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Overview

The RCMAP parameter group defines the default mapping of the four primary control axes (Roll, Pitch, Yaw, Throttle) to RC input channels.

By default, ArduPilot follows the AETR (Aileron, Elevator, Throttle, Rudder) or TAER standards. However, if your transmitter uses a different channel order, you can use these parameters to remap the logic without changing physical wires.

Key Concepts

1. Axis Mapping

  • RCMAP_ROLL: Maps the Roll (Aileron) function to a channel (1-16).
  • RCMAP_PITCH: Maps the Pitch (Elevator) function to a channel.
  • RCMAP_THROTTLE: Maps the Throttle function to a channel.
  • RCMAP_YAW: Maps the Yaw (Rudder) function to a channel.

Developer Notes

  • Library: libraries/AP_RCProtocol.
  • Standard Defaults:
    • Channel 1: Roll
    • Channel 2: Pitch
    • Channel 3: Throttle
    • Channel 4: Yaw

Pitch channel

RCMAP_PITCH: Pitch channel

Description

Pitch channel number. This is useful when you have a RC transmitter that can't change the channel order easily. Pitch is normally on channel 2, but you can move it to any channel with this parameter.

Values

  • Range: 1 to 16
  • Increment: 1
  • Default: 2

Description

This parameter maps the physical radio channel for Pitch (Elevator) to the autopilot's internal Pitch control.

  • Usage: If your radio outputs Elevator on Channel 2 (Default), leave this at 2. If it uses a different order (e.g., AETR vs TAER), adjust this to match.
  • Reboot Required: You MUST reboot the flight controller for changes to this parameter to take effect.
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RCMAP_FORWARD

Default 0
Range 1 16

Forward Channel Mapping (RCMAP_FORWARD)

Description

RCMAP_FORWARD allows you to customize which stick or switch on your transmitter controls the vehicle's forward/reverse movement.

This is primarily used for 6-DOF multicopters (omnicopters) and Sub/ROV applications where the standard 4-axis control (Roll, Pitch, Throttle, Yaw) is expanded to include direct translation.

Tuning & Behavior

  • Default: 0 (Disabled/Unmapped).
  • Usage: Set to the channel number (e.g. 6) that your transmitter is sending the forward-translation signal on.
  • Reboot Required: Yes.
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RCMAP_LATERAL

Default 0
Range 1 16

Lateral Channel Mapping (RCMAP_LATERAL)

Description

RCMAP_LATERAL allows you to customize which stick or switch controls the vehicle's left/right strafing movement.

This is essential for vehicles capable of lateral translation without rolling, such as 6-DOF drones and ROVs.

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Roll channel

RCMAP_ROLL: Roll channel

Description

Roll channel number. This is useful when you have a RC transmitter that can't change the channel order easily. Roll is normally on channel 1, but you can move it to any channel with this parameter.

Values

  • Range: 1 to 16
  • Increment: 1
  • Default: 1

Description

This parameter maps the physical radio channel for Roll (Aileron) to the autopilot's internal Roll control.

  • Usage: If your radio outputs Aileron on Channel 3 instead of Channel 1, set this parameter to 3.
  • Why it matters: Allows ArduPilot to work with any radio brand (Futaba, Spektrum, FrSky) regardless of their native channel order (AETR, TAER, etc.).
  • Reboot Required: You MUST reboot the flight controller for changes to this parameter to take effect.
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Throttle channel

RCMAP_THROTTLE: Throttle channel

Description

Throttle channel number. This is useful when you have a RC transmitter that can't change the channel order easily. Throttle is normally on channel 3, but you can move it to any channel with this parameter.

Values

  • Range: 1 to 16
  • Increment: 1
  • Default: 3

Description

This parameter maps the physical radio channel for Throttle to the autopilot's internal Throttle control.

  • Usage: If your radio outputs Throttle on Channel 3 (Default), leave this at 3. Adjust if using a non-standard radio configuration.
  • Reboot Required: You MUST reboot the flight controller for changes to this parameter to take effect.
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Yaw channel

RCMAP_YAW: Yaw channel

Description

Yaw channel number. This is useful when you have a RC transmitter that can't change the channel order easily. Yaw (also known as rudder) is normally on channel 4, but you can move it to any channel with this parameter.

Values

  • Range: 1 to 16
  • Increment: 1
  • Default: 4

Description

This parameter maps the physical radio channel for Yaw (Rudder) to the autopilot's internal Yaw control.

  • Usage: If your radio outputs Rudder on Channel 4 (Default), leave this at 4. If you have a 4-channel radio and want to swap Rudder and Aileron, you would change this and RCMAP_ROLL.
  • Reboot Required: You MUST reboot the flight controller for changes to this parameter to take effect.
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RCIN Parameter Group Relay Configuration (RELAY)