README
off_highway_can
The off_highway_can package provides a C++ library to
receive
can_msgs/Frame
orsocketcan_msgs/FdFrame
ROS messages and decode their bytes into custom C++ message structures,encode the bytes of
can_msgs/Frame
orsocketcan_msgs/FdFrame
ROS messages from custom C++ message structures and send them.
The list of message structures containing the definition of a CAN message and signals need to be filled by derived classes for CAN node specific functionality. The more generic handling of a cyclic redundancy check and a rolling message counter per message is provided by the library. Have a look directly into the CAN message structure definition for further information.
Classes
Receiver
The off_highway_can::Receiver
is an abstract base class and needs to be derived for specific
sensor types and behavior. It provides the functionality to process
can_msgs/Frame
or
socketcan_msgs/FdFrame
ROS messages and decode configured ones based on provided message definitions. The decoded signal
values are forwarded to the derived class for user-defined processing of them.
The off_highway_can::Receiver
allows to switch between normal and FD CAN frames via the
constructor argument use_fd
.
The processing chain is based completely on message callbacks and thus event-based. The needed
processing time per message can be logged as ROS debug message at runtime with the compile time
optionCOMPILE_DEBUG_LOG
.
Furthermore, the off_highway_can::Receiver
provides a watchdog which checks whether any configured
message was received in the period of time defined by the parameter timeout
and sends a diagnostic
error on the /diagnostics
topic when a timeout occurs.
Subscribed Topics
from_can_bus (
can_msgs/Frame
)CAN frames to decode
Disabled by
use_fd
constructor argument
from_can_bus_fd (
socketcan_msgs/FdFrame
)CAN FD frames to decode
Enabled by
use_fd
constructor argument
Published Topics
/diagnostics (
diagnostic_msgs/DiagnosticArray
)Update Rate: normally 1 Hz, can be forced
Diagnostic error in base class only contains timeout status
Parameters
See receiver_params.yaml.
Sender
The off_highway_can::Sender
is an abstract base class and needs to be derived for specific
behavior. It provides the functionality to send
can_msgs/Frame
or
socketcan_msgs/FdFrame
ROS messages by encoding configured CAN messages as bytes based on provided message definitions. The
encoded signal values are published to the to_can_bus
or to_can_bus_fd
topic.
The off_highway_can::Sender
allows to switch between normal and FD CAN frames via the constructor
argument use_fd
.
The encoding and publishing chain is just a method call and thus event-based. The needed processing
time to encode and publish all configured messages can be logged as ROS debug message at runtime
with the compile time optionCOMPILE_DEBUG_LOG
.
Furthermore, the off_highway_can::Sender
provides a watchdog which checks whether a ROS message
was published in a defined by the parameter timeout
and sends a diagnostic error on the
/diagnostics
topic when a timeout occurs.
Published Topics
to_can_bus (
can_msgs/Frame
)Encoded CAN frames
Disabled by
use_fd
constructor argument
to_can_bus_fd (
socketcan_msgs/FdFrame
)CAN FD frames to decode
Enabled by
use_fd
constructor argument
/diagnostics (
diagnostic_msgs/DiagnosticArray
)Update Rate: normally 1 Hz, can be forced
Diagnostic status in base class only contains timeout status
Parameters
See sender_params.yaml.
Free and Open Source Software (FOSS)
This library uses the libcan-encode-decode library for encoding and decoding raw bytes into / from floating values. See the FOSS documentation for further information.