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RC Gyro's in Bots
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tunna



Joined: 13 Oct 2004
Posts: 17
Location: Central UK


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Hi again ,not advertising for any gain!!!,but Techno Bots is if used correctly
is a brilliant place to pick up helpful tips, the Uk has gone through this learning curve, and what we have learned and where we have learned it from is free to all who wish to look,so dont understand your comments,
I could have said look at Paul Hills site which contains more Robot Combat
info than any other current site ,but doesnt say where to buy from,so the viewer is left to search again,I under stand that there is no dedicated Aussie Bot supplier, as of yet, and the world being a smaller place by the day, technobots is within reach for that bit of kit that may just be a little difficult to aquire out there, still if this type of help is not of use to you guys , it wont be mentioned again,

Bulldog Breed

Post Wed May 18, 2005 5:03 pm 
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Valen
Experienced Roboteer


Joined: 07 Jul 2004
Posts: 4433
Location: Sydney


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we dont mind helpfull comments
thats the whole point

but where 80% of the post is a plug for your site and theres 6 of them on a whole bunch of threads it becomes more blatant advertising.
i as much as any ausie likes a well excecuted plug but its a little over the top.
perhaps put a link in your sig or some such?

might be usefull if you reccomend some specific parts, better still if you can say dont use part-x because of y and z
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Post Wed May 18, 2005 5:14 pm 
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tunna



Joined: 13 Oct 2004
Posts: 17
Location: Central UK


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Er first thing first, its not my site , their location is at the other end of the UK to me,but suffice to say ,you have to find these things out for yourselves ,

Bulldog Breed

Post Wed May 18, 2005 6:37 pm 
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Philip
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Joined: 18 Jun 2004
Posts: 3842
Location: Queensland near Brisbane


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I have bought products from Technobots and their service was spot on, however I bought my GWS gyro from Budget Hobbies. The cost was the same from either supplier so I decided to support the local guy. BTW the local guy is an expat pom.
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Post Thu May 19, 2005 9:52 am 
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Philip
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Joined: 18 Jun 2004
Posts: 3842
Location: Queensland near Brisbane


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A little after thought.

I would also like to say that I have recieved a lot of helpful advice from people such as Tony. I find that they are very generous with their advice.
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Post Thu May 19, 2005 10:27 am 
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Spockie-Tech
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Joined: 31 May 2004
Posts: 3160
Location: Melbourne, Australia


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I'm sure Tony is a great guy and I've heard good things about TechnoBots, so I have no problem with either of them, which is why I didnt say anything until the plug-factor got a bit too high..

I understand that "Supplier X" may well have already done the research about what works and what doesnt, so just advising someone to "buy all your stuff from X and you will have no trouble" might be good advice in their mind, but..

Most of us builder characters like to know the reasons *why* things do or dont work and gain an understanding of what they are doing - so saying "all you need to know is available on TechnoBots" is not true, the sum total of knowledge I can find regarding Gyro's on TechnoBots is..

---
We now stock the very popular GWS gyro as used in many robots to help steer.

PG-03 Gyro
"A 7g piezo gyro just larger than a £1 coin. Suitable for use with Futaba, JR, Hi-tec, Sanwa, Multiplex systems. Fitted with JR/Futaba style plug. With the PC-3, you can remotely turn the gyro on/off.

PC-3 Gyro Switch
Just plug into an additional channel on your receiver and turn the gyro on / off via the transmitter. This is especially useful in robots as a gyro slows full body spins."

---

So, 1 Model of Gyro, and 1 remote disarm switch for sale. No mention of anything about how they work, what they do, why you might need a disarm switch if your bot is invertible, or any tech info at all.. just a "this is what you need - buy this".. thats hardly everything you need to know..

