Servers by jDrones

Pixhawk 2.1 to Sabertooth 2x32 nothing

Ok if I see 4.8 volts going into power and I see 30millivolts coming out does this pose an issue

Correction I think I should be getting from 167 to 332 MV
Atleast that’s what I’m getting from RC to Sabertooth

What? 167 to 332 mV from where?

To further understand why I’m not get any functionality from this black cube I decided to measure some outputs
If I connect the receiver to the Sabertooth 2x32 without the cube
I get a mV range of 167mV to 332mV output from receiver.
Then when connecting the Pixhawk cube between the RC receiver and the Sabertooth I get 32mV output from the Pixhawk Cube.
Has anyone taken the same measurements.
Input voltage to the receiver and cube is 5 volts

The output from the receiver is PPM/Sbus. Measuring it with a volt meter is meaningless.

I can see your trying to help, I will go through each step and try to work out how to solve this issue.

Trying. Some of these questions I asked and some other comments:
Is your Transmitter setup for AETR order?
Is it setup for Mode 2?
Are you trying to control the rover with the right stick, up/down for throttle, right/left for steer?
Do the channells move with the sticks in Mission Planner Radio calibration screen?
What is the PILOT_STEER parameter set to?
I believe you want the Sabertooth dip switches like this. 1-Off, 2-On, 3-Off, 4-Off, 5,On, 6-On Which is:
1-Off
2-On
3-Battery
4-Independent
5-Linear
6-Transmitter

Servo Output 1 to left motor ESC input
Servo Output 3 to right motor ESC input

@Rooster This stuff is very confusing, there’s a lot going on. I made a post about this exact situation a few months back (so I wouldn’t forget). Maybe it can help you:

Like @dkemxr said, try plugging two channels of the receiver into the S1 and S2 terminals on the Sabertooth. If your Sabertooth is working, moving the sticks in some direction should result in some detectable change in rotation on your motors.

Be careful about how you set the DIP switches on the Sabertooth. For skid steer I think you want the Pixhawk to mix the throttle and steering channels. The Sabertooth can mix them if you set one of the DIP switches but then it gets double mixed and things get really funky.

I hope this helps.

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That’s why you want it set for Independent. Ardurover is not suppling throttle on one chan and steering on the other. It’s output is 2 chan mixed. But there are several things you can get wrong. The most common is confusing inputs and outputs.

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Morning Drew
I can report some degree of success as I can now move the wheels
It requires more calibration to achieve the correct movement
I can’t tell you how much your article was so beneficial.
My initial concerns were that maybe I had blown up the cube before I started.
Where I have failed is to understand what change made a difference.
Once I get both wheels to move correctly I will make sure I record all calibrations.
And report back to you.
As a new person to this technology it’s great to know you and Dave are here to help.
To both of you keep in mind your helpfulness is 100% appreciated

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Hi Dave,
Really appreciate your help I’m now getting movement

@Rooster, Glad it was helpful. I’m actually putting together another rover and had to reference that page last night to see how I needed to set things up. I managed to get it to work so I’ll share a few things I’d forgotten (and may not have addressed in that article):

Make sure the 0V terminal on the Sabertooth is connected to a ground pin (labeled with a “-”) on the servo rail of the Pixhawk. I forgot to do this and the motors would turn in random directions regardless of how I moved the transmitter sticks until I connected them.

Also, if the wheels are rotating in the wrong direction (reverse of what you want relative to stick movements on the transmitter), start by swapping the motor wires where they connect to the Sabertooth. I’d avoid messing with servo reversing in mission planner or on your physical controller if you can. You might get things to work in manual mode, but in auto mode the reversing can make things behave very strangely.

When you say you can move the wheels, what kind of motion are you seeing? Do they just randomly rotate? Or is the motion related to the stick motions on the transmitter?

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Ok so it is down to the final stage, and again appreciate your help.
This is what I’m able to achieve
RC controller one paddle (right side) up down controls left motor
Mission planner servo output position 1 function = RCPassthru controls right motor forward reverse function can only work on (function RCPassthru).
RC controller same right side paddle left and right control right side motor. Mission planner servo output position 2 function = RCPassthru controls left motor forward reverse function can only work on function
RCPassthru

If I can understand how to calibrate the following
Either position 2 or 3 to control throttle on both motors
Position 1 to control both motors for left and right moving each motor is opposite directions

BTW when this is all done I’m happy to compose a paper to help the next newcomer

Champagne for everyone
It’s all working as per the most desired outcome
Right paddle down both wheels forward
Right paddle up both in reverse
Right paddle to the right right wheel back and left forward
Left paddle to the left right wheel forward and left wheel backwards

Drew we both might agree if this all went right at the start what would I have learnt =0
What I did learn was how not to understand a very powerful ArduPilot and a well made Pixhawk black cube that allowed me to make mistakes and not blow up expensive modules
I’m now going to open a bottle of champagne, at the same time take notes of all settings
Again a special thanks to Dave and Drew
PS the last thing I did was to reset my transmitter back to factory settings and then the whole thing just worked :tropical_drink::tropical_drink::tropical_drink::tropical_drink:

Glad to hear it! I find the more buttons and settings you mess with, the worse things seem to go. Happy roving!

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Glad you got this sorted, I had responded in a few placed to this and was about to share a blog post I’m putting together on this, this is not finished and I will be sharing on the main blog once done but my help.

Ardurover Setup & Configuration with Sabertooth 2x32 & Cube Autopilot.

I have slowly been working on a scout rover build and though I would share some info as I have not seen a lot posted with this setup especially for the Sabertooth motor controller from Dimension Engineering.

The idea of this project is a low level scout rover with FPV and front object avoidance.

