This repository contains a minimal example to implement advanced controller in control toolbox with ROS. Most of material is derived from the official tutorial expect that the main objective begin showing the basics in design a controller for ROS integration close to real application.
Control toolbox need to be installed and sourced first.
Optional: rqt_multiplot
The problem used in this example is a simple second order system dynamics control. A physical example of the such system can be a damped oscillator shown in below.
Dynamics of the system follows the following ODE and velocity and position of the frictionless car are the state of the system.
where y is the position, y dot is the velocity of the car.
The state space model of the system is
with the parameter of k_{dc} = 1, omega_n = 0.1 and zeta = 0.5. The control problem is to track the set point x_ref with optimal control u.
oscillator_dynamics.cpp shows how to create a simulator in ROS environment for the control problem, allows the user to control the system via joystick. Run the example with:
roslaunch ct_example oscillator_dynamic_manual.launch
You can use any rosjoy compatiable joystick controller to manuipulate the system. To view current state of the system try rostopic echo /position in command line or rqt for visulisation. Two configuration files multiplot.xml and view.perspective are provided under rqt_settings folder.
oscillator_lqr_controller.cpp demonstrates the design of LQR controller. The optimal control problem is to find the control input u to minimise the total cost.
roslaunch ct_example oscillator_lqr_control.launch
You can play around by publishing different reference position in rqt. Note that the x in the message represents the postion while y in the message represents the velocity of the car.
oscillator_ilqr_controller.cpp illustrates the implementation of ILQR controller.
roslaunch ct_example oscillator_ilqr_control.launch
Similarly, you can change the reference point in the rqt GUI.
The final example oscillator_mpc_controller.cpp is the Model Predictive Controller for the damped oscillator system.
roslaunch ct_example oscillator_mpc_control.launch