I use ROS in virtualbox which install Ubuntun. And connect ROS to Arduino.
Here is my adruino code, which I receive command from ROS, and use this command to control a differential drive car.
Here is my arduino code with a loop 20 hz, and the ros node publish to arduino is 10 hz. Just publish float data not string. When I run, first it's ok but later it said
[ERROR] [WallTime: 1433956349.977347]
Lost sync with device, restarting..
When i change ros node publish rate to 1 hz, it works fine.
Is that problem running out of SRAM?
#include <ros.h>
#include <std_msgs/Float32.h>
#define DIR_R 7 //Right motor Direction control line
#define DIR_L 8 //Left motor Direction control line
#define PWM_R 9 //Right motor PWM control line
#define PWM_L 10 //Left motor PWM control line
#define LED 13
#define SPEED 45
ros::NodeHandle nh;
int rightSpeed, leftSpeed;
double relative_angle;
void messageCb(const std_msgs::Float32& str){
//int rightSpeed, leftSpeed;
if(str.data == -1){ //no free-space front Zumo robot, rotate to find another one
rightSpeed =SPEED;
leftSpeed =SPEED;
rotatePort(rightSpeed, leftSpeed, 500, 1);
searchPort(200,200);
}
else
{
relative_angle=abs(90.0-str.data);
if (relative_angle <= 2.0) //optional direction in front of Zumo robot
{
rightSpeed =SPEED;
leftSpeed =SPEED;
forwardPort(rightSpeed, leftSpeed, 500, 1);
}
else
{
if (str.data <90.0)
{
rightSpeed =SPEED - relative_angle/90.0*SPEED;
leftSpeed =SPEED + relative_angle/90.0*SPEED;
turnPort(rightSpeed, leftSpeed, 500, 1);
}
else
{
rightSpeed =SPEED + relative_angle/90.0*SPEED;
leftSpeed =SPEED - relative_angle/90.0*SPEED;
turnPort(rightSpeed, leftSpeed, 500, 1);
}
}
}
}
ros::Subscriber<std_msgs::Float32> sub("/space1/move_zumo", &messageCb);
void setup(){
pinMode(LED, OUTPUT);
pinMode(DIR_R, OUTPUT);
pinMode(DIR_L, OUTPUT);
pinMode(PWM_R, OUTPUT);
pinMode(PWM_L, OUTPUT);
nh.initNode();
nh.subscribe(sub);
}
void loop(){
nh.spinOnce();
delay(50);
}
void rotatePort (int rs, int ls, int T1, int T2)
{
digitalWrite(DIR_R, LOW);
digitalWrite(DIR_L, HIGH);
analogWrite(PWM_R, rs);
analogWrite(PWM_L, ls);
delay(T1);
analogWrite(PWM_R, 0);
analogWrite(PWM_L, 0);
delay(T2);
}
void forwardPort (int rs, int ls, int T1, int T2)
{
digitalWrite(DIR_R, LOW);
digitalWrite(DIR_L, LOW);
analogWrite(PWM_R, rs);
analogWrite(PWM_L, ls);
delay(T1);
analogWrite(PWM_R, 0);
analogWrite(PWM_L, 0);
delay(T2);
}
void turnPort(int rs, int ls, int T1, int T2)
{
digitalWrite(DIR_R, LOW);
digitalWrite(DIR_L, LOW);
analogWrite(PWM_R, rs);
analogWrite(PWM_L, ls);
delay(T1);
analogWrite(PWM_R, 0);
analogWrite(PWM_L, 0);
delay(T2);
}
void searchPort(int T1, int T2)
{
digitalWrite(LED,HIGH);
delay(T1);
digitalWrite(LED,LOW);
delay(T2);
}