hi i create a custom_hardware_interface using with our tutorial
here is my files one by one
#include “…/include/kevell_hardware_interface/kevell_hardware_interface.hpp”
#include <hardware_interface/types/hardware_interface_type_values.hpp>
hardware_interface::CallbackReturn KevellHardware::on_init(const hardware_interface::HardwareInfo &info) {
RCLCPP_INFO(rclcpp::get_logger(“KevellHardware”), “Initializing hardware…”);
// Initialize serial communication
try {
serial_conn.setPort("/dev/ttyUSB0");
serial_conn.setBaudrate(115200);
serial_conn.open();
RCLCPP_ERROR(rclcpp::get_logger("KevellHardware"), "open a serial port successfully...");
} catch (const serial::IOException &e) {
RCLCPP_ERROR(rclcpp::get_logger("KevellHardware"), "Unable to open serial port: %s", e.what());
return hardware_interface::CallbackReturn::ERROR;
}
if (!serial_conn.isOpen()) {
RCLCPP_ERROR(rclcpp::get_logger("KevellHardware"), "Serial port not open.");
return hardware_interface::CallbackReturn::ERROR;
}
for (const hardware_interface::ComponentInfo & joint : info_.joints)
{
// DiffBotSystem has exactly two states and one command interface on each joint
if (joint.command_interfaces.size() != 1)
{
RCLCPP_FATAL(
rclcpp::get_logger(“DiffDriveArduinoHardware”),
“Joint ‘%s’ has %zu command interfaces found. 1 expected.”, joint.name.c_str(),
joint.command_interfaces.size());
return hardware_interface::CallbackReturn::ERROR;
}
if (joint.command_interfaces[0].name != hardware_interface::HW_IF_VELOCITY)
{
RCLCPP_FATAL(
rclcpp::get_logger("DiffDriveArduinoHardware"),
"Joint '%s' have %s command interfaces found. '%s' expected.", joint.name.c_str(),
joint.command_interfaces[0].name.c_str(), hardware_interface::HW_IF_VELOCITY);
return hardware_interface::CallbackReturn::ERROR;
}
if (joint.state_interfaces.size() != 2)
{
RCLCPP_FATAL(
rclcpp::get_logger("DiffDriveArduinoHardware"),
"Joint '%s' has %zu state interface. 2 expected.", joint.name.c_str(),
joint.state_interfaces.size());
return hardware_interface::CallbackReturn::ERROR;
}
if (joint.state_interfaces[0].name != hardware_interface::HW_IF_POSITION)
{
RCLCPP_FATAL(
rclcpp::get_logger("DiffDriveArduinoHardware"),
"Joint '%s' have '%s' as first state interface. '%s' expected.", joint.name.c_str(),
joint.state_interfaces[0].name.c_str(), hardware_interface::HW_IF_POSITION);
return hardware_interface::CallbackReturn::ERROR;
}
if (joint.state_interfaces[1].name != hardware_interface::HW_IF_VELOCITY)
{
RCLCPP_FATAL(
rclcpp::get_logger("DiffDriveArduinoHardware"),
"Joint '%s' have '%s' as second state interface. '%s' expected.", joint.name.c_str(),
joint.state_interfaces[1].name.c_str(), hardware_interface::HW_IF_VELOCITY);
return hardware_interface::CallbackReturn::ERROR;
}
}
RCLCPP_INFO(rclcpp::get_logger("KevellHardware"), "Hardware initialized successfully.");
return hardware_interface::CallbackReturn::SUCCESS;
}
hardware_interface::CallbackReturn KevellHardware::on_activate(const rclcpp_lifecycle::State &) {
RCLCPP_INFO(rclcpp::get_logger(“KevellHardware”), “Activating hardware…”);
return hardware_interface::CallbackReturn::SUCCESS;
}
hardware_interface::CallbackReturn KevellHardware::on_deactivate(const rclcpp_lifecycle::State &) {
RCLCPP_INFO(rclcpp::get_logger(“KevellHardware”), “Deactivating hardware…”);
return hardware_interface::CallbackReturn::SUCCESS;
}
std::vector<hardware_interface::StateInterface> KevellHardware::export_state_interfaces() {
RCLCPP_INFO(rclcpp::get_logger(“KevellHardware”), “Exporting state interfaces…”);
std::vector<hardware_interface::StateInterface> state_interfaces;
state_interfaces.emplace_back(hardware_interface::StateInterface("left_wheel_joint", hardware_interface::HW_IF_POSITION, &position_states[0]));
state_interfaces.emplace_back(hardware_interface::StateInterface("left_wheel_joint", hardware_interface::HW_IF_VELOCITY, &velocity_states[0]));
state_interfaces.emplace_back(hardware_interface::StateInterface("right_wheel_joint", hardware_interface::HW_IF_POSITION, &position_states[1]));
