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Overview

The GRIP parameter group configures the Gripper / Cargo Release subsystem. This allows the vehicle to carry, grab, and release payloads using various mechanisms (Servo, EPM, or DroneCAN).

Key Concepts

1. Gripper Types (GRIP_TYPE)

Defines the hardware interface for the gripper.

  • 1 (Servo): Standard PWM servo that moves between two positions.
  • 2 (EPM): Electro-Permanent Magnet (e.g., OpenEPM). Uses a short pulse to magnetize/de-magnetize.
  • 3 (DroneCAN): CAN-based gripper devices.

2. Grab and Release Positions

For servo-based grippers, defines the PWM endpoints.

  • GRIP_GRAB: PWM value to close the gripper.
  • GRIP_RELEASE: PWM value to open the gripper.
  • GRIP_NEUTRAL: PWM value for idle/disengaged state.

3. Automation (GRIP_AUTOCLOSE)

Can automatically close the gripper when a landing or proximity to a target is detected.

Parameter Breakdown

  • GRIP_ENABLE: Master switch.
  • GRIP_TYPE: Hardware driver selection.
  • GRIP_CAN_ID: Node ID for DroneCAN grippers.

Integration Guide

  1. Pin: Map a servo output to Gripper (Function 28).
  2. Enable: Set GRIP_ENABLE = 1 and GRIP_TYPE.
  3. Calibrate: Set the GRAB and RELEASE PWM values so the mechanism operates without binding.
  4. Control: Map an RC channel to Gripper (RC Option 19) to control it manually.

Developer Notes

  • Library: libraries/AP_Gripper.

GRIP_AUTOCLOSE

s
Default 0.0
Range 0.25 255

Gripper Autoclose time (GRIP_AUTOCLOSE)

Description

Automates the closure of the gripper after a successful release. This is often used to return a mechanical claw to its idle/stowed position.

  • 0 disables automatic closure.
View Source

GRIP_CAN_ID

Default 0
Range 0 255

EPM UAVCAN Hardpoint ID (GRIP_CAN_ID)

Description

Uniquely identifies the EPM module on the DroneCAN bus.

GRIP_ENABLE

Default 0
Range 0 1

Gripper Enable/Disable (GRIP_ENABLE)

Description

Master switch for the onboard gripper system, used for delivering or picking up cargo.

Tuning & Behavior

  • Default Value: 0 (Disabled)
  • Requires reboot to make other GRIP_ parameters visible.
View Source

GRIP_GRAB

PWM
Default 1900
Range 1000 2000

Gripper Grab PWM (GRIP_GRAB)

Description

The PWM signal value that triggers the "Closed" or "Grab" position of the gripper.

View Source

GRIP_NEUTRAL

PWM
Default 1500
Range 1000 2000

Neutral PWM (GRIP_NEUTRAL)

Description

The idle position for the gripper servo. For EPM, this is the "neutral" state where no power is being applied to the magnets.

View Source

GRIP_REGRAB

s
Default 0
Range 0 255

EPM Gripper Regrab interval (GRIP_REGRAB)

Description

For Electro-Permanent Magnets (EPM), defines how often the flight controller should send a "Grab" pulse to ensure the cargo remains securely attached, compensating for physical jostling.

  • 0 disables automatic regrabbing.
View Source

GRIP_RELEASE

PWM
Default 1100
Range 1000 2000

Gripper Release PWM (GRIP_RELEASE)

Description

The PWM signal value that triggers the "Open" or "Release" position of the gripper.

View Source

GRIP_TYPE

Default 0
Range 0 2

Gripper Type (GRIP_TYPE)

Description

Defines the mechanical interface for the gripper.

  • 0: None
  • 1: Servo (Standard PWM servo mechanism)
  • 2: EPM (Electro-Permanent Magnet)
View Source
GPS / GNSS Configuration (GPS) Ground Steering Configuration (GROUND)