// Copyright 2026 Simon Sagmeister #include "ocd_aerodynamics_models_cpp/ride_height.hpp" #include #include #include #include #include "tum_helpers_cpp/numerical.hpp" namespace tam::ocd::aerodynamics { types::AeroModelOutput RideHeightAerodynamicsModel::evaluate(types::AeroModelInput const & u) { auto sign = [](double x) { if (x < 0) { return -1; } else { return 1; } }; types::AeroModelOutput out; double l_r = p_.l - p_.l_f; // Assumption of Aero centre placed on the axles double delta_z_front = u.z_m - p_.l_f * u.pitch_angle_rad; double delta_z_rear = u.z_m + l_r * u.pitch_angle_rad; // current RH = static RH - displacement - cog shift double current_rh_front = -(p_.static_ride_height_front_m - delta_z_front); double current_rh_rear = -(p_.static_ride_height_rear_m - delta_z_rear); // Lift Coefficient as 3rd order surfaces double c_l_front = p_.c0 + p_.c1_F * current_rh_front + p_.c2_F * std::pow(current_rh_front, 2) + p_.c3_F * std::pow(current_rh_front, 3) + p_.c1_R * current_rh_rear + p_.c2_R * std::pow(current_rh_rear, 2) + p_.c3_R * std::pow(current_rh_rear, 3) + p_.c4 * current_rh_front * current_rh_rear + p_.c5 * std::pow(current_rh_front, 2) * current_rh_rear + p_.c6 * current_rh_front * std::pow(current_rh_rear, 2); double c_l_rear = p_.a0 + p_.a1_F * current_rh_front + p_.a2_F * std::pow(current_rh_front, 2) + p_.a3_F * std::pow(current_rh_front, 3) + p_.a1_R * current_rh_rear + p_.a2_R * std::pow(current_rh_rear, 2) + p_.a3_R * std::pow(current_rh_rear, 3) + p_.a4 * current_rh_front * current_rh_rear + p_.a5 * std::pow(current_rh_front, 2) * current_rh_rear + p_.a6 * current_rh_front * std::pow(current_rh_rear, 2); // Clipping the lift values c_l_front = std::clamp(c_l_front, 0.0, 5.0); c_l_rear = std::clamp(c_l_rear, 0.0, 5.0); // Output forces 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); 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); // Minus for Fz since lift coefficient are positive out.force_cog_N.z = -0.5 * (c_l_front + c_l_rear) * p_.air_density_kgpm3 * p_.A_m2 * std::pow(u.vx_mps, 2); // Front and Rear Split double f_l_front = -0.5 * c_l_front * p_.air_density_kgpm3 * p_.A_m2 * std::pow(u.vx_mps, 2); double f_l_rear = -0.5 * c_l_rear * p_.air_density_kgpm3 * p_.A_m2 * std::pow(u.vx_mps, 2); // Output Torques out.torque_Nm.y = (f_l_rear * l_r) - (f_l_front * p_.l_f); out.torque_Nm.x = 0; out.torque_Nm.z = 0; imr_.ride_height_front_m = current_rh_front; imr_.ride_height_rear_m = current_rh_rear; return out; } void RideHeightAerodynamicsModel::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 + "l_f", &(p_.l_f), 1.6, tam::pmg::ParameterType::DOUBLE, ""); param_manager->declare_parameter( name_prefix + "l", &(p_.l), 3.0, tam::pmg::ParameterType::DOUBLE, ""); // Ride Heights param_manager->declare_parameter( name_prefix + "static_ride_height_front_m", &(p_.static_ride_height_front_m), 0.0, tam::pmg::ParameterType::DOUBLE, ""); param_manager->declare_parameter( name_prefix + "static_ride_height_rear_m", &(p_.static_ride_height_rear_m), 0.0, tam::pmg::ParameterType::DOUBLE, ""); // Surface Coefficients param_manager->declare_parameter( name_prefix + "c0", &(p_.c0), 0.0, tam::pmg::ParameterType::DOUBLE, ""); param_manager->declare_parameter( name_prefix + "c1_F", &(p_.c1_F), 0.0, tam::pmg::ParameterType::DOUBLE, ""); param_manager->declare_parameter( name_prefix + "c2_F", &(p_.c2_F), 0.0, tam::pmg::ParameterType::DOUBLE, ""); param_manager->declare_parameter( name_prefix + "c3_F", &(p_.c3_F), 0.0, tam::pmg::ParameterType::DOUBLE, ""); param_manager->declare_parameter( name_prefix + "c1_R", &(p_.c1_R), 0.0, tam::pmg::ParameterType::DOUBLE, ""); param_manager->declare_parameter( name_prefix + "c2_R", &(p_.c2_R), 0.0, tam::pmg::ParameterType::DOUBLE, ""); param_manager->declare_parameter( name_prefix + "c3_R", &(p_.c3_R), 0.0, tam::pmg::ParameterType::DOUBLE, ""); param_manager->declare_parameter( name_prefix + "c4", &(p_.c4), 0.0, tam::pmg::ParameterType::DOUBLE, ""); param_manager->declare_parameter( name_prefix + "c5", &(p_.c5), 0.0, tam::pmg::ParameterType::DOUBLE, ""); param_manager->declare_parameter( name_prefix + "c6", &(p_.c6), 0.0, tam::pmg::ParameterType::DOUBLE, ""); param_manager->declare_parameter( name_prefix + "a0", &(p_.a0), 0.0, tam::pmg::ParameterType::DOUBLE, ""); param_manager->declare_parameter( name_prefix + "a1_F", &(p_.a1_F), 0.0, tam::pmg::ParameterType::DOUBLE, ""); param_manager->declare_parameter( name_prefix + "a2_F", &(p_.a2_F), 0.0, tam::pmg::ParameterType::DOUBLE, ""); param_manager->declare_parameter( name_prefix + "a3_F", &(p_.a3_F), 0.0, tam::pmg::ParameterType::DOUBLE, ""); param_manager->declare_parameter( name_prefix + "a1_R", &(p_.a1_R), 0.0, tam::pmg::ParameterType::DOUBLE, ""); param_manager->declare_parameter( name_prefix + "a2_R", &(p_.a2_R), 0.0, tam::pmg::ParameterType::DOUBLE, ""); param_manager->declare_parameter( name_prefix + "a3_R", &(p_.a3_R), 0.0, tam::pmg::ParameterType::DOUBLE, ""); param_manager->declare_parameter( name_prefix + "a4", &(p_.a4), 0.0, tam::pmg::ParameterType::DOUBLE, ""); param_manager->declare_parameter( name_prefix + "a5", &(p_.a5), 0.0, tam::pmg::ParameterType::DOUBLE, ""); param_manager->declare_parameter( name_prefix + "a6", &(p_.a6), 0.0, tam::pmg::ParameterType::DOUBLE, ""); } } // namespace tam::ocd::aerodynamics