state_interfaces.emplace_back(hardware_interface::StateInterface("right_wheel_joint", hardware_interface::HW_IF_VELOCITY, &velocity_states[1]));
return state_interfaces;
}
std::vector<hardware_interface::CommandInterface> KevellHardware::export_command_interfaces() {
RCLCPP_INFO(rclcpp::get_logger(“KevellHardware”), “Exporting command interfaces…”);
std::vector<hardware_interface::CommandInterface> command_interfaces;
command_interfaces.emplace_back(hardware_interface::CommandInterface("left_wheel_joint", hardware_interface::HW_IF_VELOCITY, &velocity_commands[0]));
command_interfaces.emplace_back(hardware_interface::CommandInterface("right_wheel_joint", hardware_interface::HW_IF_VELOCITY, &velocity_commands[1]));
return command_interfaces;
}
hardware_interface::return_type KevellHardware::read(const rclcpp::Time &, const rclcpp::Duration &) {
if (!serial_conn.isOpen()) {
RCLCPP_ERROR(rclcpp::get_logger(“KevellHardware”), “Serial connection lost!”);
return hardware_interface::return_type::ERROR;
}
std::string response;
try {
serial_conn.write("READ\n");
response = serial_conn.readline();
} catch (const serial::IOException &e) {
RCLCPP_ERROR(rclcpp::get_logger("KevellHardware"), "Serial read error: %s", e.what());
return hardware_interface::return_type::ERROR;
}
// Example parsing: "ENC 500 480"
int left_encoder, right_encoder;
if (sscanf(response.c_str(), "ENC %d %d", &left_encoder, &right_encoder) == 2) {
position_states[0] = (left_encoder / ticks_per_revolution) * 2 * M_PI;
position_states[1] = (right_encoder / ticks_per_revolution) * 2 * M_PI;
velocity_states[0] = (position_states[0] - left_encoder_prev) / 0.1;
velocity_states[1] = (position_states[1] - right_encoder_prev) / 0.1;
left_encoder_prev = left_encoder;
right_encoder_prev = right_encoder;
} else {
RCLCPP_ERROR(rclcpp::get_logger("KevellHardware"), "Invalid encoder data received!");
return hardware_interface::return_type::ERROR;
}
return hardware_interface::return_type::OK;
}
hardware_interface::return_type KevellHardware::write(const rclcpp::Time &, const rclcpp::Duration &) {
if (!serial_conn.isOpen()) {
RCLCPP_ERROR(rclcpp::get_logger(“KevellHardware”), “Serial connection lost!”);
return hardware_interface::return_type::ERROR;
}
char command[50];
snprintf(command, sizeof(command), "CMD %.2f %.2f\n", velocity_commands[0], velocity_commands[1]);
try {
serial_conn.write(command);
} catch (const serial::IOException &e) {
RCLCPP_ERROR(rclcpp::get_logger("KevellHardware"), "Serial write error: %s", e.what());
return hardware_interface::return_type::ERROR;
}
return hardware_interface::return_type::OK;
}
#include <pluginlib/class_list_macros.hpp>
PLUGINLIB_EXPORT_CLASS(KevellHardware, hardware_interface::SystemInterface)
and launch file
import os
import launch
import launch_ros.actions
from launch.substitutions import Command, FindExecutable, PathJoinSubstitution
from launch_ros.substitutions import FindPackageShare
from ament_index_python.packages import get_package_share_directory
def generate_launch_description():
robot_description_content = Command(
[
PathJoinSubstitution([FindExecutable(name="xacro")]),
" ",
PathJoinSubstitution(
[FindPackageShare("kevell_hardware_interface"), "urdf", "robot_urdf.xacro"]
),
]
)
robot_description = {"robot_description": robot_description_content}
kevell_hardware_config = os.path.join(
get_package_share_directory('kevell_hardware_interface'), 'config', 'kevell_controllers.yaml'
)
return launch.LaunchDescription([
launch_ros.actions.Node(
package='controller_manager',
executable='ros2_control_node',
parameters=[robot_description,kevell_hardware_config],
output='screen'
),
launch_ros.actions.Node(
package='robot_state_publisher',
executable='robot_state_publisher',
parameters=[robot_description],
output='screen'
),
launch_ros.actions.Node(
package='controller_manager',
executable='spawner',
arguments=["joint_state_broadcaster", "--controller-manager", "/controller_manager"],
output='screen'
),
launch_ros.actions.Node(
package='controller_manager',
executable='spawner',
