// Copyright 2026 Simon Sagmeister #include "ocd_aerodynamics_models_cpp/default.hpp" #include #include #include #include #include "tum_helpers_cpp/numerical.hpp" namespace tam::ocd::aerodynamics { types::AeroModelOutput DefaultAerodynamicsModel::evaluate(types::AeroModelInput const & u) { // vx, vy - long/lat velocity in m/s, theta - pitch angle in rad auto sign = [](double x) { if (x < 0) { return -1; } else { return 1; } }; types::AeroModelOutput out; // Lift cofficient multiplier interpolation double delta_c_l = tam::helpers::numerical::interp( u.vx_mps, p_.c_l_velocity_scaling__vel_mps, p_.c_l_velocity_scaling__delta_c_l); // Aero center translation interpolation double aero_center_translation_m = tam::helpers::numerical::interp( u.pitch_angle_rad, p_.pitch_aero_center_translation__pitch_rad, p_.pitch_aero_center_translation__aero_center_translation_m); out.force_cog_N.x = -0.5 * p_.c_d * p_.air_density_kgpm3 * p_.A_m2 * std::pow(u.vx_mps, 2) * sign(u.vx_mps); // To be precise the area of calculating the drag here is different for lateral movement // but this is neglected here out.force_cog_N.y = -0.5 * p_.c_d * p_.air_density_kgpm3 * p_.A_m2 * std::pow(u.vy_mps, 2) * sign(u.vy_mps); out.force_cog_N.z = 0.5 * (p_.c_l + delta_c_l) * p_.air_density_kgpm3 * p_.A_m2 * std::pow(u.vx_mps, 2); // Aero Balance out.torque_Nm.y = -out.force_cog_N.z * (p_.d_aero_center_cog_m + aero_center_translation_m); // Zero for everything else out.torque_Nm.x = 0; out.torque_Nm.z = 0; return out; } void DefaultAerodynamicsModel::declare_parameters( tam::pmg::ParamReferenceManager * param_manager, std::string name_prefix) { param_manager->declare_parameter( name_prefix + "air_density_kgpm3", &(p_.air_density_kgpm3), 1.225, tam::pmg::ParameterType::DOUBLE, ""); // Base parameters param_manager->declare_parameter( name_prefix + "A_m2", &(p_.A_m2), 1.0, tam::pmg::ParameterType::DOUBLE, ""); param_manager->declare_parameter( name_prefix + "c_d", &(p_.c_d), 1.0, tam::pmg::ParameterType::DOUBLE, ""); param_manager->declare_parameter( name_prefix + "c_l", &(p_.c_l), -1.5, tam::pmg::ParameterType::DOUBLE, ""); param_manager->declare_parameter( name_prefix + "d_aero_center_cog_m", &(p_.d_aero_center_cog_m), 0.0, tam::pmg::ParameterType::DOUBLE, ""); // Velocity scaling of cl param_manager->declare_parameter( name_prefix + "c_l_velocity_scaling.vel_mps", &(p_.c_l_velocity_scaling__vel_mps), std::vector{0, 100}, tam::pmg::ParameterType::DOUBLE_ARRAY, ""); param_manager->declare_parameter( name_prefix + "c_l_velocity_scaling.delta_c_l", &(p_.c_l_velocity_scaling__delta_c_l), std::vector{0, 0}, tam::pmg::ParameterType::DOUBLE_ARRAY, ""); // Pitch correction since pitch moves the center of aero forces param_manager->declare_parameter( name_prefix + "pitch_aero_center_translation.pitch_rad", &(p_.pitch_aero_center_translation__pitch_rad), std::vector{-M_PI, M_PI}, tam::pmg::ParameterType::DOUBLE_ARRAY, ""); param_manager->declare_parameter( name_prefix + "pitch_aero_center_translation.aero_center_translation_m", &(p_.pitch_aero_center_translation__aero_center_translation_m), std::vector{0, 0}, tam::pmg::ParameterType::DOUBLE_ARRAY, ""); } } // namespace tam::ocd::aerodynamics