nav_catapult module

Catapult launch timing system.

• Phase 1: Zero Roll, Climb Pitch, Zero Throttle
• Phase 2: After detecting the Start Acceleration
  Zero Roll, Climb Pitch, Full Throttle
• Phase 3: After getting the GPS heading (time based)
  Place climb 300m in front of us
  GoTo(climb)
  

Example for airframe file

Add to your firmware section:

<module name="nav_catapult"/>

Module configuration options

Airframe file section

• section name: CATAPULT prefix: NAV_CATAPULT_
  • name ACCELERATION_THRESHOLD value: 1.5
    Description: acceleration threshold in multiples of g
  • name ACCELERATION_DETECTION value: 5
    Description: number acceleration measurments above threshold for launch detection
  • name MOTOR_DELAY value: 0.75
    Description: delay until motor is turned on in seconds
  • name HEADING_DELAY value: 3.0
    Description: delay until heading is unlocked in seconds
  • name INITIAL_PITCH value: 0.175
    Description: inital pitch in radians (default 10deg)
  • name INITIAL_THROTTLE value: 1.0
    Description: initial throttle (0.0 to 1.0)
  • name CLIMB_DISTANCE value: 300
    Description: distance of the climb waypoint in front of the catapult
  • name TIMEOUT value: 30.
    Description: timeout to disarm the high freq module

Module functions

Init Functions

These initialization functions are called once on startup.

• nav_catapult_init()

Periodic Functions

These functions are called periodically at the specified frequency from the module periodic loop.

• nav_catapult_highrate_module()
  • Running at maximum module frequency.
  • Autorun: TRUE
    Periodic function automatically starts after init.

Files

Header Files

The following headers are automatically included in modules.h

• nav_catapult.h

Source Files

• modules/nav/nav_catapult.c

Raw nav_catapult.xml file:

<!DOCTYPE module SYSTEM "module.dtd">

<module name="nav_catapult" dir="nav">
  <doc>
    <description>
      Catapult launch timing system.
      - Phase 1: Zero Roll, Climb Pitch, Zero Throttle
      - Phase 2: After detecting the Start Acceleration\n
                 Zero Roll, Climb Pitch, Full Throttle
      - Phase 3: After getting the GPS heading (time based)\n
                 Place climb 300m in front of us\n
                 GoTo(climb)\n
<!--
Block example:
@verbatim
<block name="Catapult Take-Off">
  <exception cond="GetPosAlt() > GetAltRef()+25" deroute="Standby"/>
  <set value="0" var="kill_throttle"/>
  <set value="0" var="autopilot_flight_time"/>
  <call fun="nav_catapult_run(WP_CLIMB)"/>
</block>
@endverbatim
-->
    </description>
    <section name="CATAPULT" prefix="NAV_CATAPULT_">
      <define name="ACCELERATION_THRESHOLD" value="1.5" description="acceleration threshold in multiples of g" unit="g"/>
      <define name="ACCELERATION_DETECTION" value="5" description="number acceleration measurments above threshold for launch detection"/>
      <define name="MOTOR_DELAY" value="0.75" description="delay until motor is turned on in seconds" unit="s"/>
      <define name="HEADING_DELAY" value="3.0" description="delay until heading is unlocked in seconds" unit="s"/>
      <define name="INITIAL_PITCH" value="0.175" description="inital pitch in radians (default 10deg)" unit="rad"/>
      <define name="INITIAL_THROTTLE" value="1.0" description="initial throttle (0.0 to 1.0)" unit="%"/>
      <define name="CLIMB_DISTANCE" value="300" description="distance of the climb waypoint in front of the catapult" unit="m"/>
      <define name="TIMEOUT" value="30." description="timeout to disarm the high freq module" unit="s"/>
    </section>
  </doc>
  <settings>
    <dl_settings name="control">
      <dl_settings name="catapult">
        <dl_setting max="5.0" min="0.05" step="0.05" module="nav/nav_catapult" var="nav_catapult.motor_delay" shortname="Motor Delay" param="NAV_CATAPULT_MOTOR_DELAY" unit="seconds"/>
        <dl_setting max="3.0" min="-3.0" step="0.1" var="nav_catapult.accel_threshold" shortname="G-Threshold" param="NAV_CATAPULT_ACCELERATION_THRESHOLD" unit="g"/>
        <dl_setting max="10." min="0.25" step="0.05" var="nav_catapult.heading_delay" shortname="Heading-Delay" param="NAV_CATAPULT_HEADING_DELAY" unit="seconds"/>
        <dl_setting max="40" min="-20" step="0.5" var="nav_catapult.initial_pitch" shortname="TO Pitch" param="NAV_CATAPULT_INITIAL_PITCH" unit="rad" alt_unit="deg"/>
        <dl_setting max="1.0" min="0.0" step="0.01" var="nav_catapult.initial_throttle" shortname="TO Gas" param="NAV_CATAPULT_INITIAL_THROTTLE" unit="percent"/>
      </dl_settings>
    </dl_settings>
  </settings>
  <header>
    <file name="nav_catapult.h"/>
  </header>
  <init fun="nav_catapult_init()"/>
  <!-- Run High Rate Lauch Detector -->
  <periodic fun="nav_catapult_highrate_module()" autorun="TRUE"/>
  <makefile target="ap|sim|nps">
    <file name="nav_catapult.c"/>
  </makefile>
</module>