arguments=["diffbot_base_controller", "--controller-manager", "/controller_manager"],
output='screen'
)
])
and the config file is
controller_manager:
ros__parameters:
update_rate: 10 # Hz
diffbot_base_controller:
type: diff_drive_controller/DiffDriveController
#left_wheel_names: ["left_wheel_joint"]
#right_wheel_names: ["right_wheel_joint"]
#command_interfaces:
#- velocity
#state_interfaces:
#- position
#- velocity
joint_state_broadcaster:
type: joint_state_broadcaster/JointStateBroadcaster
joints: ["left_wheel_joint", "right_wheel_joint"]
diffbot_base_controller:
ros__parameters:
publish_rate: 50.0
left_wheel_names: [“left_wheel_joint”]
right_wheel_names: [“right_wheel_joint”]
wheels_per_side: 1
wheel_separation: 0.3
wheel_radius: 0.05
base_frame_id: base_link
use_stamped_vel: false
linear.x.has_velocity_limits: false
linear.x.has_acceleration_limits: false
linear.x.has_jerk_limits: false
linear.x.max_velocity: 1.0 # Changed from 0.0 to avoid divide-by-zero errors
linear.x.min_velocity: -1.0 # Allow backward motion
linear.x.max_acceleration: 1.0
linear.x.min_acceleration: -1.0
linear.x.max_jerk: 0.5
linear.x.min_jerk: -0.5
angular.z.has_velocity_limits: false
angular.z.has_acceleration_limits: false
angular.z.has_jerk_limits: false
angular.z.max_velocity: 1.0
angular.z.min_velocity: -1.0
angular.z.max_acceleration: 1.0
angular.z.min_acceleration: -1.0
angular.z.max_jerk: 0.5
angular.z.min_jerk: -0.5
but i got a error is below
kevell@kevell-All-Series:~/hardware$ ros2 launch kevell_hardware_interface control_launch.py
[INFO] [launch]: All log files can be found below /home/kevell/.ros/log/2025-02-28-19-03-32-798911-kevell-All-Series-19436
[INFO] [launch]: Default logging verbosity is set to INFO
[INFO] [ros2_control_node-1]: process started with pid [19439]
[INFO] [robot_state_publisher-2]: process started with pid [19441]
[INFO] [spawner-3]: process started with pid [19443]
[INFO] [spawner-4]: process started with pid [19445]
[ros2_control_node-1] [WARN] [1740749613.110076083] [controller_manager]: [Deprecated] Passing the robot description parameter directly to the control_manager node is deprecated. Use ‘~/robot_description’ topic from ‘robot_state_publisher’ instead.
[ros2_control_node-1] [INFO] [1740749613.110290349] [resource_manager]: Loading hardware ‘KevellHardware’
[robot_state_publisher-2] Warning: link ‘chassis’ material ‘white’ undefined.
[robot_state_publisher-2] at line 84 in ./urdf_parser/src/model.cpp
[robot_state_publisher-2] Warning: link ‘chassis’ material ‘white’ undefined.
[robot_state_publisher-2] at line 84 in ./urdf_parser/src/model.cpp
[robot_state_publisher-2] Warning: link ‘left_wheel’ material ‘blue’ undefined.
[robot_state_publisher-2] at line 84 in ./urdf_parser/src/model.cpp
[robot_state_publisher-2] Warning: link ‘left_wheel’ material ‘blue’ undefined.
[robot_state_publisher-2] at line 84 in ./urdf_parser/src/model.cpp
[robot_state_publisher-2] Warning: link ‘right_wheel’ material ‘blue’ undefined.
[robot_state_publisher-2] at line 84 in ./urdf_parser/src/model.cpp
[robot_state_publisher-2] Warning: link ‘right_wheel’ material ‘blue’ undefined.
[robot_state_publisher-2] at line 84 in ./urdf_parser/src/model.cpp
[robot_state_publisher-2] [INFO] [1740749613.111400508] [robot_state_publisher]: got segment base_link
[ros2_control_node-1] [INFO] [1740749613.112011579] [resource_manager]: Initialize hardware ‘KevellHardware’
[ros2_control_node-1] [INFO] [1740749613.112055724] [KevellHardware]: Initializing hardware…
[robot_state_publisher-2] [INFO] [1740749613.112311681] [robot_state_publisher]: got segment chassis
[robot_state_publisher-2] [INFO] [1740749613.112346758] [robot_state_publisher]: got segment left_wheel
[robot_state_publisher-2] [INFO] [1740749613.112363006] [robot_state_publisher]: got segment right_wheel
[ros2_control_node-1] [ERROR] [1740749613.115097096] [KevellHardware]: open a serial port successfully…
[ros2_control_node-1] [INFO] [1740749613.115144954] [KevellHardware]: Hardware initialized successfully.
