mirror of https://github.com/ArduPilot/ardupilot
113 lines
3.9 KiB
Python
113 lines
3.9 KiB
Python
import math
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import random
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import time
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import util
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from pymavlink.rotmat import Vector3, Matrix3
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class Aircraft(object):
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"""A basic aircraft class."""
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def __init__(self):
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self.home_latitude = 0
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self.home_longitude = 0
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self.home_altitude = 0
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self.ground_level = 0
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self.frame_height = 0.0
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self.latitude = self.home_latitude
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self.longitude = self.home_longitude
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self.altitude = self.home_altitude
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self.dcm = Matrix3()
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# rotation rate in body frame
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self.gyro = Vector3(0, 0, 0) # rad/s
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self.velocity = Vector3(0, 0, 0) # m/s, North, East, Down
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self.position = Vector3(0, 0, 0) # m North, East, Down
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self.mass = 0.0
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self.update_frequency = 50 # in Hz
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self.gravity = 9.80665 # m/s/s
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self.accelerometer = Vector3(0, 0, -self.gravity)
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self.wind = util.Wind('0,0,0')
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self.time_base = time.time()
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self.time_now = self.time_base + 100*1.0e-6
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self.gyro_noise = math.radians(0.1)
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self.accel_noise = 0.3
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def on_ground(self, position=None):
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"""Return true if we are on the ground."""
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if position is None:
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position = self.position
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return (-position.z) + self.home_altitude <= self.ground_level + self.frame_height
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def update_position(self):
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"""Update lat/lon/alt from position."""
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bearing = math.degrees(math.atan2(self.position.y, self.position.x))
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distance = math.sqrt(self.position.x**2 + self.position.y**2)
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(self.latitude, self.longitude) = util.gps_newpos(self.home_latitude, self.home_longitude,
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bearing, distance)
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self.altitude = self.home_altitude - self.position.z
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velocity_body = self.dcm.transposed() * self.velocity
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self.accelerometer = self.accel_body.copy()
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def set_yaw_degrees(self, yaw_degrees):
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"""Rotate to the given yaw."""
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(roll, pitch, yaw) = self.dcm.to_euler()
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yaw = math.radians(yaw_degrees)
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self.dcm.from_euler(roll, pitch, yaw)
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def time_advance(self, deltat):
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"""Advance time by deltat in seconds."""
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self.time_now += deltat
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def setup_frame_time(self, rate, speedup):
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"""Setup frame_time calculation."""
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self.rate = rate
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self.speedup = speedup
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self.frame_time = 1.0/rate
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self.scaled_frame_time = self.frame_time/speedup
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self.last_wall_time = time.time()
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self.achieved_rate = rate
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def adjust_frame_time(self, rate):
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"""Adjust frame_time calculation."""
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self.rate = rate
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self.frame_time = 1.0/rate
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self.scaled_frame_time = self.frame_time/self.speedup
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def sync_frame_time(self):
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"""Try to synchronise simulation time with wall clock time, taking
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into account desired speedup."""
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now = time.time()
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if now < self.last_wall_time + self.scaled_frame_time:
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time.sleep(self.last_wall_time+self.scaled_frame_time - now)
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now = time.time()
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if now > self.last_wall_time and now - self.last_wall_time < 0.1:
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rate = 1.0/(now - self.last_wall_time)
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self.achieved_rate = (0.98*self.achieved_rate) + (0.02*rate)
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if self.achieved_rate < self.rate*self.speedup:
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self.scaled_frame_time *= 0.999
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else:
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self.scaled_frame_time *= 1.001
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self.last_wall_time = now
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def add_noise(self, throttle):
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"""Add noise based on throttle level (from 0..1)."""
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self.gyro += Vector3(random.gauss(0, 1),
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random.gauss(0, 1),
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random.gauss(0, 1)) * throttle * self.gyro_noise
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self.accel_body += Vector3(random.gauss(0, 1),
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random.gauss(0, 1),
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random.gauss(0, 1)) * throttle * self.accel_noise
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