Turtlesim pose
I'm using the following code to generate a time-dependent velocity command for the turtle
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int main(int argc, char**argv) {
ros::init(argc, argv, "pub_one");
ros::NodeHandle n;
ros::Publisher pub = n.advertise<turtlesim::velocity>("/turtle1/command_velocity", 1000); srand(time(0)); double secs1 =ros::Time::now().toSec();
while(pub.getNumSubscribers() == 0) ros::Duration(0.1).sleep();
ros::Rate r(1);
while(true) {
turtlesim::Velocity msg;
double secs2 =ros::Time::now().toSec();
double secs3=secs2-secs1;
msg.linear=.2*secs3;
msg.angular=.2*secs3;
pub.publish(msg);
ROS_INFO("Sending random velocity command: linear=%f angular=%f time=%f", msg.linear, msg.angular,secs3);
ros::spinOnce();
r.sleep(); } }
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I don't know how I can change the code to get the position of the turtle at each time?
In fact, I wanna make a feedback control by using the position of the turtle and a desired position.
I really appreciate if you help me in this case!