Hi,
I’m a technology instructor at a new Applied Tech HS setting up a long term rover project and working out the kinks over the summer. I will ultimately be using the Dagu wild thumper and a sabretooth dual brushed esc. for our projects.
For now, due to time constraints, I picked up a Dagu Rover 5 and a t rex dual motor controller. I’ve had success setting the rover 5 up as a straight up RC vehicle using a spektrum dx4c rc car controller and receiver.
Given that success, I now want to introduce the 3DR Pixhawk auto pilot and having a difficult time getting it to work.
Mission planner reads channel inputs but the T Rex isn’t seeing the signals and thus no outputs. The T Rex blinks rapidly green. I was able to calibrate channels in the trex calibrate mode but once I reboot with jumper off it isn’t responding.
Regardless of where i place outputs on the pixhawk the only channels I get response on are pitch and roll - I’ve got the mixing jumper in place and wonder if there is an issue there as Pixhawk would do the mixing? Regardless with or without the mixing jumper, I’m not getting any signal to the trex.
I assume the trex should remain in rc mode? or would this be an analog input?
I have a lot of experience with the Pixhawk on multicopters but a bit confused with the rover clearly.
Any help greatly appreciated
Very nice project, be sure to post images and results in a topic here.
If it’s not already done, you might want to take a look at the setup page for ArduRover HERE.
First thing to do is to do the “Initial Setup” in the Mission Planner where you will flash the new ArduRover firmware on the PixHawk.
One important thing is to set your outputs for “tank” like they say in the tutorial:
[highlight=#ff6600]If, however, you have a treaded tank or some other vehicle that uses different speed motors on each side to steer, use the Skid Steer settings[/highlight]
Let us know how it went
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Hi Eric,
Thanks for the response. I did flash the rover firmware and done compass calibration.
I think the issue is the channel config between the spektrum ground receiver and the ppm converter, and how the t rex connects to out puts on the pixhawk.
Any wiring diagrams would be helpful.
You might want to try with a standard RC receiver without PPM first ?
pixhawk requires PPM will not work with PWM. I’ve switched over to air controller and receiver now and getting 1 motor pair (left side) to move fore and aft but no spin on the opposite side. Removing mix jumper causes the rover to roll fwd with no input.
That’s probably the option here:
If, however, you have a treaded tank or some other vehicle that uses different speed motors on each side to steer, use the Skid Steer settings
Ive got skid steer in/out both attributed (1)
Also tried skid steer in at (1) and skid steer out at (0)
mix jumper removed still causes it roll with no input. with jumper on I can turn but no forward motion.
Thanks for your help
Should it still be set as an RC device? I assume so
The Skit Steer option should be set on the Sabertooth at first yes.
But what APM is saying is it need to be set in the PixHawk settings so it will send the right signals.
im using the t rex now just for this build - sabretooth will be on the wild thumper
this is robot5
my questions:
Should both skid steer in and out be attribute as (1)? or just skid steer in?
Aside from 2 motor leads to the t rex, should there be any other connections between pixhawk and t rex?
The t rex indicates motor out put on both sides via led but not turning on right side of vehicle.
Seems like I am able to control flight modes via switch on rc but perhaps have motor connections wrong? or rc connections wrong?
We never did this particular setup but.
]Setup the TRex to be in Tank mode/:m]
]Connect both RC connection the PixHawk (should be the only connection yes) Positive - Negative - Two signals/:m]
]Set the Mission Planner to a Tank mode too (rover.ardupilot.com/wiki/skid-st … er-tuning/)/:m]
If you have only one side that is working, you might not be in Tank mode on both the PixHawk and TRex.
One thing you can try, is to put a Servo instead on the PixHawk outputs to see if there is a signal out on both outputs.
eric - thanks once again for your rapid response.
I’m confused by what you state though.
I have mission planner set for rover - when you say tank mode - I’m not sure what you mean - its a tracked vehicle so I ganged the front and rear motors on each side to operate as one motor like the dagu wild thumper has already prewired to do.
I’ve been messing around with Skid steer in and out lines but don’t see any difference in behavior.
I have the rover in MIX mode with the jumper in place - once I remove the jumper, the vehicle begins to move the left motors very slowly. I have yet to see the right motor operate with pixhawk in the loop.
Since the DIY drones 3DR wiki is for APM and not Pixhawk it is quite confusing as to what channels go where.
My other thought is whether pin 5 on the trex should be connected in some way to the pixhawk to set autonomous vs manual control though I think that is for an arduino or other non PWM RC input. My sense is that it should be set as an RC device since the out put from pixhawk would operate as an rc device and auto/manual control would be flight mode based.
Any other resources you might suggest?
Thanks!
…adding to this thread as it applies to original post. My HS students have built 6 wheel Dagu Wild Thumper rovers. First they set up as a straight rc input vehicle without issue. We are using aircraft transmitters Spektrum DX6.We have the two channels set as pitch and roll and able to operate the vehicle with the right tx stick.Next step is to incorporate a pixhawk board to enable autonomous mission planning but I can’t seem to get the rover to operate with one stick skid steer operation.Im familiar with pixhawk having used it in aircraft and had success setting this up in the past but I have yet to duplicate with pixhawk.Im using a sabretooth 2x12 ESC and have tried settng switch 4 for independent or mixed mode and attributing skid steer in and out in mission planner params.I’m able to get the pitch and roll channels recognized in the calibration but I’m only able to get output on the roll channel. when roll is invoked I get one side of the vehicle spinning one way and the other spins opposite to turn on its axis - this is good and what I want but there is no output on the pitch channel.Scratching my head here. Is there something I’m missing?Thanks for any help
The information for APM Rover applications is not well documented. Here is what they say on their Wiki:
The skidsteer parameters are used to configure vehicles that have fixed wheels and steer like tank tracks (do not use servos to steer the wheels but rather use differential speed between the left and right wheels). The parameters are: SKID_STEER_OUT and SKID_STEER_IN. When enabled, flight controller’s ouput RC1 is used for the left track control, and ouput RC3 is used for right track control.
I really appreciate this reply also as I’m new to this technology platform but I have noticed that there is always someone willing to help.
Thankyou
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Hi stevecohen, it;s been a very long time but have you managed to get this pixhawk based rover to operate with the trex motor controller?