Sorry to be bitchy about it, but if I wanted to just be told "This is what works, just buy it and be happy" then I probably wouldnt be into a hobby like Bot Building.. I enjoy the learning, not just being handed a solution for a price with no information about it.
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Post Thu May 19, 2005 11:18 am 
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tunna



Joined: 13 Oct 2004
Posts: 17
Location: Central UK


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Firstly I have to say that a gyro isnt the answer to all drive control problems,they work well, on machines that have been constructed with good balance, ie weight distributed well ,about the wheel positions, machines built this way can turn on a sixpence, but of course the gyro tries its best to stop this, so one answer is to fit a device in between
the gyro , receiver, and servo, if you use servos, that is, this device is very cheap to buy, works on a spare channel of the receiver, and you can turn on or off the gyro as required, hope this helps,

Bulldog Breed

ps you can also use this device on solid state controls,and they weigh only a few grammes

Post Sun May 22, 2005 2:43 am 
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Philip
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Joined: 18 Jun 2004
Posts: 3842
Location: Queensland near Brisbane


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Here are a couple of pointers that were in the FAQ section at Technobots. I realise that the same info and more can be found else where on the web.

Gyro section

A gyro is an electronic device that senses rotational movement. They are commonly used in helicopters but are found in many robots. Not all robots will benefit from a gyro but many do. It is quite common (especially with 4QD speed controllers) to experience difficulty in getting both wheels to 'kick off' at the same time in both forwards and reverse. Apart from mechanical differences, this we believe is largely caused by a lack of symmetry around the neutral point on speed controllers. Dual channel controllers such as the Roboteq do not suffer from this as both channels are well matched.

Firstly, you cannot use a gyro in systems that use tank steer. Your set-up must have a mixer function (see topics on mixers) that uses a speed and steer signal. The gyro connects between the steer channel from the radio receiver and the steer input to the mixer (or steer input to the speed controller if its integral).

Mixer section

Imagine a tank drive where the left hand stick controls the left hand track and the right hand stick controls the right hand track. To turn clockwise on the spot, the tank drive would push the left hand stick fully up and the right stand all the way down.

A mixer differs in that the 2 input signals are fowards / reverse and left / right (or anti-clockwise / clockwise as left and rights can be confusing depending on whether the vehicle is coming towards you are going away from you). This means you can control the vehicle with a single joystick with up / down ('Y' axis' being forwards / reverse, and left / right ('X' axis) being anti-clockwise / clockwise.

Technobots can offer a number of mixers, some are suitable for the Electronize range and some are only suitable for the 4QD range. The Roboteq and Rex's Robot Challenge speed controllers have the mixer function built in.
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Post Sun May 22, 2005 6:46 am 
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tunna



Joined: 13 Oct 2004
Posts: 17
Location: Central UK


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Hey Guys all this talk about gyros,reminds me of a long chat I had with the great George Francis, of Chaos 11 fame ,I asked him how difficult it was to drive Chaos without the gyro, and he said that it was a little (fitchy)
Ipswich speak for not very controllable!! but he gave me a good lesson
in the use of the trimmers, mounted in the back of my Futaba Skysport 6A
it made Bulldog a lot less fierce ,allowed me to be able to control the the obvious power we had on board ,we have two settings that are swichable 1-absolutly manic, and 2 more refined, both go through the Gyro ,
but in rate 1 the gyro is less noticable ,very usefull when you have a 100 kg spinner bearing down on you threatening to rip you to bits,

hope this helps (Bulldog Breed)

Post Mon May 23, 2005 6:00 am 
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Spockie-Tech
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Joined: 31 May 2004
Posts: 3160
Location: Melbourne, Australia


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We added a Gyro to "Scoopy Doo" and found it made a *huge* improvement in the driveability for Mel..

Scoopy being a 2WD bot, with the drive at the rear, and the front support points on the corners, what would often happen (imo) is that a slight irregularity on the floor going under a wheel would leave most of the weight sitting on the 3 level corners and the slightly elevated wheel would slip momentarily, causing her to veer off in one direction or another when trying to go straight.

Fast reactions on the stick with correcting tweaks were necessary to keep her going in a straight line.. something most drivers probably dont even realise they are doing if they are keeping up, but it all adds to the load of making her do what you want to and keeping on target.

