mirror of https://github.com/ArduPilot/ardupilot
AP_Follow: library to track and follow another vehicle
This commit is contained in:
Randy Mackay
parent
be804aa74e
commit
c1dbd67a9b
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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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#include <AP_HAL/AP_HAL.h>
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#include <GCS_MAVLink/GCS.h>
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#include "AP_Follow.h"
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#include <ctype.h>
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#include <stdio.h>
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extern const AP_HAL::HAL& hal;
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#define AP_FOLLOW_TIMEOUT_MS 3000 // position estimate timeout after 1 second
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#define AP_FOLLOW_SYSID_TIMEOUT_MS 10000 // forget sysid we are following if we haave not heard from them in 10 seconds
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#define AP_GCS_INTERVAL_MS 1000 // interval between updating GCS on position of vehicle
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#define AP_FOLLOW_OFFSET_TYPE_NED 0 // offsets are in north-east-down frame
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#define AP_FOLLOW_OFFSET_TYPE_RELATIVE 0 // offsets are relative to lead vehicle's heading
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#define AP_FOLLOW_POS_P_DEFAULT 0.1f // position error gain default
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// table of user settable parameters
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const AP_Param::GroupInfo AP_Follow::var_info[] = {
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// @Param: _ENABLE
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// @DisplayName: Follow enable/disable
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// @Description: Enabled/disable following a target
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// @Values: 0:Disabled,1:Enabled
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// @User: Standard
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AP_GROUPINFO_FLAGS("_ENABLE", 1, AP_Follow, _enabled, 0, AP_PARAM_FLAG_ENABLE),
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// 2 is reserved for TYPE parameter
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// @Param: _SYSID
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// @DisplayName: Follow target's mavlink system id
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// @Description: Follow target's mavlink system id
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// @Range: 0 255
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// @User: Standard
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AP_GROUPINFO("_SYSID", 3, AP_Follow, _sysid, 0),
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// 4 is reserved for MARGIN parameter
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// @Param: _DIST_MAX
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// @DisplayName: Follow distance maximum
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// @Description: Follow distance maximum. targets further than this will be ignored
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// @Units: m
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// @Range: 1 1000
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// @User: Standard
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AP_GROUPINFO("_DIST_MAX", 5, AP_Follow, _dist_max, 100),
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// @Param: _OFS_TYPE
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// @DisplayName: Follow offset type
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// @Description: Follow offset type
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// @Values: 0:North-East-Down, 1:Relative to lead vehicle heading
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// @User: Standard
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AP_GROUPINFO("_OFS_TYPE", 6, AP_Follow, _offset_type, AP_FOLLOW_OFFSET_TYPE_NED),
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// @Param: _OFS_X
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// @DisplayName: Follow offsets in meters north/forward
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// @Description: Follow offsets in meters north/forward. If positive, this vehicle fly ahead or north of lead vehicle. Depends on FOLL_OFS_TYPE
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// @Range: -100 100
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// @Units: m
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// @Increment: 1
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// @User: Standard
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// @Param: _OFS_Y
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// @DisplayName: Follow offsets in meters east/right
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// @Description: Follow offsets in meters east/right. If positive, this vehicle fly to the right or east of lead vehicle. Depends on FOLL_OFS_TYPE
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// @Range: -100 100
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// @Units: m
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// @Increment: 1
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// @User: Standard
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// @Param: _OFS_Z
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// @DisplayName: Follow offsets in meters down
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// @Description: Follow offsets in meters down. If positive, this vehicle fly below the lead vehicle
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// @Range: -100 100
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// @Units: m
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// @Increment: 1
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// @User: Standard
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AP_GROUPINFO("_OFS", 7, AP_Follow, _offset, 0),
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// @Param: _YAW_BEHAVE
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// @DisplayName: Follow yaw behaviour
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// @Description: Follow yaw behaviour
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// @Values: 0:None,1:Face Lead Vehicle,2:Same as Lead vehicle,3:Direction of Flight
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// @User: Standard
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AP_GROUPINFO("_YAW_BEHAVE", 8, AP_Follow, _yaw_behave, 1),
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// @Param: _POS_P
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// @DisplayName: Follow position error P gain
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// @Description: Follow position error P gain. Converts the difference between desired vertical speed and actual speed into a desired acceleration that is passed to the throttle acceleration controller
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// @Range: 0.01 1.00
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// @Increment: 0.01
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// @User: Standard
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AP_SUBGROUPINFO(_p_pos, "_POS_", 9, AP_Follow, AC_P),
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AP_GROUPEND
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};
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/*
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The constructor also initialises the proximity sensor. Note that this
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constructor is not called until detect() returns true, so we
