## Getting Started as a new member

by Garrett Pierson on September 03, 2019

# Contents

This guide is intended for new group members with limited exposure to ROS and other tools used in the HIRO Group. This page in conjunction with the new member to-do list page will help you through setting up all of the software so that you can get started working on your project with minimal frustration.

# When Should I Ask For Help?

Coding can be very frustrating, but learning when to ask for help can reduce the time you spend looking for answers on Stack Overflow and keep making progress on your project. Struggling with problems and learning to utilize online resources is a valuable skill that takes time and frustration to develop, but this does not mean you should not ask for help. Below are some simple guidelines for when you should ask for help on a problem.

1. Google it! Take the error messages or type what you are trying to do and search for answers using Google. This should always be your first step after trying for a solid 15-20 minutes on your own. Carefully read through at least the first page for answers to your problems and refer to the tutorials. Try this for an hour, then if you can not figure it out, ask one of the other members.

2. Ask an Undergraduate Student! You should introduce yourself to everyone in the lab and get to know them (everyone is also listed on the website under people) are struggling and make a hypothesis of why you are having a problem. If the undergraduates cannot quickly solve the issue or if you are specifically working with a graduate student, you should do some more searching online and review your code to see if something small was overlooked. If this does not work, go ask a graduate student.

3. Ask a Graduate Student! Find a master’s or PhD student and, like before, have an understanding of your problem, where you are struggling, and what you have tried. They should be able to help you with most issues you will encounter. If you are working on something specific and the graduate students in the lab are not sure how to help, you should ask Alessandro for advice on how to proceed.

# Development Goals

## 1. Learn how to use Linux

If you have never used Linux before, please try this tutorial first to learn some basic command line tools.

## 2. Install the software (see preliminaries)

• Consider dual booting with Ubuntu 16.04:
• Add paths to your ~/.bashrc to source your workspaces. Access this via the command line by opening the file with an editor like gedit or Sublime Text. Then add the command source $HOME/<yourwsname_ws>/devel/setup.bash to the end of the .bashrc file. ## 3. Work through the ROS Tutorials Beginner Level (1-20) • Focus on package creation and how to execute your programs • Understand how to set up targets for the programs you want to run • This is done by going to your Cmake file in your workspace/package and going to the build section. From there you need to follow the instructions in the comments and: • Specify additional locations of header files. Include_Directories (${catkin_INCLUDE_DIRS}
~/src/ros_devel_ws/devel/include
~/src/ros_devel_ws/devel/include/intera_core_msgs
~/src/ros_devel_ws/src/your_package/include/your_package
)

• Declare a C++ Executable.
add_executable(target_name src/target_name.cpp)

• Add Cmake Target Dependencies of the Executable.
add_dependencies(target_name ${${PROJECT_NAME}_EXPORTED_TARGETS} ${catkin_EXPORTED_TARGETS})  • Specify Libraries to Link a Library or Executable Target Against. target_link_libraries(target_name${catkin_LIBRARIES})

• Take a look at the Cmake tutorials linked in the new member to-do list section.
• Make sure to pay attention to publishers and subscribers as they are essential to ROS.

## 4. Get something moving! (See Section 5 for Example Code)

• Run some of the example programs like the wobble program on the Intera SDK Gazebo site for Sawyer.
• Write a program that can move the Sawyer arm around in Gazebo. As an extension, create a basic menu system so that the user can send poses to the Sawyer.
• Write a program that records the joint angles when the cuff button on the Sawyer arm is pressed–please get training from a graduate student before using the robot. With the recorded poses, after the user is done moving the arm, have the Sawyer arm reenact these poses in the order they occurred. You will need to limit the maximum speed of the arm as this can be dangerous.
• Send an image to the Sawyer display.

## 5. Example Code

  #include "ros/ros.h"
#include <iostream>
#include <sstream>

int main(int argc, char **argv)
{
ros::init(argc, argv, "pub");
ros::NodeHandle n;

ros::Rate loop_rate(1);
float target = 1.0;

while(ros::ok())
{
msg.target = 1.0 - target;
target = msg.target;
msg.speed_ratio = 0.5;
msg.pan_mode = 0;
joint_pub.publish(msg);
ros::spinOnce();
loop_rate.sleep();
}
return 0;
}

• Send a pose to Sawyer.

  #include "ros/ros.h"
#include <iostream>
#include <sstream>
#include "JointCommand.h"

int main(int argc, char **argv) {
ros::init(argc, argv, "pub");
ros::NodeHandle n;

ros::Rate loop_rate(1);

float position = 2.0;
intera_core_msgs::JointCommand msg;

msg.mode = 1;
msg.names[0] = "j0";
msg.position[0] = position;

joint_pub.publish(msg);
ros::spinOnce();
loop_rate.sleep();
return 0;
}