C++ API (Doxygen via Breathe)¶

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The Read the Docs build runs doxygen Doxyfile in the docs folder as a pre-build step so the XML should be generated automatically.

struct DriverErrorCounters¶

#include <types.hpp>

Public Functions

inline void reset()¶

Public Members

uint64_t no_data = 0¶

uint64_t decode_failure = 0¶

uint64_t encode_failure = 0¶

uint64_t size_mismatch = 0¶

uint64_t serial_read_error = 0¶

uint64_t serial_write_error = 0¶

uint64_t invalid_control_char = 0¶

uint64_t no_command = 0¶

class ILittlebotDriver¶

#include <i_littlebot_driver.hpp>

Subclassed by littlebot_base::LittlebotDriver

Public Functions

ILittlebotDriver(const ILittlebotDriver&) = delete¶: Prevent copy and assignment.

ILittlebotDriver &operator=(const ILittlebotDriver&) = delete¶

virtual ~ILittlebotDriver() = default¶: Deconstructor for the ILittlebotDriver class.

virtual DriverError init() noexcept = 0¶

Initialize the driver.

Returns:: DriverError The result of the initialization

virtual void readRTData(WheelRTData &state) const noexcept = 0¶

Read the current state from the RT buffer.

Note

This method is RT-safe (control loop)

Parameters:: state – Reference to WheelRTData structure to store the read data

virtual void writeRTData(const WheelRTData &command) noexcept = 0¶

Write the command to the RT buffer.

Note

This method is RT-safe (control loop)

Parameters:: command – Reference to WheelRTData structure containing the command data

virtual bool requestStatus() noexcept = 0¶

Receive data from the hardware and update the RT buffer.

Note

This method is NOT RT-safe (executor / IO thread)

Returns:: true if data was received successfully
Returns:: false if an error occurred

virtual bool sendCommand() noexcept = 0¶

Send command data to the hardware.

Note

This method is NOT RT-safe (executor / IO thread)

Returns:: true if data was sent successfully
Returns:: false if an error occurred

virtual DriverError getLastError() const noexcept = 0¶

Get the last error that occurred.

Returns:: DriverError The last error code

virtual const DriverErrorCounters &getErrorCounters() const noexcept = 0¶

Get the error counters.

Returns:: const DriverErrorCounters& Reference to the error counters structure

Public Static Attributes

static constexpr char kCommandChar = {'C'}¶: Command control characters.

static constexpr char kStatusChar = {'S'}¶: Status control characters.

Protected Functions

ILittlebotDriver() = default¶: Default constructor for the ILittlebotDriver class.

class ILittlebotDriverFactory¶

#include <i_littlebot_driver_factory.hpp>

Subclassed by littlebot_base::LittlebotDriverFactory

Public Functions

virtual ~ILittlebotDriverFactory() = default¶

virtual std::expected<std::shared_ptr<ILittlebotDriver>, DriverError> create(const std::string &port, int baudrate, const std::vector<std::string> &joint_names) = 0¶

template<typename T> class IRTBuffer¶

#include <i_rt_buffer.hpp>

Public Functions

virtual ~IRTBuffer() = default¶

virtual const T *readRT() noexcept = 0¶

virtual void writeNonRT(const T &data) = 0¶

class ISerialPort¶

#include <i_serial_port.hpp>

Subclassed by littlebot_base::SerialPort

Public Functions

virtual ~ISerialPort() = default¶: Deconstructor for the ISerialPort class.

virtual SerialError open(std::string port, int baudrate) noexcept = 0¶

Open the serial port.

Parameters:

port – Serial port device path (e.g., “/dev/ttyUSB0”)
baudrate – Baud rate for the serial communication

Returns:

SerialError indicating success or type of failure

virtual SerialError close() noexcept = 0¶

Close the serial port.

Returns:: SerialError indicating success or type of failure

virtual int read(std::vector<uint8_t> &payload) noexcept = 0¶

Read Packet from the serial port.

Parameters:: payload – Vector to store the read packet data. Implementations must ensure the frame size never exceeds kMaxFrameSize.
Returns:: Number of bytes read

virtual int write(const std::vector<uint8_t> &payload) noexcept = 0¶

Write Packet to the serial port.

Parameters:: payload – Vector containing the packet data to write payload.size() must be <= kMaxFrameSize.
Returns:: Number of bytes written

inline virtual bool isOpen() const noexcept¶

Check if the serial port is open.

