VehicleAckermann_ControllerFrontSteerPID.cpp

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/*+-------------------------------------------------------------------------+
  |                       MultiVehicle simulator (libmvsim)                 |
  |                                                                         |
  | Copyright (C) 2014-2023  Jose Luis Blanco Claraco                       |
  | Copyright (C) 2017  Borys Tymchenko (Odessa Polytechnic University)     |
  | Distributed under 3-clause BSD License                                  |
  |   See COPYING                                                           |
  +-------------------------------------------------------------------------+ */

#include <mvsim/VehicleDynamics/VehicleAckermann.h>

#include "xml_utils.h"

using namespace mvsim;
using namespace std;

DynamicsAckermann::ControllerFrontSteerPID::ControllerFrontSteerPID(
        DynamicsAckermann& veh)
        : ControllerBase(veh),
          setpoint_lin_speed(0),
          setpoint_steer_ang(0),
          KP(100),
          KI(0),
          KD(0),
          max_torque(100.0),
          twist_control_(veh)
{
        // Get distance between wheels:
        r2f_L_ = veh_.wheels_info_[WHEEL_FL].x - veh_.wheels_info_[WHEEL_RL].x;
        ASSERT_(r2f_L_ > 0.0);
}

// See base class docs
void DynamicsAckermann::ControllerFrontSteerPID::control_step(
        const DynamicsAckermann::TControllerInput& ci,
        DynamicsAckermann::TControllerOutput& co)
{
        // Equivalent v/w velocities:
        const double v = setpoint_lin_speed;
        double w;
        if (setpoint_steer_ang == 0.0)
        {
                w = 0.0;
        }
        else
        {
                // ang = atan(r2f_L/R)  ->  R= r2f_L / tan(ang)
                // R = v/w              ->   w=v/R
                const double R = r2f_L_ / tan(setpoint_steer_ang);
                w = v / R;
        }

        // Let the twist controller do the calculations:
        twist_control_.setpoint_lin_speed = v;
        twist_control_.setpoint_ang_speed = w;

        twist_control_.KP = KP;
        twist_control_.KI = KI;
        twist_control_.KD = KD;
        twist_control_.max_torque = max_torque;

        twist_control_.control_step(ci, co);
        co.steer_ang = setpoint_steer_ang;      // Mainly for the case of v=0
}

void DynamicsAckermann::ControllerFrontSteerPID::load_config(
        const rapidxml::xml_node<char>& node)
{
        TParameterDefinitions params;
        params["KP"] = TParamEntry("%lf", &KP);
        params["KI"] = TParamEntry("%lf", &KI);
        params["KD"] = TParamEntry("%lf", &KD);
        params["max_torque"] = TParamEntry("%lf", &max_torque);

        // Initial speed.
        params["V"] = TParamEntry("%lf", &this->setpoint_lin_speed);
        params["STEER_ANG"] = TParamEntry("%lf_deg", &this->setpoint_steer_ang);

        parse_xmlnode_children_as_param(node, params);
}

void DynamicsAckermann::ControllerFrontSteerPID::teleop_interface(
        const TeleopInput& in, TeleopOutput& out)
{
        ControllerBase::teleop_interface(in, out);

        switch (in.keycode)
        {
                case 'W':
                case 'w':
                        setpoint_lin_speed += 0.1;
                        break;

                case 'S':
                case 's':
                        setpoint_lin_speed -= 0.1;
                        break;

                case 'A':
                case 'a':
                        setpoint_steer_ang += 1.0 * M_PI / 180.0;
                        mrpt::keep_min(setpoint_steer_ang, veh_.getMaxSteeringAngle());
                        break;

                case 'D':
                case 'd':
                        setpoint_steer_ang -= 1.0 * M_PI / 180.0;
                        mrpt::keep_max(setpoint_steer_ang, -veh_.getMaxSteeringAngle());
                        break;
                case ' ':
                        setpoint_lin_speed = .0;
                        break;
        };
        out.append_gui_lines += "[Controller=" + string(class_name()) +
                                                        "] Teleop keys:\n"
                                                        "w/s=incr/decr lin speed.\n"
                                                        "a/d=left/right steering.\n"
                                                        "spacebar=stop.\n";
        out.append_gui_lines += mrpt::format(
                "setpoint: v=%.03f steer=%.03f deg\n", setpoint_lin_speed,
                setpoint_steer_ang * 180.0 / M_PI);
}