The parts used for this build are

  • Servocity Prowler Rover Chassis
  • Hex Cube Purple & Carrier Board Mini
  • Mauch HL Series BEC & Current Sensor
  • Sabertooth 2 x32 Motor Controller
  • Herelink
  • Here GPS
  • LED Torchlight
  • Camera TBC

At the heart of this build is the Cube Purple Autopilot that’s mounted to the carrier board mini, this gives a compact setup with all the inputs I need, the Purple is ideal choice for this compared to the Cube black and others as its only single non isolated IMU.

This is then controlling the Sabertooth 2x32A Brushed motor controller, I choose this for its vast range of features that include

  • Simple Switch configuration for basic setup

  • Dual channel motor driver capable of supplying 32 amps on each channel with peak currents up to 64 amps per output

  • Multiple Inputs - PWM radio control, analog, TTL serial or USB.

  • Regenerative drive and braking.

  • Operating modes include tank/skid or traditional mixing, Inputs have automatic calibration range calibration, expo options and multiple modes.

  • Auxiliary controllable power outputs allow the Sabertooth 2x32 to operate from a power supply without a parallel battery, or automatic control of electromagnetic brakes 8A Max.

  • 5V 1A Aux output for accessories

  • Enhanced configuration options via PC or Mac Application.

Autopilot Setup

As shown in the top image the Cube is fitted with Here GPS and is powered by Mauch HL series BEC and current sensor, Herelink is connected to the Cube via UART and SBUS, the Herelink Air unit is powered by the 5V output on the Sabertooth.

The Cube drives the controllers via PWM outputs that are connected from servo channels 1 and 3 to S1 and S2 on the driver, you should also note you need to also connect a ground wire from the 0v output on the input screw block to one of the ground pins on the servo header.

Motor Controller

The Sabertooth has some standard basic configurations assigned to the 6 switches located on the PCB, for most RC type applications the “Radio Control” config get you close but you will need to set switch 4 depending on your motor configuration and switch 3 depending on your battery setup.

Standard Switch Config

For my rover I have set it up for skid/tank steering with left and right motor being wired in parallel.

The config for this starts with the “Radio Control” setup shown above however switch 4 is set to “Independent” or “Off”, this means input S1 will drive one motor channel M1A & M1B output and S2 drive M2A & M2B .

If you wanted to use it with more traditional steering via a servo you would leave it set switch 4 to “Mixed” or “On” .

Ardurover

In Ardurover you will need to ensure your remote is properly connected and calibrated, you can follow the guide on this https://ardupilot.org/rover/docs/common-radio-control-calibration.html

To set the correct motor outputs from the autopilot you will need to configures the servo motor outputs to send the signal to the motor driver, depending on your setup it will generally be one of 2 ways, skid or separate steering and throttle.

For my setup with skid steering this would be

  • [SERVO1_FUNCTION] = 73 (Throttle Left)
  • [SERVO3_FUNCTION] = 74 (Throttle Right)

For other steering types you should follow the setup recomendations on https://ardupilot.org/rover/docs/rover-motor-and-servo-configuration.html

Ardurover Control Modes

By default rover will set the mode to “Hold”, this will prevent any control movement even when armed, you will need to choose the desired mode to use the rover, “Manual” mode will generally be the best place to start to check proper functionality of the system, in skid mode this will correctly move both output 1 and 3 as you move your sticks.

Satbertooth Aux Output

The Sabertooth also has two open collector outputs that can sink upto 8A each, these can be configured to be either switching or variable power outputs based on the input A1 or A2, these need to be specially configured in the DEScribe application in PC or Mac. These can be used to drive brakes, fans, solenoids, valves, heaters or similar medium power devices.

I have used one of these output to control an onboard LED light, this is configured as Servo output 4 is set as a switched output and is connected to A1, then in DEScribe I have configured.

Note these are open collector so you need to connect the positive to battery and the negative via the output.

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Hi Drew
Can I please have you email as I’d like to chat

Hi Ian,
For some reason I’m spending days trying to understand what I’m doing wrong
What ever config I try I cannot get Throttle left and throttle right to operate my drive motors
I’m using a sabertooth 2x32 with a Pixhawk 2.1 black cube via a Flysky FS-I6X
I have the Ublox Zed-f9p fixed and ready to go
The only way I can get the wheels to drive is when i place the outputs RCpassthru but this is useless in mission planner.
Get a bit desperate now after burning days on this issue
If you are able to help it would be extremely appreciated

Hi Drew
Got my Ardusimple zed-f9p modules with Xbee radios and all working but I’m back to my original issue with the drive motors. What I failed to explain was how I got them to operate, and now understand that both motors, Sabertooth, Pixhawk, are all laughing at me :cry:
I need to be strong here and show them who is boss man :face_with_monocle:
So I went back and followed your instructions hoping to find an error in my configs
Start with the sabertooth Its set to the following 1=off, 2=ON, 3=On, 4=Off, 5=Off, 6=Off.
Keep in mind that I’m using 2 X12 volt lead acid batteries.

As per instructions the following changes were made in ConfigTuning full parameter list
RCMAP was 2,1,3,4 Now 3,1,2,4
PILOT_STEER_TYPE=1

RC settings as follows
RX setup output mode OUTPUT>PWM SERIAL>i-BUS

Wiring Config
Cube output servo channels 1 & 3 for signal and common negative

So here is what happens
Inital setup>Servo Ouput Screen
if I select RCpassthru I get the motors to operate from left and right paddles of course if I move the output servo wires over from 1&3 to 1&2 I get to use one paddle

Hi Drew
First mission completed
just need to tune the steering and throttle thank-you for that well written instructional guidance

Servers by jDrones