Parachute

This topic describes how to set up manual and automatic parachute release.

Warning

Support for this feature was introduced in Copter 3.2. This feature is still experimental and should be used with caution.

Video above is from Henri’s DIYDrones discussion that led to this feature being added to Copter.

What you will need

A complete parachute mechanism like one of these:

OR if you prefer a DIY solution, parachute release mechanism that can be triggered by a PWM signal (i.e. a Servo) and a parachute large enough to slow your multicopter’s decent to less than 5m/s. Some recommended parachute vendors:

Connecting to the Pixhawk

The parachute release mechanism can be triggered from either a Relay or a PWM (i.e. Servo) but because of an issue with the Relay pins being pulled high at start-up, we recommend using PWM, in particular any of the Pixhawk’s AUX OUT 1 to 4 pins.

../_images/Parachute_Pixhawk.jpg

Setup through the mission planner

To configure the parachute release please first connect with the Mission Planner and then open the Config/Tuning >> Full Parmeter List page and set the following parameters.

  • CHUTE_ENABLED = “1”
  • CHUTE_TYPE = “10” to release with a servo
  • CHUTE_SERVO_ON should be set to the servo position required to release the parachute
  • CHUTE_SERVO_OFF should be the “resting” servo position. I.e. the position the servo is in before the parachute is released
  • RC9_FUNCTION = “27”. RC9 refers to the Pixhawk’s AUX OUT 1. To use AUX OUT2 instead set RC10_FUNCTION to 27, etc.
../_images/Parachute_MPSetup1.png ../_images/Parachute_MPSetup2.png

Setup Ch7 to manually deploy the parachute from the Mission Planner’s Extended Tuning page.

../_images/Parachute_MPSetup_Ch7.png

When will the parachute deploy?

When the “Crash Check” feature determines that the vehicle has lost attitude control and has begun falling, the motors will be stopped and the parachute will deploy automatically. The following must all be true for a full 2 seconds for the crash checker to trigger the parachute release:

  • The motors are armed
  • The vehicle is not “landed” (the vehicle will consider itself landed if the output throttle is less than 25%, the motors have hit their lower limit, the vehicle is not rotating by more than 20deg/sec and the pilot is not requesting a climb. All this must be true for 1 second for the vehicle to consider itself landed)
  • The vehicle is not in FLIP or ACRO flight mode
  • the roll and/or pitch angle of the vehicle is 20 degrees off from the target lean angle
  • the barometer shows the vehicle is not climbing
  • the vehicle is above the CHUTE_ALT_MIN altitude

Testing the chute

Depending upon the release mechanism a parachute deployment can be dangerous so please take care when performing these tests, removing the parachute and vehicle propellers as is appropriate.

To test manual deployment:

  • Set the CHUTE_ALT_MIN parameter to zero to disable the minimum altitude check
  • Arm the vehicle in stabilize mode and raise the throttle above minimum
  • move the Ch7 switch to the high position

You should see the motors stop, the parachute servo move and if telemetry is attached, “Parachute: Released!” should appear on the Flight Data screen’s HUD.

To test the automatic deployment:

  • Set the CHUTE_ALT_MIN parameter to zero to disable the minimum altitude check
  • Arm the vehicle in stabilize mode and raise the throttle above minimum
  • somehow tilt the vehicle over by at least 20 degrees

After 2 seconds, the motors should stop, the parachute servo will move and if telemetry is attached, “Parachute: Released!” should appear on the Flight Data screen’s HUD.

After the test is complete, return the CHUTE_ALT_MIN to the desired altitude (default is 10m)