mirror of https://github.com/ArduPilot/ardupilot
84 lines
3.1 KiB
C++
84 lines
3.1 KiB
C++
/// -*- tab-width: 4; Mode: C++; c-basic-offset: 4; indent-tabs-mode: nil -*-
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/*
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This program is free software: you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation, either version 3 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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/*
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simple electric motor simulator class
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*/
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#include "SIM_Motor.h"
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#include <AP_Motors/AP_Motors.h>
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using namespace SITL;
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// calculate rotational accel and thrust for a motor
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void Motor::calculate_forces(const Aircraft::sitl_input &input,
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const float thrust_scale,
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uint8_t motor_offset,
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Vector3f &rot_accel,
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Vector3f &thrust) const
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{
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// fudge factors
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const float arm_scale = radians(5000);
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const float yaw_scale = radians(400);
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// get motor speed from 0 to 1
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float motor_speed = constrain_float((input.servos[motor_offset+servo]-1100)/900.0, 0, 1);
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// the yaw torque of the motor
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Vector3f rotor_torque(0, 0, yaw_factor * motor_speed * yaw_scale);
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// get thrust for untilted motor
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thrust(0, 0, -motor_speed);
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// define the arm position relative to center of mass
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Vector3f arm(arm_scale * cosf(radians(angle)), arm_scale * sinf(radians(angle)), 0);
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// work out roll and pitch of motor relative to it pointing straight up
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float roll = 0, pitch = 0;
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// possibly roll and/or pitch the motor
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if (roll_servo >= 0) {
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uint16_t servoval = input.servos[roll_servo+motor_offset];
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if (roll_min < roll_max) {
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roll = constrain_float(roll_min + (servoval-1000)*0.001*(roll_max-roll_min), roll_min, roll_max);
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} else {
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roll = constrain_float(roll_max + (2000-servoval)*0.001*(roll_min-roll_max), roll_max, roll_min);
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}
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}
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if (pitch_servo >= 0) {
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uint16_t servoval = input.servos[pitch_servo+motor_offset];
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if (pitch_min < pitch_max) {
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pitch = constrain_float(pitch_min + (servoval-1000)*0.001*(pitch_max-pitch_min), pitch_min, pitch_max);
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} else {
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pitch = constrain_float(pitch_max + (2000-servoval)*0.001*(pitch_min-pitch_max), pitch_max, pitch_min);
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}
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}
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// possibly rotate the thrust vector and the rotor torque
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if (!is_zero(roll) || !is_zero(pitch)) {
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Matrix3f rotation;
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rotation.from_euler(radians(roll), radians(pitch), 0);
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thrust = rotation * thrust;
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rotor_torque = rotation * rotor_torque;
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}
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// calculate total rotational acceleration
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rot_accel = (arm % thrust) + rotor_torque;
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// scale the thrust
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thrust = thrust * thrust_scale;
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}
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