mirror of https://github.com/ArduPilot/ardupilot
235 lines
11 KiB
Lua
235 lines
11 KiB
Lua
-- Copter descends very rapidly in a spiral pattern to a preset altitude above home
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--
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-- CAUTION: This script only works for Copter 4.2 (and higher)
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-- this script waits for the vehicle to be changed to Guided mode and then:
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-- a) flies a spiral pattern using the velocity and acceleration control
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-- b) slows the spiral and stops at the preset altitude
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-- c) switches to RTL
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-- constants
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local copter_guided_mode_num = 4 -- Guided mode is 4 on copter
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local copter_rtl_mode_num = 6 -- RTL is 6 on copter
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local circle_radius_rate_max_ms = 1 -- radius expands at max of this many m/s
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local circle_radius_accel_mss = 1 -- radius expansion speed accelerates at this many m/s/s
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local accel_xy = 1 -- horizontal acceleration in m/s^2
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local accel_z = 1 -- target vertical acceleration is 1m/s/s
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local speed_z_slowdown = 0.1 -- target vertical speed during final slowdown
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-- timing and state machine variables
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local stage = 0 -- stage of descent
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local last_update_ms -- system time of last update
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local dt = 0.01 -- update rate of script (0.01 = 100hz)
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local interval_ms = 1 -- update interval in ms
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local last_print_ms = 0 -- pilot update timer
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local auto_last_id = -1 -- unique id used to detect if a new NAV_SCRIPT_TIME command has started
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-- control related variables
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local circle_center_pos = Vector3f()-- center of circle position as an offset from EKF origin
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local circle_radius = 0 -- target circle's current radius (this is slowly expanded to circle_radius_max)
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local circle_radius_rate_ms = 0 -- target circle's radius is increasing at this rate in m/s
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local circle_angle_rad = 0 -- current target angle on circle (in radians)
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local target_alt_D = 0 -- target altitude in m from EKF origin (Note: down is positive)
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local speed_xy = 0 -- target horizontal speed (i.e. tangential velocity or horizontal speed around the circle)
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local speed_z = 0 -- target descent rate currently
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local target_yaw_deg = 0 -- target yaw in degrees (degrees is more convenient based on interface)
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-- create and initialise parameters
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local PARAM_TABLE_KEY = 75 -- parameter table key must be used by only one script on a particular flight controller
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assert(param:add_table(PARAM_TABLE_KEY, "FDST_", 6), 'could not add param table')
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assert(param:add_param(PARAM_TABLE_KEY, 1, 'ACTIVATE', 0), 'could not add FDST_ACTIVATE param') -- 0:active in Guided, 1:active in Auto's NAV_SCRIPT_TIME command
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assert(param:add_param(PARAM_TABLE_KEY, 2, 'ALT_MIN', 50), 'could not add FDST_ALT_MIN param') -- copter will stop at this altitude above home
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assert(param:add_param(PARAM_TABLE_KEY, 3, 'RADIUS', 10), 'could not add FDST_RADIUS parameter') -- target circle's maximum radius
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assert(param:add_param(PARAM_TABLE_KEY, 4, 'SPEED_XY', 5), 'could not add FDST_SPEED_XY param') -- max target horizontal speed
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assert(param:add_param(PARAM_TABLE_KEY, 5, 'SPEED_DN', 10), 'could not add FDST_SPEED_DN param') -- target descent rate
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assert(param:add_param(PARAM_TABLE_KEY, 6, 'YAW_BEHAVE', 0), 'could not add FDST_YAW_BEHAVE param') -- 0:yaw does not change 1:yaw points toward center
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-- bind parameters to variables
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local activate_type = Parameter("FDST_ACTIVATE") -- activate type 0:Guided, 1:Auto's NAV_SCRIPT_TIME
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local alt_above_home_min = Parameter("FDST_ALT_MIN") -- copter will stop at this altitude above home
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local circle_radius_max = Parameter("FDST_RADIUS") -- target circle's maximum radius
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local speed_xy_max = Parameter("FDST_SPEED_XY") -- max target horizontal speed
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local speed_z_max = Parameter("FDST_SPEED_DN") -- target descent rate
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local yaw_behave = Parameter("FDST_YAW_BEHAVE") -- 0:yaw is static, 1:yaw points towards center of circle
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-- the main update function
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function update()
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-- update dt
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local now_ms = millis()
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if (last_update_ms) then
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dt = (now_ms - last_update_ms):tofloat() / 1000.0
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end
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if (dt > 1) then
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dt = 0
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end
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last_update_ms = now_ms
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-- determine if progress update should be sent to user
