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Show and Tell / Re: Ludwig/Taigen SU-152 (early production)
« Last post by LukeZ on August 21, 2019, 01:44:36 PM »
Great, thanks for reporting back. I'm glad everything is working.

The timeout settings was actually a different issue which I don't think you had, but I discovered it while doing testing on this. It only happened with a unique combination of functions and only with iBus, which is why I originally thought it might be related, but in the end it wasn't. The issue with the Benedini was actually a bug in that code specifically. Of course it had worked at one time, but what happens is that changes are made later and these always have unintended consequences in other places so later we find something that used to work but does no longer and we have to change something yet again.

When I mentioned exponential I actually had in mind the settings you can adjust on your transmitter, and your i6X does have it. It's true the Sabertooth has an exponential setting as well but I don't think it's very useful because there is no adjustment for it, it's either on or off. I would leave that off. On the transmitter you can adjust the expo curve from 0-100% so you have the ability to finetune it. But if the end-point adjustment works for you then no need to do anything else.

I am subscribed to your thread over at RCTW and I will definitely be following along closely as you complete this beautiful model!
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Show and Tell / Re: Ludwig/Taigen SU-152 (early production)
« Last post by Raminator 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)
« Last post by LukeZ on August 20, 2019, 10:18:02 PM »
Ram, I've posted a firmware update (version 0.93.52). I believe it will fix your Benedini engine problem, but let me know your results.
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Show and Tell / Re: Ludwig/Taigen SU-152 (early production)
« Last post by LukeZ on August 20, 2019, 02:04:42 PM »
Good, sounds like we've solved the gearbox issue. I had forgotten I'd written a section on the 2x12 RC in the wiki. I actually updated it just now because I think it wasn't entirely correct before, and I've linked to this thread for anyone else with the same problems.

Yes I agree with you the PDSGB gearbox has very sensitive steering, I think it is simply due to the way that it is designed. What we need is an "inertia" setting for the steering channel but that isn't really practical. Rather than modifying the endpoints on your radio, you might want to try using exponential instead. This will make steering less sensitive around center stick, but you will still have full travel at the ends so you don't lose any steering ability if you need it.

As for the Benidini issue - I have been able to reproduce it on my end which is good because it means I can solve it. I have not gotten very far into it quite yet. As I have time this week or possibly this weekend I will get to the bottom of it and let you know what I find.

Can I ask what radio you are using? I am guessing a FlySky iBus system but I can't be sure. 

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Show and Tell / Re: Ludwig/Taigen SU-152 (early production)
« Last post by Raminator 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)
« Last post by LukeZ on August 19, 2019, 02:20:22 PM »
Ok, that explains it. When using serial control, when we tell the Sabertooth to stop the motors, we say "stop" and there is no ambiguity or possibility of miscommunication. When we use RC, it is sort of as if I said "I'm going to move my hand up and down, when it gets to about the level of my waist then stop." It is not precise at all and therefore what the TCB thinks is "stop" is not necessarily the same thing as what the Sabertooth thinks is stop.

I have not tested the RC versions of the Sabertooths before. But I have just taken a look at the manual for the 2x12 RC from here. There does appear to be a calibration routine that may solve your issue.

The first thing you can try is to set Dipswitch #5 on the Sabertooth (not the TCB) to the down position. This tells the Sabertooth to use the saved calibration settings which by default should be correct. However if you still have unwanted movement, you will need to move to the next approach:

- With the Sabertooth off, put dipswitch #5 on the Sabertooth in the up position, and dipswitch #6 in the down position. All the others should be as shown in the Wiki (in other words, 1 and 2 down, 3, 4 up).
- Leave the servo cables from the TCB to the Sabertooth disconnected. Power on the Sabertooth and power on the TCB. Make sure the Engine is off on the TCB.
- Now connect the two servo cables. They will be transmitting the "off" signal and the Sabertooth should memorize this.
- Now turn on the engine from the TCB and move your controls to their maximum (both throttle and steering). The Sabertooth should memorize the maximum travel.
- Now turn Dipswitch #6 on the Sabertooth back to the up position.
- Now disconnect power.
- Now turn Dipswitch #5 on the Sabertooth to the down position and leave it there. This will be the final setting. 1, 2 and 5 will be down, 3, 4, and 6 will be up.

Now you can operate the tank normally and it should theoretically work. Let me know the results. Sadly if there are still problems I'm afraid you might have to trade in  your 2x12 RC for the full-featured 2x12.

I wonder if moving your receiver helped at all with the Benedini issue?


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Show and Tell / Re: Ludwig/Taigen SU-152 (early production)
« Last post by Raminator 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)
« Last post by LukeZ on August 18, 2019, 01:27:27 PM »
Hi Ram, that's a beautiful model and I love how tidy you've kept the interior! I have a PDSGB gearbox as well and I think it's the bees knees, I will be happy to try to see if I can reproduce the issue on my end. I've have no problems with  mine so I'm sure we can sort it out.

Can you post your OPZ file here so I can take a look?

I'm curious how you are driving the Sabertooth. In your photos I see two RC leads attached to RC outputs 1 and 2 which are for the left and right tank treads. It is in fact possible to drive the Sabertooth using RC, but I would recommend using the MOTOR SERIAL output instead. I also don't see any servo leads on RC outputs 3-5 which I you will need for your three turret servo motors (but maybe you have just disconnected them to take off the upper hull for pictures).

As for the Benedini (and possibly also your PDSGB issue) it almost sounds like possibly the radio setup is a bit off. You may want to perform that task once again.

The other thing I would do is move your receiver antennas away from the TCB and route them back over the side by the battery. It looks to me like you're using one of the 2-way FlySky receivers, which has 2 antennas. In addition to receiving these receivers actually also transmit information back to the transmitter, and those transmissions can definitely cause interference.
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Show and Tell / Re: Ludwig/Taigen SU-152 (early production)
« Last post by Raminator 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)
« Last post by Raminator 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.
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