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already know that we should setup the proximity sensor
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*/
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AP_Follow::AP_Follow(const AP_AHRS &ahrs) :
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_ahrs(ahrs),
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_p_pos(AP_FOLLOW_POS_P_DEFAULT)
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{
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AP_Param::setup_object_defaults(this, var_info);
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_sysid_to_follow = _sysid;
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}
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// get target's estimated location
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bool AP_Follow::get_target_location_and_velocity(Location &loc, Vector3f &vel_ned) const
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{
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// exit immediately if not enabled
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if (!_enabled) {
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return false;
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}
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// check for timeout
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if ((_last_location_update_ms == 0) || (AP_HAL::millis() - _last_location_update_ms > AP_FOLLOW_TIMEOUT_MS)) {
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return false;
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}
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// calculate time since last actual position update
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const float dt = (AP_HAL::millis() - _last_location_update_ms) * 0.001f;
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// get velocity estimate
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if (!get_velocity_ned(vel_ned, dt)) {
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return false;
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}
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// project the vehicle position
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Location last_loc = _target_location;
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location_offset(last_loc, vel_ned.x * dt, vel_ned.y * dt);
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last_loc.alt -= vel_ned.z * 10.0f * dt; // convert m/s to cm/s, multiply by dt. minus because NED
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// return latest position estimate
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loc = last_loc;
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return true;
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}
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// get distance vector to target (in meters) and target's velocity all in NED frame
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bool AP_Follow::get_target_dist_and_vel_ned(Vector3f &dist_ned, Vector3f &dist_with_offs, Vector3f &vel_ned)
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{
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// get our location
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Location current_loc;
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if (!_ahrs.get_position(current_loc)) {
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return false;
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}
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// get target location and velocity
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Location target_loc;
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Vector3f veh_vel;
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if (!get_target_location_and_velocity(target_loc, veh_vel)) {
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return false;
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}
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// calculate difference
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const Vector3f dist_vec = location_3d_diff_NED(current_loc, target_loc);
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// fail if too far
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if (is_positive(_dist_max.get()) && (dist_vec.length() > _dist_max)) {
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return false;
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}
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// initialise offsets from distance vector if required
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init_offsets_if_required(dist_vec);
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// get offsets
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Vector3f offsets;
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if (!get_offsets_ned(offsets)) {
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return false;
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}
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// return results
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dist_ned = dist_vec;
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dist_with_offs = dist_vec + offsets;
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vel_ned = veh_vel;
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return true;
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}
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// get target's heading in degrees (0 = north, 90 = east)
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bool AP_Follow::get_target_heading(float &heading) const
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{
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// exit immediately if not enabled
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if (!_enabled) {
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return false;
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}
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// check for timeout
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if ((_last_heading_update_ms == 0) || (AP_HAL::millis() - _last_heading_update_ms > AP_FOLLOW_TIMEOUT_MS)) {
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return false;
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}
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// return latest heading estimate
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heading = _target_heading;
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return true;
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}
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// handle mavlink DISTANCE_SENSOR messages
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void AP_Follow::handle_msg(const mavlink_message_t &msg)
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{
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// exit immediately if not enabled
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if (!_enabled) {
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return;
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}
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// skip our own messages
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if (msg.sysid == mavlink_system.sysid) {
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return;
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}
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// skip message if not from our target
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if ((_sysid_to_follow != 0) && (msg.sysid != _sysid_to_follow)) {
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if (_sysid == 0) {
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// maybe timeout who we were following...