Returns:: true if the serial port is open
Returns:: false if the serial port is closed

Public Static Attributes

static constexpr size_t kMaxFrameSize = 256¶: Maximum size of a frame that can be sent/received.

Protected Functions

ISerialPort() = default¶: Constructor for the ISerialPort class.

ISerialPort(const ISerialPort&) = delete¶: Prevent copy and assignment.

ISerialPort &operator=(const ISerialPort&) = delete¶

virtual void readStream() noexcept = 0¶: Read data stream from the serial port.

virtual bool tryExtractFrame(std::vector<uint8_t> &payload) noexcept = 0¶

Get data from the received packet.

Parameters:: buffer – Shared pointer to string buffer to store received data
Returns:: true if a complete frame was extracted
Returns:: false if no complete frame was available

virtual void buildFrame(const std::vector<uint8_t> &payload, std::string &frame) noexcept = 0¶

Build packet to be sent through serial port.

Parameters:

payload – Vector containing the packet data to send
frame – String to store the built packet

Protected Attributes

std::vector<uint8_t> rx_buffer_¶: Buffer to store received data.

libserial::Serial serial_¶: Serial object from libserial.

bool is_open_ = {false}¶: Flag to indicate if the serial port is open.

Protected Static Attributes

static constexpr char kStartByte = {'['}¶: Character to start the message.

static constexpr char kEndByte = {']'}¶: Character to end the message.

class LittlebotDriver : public littlebot_base::ILittlebotDriver ¶

#include <littlebot_driver.hpp>

Public Functions

LittlebotDriver(std::shared_ptr<ISerialPort> serial_port, std::shared_ptr<IRTBuffer<WheelRTData>> rt_state_buffer, std::shared_ptr<IRTBuffer<WheelRTData>> rt_command_buffer, const std::vector<std::string> &joint_names, std::string port, int baudrate)¶

Construct a new Littlebot Driver object.

Parameters:

serial_port – Shared pointer to the serial port interface
rt_state_buffer – Shared pointer to the real-time buffer interface for wheel state data
rt_command_buffer – Shared pointer to the real-time buffer interface for wheel command data
joint_names – Vector of joint names
port – Serial port name
baudrate – Serial port baudrate

~LittlebotDriver() override = default¶

virtual DriverError init() noexcept override¶

Initialize the driver.

Override the virtual method from ILittlebotDriver

virtual void readRTData(WheelRTData &state) const noexcept override¶

Read the current state from the RT buffer.

Override the virtual method from ILittlebotDriver

virtual void writeRTData(const WheelRTData &command) noexcept override¶

Write the command to the RT buffer.

Override the virtual method from ILittlebotDriver

virtual bool requestStatus() noexcept override¶

Receive data from the hardware and update the RT buffer.

Override the virtual method from ILittlebotDriver

virtual bool sendCommand() noexcept override¶

Send command data to the hardware.

Override the virtual method from ILittlebotDriver

inline virtual DriverError getLastError() const noexcept override¶

Get the last error that occurred.

Override the virtual method from ILittlebotDriver

inline virtual const DriverErrorCounters &getErrorCounters() const noexcept override¶

Get the error counters.

Override the virtual method from ILittlebotDriver

Private Members

DriverErrorCounters error_counters_¶: Error counters for the driver.

DriverError last_error_ = {DriverError::None}¶: Last error that occurred.

std::shared_ptr<ISerialPort> serial_port_¶: Serial port interface.

std::shared_ptr<IRTBuffer<WheelRTData>> rt_state_buffer_¶: RT buffer interface for wheel data states.

std::shared_ptr<IRTBuffer<WheelRTData>> rt_command_buffer_¶: RT buffer interface for wheel data commands.

std::string port_¶: Serial port name.

int baudrate_ = {0}¶: Serial port baudrate.

std::vector<littlebot_base::Wheel> wheels_¶: Vector of wheels (Not RT-safe)

Private Static Functions

static DriverError mapSerialError(SerialError error) noexcept¶

Map SerialError to DriverError.

