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Show and Tell / Re: Ludwig/Taigen SU-152 (early production)

« on: August 24, 2019, 05:54:19 AM »

After troubleshooting the electronics with Luke, I spent this afternoon adjusting the servos and drivetrain. We now have 100% functionality!

It's got the full range of elevation (-5 to +18°) and traverse (+/-12°). Track tension could do with a bit of adjustment, but it seems to be more of an issue on carpet than dirt or grass. The xenon flash looks great through the muzzle brake and is exceptionally bright, but the camera doesn't pick it up very well. I'm also very impressed with the PDSGB, it pulls like a train. The tank has no trouble steering on or climbing over anything, and drives nice and straight without the wobble or gentle curving I've experienced with regular gearboxes.

It's a shame the TCB is out of production for the time being, it's easily the nicest-driving board out there. I'm glad I stocked up on a few while they were still available from HobbyKing.

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Show and Tell / Re: Ludwig/Taigen SU-152 (early production)

« on: August 21, 2019, 03:21:18 AM »

Cheers Luke, that firmware update has fixed it. I've had a little bit of a test run this evening and everything's now working 100%. I'm using the FlySky i6x transmitter and FlySky X6B iBus receiver, so did the Benedini issue have something to do with the timeout settings you addressed?

I tried exponential response mode on the Sabertooth, and while it does make small steering adjustments easier than the linear mode I still get Heng Long-style superspins at more than half stick. I've gone back to linear mode with the endpoints at 33%; it's driveable at speed, and full stick lets me turn on one track (the KV-1S and by extension SU-152 gearbox couldn't neutral steer). All in all I'm really happy with how everything's working now. Thank you again for all your help, I really appreciate it!

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Show and Tell / Re: Ludwig/Taigen SU-152 (early production)

« on: August 20, 2019, 06:08:55 AM »

Dipswitch 5 was already set to off as per the wiki page, so for the sake of thoroughness I tried switching it on. The motors didn't creep, but both the throttle and steering were wildly oversensitive and twitchy (and interestingly, ignored the TCB's inertia constraints). I figured that since the motors weren't moving of their own volition in that setup, then the ESC itself was probably capable and there must have been a calibration issue like you said.

I ran through the manual calibration routine you outlined, and so far it looks like the motors are behaving the way they ought to. The motors stay stopped when they ought to, and the tank can drive in a nice straight line again. Throttle response is nice and smooth, but steering is extremely sensitive so I've mapped the channel's endpoints to 33% on the radio which makes it a lot more driveable. I don't know if that's expected behaviour from the PDSGB setup or if it's still a calibration issue, but in the meanwhile it's 100% better than it was before. I'll look to upgrade to the serial Sabertooth when there's something in the hobby budget again.

The Benedini still automatically starts when the TCB is powered on. I've confirmed the issue with a second TBS Mini (using the default TCB configuration as shipped from Thomas), so it doesn't seem like a parameter or prop setting. Oddly enough, if the TCB is switched on before the radio transmitter, the Benedini doesn't play its engine sounds. When the transmitter is turned on, the Benedini starts the engine sounds, like it's reading a channel incorrectly or something. I wonder if there's a default channel the TBS expects to read? I'll play around with the radio setup and see if assigning the functions to other channels makes a difference.

Thanks again for your help, Luke!

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Show and Tell / Re: Ludwig/Taigen SU-152 (early production)

« on: August 19, 2019, 06:14:05 AM »

Thanks, Luke.

I have the Sabertooth hooked up to the RC outputs since it's the non-serial version. I know it worked fine with traditional gearboxes when I was testing the TCB on an Arduino Mega a few years ago, but is it likely to be an issue with the DKLM gearbox? I've double-checked that the dip switch setup for the ESC matches the wiki page.

I've run through the radio setup again, and created a new .opz from scratch but the problems still persist. I've attached the most recent one to this post. I relocated the receiver to the right-hand wall of the hull so the antennae were as far from the TCB/TBS/ESC as possible, but it made no difference.

I powered the tank up and watched it through OP Config's snoop; the TCB would recognise forward/backward and motor stop commands, but both the propulsion and steering motors continued at low speed despite what the TCB ought to have been telling them to do. Turning the engine off and disengaging the transmission do not affect this behaviour.

At this point I can only assume I've missed something too blindingly obvious for me to notice, or that the RC Sabertooth doesn't like the PDSGB for whatever reason.

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Show and Tell / Re: Ludwig/Taigen SU-152 (early production)

« on: August 18, 2019, 04:32:47 AM »

I've recently sorted out the TCB setup. There's a DKLM PDSGB being driven by a Sabertooth 2x12 RC which is wedged between the speaker box and hull walls (I added some thermally conductive tape between the ESC's heatsink and the aluminium tub, because why not?), with a Benedini TBS Mini snuggled underneath the TCB itself. Switches are accessible under the transmission cover hatches, and there's a heavily modified Clark recoil unit to control the enormous aluminium gun. There's also a high-intensity flash unit to fit inside the muzzle brake.

The TCB has been great, I've been able to get everything working but I've run into a few issues. For one, the Benedini starts the engine sound as soon as the system is powered on, even though the TBS is set to manual start and the function triggers are set correctly. I have to quickly switch the engine on and off again to get the sound and engine behaviour to sync up.

More troubling, though, is that the PDSGB will run one or both motors at low speed by itself. With the throttle set to 0, the drive motor will twitch and creep at low speed. It doesn't seem smooth, it's more like it is pulsing on and off at high speed. Similarly, when driving forward in an (ostensibly) straight line, the steering motor will gently veer the tank off to one side. Adjusting the trim on the radio doesn't affect it, so it's not like the board is receiving any steering input.

I have confirmed that the motors themselves are okay (they behave as would be expected when the vehicle is set to dual drive motors in OP Config), so I can only assume it's an issue with the TCB's control when set to single drive motor, or the ESC's interpretation of those instructions. What would be the way to narrow this down?

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Show and Tell / Ludwig/Taigen SU-152 (early production)

« on: August 18, 2019, 04:26:19 AM »

This has been a long-term intermittent project, but it's starting to get interesting. There's a few years' worth of back and forth to get to this point (covered at RCTW here), but now I've got an SU-152 CNC styrene kit from Chris Ludwig paired with a Heng Long KV-1 upper hull and a Taigen KV-1 metal lower hull and running gear.