Variable not incrementing?

asked 2016-10-06 15:34:19 -0500

215 gravatar image

updated 2016-10-06 15:38:40 -0500

I am at the moment trying to communicate between my arduino uno and ROS (rosserial) such that an outside node can connect, and ask for a service.

I currently able to make them communicate (which entail that I have have made a publisher and subscriber which other nodes can sent to)

The information that should be published is how far my motor has moved, which is incremented in a ISR routine. Problem is that when an outside node is asking for a service, does the publishing node print the current position of the motor, which currently always zero. The actual service is also never performed, meaning that the program never enters the stage where it should perform something.

I suspect the error to be in the .cpp file,

void compute_speed_profile(signed int motor_steps, unsigned int motor_accel, unsigned int motor_decel, unsigned int motor_speed)

It seems like even though the global_state flags is becoming true, is it not going into to the else part of the if/else statement, and thereby not making the motor, and the moved_step count increment. How do fix this else that does not respond to the state of the global_state bool?

This is the .cpp which contains the function declarations and the ISR routine:

.cpp - function

#include "speed_profile.h"

speed_profile profile;

ros::NodeHandle nh;

std_msgs::Int16 status_step_count;
ros::Publisher chatter("tipper_status", &status_step_count);

bool global_state = false;;
void call_back( const std_msgs::Empty & msg)
  global_state = true;


ros::Subscriber<std_msgs::Empty> sub("tipper_control", &call_back );

void output_pin_setup()
  profile.moved_steps = 0;


void timer1_setup()
  // Tells what part of speed ramp we are in.
  profile.run_state = STOP;

  // Timer/Counter 1 in mode 4 CTC (Not running).
  TCCR1B = (1 << WGM12);

  // Timer/Counter 1 Output Compare A Match Interrupt enable.
  TIMSK1 = (1 << OCIE1A);

void compute_speed_profile(signed int motor_steps, unsigned int motor_accel, unsigned int motor_decel, unsigned int motor_speed)
  if(global_state == false)
    //do nothing
  else //---- ------- ERROR MIGHT BE DUE TO THIS

    unsigned int steps_to_speed;  // Steps required to achieve the the speed desired
    unsigned int acceleration_step_limit; // If desired speed is not achieved, will this variable contain step_limit to when to stop accelerating.

    if (motor_steps < 0)
      profile.dir = CCW;
      motor_steps = -motor_steps;
      profile.dir = CW;


  // If moving only 1 step.
    if (motor_steps == 1)
    // Move one step
      profile.accel_count = -1;
    // in DECEL state.
      profile.run_state = DECEL;
    // Just a short delay so main() can act on 'running'.
      profile.first_step_delay = 1000;
      OCR1A = 10;
    // Run Timer/Counter 1 with prescaler = 8.
      TCCR1B |= ((0 << CS12) | (1 << CS11) | (0 << CS10));
    else if (motor_steps != 0)
    // Set max speed limit, by calc min_delay to use in timer.
    // min_delay = (alpha / tt)/ w
      profile.min_time_delay = A_T_x100 / motor_speed;

    // Set accelration by calc the first (c0) step delay .
    // first_step_delay = 1/tt * sqrt(2*alpha/accel)
    // first_step_delay = ( tfreq*0.676/100 )*100 * sqrt( (2*alpha*10000000000) / (accel*100) )/10000
      profile.first_step_delay = (T1_FREQ_148 * sqrt(A_SQ / motor_accel)) / 100;

    // Find out ...
edit retag flag offensive close merge delete