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local update_user = false
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if (now_ms - last_print_ms > 5000) then
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last_print_ms = now_ms
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update_user = true
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end
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-- reset stage until activated in Guided or Auto mode
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if (activate_type:get() == 0) then
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-- activate_type 0: reset stage when disarmed or not in Guided mode
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if not arming:is_armed() or (vehicle:get_mode() ~= copter_guided_mode_num) then
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stage = 0
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if (update_user and arming:is_armed()) then
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gcs:send_text(6, "Fast Descent: waiting for Guided")
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end
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return update, interval_ms
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end
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else
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-- activate_type 1: reset stage when disarmed or not in Auto executing NAV_SCRIPT_TIME command
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auto_last_id, cmd, arg1, arg2, arg3, arg4 = vehicle:nav_script_time()
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if not arming:is_armed() or not auto_last_id then
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stage = 0
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if (update_user and arming:is_armed()) then
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gcs:send_text(6, "Fast Descent: waiting for NAV_SCRIPT_TIME")
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end
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return update, interval_ms
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end
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end
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if (stage == 0) then -- Stage0: initialise
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local home = ahrs:get_home()
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local curr_loc = ahrs:get_location()
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if home and curr_loc then
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circle_center_pos = ahrs:get_relative_position_NED_origin()
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circle_radius_rate_ms = 0 -- reset circle radius expandion rate to zero
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circle_radius = 0 -- reset circle radius to zero
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if yaw_behave:get() == 0 then
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-- yaw does not move so reset starting angle to current heading
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circle_angle_rad = ahrs:get_yaw()
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else
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-- yaw points towards center so start 180deg behind vehicle
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circle_angle_rad = ahrs:get_yaw() + math.pi
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if (circle_angle_rad >= (math.pi * 2)) then
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circle_angle_rad = circle_angle_rad - (math.pi * 2)
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end
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end
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target_yaw_deg = math.deg(ahrs:get_yaw()) -- target heading will be kept at original heading
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target_alt_D = circle_center_pos:z() -- initialise target alt using current position (Note: down is positive)
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speed_xy = 0
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speed_z = 0
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stage = stage + 1 -- advance to next stage
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gcs:send_text(5, "Fast Descent: starting")
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end
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elseif (stage == 1) then -- Stage1: descend
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-- get current position
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local rel_pos_home_NED = ahrs:get_relative_position_NED_home()
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-- increase circle radius
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circle_radius_rate_ms = math.min(circle_radius_rate_ms + (circle_radius_accel_mss * dt), circle_radius_rate_max_ms) -- accelerate radius expansion
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circle_radius = math.min(circle_radius + (circle_radius_rate_ms * dt), circle_radius_max:get()) -- increase radius
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-- calculate horizontal and vertical speed
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if (circle_radius < circle_radius_max:get()) then
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speed_xy = math.max(speed_xy - (accel_xy * dt), 0) -- decelerate horizontal speed to zero
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speed_z = math.max(speed_z - (accel_z * dt), 0) -- decelerate vertical speed to zero
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else
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-- calculate conversion between alt-above-home and alt-above-ekf-origin
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local home_alt_above_origin = 0
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local home = ahrs:get_home()
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local ekf_origin = ahrs:get_origin()
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if home and ekf_origin then
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local dist_NED = home:get_distance_NED(ekf_origin)
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home_alt_above_origin = dist_NED:z()
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end
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-- calculate target speeds
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local target_dist_to_alt_min = -target_alt_D - home_alt_above_origin - alt_above_home_min:get() -- alt target's distance to alt_min
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if (target_dist_to_alt_min > 0) then
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local speed_z_limit = speed_z_max:get()
