QuadPlane Frame setup¶
The QuadPlane code supports several frame arrangements of quadcopter, hexacopter, octacopter and octaquad multicopter frames.
The motor order and output channel is the same as for copter (see Copter motor layout) except that the default output channel numbers start at 5 instead of 1.
Tailsitter Planes configuration is a special case. See Tailsitter notes below
For example, with the default Quad-X frame the motors are on outputs 5 to 8. The arrangement is:
- Output 5: Front right motor, counter-clockwise
- Output 6: Rear left motor, counter-clockwise
- Output 7: Front left motor, clockwise
- Output 8: Rear right motor, clockwise
You can remember the clockwise/counter-clockwise rule by “motors turn in towards the fuselage”, except for the H configuration, there all directions are inverted!
Another common setup is an octa-quad, which uses the following ordering
- Output 5: Front right top motor, counter-clockwise
- Output 6: Front left top motor, clockwise
- Output 7: Rear left top motor, counter-clockwise
- Output 8: Rear right top motor, clockwise
- Output 9: Front left bottom motor, counter-clockwise
- Output 10: Front right bottom motor, clockwise
- Output 11: Rear right bottom motor, counter-clockwise
- Output 12: Rear left bottom motor, clockwise
You can remember the clockwise/counter-clockwise rule for an octa-quad by “top motors turn in towards the fuselage, bottom motors turn out away from the fuselage”.
The normal plane outputs are assumed to be on 1 to 4 as usual. Only vertical lift outputs (5 to 8 on a quad setup) run at high PWM rate (400Hz). In a quad setup you can also use channels 9 to 14 in any way you like, just as with the normal Plane code.
You can optionally move the quad motors to be on any other channel above 4, using the procedure outlined in the section further below.
Frame Types and Classes¶
- 1 for quad
- 2 for hexa
- 3 for octa
- 4 for octaquad
- 5 for Y6
- 7 for Tri
- 10 for Tailsitter
Within each of these frame classes the Q_FRAME_TYPE chooses the motor layout
- 0 for plus frame
- 1 for X frame
- 2 for V frame
- 3 for H frame
- 11 for FireFly6Y6 (for Y6 only)
Frame Type 7 is Tricopter and can be either non-Tiltrotor configuration, or Tiltrotor configured using either Vectored or Non-Vectored yaw control. If using non-Tiltrotor or Non-Vectored Yaw Tilt-rotor, the yaw control output is setup as Motor 7 (
SERVOn_FUNCTION = 39) using a tilt mechanism for the yaw motor, Motor 4. You should set up the yaw servo’s maximum lean angle in degrees with Q_M_YAW_SV_ANGLE. This lean angle assumes that
SERVOn_MAX, represent +/- 90 degrees, with
SERVOn_TRIM representing 0 degrees lean.
Tailsitters mount the VTOL motors facing up when the QuadPlane’s nose is pointing straight up, hence the name Tailsitter.
Copter Tailsitters Q_FRAME_CLASS is the same as a normal QuadPlane, but the Q_TAILSIT_MOTMX bitmask is non-zero, which sets which VTOL motors are active in normal Plane modes, but also indicates that it is a Copter Tailsitter frame. See Tailsitter section for more information
Single/ Dual Motor Tailsitter¶
Single/ Dual Motor Tailsitters (Q_FRAME_CLASS =10) are a special case. Since this can be used on a conventional single motor plane for “3D” style flying, the standard single motor configuration with the Throttle (motor) output on SERVO3 is automatically configured. If you are using twin engines, then you may want to manually configure two outputs for Throttle Left and Throttle Right, instead of Throttle, if you want differential thrust. If you are using a twin, vectored thrust tailsitter, then you will need to manually configure four outputs for Throttle Left, Throttle Right, Left Motor Tilt and Right Motor Tilt. See Tailsitter section for more information
Using different channel mappings¶
You can remap what output channels the quad motors are on by setting values for SERVOn_FUNCTION. This follows the same approach as other output functions.
Note that you do not need to set any of the SERVOn_FUNCTION values unless you have a non-standard motor ordering, using vectored thrust, or are a Tailsitter. It is highly recommended that you use the standard ordering and do not set the SERVOn_FUNCTION parameters, leaving them at zero. They will be automatically set to the right values for your frame on boot.
The output function numbers are:
- 33: motor1
- 34: motor2
- 35: motor3
- 36: motor4
- 37: motor5
- 38: motor6
- 39: motor7
- 40: motor8
So to put your quad motors on outputs 9 to 12 (the auxillary channels on a Pixhawk) you would use these settings in the advanced parameter list: