ranger_ros

ranger

• ranger mini is the name of the following car

  

Communicate Flow

• The ugv_sdk communicate with the car by can protocol
• The ranger_ros package call the function GetRangerState to get the newest machine information, call the SetMotionCommand to set linear velocity 、angle、etc, call the SetMotionMode to change the motion mode
• Ranger mini have 4 type of motion mode. see ranger mini manual from agilex develop manuals
• pub ranger_ros can set motion mode
• subscribe ranger_status can get the robot status

Params

see ranger_base/launch/ranger_mini_base.launch

• is_ranger_mini : ranger mini or ranger pro
• port_name: can port name , usually is can0
• simulated_robot: sim robot for test or not
• odom_frame: the odometry frame name in tf
• base_frame: the base link frame name in tf
• odom_topic_name: the odometry topic name
• pub_odom_tf: publish tf transformation of odometry frame or not. if true publish

Build

dependencies:

• ROS1 melodic or newer

assume your ros workspace is ~/agilex_ws

# install ugv_sdk
cd ~/agilex_ws/src
git clone https://github.com/agilexrobotics/ugv_sdk.git
cd ugv_sdk
git checkout -b v2.x origin/v2.x
cd ../
catkin_make install --pkg ugv_sdk

# source the packages
source devel/setup.bash

# install ranger_ros
cd ~/agilex_ws/src/
git clone https://github.com/agilexrobotics/ranger_ros.git

# install the ascent library at first
cd ranger_ros/ranger_base/ascent
mkdir -p build && cd build && cmake -DBUILD_TESTING=OFF .. && sudo make install

cd ~/agilex_ws/
catkin_make install # or just catkin_make

# if you catch error:  ranger_msgs/RangerSetting.h: No such file or directory
# then install `ranger_msgs` first
catkin_make install --pkg ranger_msgs

# for install
catkin_make install

Run

# run ranger_ros
cd ~/agilex_ws
source devel/setup.bash
roslaunch ranger_bringup ranger_minimal.launch

use keyboard to control

the default motion mode is Head-Back Ackermann

# if you want to remote control the car by keyboard
sudo apt install ros-$ROS_DISTRO-teleop-twist-keyboard
roslaunch ranger_bringup ranger_teleop_keyboard.launch

---

Ros Topic Examples

• Input: the car linear velocity and the heading angle
• Output: total linear velocity, x direction velocity, y direction velocity, angular velocity, central steer angle and rotate radius, .etc

Publish topic to control the car

see ranger_ros/ranger_examples/src/input.cpp for details

////----------------control by ros topic---------------------------------
ros::Publisher motion_mode =
    node.advertise<ranger_msgs::RangerSetting>("/ranger_setting", 1);
ranger_msgs::RangerSetting setting;
setting.motion_mode = ranger_msgs::RangerSetting::MOTION_MODE_ACKERMAN;
motion_mode.publish(setting);

////------------------move by ros topic --------------------------------
ros::Publisher move_cmd =
    node.advertise<geometry_msgs::Twist>("/cmd_vel", 10);
geometry_msgs::Twist cmd;
cmd.linear.x = 0.1;                   // the motor will run at 0.1m/s
cmd.angular.z = 30.0 / 180.0 * M_PI;  // the heading angle of the car

// publish robot state at 50Hz while listening to twist commands
ros::Rate rate(50);
while (ros::ok()) {
    ros::spinOnce();

    // /cmd_vel topic must send at 50Hz, even stop need send 0m/s
    move_cmd.publish(cmd);

    rate.sleep();
}

or publish by command line

# 0 Ackrmann, 1 Slide, 2 Round, 3 Sloping
# 0 前后阿克曼，1 斜移,   2 自旋,  3  侧移
rostopic pub -1 /ranger_setting ranger_msgs/RangerSetting -- '[0, 0, setting_frame]' '1'

rostopic pub /cmd_vel geometry_msgs/Twist --rate 50 '[0.1, 0.0, 0.0]' '[0.0, 0.0, 0.52358]'  # 0.52358 = 30 degree

Subcribe the car output

see ranger_ros/ranger_examples/src/output.cpp for details

ros::Subscriber status_sub = node.subscribe<ranger_msgs::RangerStatus>(
    "/ranger_status", 10, StatusCallback);

void StatusCallback(ranger_msgs::RangerStatus::ConstPtr msg) {
    std::cout << "linear velocity: " << msg->linear_velocity << std::endl;
    std::cout << "angular velocity: " << msg->angular_velocity << std::endl;
    std::cout << "x direction linear velocity: " << msg->x_linear_vel << std::endl;
    std::cout << "y direction linear linear velocity: " << msg->y_linear_vel << std::endl;
    std::cout << "rotate radius: " << msg->motion_radius << std::endl;
    std::cout << "car heading angle: " << msg->steering_angle << std::endl;
    // ...etc
}

or show the data by rostopic

rostopic echo /ranger_status

---

Sdk API Examples

0. enable can control

robot->Connect("can0");
robot->EnableCommandedMode();

1. set motion mode

see ranger_ros/ranger_examples/src/change_the_mode.cpp for more details

robot->Connect("can0");
robot->EnableCommandedMode();

// 0 Arckmann 1 Slide 2 round, 3 Sloping
// 0 前后阿克曼 1 横移  2 自旋  3 侧移 
robot->SetMotionMode(0);
//  robot->SetMotionMode(1);
//  robot->SetMotionMode(2);
//  robot->SetMotionMode(3);

2. set the movement linear velocity and angle of the car

see ranger_ros/ranger_examples/src/control_the_car.cpp for more details

robot->SetMotionCommand(0.1, 30.0/180.0 * M_PI); // steer angle = 30°

// or write them in a function
void Ackermann() {
  robot->SetMotionMode(0);
  // or
  robot->SetMotionMode(RangerSetting::MOTION_MODE_ACKERMAN);
  l_v = 0.1;                  // m/s
  angle_z = 30 / 180 * M_PI;  // rad
}
void Slide() {
  robot->SetMotionMode(1);
  // or
  robot->SetMotionMode(RangerSetting::MOTION_MODE_SLIDE);
  l_v = 0.1;                  // m/s
  angle_z = 30 / 180 * M_PI;  // rad
}
void Round() {
  robot->SetMotionMode(2);
  // or
  robot->SetMotionMode(RangerSetting::MOTION_MODE_ROUND);
  l_v = 0.1;
  // angle_z is not used
}
void Sloping() {
  robot->SetMotionMode(3);
  // or
  robot->SetMotionMode(RangerSetting::MOTION_MODE_SLOPING);
  l_v = 0.1;
  // angle_z is not used
}

use odometry

• subscribe /odom topic