[ros2_control_node-1] [INFO] [1740749613.115166922] [resource_manager]: Successful initialization of hardware ‘KevellHardware’
[ros2_control_node-1] [INFO] [1740749613.115178039] [KevellHardware]: Exporting state interfaces…
[ros2_control_node-1] [INFO] [1740749613.115286870] [KevellHardware]: Exporting command interfaces…
[ros2_control_node-1] [INFO] [1740749613.115452671] [resource_manager]: ‘configure’ hardware ‘’
[ros2_control_node-1] [INFO] [1740749613.115467618] [resource_manager]: Successful ‘configure’ of hardware ‘’
[ros2_control_node-1] [INFO] [1740749613.115475789] [resource_manager]: ‘activate’ hardware ‘’
[ros2_control_node-1] [INFO] [1740749613.115483704] [KevellHardware]: Activating hardware…
[ros2_control_node-1] [INFO] [1740749613.115491566] [resource_manager]: Successful ‘activate’ of hardware ‘’
[ros2_control_node-1] [INFO] [1740749613.121765422] [controller_manager]: update rate is 10 Hz
[ros2_control_node-1] [WARN] [1740749613.122487251] [controller_manager]: No real-time kernel detected on this system. See [Controller Manager — ROS2_Control: Rolling Feb 2025 documentation] for details on how to enable realtime scheduling.
[ros2_control_node-1] [ERROR] [1740749613.123014530] [KevellHardware]: Invalid encoder data received!
[ros2_control_node-1] [INFO] [1740749613.410553873] [controller_manager]: Loading controller ‘joint_state_broadcaster’
[ros2_control_node-1] [INFO] [1740749613.435844232] [controller_manager]: Loading controller ‘diffbot_base_controller’
[spawner-3] [INFO] [1740749613.444040377] [spawner_joint_state_broadcaster]: Loaded joint_state_broadcaster
[ros2_control_node-1] [INFO] [1740749613.523164696] [controller_manager]: Configuring controller ‘joint_state_broadcaster’
[ros2_control_node-1] [INFO] [1740749613.523369036] [joint_state_broadcaster]: ‘joints’ or ‘interfaces’ parameter is empty. All available state interfaces will be published
[spawner-4] [INFO] [1740749613.542315886] [spawner_diffbot_base_controller]: Loaded diffbot_base_controller
[ros2_control_node-1] [INFO] [1740749613.622852558] [controller_manager]: Configuring controller ‘diffbot_base_controller’
[ros2_control_node-1] [ERROR] [1740749613.822659800] [joint_state_broadcaster]: None of requested interfaces exist. Controller will not run.
[ros2_control_node-1] [WARN] [1740749613.822701272] [joint_state_broadcaster]: Error occurred while doing error handling.
[ros2_control_node-1] [ERROR] [1740749613.822740574] [controller_manager]: After activation, controller ‘joint_state_broadcaster’ is in state ‘unconfigured’ (1), expected ‘active’ (3).
[ros2_control_node-1] [ERROR] [1740749613.923127704] [resource_manager]: Not acceptable command interfaces combination:
[ros2_control_node-1] Start interfaces:
[ros2_control_node-1] [
[ros2_control_node-1] left_wheel_joint/velocity
[ros2_control_node-1] right_wheel_joint/velocity
[ros2_control_node-1] ]
[ros2_control_node-1] Stop interfaces:
[ros2_control_node-1] [
[ros2_control_node-1] ]
[ros2_control_node-1] Not available:
[ros2_control_node-1] [
[ros2_control_node-1] left_wheel_joint/velocity
[ros2_control_node-1] right_wheel_joint/velocity
[ros2_control_node-1] ]
[ros2_control_node-1]
[ros2_control_node-1] [ERROR] [1740749613.923163006] [controller_manager]: Could not switch controllers since prepare command mode switch was rejected.
[spawner-3] [INFO] [1740749613.923917841] [spawner_joint_state_broadcaster]: Configured and activated joint_state_broadcaster
[spawner-4] [ERROR] [1740749613.924526640] [spawner_diffbot_base_controller]: Failed to activate controller
[INFO] [spawner-3]: process has finished cleanly [pid 19443]
[ERROR] [spawner-4]: process has died [pid 19445, exit code 1, cmd ‘/opt/ros/humble/lib/controller_manager/spawner diffbot_base_controller --controller-manager /controller_manager --ros-args’].
^C[WARNING] [launch]: user interrupted with ctrl-c (SIGINT)
[robot_state_publisher-2] [INFO] [1740749623.278484912] [rclcpp]: signal_handler(signum=2)
[ros2_control_node-1] [INFO] [1740749623.278484852] [rclcpp]: signal_handler(signum=2)
[INFO] [ros2_control_node-1]: process has finished cleanly [pid 19439]
[INFO] [robot_state_publisher-2]: process has finished cleanly [pid 19441]
so expertise i have mess about confusion please help for me
