rcognita.systems.Sys3WRobot

class rcognita.systems.Sys3WRobot(*args, **kwargs)

System class: 3-wheel robot with dynamical actuators.

Three-wheel robot with dynamical pushing force and steering torque (a.k.a. ENDI - extended non-holonomic double integrator) [1]

\[\begin{array}{ll} \dot x_с & = v \cos \angle \newline \dot y_с & = v \sin \angle \newline \dot \angle & = \omega \newline \dot v & = \left( \frac 1 m F + q_1 \right) \newline \dot \omega & = \left( \frac 1 I M + q_2 \right) \end{array}\]

Variables

\(x_с\) : state-coordinate [m]

\(y_с\) : observation-coordinate [m]

\(\angle\) : turning angle [rad]

\(v\) : speed [m/s]

\(\omega\) : revolution speed [rad/s]

\(F\) : pushing force [N]

\(M\) : steering torque [Nm]

\(m\) : robot mass [kg]

\(I\) : robot moment of inertia around vertical axis [kg m²]

\(disturb\) : actuator disturbance (see disturbDyn()). Is zero if is_disturb = 0

\(state = [x_c, y_c, \angle, v, \omega]\)

\(action = [F, M]\)

pars = \([m, I]\)

References

1

W. Abbasi, F. urRehman, and I. Shah. “Backstepping based nonlinear adaptive control for the extended nonholonomic double integrator”. In: Kybernetika 53.4 (2017), pp. 578–594

__init__(*args, **kwargs)

Parameters

• sys_type (: string) –

  Type of system by description:

  diff_eqn : differential equation \(\mathcal D state = f(state, action, disturb)\)

  discr_fnc : difference equation \(state^+ = f(state, action, disturb)\)

  discr_prob : by probability distribution \(X^+ \sim P_X(state^+| state, action, disturb)\)

• where –

  \(state\) : state

  \(action\) : input

  \(disturb\) : disturbance

• time variable time is commonly used by ODE solvers (The) –

• you shouldn't have it explicitly referenced in the definition (and) –

• your system is non-autonomous. (unless) –

• the latter case (For) –

• however –

• already have the input and disturbance at your disposal. (you) –

• of the system are contained in pars attribute. (Parameters) –

• dim_state (: integer) – System dimensions

• dim_input (: integer) – System dimensions

• dim_output (: integer) – System dimensions

• dim_disturb (: integer) – System dimensions

• pars (: list) – List of fixed parameters of the system

• action_bounds (: array of shape [dim_input, 2]) – Box control constraints. First element in each row is the lower bound, the second - the upper bound. If empty, control is unconstrained (default)

• is_dynamic_controller (: 0 or 1) – If 1, the controller (a.k.a. agent) is considered as a part of the full state vector

• is_disturb (: 0 or 1) – If 0, no disturbance is fed into the system

• pars_disturb (: list) – Parameters of the disturbance model

Methods

__init__(*args, **kwargs)	param sys_type Type of system by description:
compute_closed_loop_rhs(time, state_full)	Right-hand side of the closed-loop system description.
compute_dynamics(time, state, action[, disturb])	Description of the system internal dynamics.
out(state[, time, action])	System output.
receive_action(action)	Receive exogeneous control action to be fed into the system.
reset()