Vehicleackermann_Drivetrain_ControllerTwistFrontSteerPID.cpp

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/*+-------------------------------------------------------------------------+
  |                       MultiVehicle simulator (libmvsim)                 |
  |                                                                         |
  | Copyright (C) 2014-2020  Jose Luis Blanco Claraco                       |
  | Copyright (C) 2017  Borys Tymchenko (Odessa Polytechnic University)     |
  | Distributed under 3-clause BSD License                                  |
  |   See COPYING                                                           |
  +-------------------------------------------------------------------------+ */

#include <mvsim/VehicleDynamics/VehicleAckermann_Drivetrain.h>
#include "xml_utils.h"

using namespace mvsim;
using namespace std;

DynamicsAckermannDrivetrain::ControllerTwistFrontSteerPID::
	ControllerTwistFrontSteerPID(DynamicsAckermannDrivetrain& veh)
        : ControllerBase(veh),
          setpoint_lin_speed(0),
          setpoint_ang_speed(0),
          KP(100),
          KI(0),
          KD(0),
          max_torque(400.0)
{
        // Get distance between wheels:
        m_dist_fWheels =
                m_veh.m_wheels_info[WHEEL_FL].y - m_veh.m_wheels_info[WHEEL_FR].y;
        m_r2f_L = m_veh.m_wheels_info[WHEEL_FL].x - m_veh.m_wheels_info[WHEEL_RL].x;

        ASSERT_(m_dist_fWheels > 0.0);
        ASSERT_(m_r2f_L > 0.0);
}

void DynamicsAckermannDrivetrain::ControllerTwistFrontSteerPID::control_step(
        const DynamicsAckermannDrivetrain::TControllerInput& ci,
        DynamicsAckermannDrivetrain::TControllerOutput& co)
{
        // 1st: desired steering angle:
        // --------------------------------
        if (setpoint_ang_speed == 0)
        {
                co.steer_ang = 0.0;
        }
        else
        {
                const double R = setpoint_lin_speed / setpoint_ang_speed;
                co.steer_ang = atan(m_r2f_L / R);
        }

        m_PID.KP = KP;
        m_PID.KI = KI;
        m_PID.KD = KD;
        m_PID.max_out = max_torque;

        const double vel_act = m_veh.getVelocityLocalOdoEstimate().vx;
        const double vel_des = setpoint_lin_speed;

        // "-" because \tau<0 makes robot moves forwards.
        co.drive_torque = -m_PID.compute(vel_des - vel_act, ci.context.dt);
}

void DynamicsAckermannDrivetrain::ControllerTwistFrontSteerPID::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["W"] = TParamEntry("%lf_deg", &this->setpoint_ang_speed);

        parse_xmlnode_children_as_param(node, params);
}

void DynamicsAckermannDrivetrain::ControllerTwistFrontSteerPID::
	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_ang_speed += 1.0 * M_PI / 180.0;
                        break;

                case 'D':
                case 'd':
                        setpoint_ang_speed -= 1.0 * M_PI / 180.0;
                        break;

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