2DOF Joyrider Flight/Race Sim Build

Looks like a blew one of my JRK 12v12's. It only drives my roll motor in one direction, and when it tries to roll the other way I get motor driver errors and no motor operation. Of course at $100 each, I don't have any spares. Not knowing what caused the failure, I'm hesitant to spend another $100 when it might just fail again.

Strange, when I cook a monster (assuming it's a real vnh2sp30 chip) they usually don't do anything but stink. An internal chip failure is rare and it's almost always been a burnt race for me, in which case the board does nothing but light up. You might be tempted to try a monster for that axis. I know the monsters are intimidating but they really are easy to work with. Contrary to popular belief the smc3 code needs no altering to work properly. I burnt up a couple monsters building my current sim (loose wires my fault) but at 7.50us it's no big deal.

My son was driving Dirt3 and rolled the car, resulting in some rather extreme motion - but nothing it hadn't done before. It appears to have blown one half of the H-bridge. The motor drives in reverse, but when trying to drive it forward the VNH2SP30 chip gives a motor driver error signal and there is no voltage output to the motor. I'm working with Pololu to troubleshoot, but best guess is it is dead. I had the JRK set to a 12A limit, plus there is a 10A self resetting breaker in line with the motor. So it shouldn't have failed, but maybe just bad luck.

I am tempted to change to a Monster Moto since one of those plus an Arduino means $15 USD compared to $200 USD for a pair of JRK's. I've quite comfortable with an Arduino so that doesn't scare me. Even if Pololu sends me a free or cheap replacement, I'll probably get some MM's on order as a backup.

While waiting for replacement parts, here is a video of the sim in action prior to the failure.

Another, slightly fuzzy video, with the cover removed. Normally the cover simply slides forward so the driver can get in and out, but it was completely removed here so you can see what is going on inside.

One of the best if not the best joyrider ever built.

woow, i will follow your thread, what material did you used for the wim covers?

it seams preatty nice!
(while waiting for spare parts, maybe you could order an arduino and motomonster... they are ultra cheap) (i have never used, but they are cheap) (i pray god to keep safe my jrks 100 usdlls in this days in mexico is ultra expensive!)

fer

jrks are expensive. You would think over time the price would go down or the product would get more features like a double chip.

U$S165 here (Argentina) almost 1/4 of a minimum salary...

The covers have have a frame made out of 1/2" square steel tubing. The panels are made of corrugated plastic, a material commonly used to make cheap yard signs. See here: http://www.homedepot.com/p/Coroplas...te-Corrugated-Plastic-Sheet-CP4896S/205351385

I have a replacement JRK on the way, plus some spare driver chips so I can repair any damaged JRK for 1/10 the cost of a new one. But I do also plan on buying a Monster Moto or two. I already have a few Arduino's laying around.

All that motion and only two motors. Cool!

jrk has been arround for awhile and the price is always the same $100, i dont think they will become cheap... thanks god for we living in a devaluated currency country there is arduino... i just wish arduino could have all the features that rjk has... in my wish the number one is the "learn position feature"

Essentially a JRK is just the equivalent of an Arduino and half of a Monster Moto an a single board. Any lacking features of the Arduino/MM setup are software and not hardware.

I'm tempted to build my own motor drive, since I've designed and made PCB's before. The problem is the loose motor drive chip's would cost me significantly more than an assembled Monster Moto. But I could integrate a pair of MM's into a pre-assembled sim driver module. That could have all the features of the JRK and more if done right, and would cost significantly less.

But I've got other projects on my plate first. I need to get my sim working again with JRK's, and then do some testing on SimTools 2.0. Plus I want to get a standard Arduino/MM setup working before trying to make and improved version.

Hope you get your sim back up soon. One of the nicest I've seen for sure. Did you tell him to drive it like he stole it?

If you have any sort of electronics background then stitching together a MM/Arduino setup with SMC3 code loaded is child's play. For the price of a MM it is not worth building your own drivers.

i started to play with arduino this week, i am amaized... but my learning curve will be a little bit hard...

yes totally agreee, arduino only needs software imprubements

Sim is running again. I did in fact blow a JRK. Vin was shorted to B. There is no visible damage, and no burned smell. Pololu recommended I set a maximum acceleration to decrease spikes. I dropped the setting from 600 (no limit) to 300 and there was no obvious difference in the responsiveness. Trying it at 60 was way too slow. I probably still need to do some tuning.

I do have a couple spare driver chips, but it may be beyond my soldering skill to replace a bad one.

I also discovered I was not running a current limit on the JRK's. This was confusing since I setup the current limit. But setting up a current limit will only cause current limit events to be logged, and nothing will happen when the current limit was hit. I had to actually enable the current limit to either temporarily or permanently shut down the driver. Once I did that on the new JRK and looked at the error counts, I discovered I hit the 12A limit all the time, even with the motor lever disconnected. Oddly the JRK utility software maxes out at 5A, so it won't show me what the actual peaks are. For now I've left the max current at 12A and enabled (NOT latched), which does cause the plots to show a lot of clipping of the duty cycle to stay under 12A, but interestingly I don't notice a different feel than when actually racing than when the current limit was turned off. Since the current limit is being enforced by the micro, it is quick but not instantaneous, so there is still risk of getting a big spike through.

I do also have a 10A self resetting breaker on each motor, but this is very slow to respond. Even at 50A, it will take 0.2 to 0.3 seconds to respond. So it is really just there for catastrophic problems.

I have some MM's coming in from China. Those will allow me to double my max current to 60A, assuming the drivers will share the current evenly. That should give me enough safety margin that my 47A PSU's become the weak link. I'm going to try to modify the typical MM/Arduino setup to allow me to implement current limiting like the JRK's have.

@cgodwin, could you please elaborate on this statement "I'm going to try to modify the typical MM/Arduino setup to allow me to implement current limiting like the JRK's have." Thanks