Run dronekit scripts by SITL on Linux 执行dronekit 脚本在Linux系统下模拟飞行

参考：http://ardupilot.org/dev/docs/setting-up-sitl-on-linux.html

Overview

The SITL simulator allows you to run Plane, Copter or Rover without any hardware. It is a build of the autopilot code using an ordinary C++ compiler, giving you a native executable that allows you to test the behaviour of the code without hardware.

SITL模拟器允许您在没有任何硬件的情况下运行Plane，Copter或Rover。它是使用普通C ++编译器构建的自动导航代码，为您提供本机可执行文件，允许您在没有硬件的情况下测试代码的行为。

Install steps

Cloning with the command line

git clone https://github.com/ArduPilot/ardupilot
cd ardupilot
git submodule update --init --recursive

Install some required packages

cd ardupilot

sudo apt-get install python-matplotlib python-serial python-wxgtk3.0 python-lxml  

sudo apt-get install python-scipy python-opencv ccache gawk git python-pip python-pexpect

Tools/scripts/install-prereqs-ubuntu.sh -y

. ~/ .profile

Install Dronekit

pip install dronekit

Update pymavlink and MAVProxy

we can not see the vehicle on the map without updating

sudo pip install --upgrade pymavlink MAVProxy

Add some directories to your search path (Facultative)

export PATH=$PATH:$HOME/ardupilot/Tools/autotest

export PATH=/usr/lib/ccache:$PATH

. ~/.bashrc

Run steps

Start SITL simulator

cd ardupilot/ArduCopter

Then start the simulator using sim_vehicle.py. The first time you run it you should use the -w option to wipe the virtual EEPROM and load the right default parameters for your vehicle.

然后使用sim_vehicle.py启动模拟器。第一次运行它时，应使用-w选项擦除虚拟EEPROM并为您的车辆加载正确的默认参数。

sim_vehicle.py -w

After the default parameters are loaded you can start the simulator normally. First kill the sim_vehicle.py you are running using Ctrl-C. Then:

加载默认参数后，您可以正常启动模拟器。首先使用Ctrl-C终止正在运行的sim_vehicle.py。然后：

sim_vehicle.py --console --map

Configure connection

we  connect to SITL by UDP 

tpye these instructions below in the console on SITL

output add 127.0.0.1:14550 

Start MAVProxy

mavproxy.py --master tcp:127.0.0.1:5760 --sitl 127.0.0.1:5501 --out 127.0.0.1:14550 --out 127.0.0.1:14551

Run scripts (.py)

you should access to the position where the script exist on a new terminal

python scriptname.py (like test.py)

#!/usr/bin/env python
# -*- coding: utf-8 -*-

"""
© Copyright 2015-2016, 3D Robotics.
simple_goto.py: GUIDED mode "simple goto" example (Copter Only)
Demonstrates how to arm and takeoff in Copter and how to navigate to points using Vehicle.simple_goto.
"""

from __future__ import print_function
import time
from dronekit import connect, VehicleMode, LocationGlobalRelative


# 通过本地的14551端口，使用UDP连接到SITL模拟器
connection_string = '127.0.0.1:14551'
print('Connecting to vehicle on: %s' % connection_string)
# connect函数将会返回一个Vehicle类型的对象，即此处的vehicle
# 即可认为是无人机的主体，通过vehicle对象，我们可以直接控制无人机
vehicle = connect(connection_string, wait_ready=True)

# 定义arm_and_takeoff函数，使无人机解锁并起飞到目标高度
# 参数aTargetAltitude即为目标高度，单位为米
def arm_and_takeoff(aTargetAltitude):
    # 进行起飞前检查
    print("Basic pre-arm checks")
    # vehicle.is_armable会检查飞控是否启动完成、有无GPS fix、卡曼滤波器
    # 是否初始化完毕。若以上检查通过，则会返回True
    while not vehicle.is_armable:
        print(" Waiting for vehicle to initialise...")
        time.sleep(1)

    # 解锁无人机（电机将开始旋转）
    print("Arming motors")
    # 将无人机的飞行模式切换成"GUIDED"（一般建议在GUIDED模式下控制无人机）
    vehicle.mode = VehicleMode("GUIDED")
    # 通过设置vehicle.armed状态变量为True，解锁无人机
    vehicle.armed = True

    # 在无人机起飞之前，确认电机已经解锁
    while not vehicle.armed:
        print(" Waiting for arming...")
        time.sleep(1)

    # 发送起飞指令
    print("Taking off!")
    # simple_takeoff将发送指令，使无人机起飞并上升到目标高度
    vehicle.simple_takeoff(aTargetAltitude)

    # 在无人机上升到目标高度之前，阻塞程序
    while True:
        print(" Altitude: ", vehicle.location.global_relative_frame.alt)
        # 当高度上升到目标高度的0.95倍时，即认为达到了目标高度，退出循环
        # vehicle.location.global_relative_frame.alt为相对于home点的高度
        if vehicle.location.global_relative_frame.alt >= aTargetAltitude * 0.95:
            print("Reached target altitude")
            break
        # 等待1s
        time.sleep(1)

# 调用上面声明的arm_and_takeoff函数，目标高度10m
arm_and_takeoff(10)

# 设置在运动时，默认的空速为3m/s
print("Set default/target airspeed to 3")
# vehicle.airspeed变量可读可写，且读、写时的含义不同。
# 读取时，为无人机的当前空速；写入时，设定无人机在执行航点任务时的默认速度
vehicle.airspeed = 3

# 发送指令，让无人机前往第一个航点
print("Going towards first point for 30 seconds ...")
# LocationGlobalRelative是一个类，它由经纬度(WGS84)和相对于home点的高度组成
# 这条语句将创建一个位于南纬35.361354，东经149.165218，相对home点高20m的位置
point1 = LocationGlobalRelative(-35.361354, 149.165218, 20)
# simple_goto函数将位置发送给无人机，生成一个目标航点
vehicle.simple_goto(point1)

# simple_goto函数只发送指令，不判断有没有到达目标航点
# 它可以被其他后续指令打断，此处延时30s，即让无人机朝向point1飞行30s
time.sleep(30)

# 发送指令，让无人机前往第二个航点
print("Going towards second point for 30 seconds (groundspeed set to 10 m/s) ...")
# 与之前类似，这条语句创建了另一个相对home高20m的点
point2 = LocationGlobalRelative(-35.363244, 149.168801, 20)
# simple_goto将目标航点发送给无人机，groundspeed=10设置飞行时的地速为10m/s
vehicle.simple_goto(point2, groundspeed=10)

# 与之前一样，延时30s
time.sleep(30)

# 发送"返航"指令
print("Returning to Launch")
# 返航，只需将无人机的飞行模式切换成"RTL(Return to Launch)"
# 无人机会自动返回home点的正上方，之后自动降落
vehicle.mode = VehicleMode("RTL")

# 退出之前，清除vehicle对象
print("Close vehicle object")
vehicle.close()