Using Python Scripts in Mission Planner

One of the cool features of the Mission Planner is that it can run Python scripts, which is an easy way to extend the functionality of the program beyond its built-in functions. It can also enable integration easily with other dlls and modules far beyond the original scope of the Mission Planner.

Overview

You can easily program your UAV to do anything, from robotic acrobatics to just script-driven missions. Python 2.x is currently supported, up to 2.7 (Mission Planner uses an implementation of IronPython internally)

Aside from the regular Python commands, these are the special Mission Planner commands you can use:

cs.VARIABLENAME = currentstate

Any variable on the status tab in the planner can be used.

Script.METHODNAME(...)

options are

• Script.Sleep(ms)

• Script.ChangeParam(name,value)

• Script.GetParam(name)

• Script.ChangeMode(mode) (same as displayed in mode setup screen ‘AUTO’)

• >Script.WaitFor(string,timeout)

• Script.SendRC(channel,pwm,sendnow)

Here’s an example, which tells a multicopter to do a roll in the air!

print 'Start Script'
for chan in range(1,9):
    Script.SendRC(chan,1500,False)
    Script.SendRC(3,Script.GetParam('RC3_MIN'),True)

Script.Sleep(5000)

while cs.lat == 0:
    print 'Waiting for GPS'
    Script.Sleep(1000)

print 'Got GPS'
jo = 10 * 13
print jo
Script.SendRC(3,1000,False)
Script.SendRC(4,2000,True)
cs.messages.Clear()
Script.WaitFor('ARMING MOTORS',30000)
Script.SendRC(4,1500,True)
print 'Motors Armed!'
Script.SendRC(3,1700,True)

while cs.alt < 50:
    Script.Sleep(50)

Script.SendRC(5,2000,True) # acro
Script.SendRC(1,2000,False) # roll
Script.SendRC(3,1370,True) # throttle

while cs.roll > -45: # top half 0 - 180
    Script.Sleep(5)

while cs.roll < -45: # -180 - -45
    Script.Sleep(5)

Script.SendRC(5,1500,False) # stabilize
Script.SendRC(1,1500,True) # level roll
Script.Sleep(2000) # 2 sec to stabilize
Script.SendRC(3,1300,True) # throttle back to land
thro = 1350 # will descend

while cs.alt > 0.1:
    Script.Sleep(300)

Script.SendRC(3,1000,False)
Script.SendRC(4,1000,True)
Script.WaitFor('DISARMING MOTORS',30000)
Script.SendRC(4,1500,True)

print 'Roll complete'

Classes Exposed by Mission Planner to Python

Mission Planner exposes classes using the following code:

Linking classes into python

scope.SetVariable(Variablename, ClassInstance);

That the following classes are exposed:

• scope.SetVariable("MAV", MainV2.comPort);

• scope.SetVariable("cs", MainV2.comPort.MAV.cs);

• scope.SetVariable("Script", this);

• scope.SetVariable("mavutil", this);

This is where you can add your own classes. For now lets us explore the important methods and properties you can use into your script using these classes.

Class Name: Script.cs

Python Variable: Script , mavutil

Method	Description
bool ChangeParam (string param, float value)
Float GetParam (string param)
bool ChangeMode (string mode)	Changes flying mode
bool SendRC (int channel, ushort pwm, bool sendnow)	Send Chxout values.

Class Name: CurrentState.cs

Python Variable: cs

Method	Type	Description
roll	float	Roll (deg)
pitch	float	Pitch (deg)
yaw	float	Yaw (deg)
lat	float	Latitude (deg)
lng	float	Longitude (deg)
groundcourse	float	Ground Course (deg)
alt	float	Altitude (dist)
altoffsethome	float	Altitude Home Offset (dist)
gpsstatus	float	GPS Status
gpshdop	float	GPS HDOP
satcount	float	Satellite Count
altd100	float	Altitude / 100
altd1000	float	Altitude / 1000
airspeed	float	Airspeed (speed)
targetairspeed	float	Airspeed Target (speed)
groundspeed	float	Ground Speed (speed)
verticalspeed	float	Vertical Speed (speed)
wind_dir	float	Wind Direction (deg)
wind_vel	float	Wind Velocity (speed)
ax, ay, az	float	Acceleration Values in x,y,z
gx, gy, gz	float	Gyro Values in x,y,z
mx, my, mz	float	Mag Values in x,y,z
failsafe	bool	Fail Safe Active or Not
rxrssi	float
chx1in, chx2in, …. chx8in	float	Input Channels from 1 to 8
ch1out, chx2out, …. chx8out	float	Output Channel form 1 to 8
nav_roll	float	Roll Target (deg)
nav_pitch	float	Pitch Target (deg)
nav_bearing	float	Bearing target (deg)
target_bearing	float	Bearing Target (deg)
wp_dist	float	Distance to Next Waypoint (dist)
alt_error	float	Altitude Error (dist)
ber_error	float	Bearing Error (dist)
aspd_error	float	Airspeed Error (speed)
wpno	float	Flying Mode
mode	String	Flying Mode
dimbrate	float	Climb Rate (speed)
tot	int	Time over target (sec)
distTraveled	float	Distance Traveled (dist)
timeInAir	float	Time in Air (sec)
turnrate	float	Turn Rate (speed)
radius	float	Turn Radius (dist)
battery_voltage	float	Battery Voltage (volt)
battery_remaining	float	Battery Remaining (%)
current	float	battery Current (Amps)
HomeAlt	float
DistToHome	float	Absolute Pressure Value
press_abs	float	Absolute Pressure Value
sonarrange	float	Sonar Range (meters)
sonarVoltage	float	Sonar Voltage (volt)
armed	bool	True if Armed

Please note that although these properties are read/write howvever writing to some of them can corrupt the status. Use methods from Script class to control the vehicle. for example use Script.ChangeMode(xmode) rather than cs.mode = xmode.

Class Name: MavLink.cs

Python Variable: MAV

Method	Description
bool setParam (string paramname, float value)	Same as Script.ChangeParam()
bool doARM (bool armit)	BE CAREFUL when using it.
byte getWPCount ( )	Gets Waypoints Count.

Using CPython Standard Libraries

You can import standard libraries from your regular Python 2.x folders by adding this line to top of your script (replacing “c:\python27\lib” with whatever the folder is on your drive):

import sys
sys.path.append(r"c:\python27\lib")

Here, for example, we’re importing the serial, os, and threading libraries, which are in two folders in a typical Python 2.7 installation. Appending the specific folder paths for those three libraries first allows us to import them with the next “import” command:

import sys
sys.path.append(r"c:\Python27\Lib\site-packages")
sys.path.append(r"c:\Python27\Lib")
import serial, os, threading

Tutorials and sample scripts

• Scripting fixed-wing acrobatics

• Adding new variables and classes

• Writing a time-based script