Servers by jDrones

Rover setup questions?


(anon94298870) #1

I am about to embark on a little rover build just for fun. I have printed this mini rover with a few modifications, and plan on using a pixracer. My one main question is do I have to also get a motor driver or will 2 simple brushed esc work to control the brushed motors that I plan on using. I have read through the wiki but still had that question. I plan on using these motors but still need a small ESC that would support up to 4s battery.

The fella that built this used this ESC but I am a bit skeptical about it.


(rmackay9) #2

I suspect the MicroRC 5A brushed motor ESC linked will work.

The output from the pixracer is normally PWM in the range of 1ms to 2ms (aka 1000 pwm to 2000 pwm). I looks to me like the ESC can probably accept this signal.


(Matthew ) #3

@rmackay9,

those look like nice little ESC’s would that be considered just MOT_PWM_TYPE, 0, 3, or 4. I suspect that its either 0 or 4.


(rmackay9) #4

@Matt_C, Yes, I think these ESCs would use MOT_PWM_TYPE of 0 (Normal).


(Matthew ) #5

@rmackay9

I have not gotten those esc’s to calibrate using mission planner. I did however get them to work by plugging them directly into X8R frsky receiver. Does esc calibration work on mission planner or do they need to be configured via the parameters screen? Trying to set up the same rover as mentined above with skid steer steering, have read the rover doc’s from here. I have the exact same parts as listed in the first post.


(rmackay9) #6

@Matt_C,

Thanks for the report.

We don’t actually support calibrating the ESCs in Rover so I’ve added it to our to-do list. My guess is that MP is showing the ESC calibration even though Rover doesn’t support it (it does work for Copter).


(Matthew ) #7

So considering that they worked with the x8r when i just wired that and a bec to the motors worked but once they are connected to the pixracer I don’t get any feedback, could I manually program the esc using the max min middle values for the esc? Short video with it working with it wired without pixracer.
With just x8r


(rmackay9) #8

Nice rover.

I can imagine a few possible causes:

  • the output pwm range from the pixracer isn’t the same as the receiver’s output range. The way to fix this is to set the SERVOx_MIN and SERVOx_MAX (where x is the output channel connected to the motors) to match the RCy_MIN and RCy_MAX (where y is the input channel for the throttle from the receiver).
  • maybe there’s no PWM output coming out the back of the pixracer. This could be because the safety switch is enabled (disable by setting BRD_SAFETY_ENABLE = 0), the vehicle is disarmed or it’s in Hold mode (try manual mode)

Hope this helps


(Matthew ) #9

is there a reason to disable the safety switch on rover is that necessary as long as you press the switch before arming? Most my knowledge base is copter and plane figured I’d dabble in rover a bit.


(rmackay9) #10

There’s no particular reason to disable the safety switch - I was thinking that perhaps on such a small rover there was no room but the parameter might have been left at BRD_SAFETY_ENABLE = 1. … The Copter experience should serve you well with Rover for the most part… although Rover is missing some features that Copter has they are coming together quickly.


(Matthew ) #11

I have managed to get the left track working through the pixracer, but am struggling setting up the right track, and I know it is how I have my radio setup but am a bit confused how you would go about setting up a radio profile. I have servo1 set to throttle left and servo3 set to throttle right, and pilot_steer_type to 1. but cannot for the lige of me get it to work on the right track, i have calibrated the radio with two stick inputs taranis x9d+ have left up/down (throttle) and right up/down (pitch) sticks programmed, am I missing something?


(rmackay9) #12

@Matt_C,

By the way, in case it’s not clear, it isn’t necessary to use two-paddle-input on a skid-steering vehicle - I actually recommend sticking with the more traditional steering and throttle input. Some users get confused with inputs-and-outputs thinking they are somehow connected… but they’re really not.

To dig in further, if you can provide a dataflash log I might be able to see the problem.


(Matthew ) #13

@rmackay9

That would be much better as some students have quite a hard time understanding the dual stick setup. I have now managed to get both track working using pilot_steer_type to 1 but would love to keep it to default of 0. I will get a df log tonight once I get home.

One other question that isn’t related to this project is about some pololu motors I got from amazon without a gearbox. Pololu HP 12V Motor with 48 CPR Encoder for 25D mm . I have looked at pololu.com and have not found any gearboxes that I could attach to them.


(Sebastian SchĂĽrmann) #14

I guess the motor is meant as a replacement part. Those motors are usually sold/bought together with a gearbox. I has a quick look with google and could not find a gearbox without motor.


(Matthew ) #15

@count74

Thanks for the info, I was afraid that that might be the case as I also scoured the net and could not locate any gearboxes either. No wonder they were so cheap hahaha, thank goodness that amazon lets you return stuff without much hassle.


(rmackay9) #16

Matt,

It should be possible to use the more common separated steering and throttle input by simply setting pilot-steer-type = 0 and then I suppose there may be some changes on the transmitter side in case you want to get both steering and throttle on the same stick… but from an AP point of view, there shouldn’t be any other changes required.


(Matthew ) #17

@rmackay9

So I got some time to mess with my little wee rover and I know that I have my controller setup absolutely incorrect, haven’t changed anything from the way I had a quad setup on it earlier, and its not the normal controller I use its a Spektrum DX6E (normally use taranis). I dont have any compasses turned on nor do I have any GPS in it at the moment. I have the oddest thing happen when I start my rover before it is armed the artificial horizon is upside down and once it is armed it flips to the correct orientation. I have done a level cal, but I cannot get the 6 point accelerometer calibration to complete it always fails on the turn vehicle upside down portion. Tlog I was unable to pull a DF log as it woudn’t download and all the DF logs had a date of 1979! In the mean time I am going to try and reflash the firmware and try and setup my controller so i have forward backward on the left stick as well as right left on the left stick. One day I will get it all working!


(Matthew ) #18

I figured I may have screwed up hooking up the motors as I had main 1 as left and main 2 as right motor (both had the appropriate servo function mapped to them) so I switched right to main 3 thinking it might have something to do with why I can only control forward backwards on left stick up down and right to left on the right stick side to side. That didn’t solve the issue, and I was using an xbox controller hooked up via usb and was streaming telem and video via uavcast. I also have some issues with it not going straight when you push forward on the throttle. If I were to generate a log file what in the bitmask could be turned off to help make it not such a big DF file? Last one I generated was so big it took hours to download via USB and I just canceled it! I have looked at the rover
Does it really matter what main we have left and right in as long as the servo function is correct?


(David Boulanger) #19

How do you like Uavcast? I’m thinking of trying it. try to post a short log. Power up, use the rover for 10 or 15 minutes, then power down. The log should be of a reasonable length.


(Matthew ) #20

@David_Boulanger

I like UAVCast, it works well for command and control, video is still a work in progress which might also be due to the fact that in Montana cell coverage is very poor in a lot of areas. Bernt the maker is very attentive to needs and is usually always reachable via discord chat to help out. He is working diligently to update the program to user requests and new features. We have had an individual arm and takeoff a VTOL from a different state without issues. For a rover this could have so many endless opportunity.