Parameters:: error – SerialError to map
Returns:: DriverError Mapped DriverError

class LittlebotDriverFactory : public littlebot_base::ILittlebotDriverFactory ¶

#include <littlebot_driver_factory.hpp>

Public Functions

virtual std::expected<std::shared_ptr<ILittlebotDriver>, DriverError> create(const std::string &port, int baudrate, const std::vector<std::string> &joint_names) override¶

class LittlebotHardwareComponent : public hardware_interface::SystemInterface¶

#include <littlebot_hardware_component.hpp>

Public Functions

LittlebotHardwareComponent() = default¶: Default constructor for the LittlebotHardwareComponent class.

~LittlebotHardwareComponent() = default¶: Deconstructor for the LittlebotHardwareComponent class.

hardware_interface::CallbackReturn on_init(const hardware_interface::HardwareComponentInterfaceParams &params) override¶: Initialize the hardware component with the given parameters.

hardware_interface::CallbackReturn on_configure(const rclcpp_lifecycle::State &state) override¶: Configure the hardware communication.

hardware_interface::CallbackReturn on_activate(const rclcpp_lifecycle::State &state) override¶

hardware_interface::CallbackReturn on_deactivate(const rclcpp_lifecycle::State &state) override¶

std::vector<hardware_interface::StateInterface> export_state_interfaces() override¶: Export the state interfaces.

std::vector<hardware_interface::CommandInterface> export_command_interfaces() override¶: Export the command interfaces.

hardware_interface::return_type read(const rclcpp::Time &time, const rclcpp::Duration &period) override¶: Read the state of the hardware component.

hardware_interface::return_type write(const rclcpp::Time &time, const rclcpp::Duration &period) override¶: Write the command to the hardware component.

inline void setDriverFactory(std::shared_ptr<ILittlebotDriverFactory> factory)¶

Set the Littlebot driver factory.

Note

This method is mainly used for testing purposes

Parameters:: factory – Shared pointer to the Littlebot driver factory

Private Members

const std::string hardware_component_name_ = {"LittlebotHardwareComponent"}¶: The name of the hardware component.

std::shared_ptr<littlebot_base::ILittlebotDriver> littlebot_driver_¶: Shared pointer to the Littlebot driver.

std::shared_ptr<ILittlebotDriverFactory> driver_factory_¶: Shared pointer to the Littlebot driver factory.

std::shared_ptr<IRTBuffer<WheelRTData>> rt_state_buffer_¶: Shared pointer to the RT buffer for wheel states.

std::shared_ptr<IRTBuffer<WheelRTData>> rt_command_buffer_¶: Shared pointer to the RT buffer for wheel commands.

rclcpp::TimerBase::SharedPtr io_timer_¶: Non-RT IO timer.

std::string serial_port_name_¶: Serial port device name.

int serial_baudrate_ = {115200}¶: Serial port baudrate.

std::vector<double> hw_commands_velocities_¶: command interface.

std::vector<double> hw_status_positions_¶: position state interface.

std::vector<double> hw_status_velocities_¶: velocity state interface.

Private Static Attributes

static constexpr int kNumCommandInterface_ = {1}¶: constant for number of command interfaces.

static constexpr int kNumStateInterface_ = {2}¶: constant for number of state interfaces.

class RosRTBuffer : public littlebot_base::IRTBuffer<littlebot_base::WheelRTData>¶

#include <ros_rt_buffer.hpp>

Public Functions

inline virtual const littlebot_base::WheelRTData *readRT() noexcept override¶

inline virtual void writeNonRT(const littlebot_base::WheelRTData &data) override¶

Private Members

realtime_tools::RealtimeBuffer<littlebot_base::WheelRTData> buffer_¶

class SerialPort : public littlebot_base::ISerialPort ¶

#include <serial_port.hpp>

Public Functions

virtual SerialError open(std::string port, int baudrate) noexcept override¶

Open the serial port.

Override the virtual method from ISerialPort

virtual SerialError close() noexcept override¶

Close the serial port.

Override the virtual method from ISerialPort

virtual int read(std::vector<uint8_t> &payload) noexcept override¶

Read packet data from the serial port.

Override the virtual method from ISerialPort

virtual int write(const std::vector<uint8_t> &payload) noexcept override¶

Write packet data to the serial port.

Override the virtual method from ISerialPort

Private Functions

virtual void readStream() noexcept override¶: Read data stream from the serial port.

virtual bool tryExtractFrame(std::vector<uint8_t> &payload) noexcept override¶

Get data from the received packet.