Also, if you suddenly slammed the drive stick from still to full-forward, there would normally be a change-of-direction as well, as (most likely) one of the drive wheels slipped and spun slightly more than the other. Again this could be corrected for manually if you were really on the ball..

Adding the gyro took the responsibilities for these corrections off the driver, and caused her to "just go straight" in a much more reliable manner. You can suddenly go from still to a full speed cross-arena charge and expect that she will go straight without requiring any steering-drift correction inputs along the way.

Its a subtle difference in some cases since a skilled driver can probably overcome the lack of automatic correction using their own fast reflexes, (Rob tried a Gyro briefly in Reboot but didnt see much benefit at the time), but I'm convinced that to those who find that your 2WD bot doesnt just instinctively do what you want it to (as it does for a more experienced driver), that you will find a noticeable improvement..

I tried putting one in Inspector General, but realised it would need a remote-disable to prevent the gyro-death-spin when the bot became inverted, so had to take it out again at that time.

However, I have recently found and purchased a cheap ($12US) remote gyro disarm switch (yes tony, the same one TechnoBots stocks Wink I found it from a hobby supplier in japan about a week before you mentioned them), that does the job I expected it would on the bench, so I.G. is most likely going to be Gyro-equipped too at the next Vic round.. Twisted Evil

Inspector General having the angle-grinder head and saw a long way away from the center of its balanced rotation point, gives it a significant amount of inertia when turning, and if its turning fast (which it can do very well as you've probably all noticed Wink ), then I need to apply some "opposite stick" to halt the turn when its aimed in the direction I want, or else it over-shoots as the rotation rate gradually slows down.

Hopefully the gyro will improve this (at least while its right side up, inverted it will have to be disarmed), so I'm expecting to be able to aim that saw for your wheels with more precision in future. Wink

So far, I quite like Gyro's, and although they do introduce more potential failure points, cost and complexity into your control system, I think unless you're a wizard on the control sticks who doesnt need to improve their driving at all (or have a 4WD bot, since they're inherently more directionally stable), then they're probably worthwhile trying..
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Post Mon May 23, 2005 10:10 am 
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timmeh
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Joined: 20 Jul 2004
Posts: 2517
Location: Victoria


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Was thinking of an idea with a gyro in an invertable bot.

Attach the gyro to a swinging arm that only swings forward and backward which the gyro should not be able to sence as they are made to only sence sideways movment and then attach a weight at the bottom of the swinging arm so when the bot is inverted the gyro flips over so then when the rc flip is activated on the esc the gyro should still work fine as it will be the right way up.


Anyone got any thoughts on this idea?
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Post Tue Aug 09, 2005 6:27 pm 
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Philip
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Joined: 18 Jun 2004
Posts: 3842
Location: Queensland near Brisbane


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Have you given any thought to how you might dampen any excessive swing in the swinging arm?
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Post Tue Aug 09, 2005 6:36 pm 
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timmeh
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Joined: 20 Jul 2004
Posts: 2517
Location: Victoria


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If you mean when it swings forward and backward from accelaration if i am correct the gyro dosent sence that movment only side to side movement therfore should not be a problem if it sways.


Unless im wrong and the gyro dose sence that?
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Last edited by timmeh on Tue Aug 09, 2005 6:44 pm; edited 1 time in total

Post Tue Aug 09, 2005 6:40 pm 
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Philip
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Joined: 18 Jun 2004
Posts: 3842
Location: Queensland near Brisbane


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You might be right at that. Marauder's wheels don't spontainiously spin when it is turned over.

Do the test and find out.
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So even the rain that falls isn't actually going to fill our dams and our river systems

Post Tue Aug 09, 2005 6:43 pm 
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Glen
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Joined: 16 Jun 2004
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wouldnt it be easier to just use a tilt switch to reverse the signal going into the gyro and therefore stop the death spin... not sure if it would work or not.

or you could just spend $12 for that remote gyro disarm brett mentioned
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Post Tue Aug 09, 2005 6:45 pm 
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