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if ((_last_location_update_ms == 0) || (AP_HAL::millis() - _last_location_update_ms > AP_FOLLOW_SYSID_TIMEOUT_MS)) {
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_sysid_to_follow = 0;
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}
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}
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return;
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}
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// decode global-position-int message
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if (msg.msgid == MAVLINK_MSG_ID_GLOBAL_POSITION_INT) {
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const uint32_t now = AP_HAL::millis();
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// get estimated location and velocity (for logging)
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Location loc_estimate{};
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Vector3f vel_estimate;
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UNUSED_RESULT(get_target_location_and_velocity(loc_estimate, vel_estimate));
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// decode message
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mavlink_global_position_int_t packet;
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mavlink_msg_global_position_int_decode(&msg, &packet);
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// ignore message if lat and lon are (exactly) zero
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if ((packet.lat == 0 && packet.lon == 0)) {
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return;
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}
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_target_location.lat = packet.lat;
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_target_location.lng = packet.lon;
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_target_location.alt = packet.alt / 10; // convert millimeters to cm
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_target_velocity_ned.x = packet.vx * 0.01f; // velocity north
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_target_velocity_ned.y = packet.vy * 0.01f; // velocity east
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_target_velocity_ned.z = packet.vz * 0.01f; // velocity down
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_last_location_update_ms = now;
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if (packet.hdg <= 36000) { // heading (UINT16_MAX if unknown)
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_target_heading = packet.hdg * 0.01f; // convert centi-degrees to degrees
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_last_heading_update_ms = now;
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}
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// initialise _sysid if zero to sender's id
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if (_sysid_to_follow == 0) {
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_sysid_to_follow = msg.sysid;
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}
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if ((AP_HAL::millis() - _last_location_sent_to_gcs > AP_GCS_INTERVAL_MS)) {
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gcs().send_text(MAV_SEVERITY_INFO, "Foll: %u %ld %ld %4.2f\n",
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(unsigned)_sysid_to_follow,
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(long)_target_location.lat,
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(long)_target_location.lng,
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(double)(_target_location.alt * 0.01f)); // cm to m
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}
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// log lead's estimated vs reported position
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DataFlash_Class::instance()->Log_Write("FOLL",
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"TimeUS,Lat,Lon,Alt,VelX,VelY,VelZ,LatE,LonE,AltE", // labels
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"sDUmnnnDUm", // units
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"F--B000--B", // mults
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"QLLifffLLi", // fmt
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AP_HAL::micros64(),
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_target_location.lat,
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_target_location.lng,
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_target_location.alt,
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(double)_target_velocity_ned.x,
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(double)_target_velocity_ned.y,
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(double)_target_velocity_ned.z,
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loc_estimate.lat,
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loc_estimate.lng,
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loc_estimate.alt
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);
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}
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}
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// get velocity estimate in m/s in NED frame using dt since last update
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bool AP_Follow::get_velocity_ned(Vector3f &vel_ned, float dt) const
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{
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vel_ned = _target_velocity_ned + (_target_accel_ned * dt);
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return true;
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}
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// initialise offsets to provided distance vector (in meters in NED frame) if required
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void AP_Follow::init_offsets_if_required(const Vector3f &dist_vec_ned)
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{
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if (_offset.get().is_zero()) {
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_offset = dist_vec_ned;
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}
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}
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// get offsets in meters in NED frame
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bool AP_Follow::get_offsets_ned(Vector3f &offset) const
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{
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const Vector3f &off = _offset.get();
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// if offsets are zero or type if NED, simply return offset vector
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if (off.is_zero() || (_offset_type == AP_FOLLOW_OFFSET_TYPE_NED)) {
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offset = off;
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return true;
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}
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// offset_type == AP_FOLLOW_OFFSET_TYPE_RELATIVE
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// check if we have a valid heading for target vehicle
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if ((_last_heading_update_ms == 0) || (AP_HAL::millis() - _last_heading_update_ms > AP_FOLLOW_TIMEOUT_MS)) {
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return false;
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}
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// rotate roll, pitch input from north facing to vehicle's perspective
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const float veh_cos_yaw = cosf(radians(_target_heading));
