File content as of revision 0:f044e2e055ff:

//  Copyright 2019 Tsung-Han Lee, National Tsing Hua Univeristy Dynamic System and Control Lab, Tommy Cheng, Skyler Chen
/***************************************************************
 **     MOBILE ROBOT LAB3 GROUP 4 [Vehicle Motion Control]
 **
 **  - Members  : Tsung-Han Lee, Tommy, Skyler
 **  - NOTE     : Modified from sample code provided
 **               by NTHU Dynamic Systems and Control Lab
 ** 
 ***************************************************************/
#include <ros.h>
#include <geometry_msgs/Twist.h>
#include "mbed.h"
#include "hallsensor_software_decoder.h"

#define Ts 0.01

Ticker controllerTimer;

/* declare pwm pin */
PwmOut pwm1(D7);
PwmOut pwm1n(D11);
PwmOut pwm2(D8);
PwmOut pwm2n(A3);

/********************* Helper Functions and Structures *******************/
typedef volatile struct Controller {
    volatile double rpm;        // rotation speed in rpm
    volatile double refRPM;     // reference rpm
    volatile double piOut;      // PI Controller output
    volatile double err;        // error
    volatile double ierr;       // integration of error
    double kp;                  // propotinal gain
    double ki;                  // integrational gain
} Controller_t;

typedef volatile struct Vehicle {
    double r;                   // radius
    double L;                   // distance between two wheel
    volatile double V;          // forward speed
    volatile double W;          // rotation speed
    volatile double refV;       // reference forward speed
    volatile double refW;       // reference rotation speed
} Vehicle_t;

/* Init Structure Instance */
Controller_t controller1 = {0.0, 0.0, 0.0, 0.0, 0.0, 0.008, 0.02};
Controller_t controller2 = {0.0, 0.0, 0.0, 0.0, 0.0, 0.008, 0.02};
Vehicle_t    car         = {0.03, 0.27, 0.0, 0.0, 0.0, 0.0};  


void initTimer();
void initPWM();
void controllerTISR();
void messageCallback(const geometry_msgs::Twist& recvMsg);
/************************************************************************/

/************************************************************************
 ** ROS Parameters Must Declare in Global Scope !!!!
 ************************************************************************/
ros::NodeHandle nh;
geometry_msgs::Twist vel_msg;
    
ros::Publisher pub("feedback_Vel", &vel_msg);
ros::Subscriber<geometry_msgs::Twist> sub("cmd_vel", &messageCallback);

/************************************************************************/
/** SERIAL DEBUG 
 ************************************************************************/
//Serial pc(USBTX, USBRX);

int main(int argc, char* argv[]) {
    /* SERIAL DEBUG */
//    pc.baud(115200);
    
    initTimer();
    initPWM();
    init_CN();
    
    nh.initNode();
    nh.subscribe(sub);
    nh.advertise(pub);

    while (1) {
        /*************************
         **  1. 2pi/60      = 0.1047197551
         **  2. 2pi/60/2    = 0.05235987756
         **************************/
        car.V = (controller1.rpm + controller2.rpm) * car.r * 0.05235987756;
        car.W = -1.0 * car.r * (controller1.rpm - controller2.rpm) / car.L * 0.1047197551;
        
        vel_msg.linear.x    = car.V;
        vel_msg.angular.z   = car.W;
        
        pub.publish(&vel_msg);
        
        nh.spinOnce();
        
        wait_ms(100);  
    }
}

void initTimer() {
    controllerTimer.attach_us(&controllerTISR, 10000.0);    
}

void initPWM() {
    pwm1.period_us(50);
    pwm1.write(0.5);
    TIM1->CCER |= 0x4;
    
    pwm2.period_us(50);
    pwm2.write(0.5);
    TIM1->CCER |= 0x40;   
}

void controllerTISR() {
    // 60.0 / 2pi = 9.549296586
    controller1.refRPM = (car.refV - car.L*car.refW/2.0) * 9.549296586 / car.r;
    controller2.refRPM = (car.refV + car.L*car.refW/2.0) * 9.549296586 / car.r;
    
//    pc.printf("%.2f, %.2f", controller1.refRPM, controller2.refRPM);
    
    /********* MOTOR 1 ******************/
    // 100/48*60/56 = 2.232142857
    controller1.rpm            = (double)wheelState1.numStateChange * 2.232142857;
    wheelState1.numStateChange = 0;
    
    controller1.err   = controller1.refRPM - controller1.rpm;
    controller1.ierr += Ts*controller1.err;
    
    if (controller1.ierr > 50.0) {
        controller1.ierr = 50.0;    
    } else if (controller1.ierr < -50.0) {
        controller1.ierr = -50.0;    
    }
    controller1.piOut = controller1.kp*controller1.err + controller1.ki*controller1.ierr;

    if (controller1.piOut > 0.5) {
        controller1.piOut = 0.5;    
    } else if (controller1.piOut < -0.5) {
        controller1.piOut = -0.5;    
    }
    
    pwm1.write(controller1.piOut + 0.5);
    TIM1->CCER |= 0x4;
    
    /********* MOTOR 2 ******************/
    // 100/48*60/56 = 2.232142857
    controller2.rpm            = (double)wheelState2.numStateChange * 2.232142857;
    wheelState2.numStateChange = 0;
    
    controller2.err   = controller2.refRPM - controller2.rpm;
    controller2.ierr += Ts*controller2.err;
    
    if (controller2.ierr > 50.0) {
        controller2.ierr = 50.0;    
    } else if (controller2.ierr < -50.0) {
        controller2.ierr = -50.0;    
    }
    controller2.piOut = -(controller2.kp*controller2.err + controller2.ki*controller2.ierr);

    if (controller2.piOut > 0.5) {
        controller2.piOut = 0.5;    
    } else if (controller2.piOut < -0.5) {
        controller2.piOut = -0.5;    
    }
    
    pwm2.write(controller2.piOut + 0.5);
    TIM1->CCER |= 0x40;
}

void messageCallback(const geometry_msgs::Twist& recvMsg) {
//    pc.printf("receiving message ...\n");
    car.refV = recvMsg.linear.x;
    car.refW = recvMsg.angular.z;
}