Rosserial - combining two message custom class

asked 2021-08-06 02:37:15 -0600

Maxdod
1 ●1 ●2 ●1

Hi, I want to create a custom message to send diagnostics info from an Arduino to ros. The message structure is the following:

motore.msg : bool heartbeat int32 speedRPM float32 wheel_speed float32 voltage float32 current int32 torque int32 temperature int32 HSinkTemp int32 statoCtl

Then diag.msg

motore FrontLeft motore FrontRight motore BackLeft motore BackRight

First test: I put the two messages in the same msg directory of package. Compiled fine, the generate the .h files in ros_lib. But when I compile the Arduino sketch I get tis error: error: invalid use of incomplete type 'class diag::diag' typedef diag::motore _FrontLeft_type; ^~~~~~

the class definition (diag):

namespace diag {

class diag : public ros::Msg { public: typedef diag::motore _FrontLeft_type; _FrontLeft_type FrontLeft; typedef diag::motore _FrontRight_type; _FrontRight_type FrontRight; typedef diag::motore _BackLeft_type; _BackLeft_type BackLeft; typedef diag::motore _BackRight_type; _BackRight_type BackRight;

diag():
  FrontLeft(),
  FrontRight(),
  BackLeft(),
  BackRight()
{
}

.... and motore.h: ...

namespace diag {

class motore : public ros::Msg { public: typedef bool _heartbeat_type; _heartbeat_type heartbeat; typedef int32_t _speedRPM_type; _speedRPM_type speedRPM; typedef float _wheel_speed_type; _wheel_speed_type wheel_speed; typedef float _voltage_type; _voltage_type voltage; typedef float _current_type; _current_type current; typedef int32_t _torque_type; _torque_type torque; typedef int32_t _temperature_type; _temperature_type temperature; typedef int32_t _HSinkTemp_type; _HSinkTemp_type HSinkTemp; typedef int32_t _statoCtl_type; _statoCtl_type statoCtl;

motore():
  heartbeat(0),
  speedRPM(0),
  wheel_speed(0),
  voltage(0),
  current(0),
  torque(0),
  temperature(0),
  HSinkTemp(0),
  statoCtl(0)
{
}

The only way to compile the code in Arduino is to put the motor class into a different namespace: .... namespace motore {

motore():
  heartbeat(0),
  speedRPM(0),
  wheel_speed(0),
  voltage(0),
  current(0),
  torque(0),
  temperature(0),
  HSinkTemp(0),
  statoCtl(0)
{
}

class diag : public ros::Msg { public: typedef motore::motore _FrontLeft_type; _FrontLeft_type FrontLeft; typedef motore::motore _FrontRight_type; _FrontRight_type FrontRight; typedef motore::motore _BackLeft_type; _BackLeft_type BackLeft; typedef motore::motore _BackRight_type; _BackRight_type BackRight;

diag():
  FrontLeft(),
  FrontRight(),
  BackLeft(),
  BackRight()
{
}

....

Now when I connect the Arduino to Rosserial (python) I get this error: Traceback (most recent call last): File "/opt/ros/melodic/lib/rosserial_python/serial_node.py", line 89, in <module> client.run() File "/opt/ros/melodic/lib/python2.7/dist-packages/rosserial_python/SerialClient.py", line 540, in run self.callbackstopic_id File "/opt/ros/melodic/lib/python2.7/dist-packages/rosserial_python/SerialClient.py", line 110, in handlePacket m = self.message() File "/home/maxdod/ros/diagnostica_ws/devel/lib/python2.7/dist-packages/diag/msg/_diag.py", line 61, in __init__ self.FrontLeft = diag.msg.motore() AttributeError: type object 'diag' has no attribute 'msg'

It seems that the message generated on ros side (melodic) create a msg field that is not defined in any place! What am I missing ? Thanks Massimo

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Comments

Creating custom messages for ros-serial is a multi-step process. 1) you define the ros .msg files and add them to CMakeLists.txt, 2) you compile the messages using catkin_make, 3) you generate the matching non-ros .h files for use on the ros-serial client side.

Have you done all 3 of these steps? Note: it is not recommended that you try to handcraft your own msg class for motore.

Mike Scheutzow ( 2021-08-06 17:43:36 -0600 )edit

Please use the button to move your "answer" into a comment (like this one), or edit your question and copy/paste it there. You should only use answer section if you are providing an actual answer to the question.

