Motor braking

Hi everyone,

I just registered myself to the forum.

I have build my first e-board (with a lot of help from examples of this forum). The board handles great but there is one problem, if I apply throttle and let the board coast for a while and then reapplying the throttle, the motor would sometimes brake.

Setup
Motor: sk3 5055 280kv (no problem with power and fast enough)
Gearing: motor 15t, wheel 30t
ESC: HK 90A boat ESC (braking works well)
Battery: s6 5000mAh

ESC is controlled by an arduino nano with a nrf24l01+. In the nano I have programmed a speed and acceleration limiter.

The nano in the board gets its signals from a modified Wii nunchuck, wich also has an arduino inside with a nrf24l01+.

Even with the bare minimum needed for controlling the ESC (without all the fancy stuff like speed limiter etc) the motor would still brake sometimes after reapplying the throttle when coasting for a while.

What could be the solution for this problem?

Edit:
I found in another topic that the esc is the problem.
For now I have fixed it by "taming" the esc with the arduino.

Hi mate

How exactly did you "tame" the esc with the arduino? I'm in the same situation as you were :lol:

I noticed my esc did not know the motor position if I let the motor coast. The same problem occured when there was a dksconnection between the tx side and rx side and it sudden'y reconnected again.
So I managed to make somekind of cruise control so the esc always gets a ppm signal and the motor never really coasts/freeruns.

It worked something like this:
The program had a counter that would go up and stay at that number until the thumbstick was pushed down (to slow down, subtracting from the counter) or pushed up (to speed up, addind to the counter). The adding and subtracting had a delay so I could control the throttle better. The signal was offcourse send to the esc. I also had the Z button as a safety switch, I had to press the button to go forward. Incase of a dangerous situation, I had a dragbrake when the Z button was released.

It was rideable but not really enjoyable. If there was a disconnection somehow, then I needed to stop the board before I could apply the throttle again. Also the throttle feels sluggish because of the delay.

I dont have the sketch anymore because I now have a VESC. I'm far from a programmer, I watched a lot of arduino coding tutorials and experimented with the esc.

I hope I gave you enough information. Good luck with your build

Thanks a heap my build is going quite well besides the ESC problem. Not quiet ready to fork out the cash for 2 Vescs just yet :wink: I found that if I set the throttle trim on my gt2e to just enough that it would make the motors turn, I would be able to keep them spinning a tiny bit after releasing the throttle enough to keep the stuttering from happening but if I applied the brakes the tiny bit of power would go away and I'd be back to square one and have to stop I saw some guys reflashing other ESCs to blheli and simonk firmwares might try that next :lol:

I hope you figure it out. Let me hear if it works with the new firmware. I'm really curious

Yeah I just got my arduino in the mail Biggest problem so far has been trying to figure out a way to get the heatsinks off without ripping apart the boards waterproof epoxy isn't the easiest stuff get through :lol:

I am interested to see how it goes. I have the same ESC laying around and the main reason why I am not using it was the stutter when reapplying throttle. Brakes on mine also were almost unnoticeable.

Yeah I'm doing my first build with dual rear 50mm's and bought 2 of the ESC's because they could handle 6s and they were cheap Just finished up the motor mounts and got a couple more rides in, the stutter feels more like reverse because when it happens it doesn't stop until the motors come to a complete stop. I've been looking around and I've only found one post so far where someone's claimed to have flashed it successfully, but it seems like an older or different version of the esc http://www.rcgroups.com/forums/showthread.php?t=1513678&page=526 I hooked up the arduino to one of the esc's through the signal wire and they seem to not have a bootloader which means I need to reflash the chip. A bunch of jargon but no harm in trying :lol:

Ok so I've experimented a lot with the esc. The first thing I did was cut off the enclosure. I did this by drilling a whole bunch of holes in the shell and ripping it apart with pliers. The whole esc is covered in this black silicone looking stuff. It was a pain to get off. On the bottom of it there were these thermal pads which would've made contact with the bottom of the case. I scraped a lot of the crap off the board and found that it had programming pads! I soldered wires to it then to my Arduino nano. Booted up a program called BLheli and couldn't find a firmware for this esc. However, I did find one called BS.hex which was similar but wouldn't let me flash until I went into expert mode, because the little chips on the boards are different. (atmel8a vs atmel168pa) still wouldn't flash and gave me a weird error, so I clicked this button called erase chip, thinking it would wipe the firmware off the esc. nope, wiped the boot loader off my arduino so now that doesn't work only way to fix it is to get another arduino with a boot loader so I'm stuck here for a while