Hey , i am working on a 4 wheel drive differential robot , ***I am using Rosserial to talk to the arduino (cmd_vel) and arduino publishes back (tf , in which the odom is there).***
Timed out waiting for transform from base_link to map to become available before running costmap, tf error: Could not find a connection between 'map' and 'base_link' because they are not part of the same tree.Tf has two or more unconnected trees.. canTransform returned after 0.101146 timeout was 0.1.
As you can see from the image , the error is `No transform from camera to odom` . I have done all simulations and it works properly ,but when i am using the Real robot , this error pops up .
What could be the error , the possibilities that i could think of are the below
1. The frames not being synced , will i have to subscribe to a /clock topic on the arduino to synchronize the /tf topic .
2. /odom as a dedicated topic doesnt exist .
Also can someone explain me the differences between
1. /odometry/filtered 
2. /velocity_controller/odom 
3. /tf topic 
Additional information , the Arduino code which communicates to kangaroo x2.
enter code here
#include
#include
#include
#include
#include
#include
#include
#include
#include
#include
#include
#include
#define TX_PIN 13 //s1
#define RX_PIN 12 //s2
// Arduino TX (pin 2) goes to Kangaroo S1
// Arduino RX (pin 3) goes to Kangaroo S2
// Independent mode channels on Kangaroo are, by default, '1' and '2'.
SoftwareSerial SerialPort(RX_PIN, TX_PIN);
KangarooSerial K(SerialPort);
//////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
//SETTINGS//////////////////////////////////////////////
#define Mixed_mode true
bool position_control = true;
/////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
#ifdef Mixed_mode
KangarooChannel Drive(K, 'D');
KangarooChannel Turn(K, 'T');
#endif
#ifndef Mixed_mode
KangarooChannel KL(K, '1');
KangarooChannel KR(K, '2');
#endif
ros::NodeHandle nh;
long WHEEL_DIST = 2 ;
///////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
std_msgs::Bool position_control_msg;
std_msgs::Bool mixed_mode_msg;
////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
double x = 1.0;
double y = 0.0;
double theta = 1.57;
void cmd_velCallback( const geometry_msgs::Twist& CVel){
//geometry_msgs::Twist twist = twist_msg;
long vel_x = CVel.linear.x*200;
long vel_th = -CVel.angular.z*200;
x += cos(theta)*CVel.linear.x*0.1;
y += sin(theta)*CVel.linear.x*0.1;
theta += CVel.angular.z*0.1;
long speed_right = (vel_th*WHEEL_DIST)/2 + vel_x;
long speed_left = (vel_x*2) - speed_right;
long right_vel = 0.0;
long left_vel = 0.0;
//right_vel = vel_th * WheelSeparation / 2.0;
//left_vel = (-1) * right_vel;
//left_vel = vel_x - vel_th * WheelSeparation / 2.0;
//right_vel = vel_x + vel_th * WheelSeparation / 2.0;
// turning
//IF MIXED MODE CONFIG
#ifdef Mixed_mode
if(int(vel_x) == 0 && int(vel_th)==0){
if (position_control){
Turn.pi(0);
Drive.pi(0);}
else{
Turn.s(0);
Drive.s(0);
}
}
// forward / backward
else if(abs(vel_x) > abs(vel_th) ){
if (position_control){
Drive.pi(vel_x);
Turn.pi(vel_th);
}
else{
Drive.s(vel_x);
Turn.s(vel_th);
}
}
// moving doing arcs
else{
if (position_control){
Drive.pi(vel_x);
Turn.pi(vel_th);}
else{
Turn.s(vel_th);
Drive.s(vel_x);
}
}
#endif
//////////////////////////////////////////////////////////////////////////////////////////////////////
//IF NOT MIXED MODE CONFIG
#ifndef Mixed_mode
if(position_control){
KL.pi(speed_left);
KR.pi(speed_right);
}
else{
KL.s(speed_left);
KR.s(speed_right);
}
#endif
}
////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
void reset_Kangaroo( std_msgs::Empty& toggle_msg){
init_kangaroo();
}
void mixed_mode_func(std_msgs::Bool& mixed_mode_topic ){
mixed_mode_msg = mixed_mode_topic;
}
void position_control_func(std_msgs::Bool& position_control_topic ){
position_control_msg = position_control_topic;
}
// ROS SUBSCRIBERS
ros::Subscriber Sub("cmd_vel", &cmd_velCallback );
ros::Subscriber reset_kangaroo("reset_kangaroo", reset_Kangaroo );
//THese two topics are to turn on and off the position_control OR mixed_mode
ros::Subscriber Position_control("position_control",position_control_func );
ros::Subscriber mixed_mode("mixed_mode",mixed_mode_func );
////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
void init_kangaroo(){
#ifdef Mixed_mode
Drive.start();
Turn.start();
Drive.home();
Turn.home();
SerialPort.println("D,start");
SerialPort.println("T,start");
SerialPort.println("D, units 100 thou = 245 lines");
SerialPort.println("T, units 100 thou = 245 lines");
#endif
#ifndef Mixed_mode
KL.start();
KR.start();
SerialPort.println("1,start");
SerialPort.println("2,start");
SerialPort.println("1, units 100 thou = 245 lines");
SerialPort.println("2, units 100 thou = 245 lines");
#endif
}
//////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
geometry_msgs::TransformStamped t;
tf::TransformBroadcaster broadcaster;
char base_link[] = "/base_link";
char odom[] = "/odom";
void odom_publisher(){
// drive in a circle
//double dx = 0.2;
//double dtheta = 0.18;
//x += cos(theta)*dx*0.1;
//y += sin(theta)*dx*0.1;
//theta += dtheta*0.1;
if(theta > 3.14)
theta=-3.14;
//tf odom->base_link
t.header.frame_id = odom;
t.child_frame_id = base_link;
t.transform.translation.x = x;
t.transform.translation.y = y;
t.transform.rotation = tf::createQuaternionFromYaw(theta);
t.header.stamp = nh.now();
broadcaster.sendTransform(t);
}
/////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
void setup(){
SerialPort.begin(9600);
init_kangaroo();
nh.initNode();
broadcaster.init(nh);
nh.subscribe(Sub);
nh.subscribe(reset_kangaroo);
nh.subscribe(Position_control);
nh.subscribe(mixed_mode);
}
void loop() {
odom_publisher();
nh.spinOnce();
delay(1);
}
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