Regarding this problem: did your message definition files compile in catkin_make without error? The content of your diag.msg file looks wrong -- I believe you need to specify the ros-package names when you use another msg type, like this: std_msgs/Header header

Mike Scheutzow ( 2021-08-07 06:41:19 -0600 )edit

Thanks Mike ! following your suggestion I solved my problem: I modified diag.msg motore/motore FrontLeft motore/motore FrontRight motore/motore BackLeft motore/motore BackRight

rostopic echo now is ok ! FrontLeft: heartbeat: False speedRPM: 10 wheel_speed: 2.45000004768 voltage: 26.0 current: 2.0 torque: 30 temperature: 27 HSinkTemp: 28 statoCtl: 0 FrontRight: heartbeat: False speedRPM: 0 wheel_speed: 0.0 voltage: 0.0 current: 0.0 torque: 0 temperature: 0 HSinkTemp: 0 statoCtl: 0 BackLeft: heartbeat: False speedRPM: 0 wheel_speed: 0.0 voltage: 0.0 current: 0.0 torque: 0 temperature: 0 HSinkTemp: 0 statoCtl: 0 BackRight: heartbeat: False speedRPM: 0 wheel_speed: 0.0 voltage: 0.0 current: 0.0 torque: 0 temperature: 0 HSinkTemp: 0 statoCtl: 0

Massimo

Maxdod ( 2021-08-07 09:34:36 -0600 )edit

Good, I'm glad it's working now. Please click the check mark in the round circle (it turns green) to indicate this solution worked for you.

Mike Scheutzow ( 2021-08-07 11:26:32 -0600 )edit

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answered 2021-08-07 02:22:39 -0600

Maxdod
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Thanks Mike. I followed these steps: 1) create a package containing the two msg: diag.msg and motore.msg 2) catkin_make of the package 3) generate ros_lib libraries for the Arduino messages 4) copied the diagnostics.h and motore.h to Arduino libraries 5) created a test sketch:

include <ros.h> include <ros node_handle.h=""> include <diag motore.h=""> include <diag diag.h="">

diag::diag diag_msg; diag::motore motor_msg; ros::NodeHandle nh; ros::Publisher diag_pub("diagnostic", &diag_msg); void setup() { // put your setup code here, to run once:

// ROS Setup nh.initNode(); nh.advertise(diag_pub); while(!nh.connected()) nh.spinOnce(); }

void loop() { // put your main code here, to run repeatedly: motor_msg.heartbeat= false; motor_msg.speedRPM= 10; motor_msg.wheel_speed=2.45; motor_msg.voltage= 26.0; motor_msg.current= 2.0; motor_msg.torque=30; motor_msg.temperature= 27; motor_msg.HSinkTemp= 28; diag_msg.FrontLeft = motor_msg; //diag_msg.fl.statoCtl= 8;

diag_pub.publish(&diag_msg); delay (5000); nh.spinOnce(); }

As I told, if I try to compile the sketch I get the error:

Users/mdore/Dropbox/Il mio Mac (MacBook-Pro-di-Massimo.local)/Documents/Arduino/libraries/Rosserial_Arduino_Library/src/diag/diag.h:16:21: error: invalid use of incomplete type 'class diag::diag' typedef diag::motore _FrontLeft_type; ^~~~~~ /Users/mdore/Dropbox/Il mio Mac (MacBook-Pro-di-Massimo.local)/Documents/Arduino/libraries/Rosserial_Arduino_Library/src/diag/diag.h:13:9: note: definition of 'class diag::diag' is not complete until the closing brace class diag : public ros::Msg ^~~~ /Users/mdore/Dropbox/Il mio Mac (MacBook-Pro-di-Massimo.local)/Documents/Arduino/libraries/Rosserial_Arduino_Library/src/diag/diag.h:17:7: error: '_FrontLeft_type' does not name a type _FrontLeft_type FrontLeft; ^~~~~~~~~~~~~~~

-------------------------- Second try:

1) I created two packages diag and motore on Ros: diagnostica_ws/src/diag and diagnostica_ws/src/motor 2) catkin_make 3) generate ros_lib libraries 4) copied diag.h on diag/diag.h and motore.h in motore/motore.h 5) compile the sketch changing the class name:

diag::diag diag_msg; motore::motore motor_msg; ros::NodeHandle nh; ros::Publisher diag_pub("diagnostic", &diag_msg); void setup() { // put your setup code here, to run once:

// ROS Setup nh.initNode(); nh.advertise(diag_pub); while(!nh.connected()) nh.spinOnce(); }

diag_pub.publish(&diag_msg); delay (5000); nh.spinOnce(); } now the compilation is fine, but the problem is on ros side, as I told you. ROS melodic runs on a x64 cpu with ubuntu 18.04lts

Probably I have to solve the compilation error on Arduino (Arduino due processor). it should be the same relationship as , fo example, Pose and Point but in my case I do not understand the problem. Thanks Massimo

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answered 2021-08-07 11:23:42 -0600

Mike Scheutzow
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Did your message definition files compile in catkin_make without error? The content of your diag.msg file looks wrong -- I believe you need to specify the ros-package name when you use another msg type, like this:

std_msgs/Header header

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