Parameters:: buffer – Shared pointer to string buffer to store received data

virtual void buildFrame(const std::vector<uint8_t> &payload, std::string &frame) noexcept override¶

Build packet to be sent through serial port.

Parameters:: buffer – Shared pointer to string buffer to store data to be sent

Private Members

std::string port_path_ = {"/dev/rfcomm0"}¶: Serial port device path (e.g., “/dev/ttyUSB0”)

int baudrate_ = {115200}¶: Communication baudrate (e.g., 9600, 115200)

Private Static Attributes

static constexpr size_t kMaxReadChunk = {ISerialPort::kMaxFrameSize}¶: Maximum number of bytes to read in one chunk.

class Wheel¶

#include <wheel.hpp>

Public Functions

Wheel() = default¶

inline explicit Wheel(std::string joint_name)¶

~Wheel() = default¶

inline void setCommandVelocity(double velocity)¶

Set the command velocity for the wheel.

Parameters:: velocity – Desired command velocity

inline void setJointName(const std::string &joint_name)¶

Set the joint name for the wheel.

Parameters:: joint_name – Name of the joint

inline void setStatusVelocity(double velocity)¶

Set the status velocity for the wheel.

Parameters:: velocity – Measured status velocity

inline void setStatusPosition(double position)¶

Set the status position for the wheel.

Parameters:: position – Measured status position

inline double getCommandVelocity() const¶: Get the command velocity for the wheel.

inline double getStatusPosition() const¶: Get the status position for the wheel.

inline double getStatusVelocity() const¶: Get the status velocity for the wheel.

inline std::string getJointName() const¶: Get the joint name for the wheel.

Private Members

double status_vel_ = {0.0}¶: Status velocity of the wheel.

double status_pos_ = {0.0}¶: Status position of the wheel.

double command_vel_ = {0.0}¶: Command velocity of the wheel.

std::string joint_name_ = {"wheel"}¶: Joint name of the wheel.

struct WheelRTData¶

#include <types.hpp>

Public Members

std::array<float, kNumWheels> command_velocity = {}¶

std::array<float, kNumWheels> status_velocity = {}¶

std::array<float, kNumWheels> status_position = {}¶

namespace hardware_interface¶

namespace littlebot_base¶

To more information about the serial library used, please visit: https://github.com/NestorDP/cppserial.

Enums

enum class SerialError¶

Values:

enumerator None¶

enumerator PortUnavailable¶

enumerator InsufficientPermissions¶

enumerator ConfigBaudrateFailed¶

enumerator ReadFailed¶

enumerator WriteFailed¶

enumerator AlreadyOpen¶

enumerator NotOpen¶

enumerator NotClosed¶

enumerator Unknown¶

enum class DriverError¶

Values:

enumerator None¶

enumerator NoData¶

enumerator DecodeFailure¶

enumerator EncodeFailure¶

enumerator SizeMismatch¶

enumerator SerialReadError¶

enumerator SerialWriteError¶

enumerator InvalidControlChar¶

enumerator NoCommand¶

enumerator SerialPortUnavailable¶

enumerator SerialInsufficientPermissions¶

enumerator SerialConfigBaudrateFailed¶

enumerator SerialReadFailed¶

enumerator SerialWriteFailed¶

enumerator SerialAlreadyOpen¶

enumerator SerialNotOpen¶

enumerator SerialNotClosed¶

enumerator Unknown¶

Variables

constexpr size_t kNumWheels = 2¶

namespace codec¶

Functions

void encode(std::vector<uint8_t> &payload, const std::vector<Wheel> &wheels)¶

Encode wheel command data into a protobuf payload.

This function serializes the command velocities of the wheels into a protobuf message suitable for transmission to the hardware.

Parameters:

payload – Output payload that will contain the serialized protobuf message
wheels – Vector of wheels providing command data

Throws:

std::runtime_error – if serialization fails

void decode(const std::vector<uint8_t> &payload, std::vector<Wheel> &wheels)¶

Decode wheel state data from a protobuf payload.

This function deserializes a protobuf message received from the hardware and updates the wheel status fields. Existing wheel metadata (e.g., joint names) is preserved.

