Servers by jDrones

Differential Thrust Boat with ArduPilot

(ahmet omer ozgen) #26

Faulty connections? or your Power module is burnt.

Btw when your device is fixed, does your gps position move a little bit?

(Steven George) #27

Hm, could be, but I don’t think so as it’s worked out before.

yes, the gps position does move a little bit.

(David Boulanger) #28

What type of power module are you using? Do you have a .bin log? Or at least a parameter list. I can’t tell what is triggering the failsafe. could be a battery failsafe.

(David Boulanger) #29

You have a red EKF in the second picture. Even a tlog would be of some help possibly.

(ahmet omer ozgen) #30

your readings are faulty. Either it’s a parameter error, connection fail or Power Module fail.
I use the Chinese generic PM with a SLA battery with no issues. Or there is a slight chance that your battery is failing(simple multimeter would prove it wrong in a second tho)

(Steven George) #31

We have the 8S Power Module that came with the Pixhawk. The paramater list is attached.

Differential Thrust Boat v6.param (13.4 KB)

Do you know where we could find the .bin or tlog files? I’ve tried going through the program files.

(ahmet omer ozgen) #32

I think you must connect the usb cable to the pixhawk and export the files on the terminal page, or the sd card can be inserted in to the laptop. But I’m not that sure tho.

good luck!

I have just completed my skid steering project. Only issue that makes me worry is the buggy gps lines

(David Boulanger) #33

Parameters look OK. On mission planner click on telemetry logs. Easiest way for dataflash logs in my opinion is pulling the card out and inserting into the computer

(Steven George) #34

Ah I see.

I’ve found and uploaded the files here.!AooOmruzHD5Lj0nqjXDL6Kmm2Fhf

(David Boulanger) #35

I just had a quick view of the tlog. rc1 - 3 in are always zero. Are you sure the transmitter is on or the receiver is working?

(David Boulanger) #36

Actually after looking at the parameters again they seem to indicate that you have not calibrated a transmitter. Are you using one? I did not notice a joystick enabled in the tlog. Also this boat has yet to be tuned. ATC and PIVOT turn plus other stuff. This has worked OK previously?

(Steven George) #37


Thanks so much for seeing that, I’ve just doublechecked our set up and it looks like I accidentally put the wire in channel 1, instead of SBUS like I normally do.

As for the tuning, we were hoping to tune it in that day, but it looks like we’ll have to try again.

We originally had two boats, one smaller RC boat, as well as a larger catamaran. Both were done using the set up of differential thrust, and we had used the smaller RC boat just because it was quicker, but now we’ve actually just nearly finished the set up for the large catamaran, pictured here.

We’re just waiting on some bullet connectors, and then we should be able to drive this (manually) in a water tank later this week, before we make it out to a lake again, via the pixhawk. We will be applying everything we’ve done on the small RC boat onto the bigger catamaran, and hopefully will be able to tune it (NAVL1_PERIOD and ATC_STR_RAT).

Thanks again for your help!

(Steven George) #38

Regarding the NAVL1_PERIOD and ATC_STR_RAT, what would you recommend is the best way to adjust these values? Do we have to try it in auto mode, change the values, and repeat as necessary?

(David Boulanger) #39

Tune the ATC stuff first and save the NAVL1 stuff for last. There are some tuning video’s Randy has made which will help you. In the past when I had the boat close I would run an Auto mission repeated a bunch of times and to a little more tweaking.

(Steven George) #40


Thanks for all your help. We’ve now managed to complete our first run of our bigger catamaran. I’ve uploaded a screenshot of the Mission Planner along with a short video of our boat in the Google Drive Link.

However, the next run for us was not as good, on one side the motor blew (I believe there was too much mechanical resistance, and when the pixhawk tried to compensate, the ESC, which has a higher current than the motor tried to give too much current and overheated the motor) and on the other the shaft disconnected from the motor.

We will now fix the connections and try again. Additionally we will cap our throttle with the Max Throttle Paramater, and reduces the speed. Next time we do it we can adjust the tuning parameters a bit more.

We would also like to try and incorporate some obstacle avoidance. We are looking at these sensors:

And the following paramaters:

Parameter Value
RNGFND_MAX_CM 700 (i.e. 700cm max range)
Parameter Use Value
RNGFND_TRIGGR_CM Distance (cm) from obstacle at which the vessel begins turning 200
RNGFND_TURN_ANGL Direction and strength of the turn – from values -450 to 450. Large positive or negative cause increases to the vessel’s maximum lateral acceleration while values near zero cause gentle turns. Negative values cause the vehicle to turn left, positive causes a turn right. 100
RNGFND_TURN_TIME Time (seconds) the vessel continues to turn after the obstacle is no longer detected before turning back to its original path 2
RNGFND_DEBOUNCE The number of consecutive readings to trigger a turn response 2
RNGFND_ORIENT Orientation of the rangefinder – ‘0’ for forward-facing and ‘4’ for backwards-facing 0
PRX_TYPE Enables rangefinders to be used as proximity sensors 4
AVOID_ENABLE Enables avoidance using proximity sensors 7

Does anyone have any prior experience with this? Any advice would be a huge help.

(David Boulanger) #41

I’ve used the Maxbotic sonar before years ago. I thought it was a waste of time actually. If it gets any water spray on it I think you may have problems. Nice amount of freeboard on those hulls. I should note here that when I was using the Maxbotics sonar it was on a helicopter and never worked well flying over grass. It may be ok on a boat but keeping it dry will be a challenge

(Steven George) #42

That’s good to know thank you. We are looking into a way to keep it dry. Since there is a large amount of freeboard, in still water the sensors will not likely get too wet, but it is not ideal. We found some other underwater sensors, but they were a bit out of budget.

Do you have any recommendations for sensors?

(David Boulanger) #43

not really. But I would like to know what are used on cars. They can be dirty, wet and they always seem to let me know when I’m parking to close to something

(ahmet omer ozgen) #44

upon the initial advice of Mr. Randy i chose the Lidar. well it worked well. he had replied that all the lidar works better than sonar. I had TfminiLidar.

I finished my differential setup with no issues in automode. I don’t know the details but a very experienced rc model builder(he builds planes boats etc instagram/expatmodeller) told me about the possible motor failures if i use a bigger prop more blades etc. So i can only say that maybe you should at a boost motor?

(alfonso riccardo) #45

Dear Steven i have same problem to configuration my taranis. I try all setting find on the forum but the motor in my veichle is not responding. If i by-pass the pixhawk and connect directly the motor to receive XR8, motor working (steer skid config), but if connect via pixhawk all motor no working. Can i ask you posted the configuration used on taranis ? I Have model x9d plus setting in mode 2. I have installed open tx software . If you posted the config you help me more. Many thanks in advance.