I’ve looked over the forums and the wikis but I haven’t been able to find anything that has solved my problem.
I’m using a Pixhawk APM with a 3DR GPS/Compass and a telemetry radio kit. I’ve managed to get it moving, but it’s only going in circles and I can’t figure out why. Please note that I’m not using an 8-channel radio (don’t even own one), but I didn’t think I would need it since I’m currently only trying to use the guided mode via the telemetry kit. I understand that I won’t be able to tune it finely this way, but it doesn’t need to be perfect, only a proof of concept that it can go from point A to point B.
What happens when I attempt to use it: as I arm the Pixhawk by holding the arming switch/button, the wheels immediately move to a position slightly turned to the right. I’ll throw in a picture to show you the alignment. When I tell it via Mission Planner to go to a location (guided mode), the wheels stay locked in the same position it went to when it was armed and the Rover drives in a circle indefinitely, regardless of whether the Rover should be making a left or right turn. In other words, no matter where I tell it to go it’s still doing the same circles.
I’ve tried tuning a lot of the settings as recommended on the wikis but I’ve had no luck. It just goes in faster or slower circles. It’s a pretty old RC vehicle that my professor had laying around and let me use, so I don’t have any kind of make or model for it. The steering servo is connected to pin 4 and the throttle is connected to pin 3, as listed on the wiki. Any suggestions on how to fix this? It also uses a 7.4V 3000mA LiPo battery (2S), could this be causing an issue?
One last thing. Is it possible to run missions in AUTO mode off of Mission Planner without the use of an 8-channel controller at all?
Thanks for your help,
Try checking the “reverse” box next to the roll (aileron) bar in the Mission Planner Radio Calibration screen.
I tried that once and it didn’t seem to help. I tried it again this morning and it’s still doing the same thing. Circles with the car’s front wheels turned slightly to the right.
I’ve been working on it for the past few hours and it doesn’t seem I’ve made any progress. I’ve narrowed down several things, however. I removed the Pixhawk and its accessories and reconnected the steering and ESC with a 4 channel receiver/controller. This was to test that it wasn’t a problem with the car/the alignment wasn’t off by default. It works fine. I also know that, during the circles that it goes in, the car speeds up when it’s trying to “go straight”, and slows down when it’s “turning around.” This means it has a general idea of where it is and where it needs to go.
This pretty much narrows it down to some sort of issue with the configuration for the steering servo. After reconnecting the Pixhawk and booting everything up, the steering servo locks into that position and if I ever so slightly try to manually move it, it stutters and wants to stay in that position. What could be causing the steering to lock into position like that?
I don’t think it’s a powering issue, I’m using a 2S 7.4V 3000mAh battery and a 3DR power module. The firmware is ArduRover 2.49.
What is the voltage of the ESC BEC that is being applied to the Pixhawk servo output power bus?
I assume that you are using the transmitter elevator joystick for forwards and backwards and the aileron joystick for steering right and left?
Have you tried driving the rover in the Manual Mode using your R/C transmitter?
Are you using a standard R/C receiver and a PPM encoder?
Have you calibrated your R/C transmitter in the Radio Calibration page?
My voltmeter is reading 6.05V DC at the Pixhawk servo output bus.
I’m using the guided mode through a telemetry radio to control the RC car. The 4-channel radio is not hooked up to the Pixhawk, as my understanding was that I could use the telemetry radio to interface directly with the Pixhawk and control it from my computer. It is the only thing that is currently communicating with the vehicle. Does this setup require an 8-channel RC controller for the guided mode?
Not good. The servo output power bus voltage should not exceed 5.5vdc.
I would start with a R/C setup and get that working in the Manual and Auto Modes before trying to control your rover through the telemetry channel.
I have no experience using the telemetry channel to control a rover so hopefully some other member on the ArduRover Forum does.