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const float veh_sin_yaw = sinf(radians(_target_heading));
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offset.x = (off.x * veh_cos_yaw) - (off.y * veh_sin_yaw);
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offset.y = (off.y * veh_cos_yaw) + (off.x * veh_sin_yaw);
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offset.z = off.z;
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return true;
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}
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@ -0,0 +1,112 @@
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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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#pragma once
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#include <AP_Common/AP_Common.h>
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#include <AP_HAL/AP_HAL.h>
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#include <AP_Param/AP_Param.h>
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#include <AP_Math/AP_Math.h>
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#include <AP_AHRS/AP_AHRS.h>
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#include <GCS_MAVLink/GCS.h>
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#include <AC_PID/AC_P.h>
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class AP_Follow
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{
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public:
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// enum for YAW_BEHAVE parameter
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enum YawBehave {
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YAW_BEHAVE_NONE = 0,
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YAW_BEHAVE_FACE_LEAD_VEHICLE = 1,
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YAW_BEHAVE_SAME_AS_LEAD_VEHICLE = 2,
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YAW_BEHAVE_DIR_OF_FLIGHT = 3
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};
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// constructor
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AP_Follow(const AP_AHRS &ahrs);
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// set which target to follow
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void set_target_sysid(uint8_t sysid) { _sysid = sysid; }
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//
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// position tracking related methods
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//
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// true if we have a valid target location estimate
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bool have_target() const;
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// get target's estimated location and velocity (in NED)
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bool get_target_location_and_velocity(Location &loc, Vector3f &vel_ned) const;
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// get distance vector to target (in meters), target plus offsets, and target's velocity all in NED frame
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bool get_target_dist_and_vel_ned(Vector3f &dist_ned, Vector3f &dist_with_ofs, Vector3f &vel_ned);
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// get position controller. this controller is not used within this library but it is convenient to hold it here
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const AC_P& get_pos_p() const { return _p_pos; }
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//
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// yaw/heading related methods
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//
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// get user defined yaw behaviour
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YawBehave get_yaw_behave() const { return (YawBehave)_yaw_behave.get(); }
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// get target's heading in degrees (0 = north, 90 = east)
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bool get_target_heading(float &heading) const;
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// parse mavlink messages which may hold target's position, velocity and attitude
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void handle_msg(const mavlink_message_t &msg);
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// parameter list
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static const struct AP_Param::GroupInfo var_info[];
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// returns true if library is enabled
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bool enabled() const { return _enabled; }
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private:
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// get velocity estimate in m/s in NED frame using dt since last update
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bool get_velocity_ned(Vector3f &vel_ned, float dt) const;
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// initialise offsets to provided distance vector (in meters in NED frame) if required
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void init_offsets_if_required(const Vector3f &dist_vec_ned);
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// get offsets in meters in NED frame
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bool get_offsets_ned(Vector3f &offsets) const;
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// references
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const AP_AHRS &_ahrs;
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// parameters
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AP_Int8 _enabled; // 1 if this subsystem is enabled
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AP_Int16 _sysid; // target's mavlink system id (0 to use first sysid seen)
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AP_Float _dist_max; // maximum distance to target. targets further than this will be ignored
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AP_Int8 _offset_type; // offset frame type (0:North-East-Down, 1:RelativeToLeadVehicleHeading)
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AP_Vector3f _offset; // offset from lead vehicle in meters
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AP_Int8 _yaw_behave; // following vehicle's yaw/heading behaviour
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AC_P _p_pos; // position error P controller
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// local variables
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bool _healthy; // true if we are receiving mavlink messages (regardless of whether they have target position info within them)
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uint8_t _sysid_to_follow = 0; // mavlink system id of vehicle to follow
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uint32_t _last_location_update_ms; // system time of last position update
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Location _target_location; // last known location of target
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Vector3f _target_velocity_ned; // last known velocity of target in NED frame in m/s
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Vector3f _target_accel_ned; // last known acceleration of target in NED frame in m/s/s
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uint32_t _last_heading_update_ms; // system time of last heading update
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float _target_heading; // heading in degrees
|
||||
uint32_t _last_location_sent_to_gcs; // last time GCS was told position
|
||||
};
|
||||
Loading…
Reference in New Issue