VOXL m500 Gimbal User’s Guide

Table of contents

  1. Gimbal Version Summary
  2. VOXL-m500-R2-G1
    1. Overview
    2. Configuration
      1. Wiring Guide
      2. PX4 Param File
      3. AUX Passthrough RC Channel
      4. Auxillary Outputs
      5. PWM Signals
    3. Usage
      1. Power Up
      2. Pitch / Yaw Control
    4. PID Tuning

Gimbal Version Summary

As a convenience, versions of the VOXL-m500 are available to test out a gimbals. Links to the off the shelf gimbal source are provided along with any configuration software used. The factory setup used is provided here as well to help others adding gimbals of their own choosing.

VOXL-m500-R2-G1

Overview

Camera not included

The -G1 configuration consists of:

  Details
Gimbal HMG MA3D
Regulator D24V22F12

It is configured with the following:

Configuration

Wiring Guide

TODO: Diagram

Gimbal control handled through the PWM output connector on VOXL-Flight J1007, Flight Core J7

Pin # Signal Name Connection
1 5VDC NC
2 PWM_CH1 Motor 1
3 PWM_CH2 Motor 2
4 PWM_CH3 Motor 3
5 PWM_CH4 Motor 4
6 PWM_CH5 Gimbal Pitch/Tilt Control (3.3V)
7 PWM_CH6 Gimbal Yaw Control (3.3V)
8 PWM_CH7 Not used
9 PWM_CH8 Not used
10 GND NC

PX4 Param File

For refernce, a PX4 parameter for setting up a Spektrum DX8 with this gimbal using channels 8/7 to pitch/yaw and enabling outputs on bootup can be found here

AUX Passthrough RC Channel

The AUX1/2 passthrough RC channels are configured via RC_MAP_AUX1 and RC_MAP_AUX2. These two channels can be configured to control pitch/yaw control on the gimbal from the RC transmitter. In the param file referenced above these are set to 8 and 7.

Auxillary Outputs

The Quadrotor x airframe is supported by the m500, which provides us feed-through of RC AUX1 and AUX2 channels to PWM_CH5 and PWM_CH6 (pins 6 and 7 above) respectively.

The AUX ouptut signals may be disarmed on bootup and only enabled after arming the vehicle which may not be desirable debugging. Setting the COM_PREARM_MODE mode to 2 (Always) enables the outputs on bootup (this is shown in the param file referenced above).

PWM Signals

The PWM signals PWM_CH5 and PWM_CH6 (pins 6 and 7 above) have a range of 1000 to 2000 us and are controlled by the PWM_AUX_MIN5/PWM_AUX_MIN6 and PWM_AUX_MAX5/PWM_AUX_MAX6 parameters. These are left as the PX4 default.

Also by default, the output is 1500 us when disarmed, which is configured by PWM_AUX_DISARMED.

Usage

Power Up

The gibmal receives power via the battery (not through the DC plug available on the power module). Upon attaching the battery, the gimbal will self stabilize in roughly 6 seconds. You can hold the camera in position during this time to stabilize into a starting point of your desire.

Pitch / Yaw Control

Using the DX4 transmitter with the params setup as above:

Channel # Switch Type Control Notes
8 Dial Pitch rotate to middle to have 0 degrees, rotate left/right to pitch up/down
7 3-Position Yaw middle position no movement, up yaw left, down yaw right

PID Tuning

  • Download SimlpeBGC v2.2b2 from here
  • The User Guide can be downloaded at the same site here

To compliment the user guide above, herer’s a high level walkthrough:

  • Open the SimlpeBGC GUI
  • Connect to the gimbal using a micro usb
  • On the GUI, under Connection, click the dropdown and select the COM port. Should connect automatically
  • On the top there are several tabs to select from: Basic Tab, Advanced Tab, RC Settings Tab, Follow mode Tab, Menu Button Tab, Realtime Data Tab, Firmware upgrade Tab

NOTE: Avoid flashing the newest firmware. Will brick the device. Would suggest avoiding the Firmware Upgrade tab altogether.

  • Before altering any values, would recommend saving the values to reference back if needed.
  • The Basic Tab, allows to set the PID’s, Motor configuration, Sensor configuration and External FC Gain
  • Highly recommend calibrating the ACC. and GYRO
  • The PID’s work well in default settings, but for more custom settings, change the values to your liking. Too high values and the gimbal becomes very twitchy and too low values make the gimbal sluggish, in general:
    • P - is like the power/resistance to change
    • I - the speed to which the gimbal will return to center
    • D - stabilizes the bumps
  • Power is the amount of power each motor is receiving. Can be set anywhere from 0-250. Recommend starting out anywhere from 80-120 to start. Too high a value and the motors start getting hot, too low and there’s not enough power to combat the wind and motions of the camera
  • Invert should be defaulted after plugging in the gimbal, if not select Auto
  • NUM Poles should be 14, unless different motors are used then this should be changed to match the poles of the motor
  • External FC Gain is left alone
  • Sensor Axis should’ve been recorded correctly after connection to usb. If not, use -Z, -Y for Axis Top and Right respectively
  • Advanced Tab, leave AHRS alone, good as is.
  • In Timings, Serial port speed is left alone
  • PWM Frequency is altered to High(silent)
  • RC Settings Tab, under RC Input mapping, Source: PWM
  • ROLL: RC_ROLL
  • PITCH: RC_PITCH
  • YAW: EXT_PITCH
  • CMD: no_input
  • Command Assignment is left alone
  • Adjust settings here for angle of gimbal and speed:
  MIN.ANGLE MAX.ANGLE ANGLE MODE LPF SPEED MODE SPEED FOLLOW.%
ROLL -45 45 X 3   50 0
PITCH -60 60 X 3   50 0
YAW -100 100   3 X 50 0
  • Use Realtime Data Tab, simultaneously as tuning the PID’s. The goal is to get a smooth slope with the least bit of oscillations with the fastest return to center