Class KinematicVessel

Inheritance Relationships

Base Type

  • public IAlgorithm

Class Documentation

class mimir::algorithm::KinematicVessel : public IAlgorithm

Kinematic planar vessel numerical simulation model.

This class implements a kinematic planar vessel that are controlled by inputs, which are velocities and rate of turn.

\begin{align} \boldsymbol{p} = \begin{bmatrix}N\\E\end{bmatrix} &\in \mathbb{R}^2 &\text{position}\\ \boldsymbol{\psi} \in \mathbb{S} &&\text{heading}\\ \boldsymbol{v} = \begin{bmatrix}u\\v\end{bmatrix} &\in \mathbb{R}^2 &\text{linear velocity}\\ \boldsymbol{r} \in \mathbb{R} &&\text{angular velocity}\\ x(t) = \begin{bmatrix}\boldsymbol{p}\\\psi\end{bmatrix}, &\quad\mathbb{R} \to \mathbb{R}^2 \times \mathbb{S}&\text{state vector} \end{align}
\begin{align} \dat x &= \begin{bmatrix}\cos(\psi)& -\sin(\psi) &0\\ \sin(\psi)& \cos(\psi) & 0\\ 0&0&1 \end{bmatrix} \begin{bmatrix}u\\v\\r\end{bmatrix}\\ \boldsymbol{u} &= \begin{bmatrix}u\\v\\r\end{bmatrix}\\ \boldsymbol{y} &= x \end{align}

Name

Symbol

Description

Causality

Variability

Default

Unit

vessel_ctrl

\(u\)

Desired: Surge, Sway rate of turn

input

discrete

[m/s, m/s, rad/s]

kinematics

\(y\)

fkin::Kinematics2D

output

continuous

position_course

\([p_0,\psi_0]\)

Initial; North, East, Yaw

parameter

fixed

\([0, 50, 0]\)

m

Warning

This simulation model is very basic and has been abandoned in favor of a higher fidelity model implemented using FMI [33].

Public Functions

explicit KinematicVessel(const YAML::Node &config, boost::statechart::fifo_scheduler<> &scheduler, boost::statechart::fifo_scheduler<>::processor_handle machine, dds::pub::Publisher publisher, dds::sub::Subscriber subscriber)

KinematicVessel constructor.

The constructor parses the specification from the given YAML node. It establishes data structures and sets up DDS readers and writers according to the input/output scheme of the algorithm. The following YAML code block shows the expected layout of the KinematicVessel map of a input config file. The inputs, outputs, and initial conditions are communicated with DDS communication. Common is their DDS topic and DDS identifier. The specification is deemed self-explanatory.

time_step_ms: 200
inputs:
  vessel_ctrl:                 # DDS type: fkin::IdVec3d
    topic: fkinVesselCtrl
    id: Vessel
    max_age_ms: -1
outputs:                       # DDS type: fkin::Kinematics2D
  kinematics:
    topic: fkinKinematics2D
    id: Vessel
initial_conditions:
  position_course:             # DDS type: fkin::IdVec3d
    topic: fkinPositionCourse
    id: Vessel
    max_wait_ms: 50
    fallback: [0, 50, 0]

Parameters

  • config – [in] YAML configuration from input file.

  • scheduler – [in] State machine scheduler, needed to post events to state machine.

  • machine – [in] State machine processor handle, needed to post events to state machine.

  • publisher – DDS data writer to send data.

  • subscriber – DDS data reader to receive data.

virtual ~KinematicVessel()

Destructor.

virtual void solve(const std::atomic<bool> &cancel_token)

See base class.

virtual void initialize(const std::atomic<bool> &cancel_token)

See base class.

virtual void timer(const std::atomic<bool> &cancel_token)

See base class.

inline virtual const char *name()

Name identifier of algorithm.

void event(boost::statechart::event_base *const event)

Helper function that queues event to state machine.

Private Functions

inline void step_time()

March simulation time one time step ahead.

KinematicVessel() = delete

Private Members

std::unique_ptr<Impl> m_impl

Holds the implementation of the algorithm.

boost::statechart::fifo_scheduler &m_scheduler

Members for state machine.

boost::statechart::fifo_scheduler::processor_handle m_stateMachine

Member for state machine.

const std::chrono::milliseconds m_time_step

Discrete time step.

std::chrono::steady_clock::time_point m_next_step

Simulation time point.

const YAML::Node m_config

YAML configuration for algorithm.