RAMSETE Controller

The RamseteController class is used to create a RAMSETE non-linear, time-varying unicycle controller, that is used for trajectory following.

Creating a RAMSETE Controller

The constructor for RamseteController requires the following two constants:

• b

  This constant should be greater than zero. b acts similar to the proportional term of a PID controller, so a larger value of b will make convergence more aggressive.

• zeta

  This constant should be between zero and one. zeta acts as a dampening constant, so larger values of zeta will provide more dampening.

A value for b and zeta that tends to work pretty well for most drives is \(b=2.0\) and \(\zeta=0.7\).

Using the RAMSETE controller

The RAMSETE controller can be used by calling the computeControl, getV, and getOmega methods:

//create a new RAMSETE controller
LouLib::Controllers::PIDController controller(2.0, 0.7);

//create a new odometry tracker (can be any type of odom tracker)
LouLib::Odometry::TwoSensorOdom odom(...);

//create a new trajectory
LouLib::Paths::Trajectory trajectory(...);

//create RAMSETE loop
for(int i = 0; i < trajectory.size(); i++){

        //compute new control
        controller.computeControl(trajectory, i, odom.getPose());

        //get computed control
        LouLib::Units::Velocity targV = controller.getV();
        LouLib::Units::AngularVelocity targOmega = controller.getOmega();

        //feed computed control into velocity controllers, the following two methods work:
        //Create a state-space model and use an LQR to compute optimal motor voltages
        //Convert targV and targOmega into target wheel velocities, and feed into motors
        ...

        //wait 10 milliseconds
        pros::delay(10);

}