Parameters:

payload – Input payload containing the serialized protobuf message
wheels – Vector of wheels to be updated with decoded state data

Throws:

std::runtime_error – if parsing fails or data size mismatches

file codec.hpp: #include <iostream>

#include <memory>

#include <string>

#include <vector>

#include “littlebot_msg.pb.h”

#include “littlebot_base/wheel.hpp”

file i_littlebot_driver.hpp: #include <memory>

#include <string>

#include <vector>

#include “littlebot_base/i_serial_port.hpp”

#include “littlebot_base/i_rt_buffer.hpp”

#include “littlebot_base/types.hpp”

#include “littlebot_base/wheel.hpp”

file i_littlebot_driver_factory.hpp: #include <expected>

#include <memory>

#include <string>

#include <vector>

#include “littlebot_base/types.hpp”

file i_rt_buffer.hpp

file i_serial_port.hpp: #include <cstdint>

#include <memory>

#include <string>

#include <vector>

#include “libserial/serial.hpp”

file littlebot_driver.hpp: #include <memory>

#include <string>

#include <vector>

#include “littlebot_base/i_littlebot_driver.hpp”

#include “littlebot_base/i_serial_port.hpp”

#include “littlebot_base/i_rt_buffer.hpp”

#include “littlebot_base/types.hpp”

#include “littlebot_base/wheel.hpp”

file littlebot_driver_factory.hpp: #include <expected>

#include <memory>

#include <string>

#include <vector>

#include “littlebot_base/i_littlebot_driver_factory.hpp”

file littlebot_hardware_component.hpp: #include <memory>

#include <string>

#include <unordered_map>

#include <utility>

#include <vector>

#include “hardware_interface/handle.hpp”

#include “hardware_interface/hardware_info.hpp”

#include “hardware_interface/system_interface.hpp”

#include “hardware_interface/types/hardware_interface_return_values.hpp”

#include “rclcpp/clock.hpp”

#include “rclcpp/duration.hpp”

#include “rclcpp/macros.hpp”

#include “rclcpp/time.hpp”

#include “rclcpp_lifecycle/node_interfaces/lifecycle_node_interface.hpp”

#include “rclcpp_lifecycle/state.hpp”

#include “littlebot_base/littlebot_driver.hpp”

#include “littlebot_base/serial_port.hpp”

#include “littlebot_base/ros_rt_buffer.hpp”

#include “littlebot_base/i_littlebot_driver_factory.hpp”

#include “littlebot_base/i_rt_buffer.hpp”

#include “littlebot_base/types.hpp”

file ros_rt_buffer.hpp: #include “realtime_tools/realtime_buffer.hpp”

#include “littlebot_base/i_rt_buffer.hpp”

#include “littlebot_base/types.hpp”

file serial_port.hpp: #include <iostream>

#include <memory>

#include <string>

#include <vector>

#include “littlebot_base/i_serial_port.hpp”

file types.hpp: #include <array>

#include <cstddef>

#include <cstdint>

file wheel.hpp: #include <iostream>

#include <memory>

#include <string>

#include <utility>

#include <vector>

file codec.cpp: #include <stdexcept>

#include “littlebot_base/codec.hpp”

file littlebot_driver.cpp: #include “littlebot_base/littlebot_driver.hpp”

#include “littlebot_base/codec.hpp”

file littlebot_driver_factory.cpp: #include “littlebot_base/littlebot_driver_factory.hpp”

#include “littlebot_base/littlebot_driver.hpp”

#include “littlebot_base/serial_port.hpp”

#include “littlebot_base/ros_rt_buffer.hpp”

file littlebot_hardware_component.cpp: #include <hardware_interface/lexical_casts.hpp>

#include <hardware_interface/types/hardware_interface_type_values.hpp>

#include <rclcpp/rclcpp.hpp>

#include “littlebot_base/littlebot_hardware_component.hpp”

#include “littlebot_base/littlebot_driver_factory.hpp”

#include “pluginlib/class_list_macros.hpp”

file serial_port.cpp: #include “littlebot_base/serial_port.hpp”

#include <algorithm>

dir /home/docs/checkouts/readthedocs.org/user_builds/littlebot/checkouts/latest/littlebot_base/include

dir /home/docs/checkouts/readthedocs.org/user_builds/littlebot/checkouts/latest/littlebot_base

dir /home/docs/checkouts/readthedocs.org/user_builds/littlebot/checkouts/latest/littlebot_base/include/littlebot_base

dir /home/docs/checkouts/readthedocs.org/user_builds/littlebot/checkouts/latest/littlebot_base/src