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speed_z_limit = math.min(speed_z_limit, math.sqrt(2.0 * target_dist_to_alt_min * accel_z)) -- limit speed so vehicle can stop at ALT_MIN
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speed_z_limit = math.max(speed_z_limit, speed_z_slowdown) -- vertical speed should never be less than 0.1 m/s when above ALT_MIN
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speed_z = math.min(speed_z + (accel_z * dt), speed_z_limit)
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speed_xy = math.min(speed_xy + (accel_xy * dt), speed_xy_max:get()) -- accelerate horizontal speed to maximum
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else
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-- below alt min so decelerate target speeds to zero
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speed_xy = math.max(speed_xy - (accel_xy * dt), 0) -- decelerate horizontal speed to zero
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speed_z = math.max(speed_z - (accel_z * dt), 0) -- decelerate vertical speed to zero
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end
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end
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-- calculate angular velocity
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local ang_vel_rads = 0
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if (circle_radius >= circle_radius_max:get()) then
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ang_vel_rads = speed_xy / circle_radius;
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end
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-- increment angular position
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circle_angle_rad = circle_angle_rad + (ang_vel_rads * dt)
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if (circle_angle_rad >= (math.pi * 2)) then
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circle_angle_rad = circle_angle_rad - (math.pi * 2)
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end
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-- calculate target position
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local cos_ang = math.cos(circle_angle_rad)
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local sin_ang = math.sin(circle_angle_rad)
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local target_pos = Vector3f()
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target_pos:x(circle_center_pos:x() + (circle_radius * cos_ang))
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target_pos:y(circle_center_pos:y() + (circle_radius * sin_ang))
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target_alt_D = target_alt_D + (speed_z * dt)
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target_pos:z(target_alt_D)
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-- calculate target velocity
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target_vel = Vector3f()
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target_vel:x(speed_xy * -sin_ang)
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target_vel:y(speed_xy * cos_ang)
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target_vel:z(speed_z)
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-- calculate target acceleration
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local centrip_accel = 0
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if (circle_radius > 0) then
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centrip_accel = speed_xy * speed_xy / circle_radius
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end
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target_accel = Vector3f()
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target_accel:x(centrip_accel * -cos_ang)
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target_accel:y(centrip_accel * -sin_ang)
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-- calculate target yaw
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if yaw_behave:get() == 1 then
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target_yaw_deg = math.deg(circle_angle_rad + math.pi)
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if target_yaw_deg > 360 then
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target_yaw_deg = target_yaw_deg - 360
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end
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end
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-- send targets to vehicle with yaw target
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vehicle:set_target_posvelaccel_NED(target_pos, target_vel, target_accel, true, target_yaw_deg, false, 0, false)
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-- advance to stage 2 when below target altitude and target speeds are zero
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if (rel_pos_home_NED) then
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if (-rel_pos_home_NED:z() <= alt_above_home_min:get() and (speed_xy==0) and (speed_z==0)) then
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stage = stage + 1
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end
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if (update_user) then
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gcs:send_text(5, string.format("Fast Descent: alt:%d target:%d", math.floor(-rel_pos_home_NED:z()), math.floor(alt_above_home_min:get())))
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end
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else
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gcs:send_text(5, "Fast Descent: lost position estimate, aborting")
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stage = stage + 1
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end
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elseif (stage == 2) then -- Stage2: done!
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stage = stage + 1
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gcs:send_text(5, "Fast Descent: done!")
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if (activate_type:get() == 0) then
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-- if activated from Guided change to RTL mode
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vehicle:set_mode(copter_rtl_mode_num)
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else
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-- if activated from Auto NAV_SCRIPT_TIME then mark command as done
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vehicle:nav_script_time_done(auto_last_id)
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end
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end
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return update, interval_ms
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end
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return update()
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