOT_OFF;
+                }
+                
+                break;
+                
+            default:
+                
+                state = ROBOT_OFF;
+        }
+    }
+}