Those spring loaded blocks look good, up until now I've used chock blocks lol.
Edit: is the "limiter" to go on the actuator for the arm to stop it over extending and breaking etc?
Those spring loaded blocks look good, up until now I've used chock blocks lol.
Edit: is the "limiter" to go on the actuator for the arm to stop it over extending and breaking etc?
The initial plan for the limiter was to use the internal micro switches of the actuator to stop any further movement backwards or forwards to stop it breaking. However I'm now thinking of creating a linear servo by adding some positioning feedback to the motor driver so it will maintain its position even if something tries to back-drive it. I've still not confirmed any of the weapon mechanics and may leap to pneumatic instead.
It's been a long time, however I've not given up. I've moved to a new city and it just so happens that this new city has a hackerspace that gives me access to a few cool tools; namely a lathe, a mill and a laser cutter. As a result I've come up with a good way of doing the wheel/pulley/motor assembly.
http://imgur.com/a/HKiDT
I need to do a few more steps before my first assembly is complete but it should be easy once I get the supplies.
My next major task is to try and get the Hardox armour plates ordered. I don't want to build the chassis only to find that the armour doesn't fit which means the chassis needs massive effort to rework. So if any one that has suggestions for places that can cut, bend/weld and drill ~4mm Hardox please do share.
Another quick update:
I received some carbide lathe tools in the post so it was time to turn another shaft adaptor. It turned out much better!
Once again the ingredients:
I've tapped the M6 hole for the grub screw and these fit nicely onto the GR02 shafts however they stick out a bit so I may have to cut a hole in the wheels. The grub screw are also cup-type ones so the cups will need to be ground down a little to improve the contact area with the flat on the shaft.
The major task remaining is securing the HTD pulleys to the shaft adaptor, I've got a fairly good idea of how I'm going to manage this I just need to do it.
My next steps for here are to complete the other 4 (and 2 spare) shaft adaptors & pulleys and then I'll be ready to attempt a trial run. of the chassis.
Last edited by Pinski1; 20th February 2014 at 23:40.
Another mini-update, I'm getting closer to having the wheels complete. The Belts have no arrived and fit quite nicely, I've also got another 2 wheel assemblies together.
And here is a shot of the electronics nicely laid out. I've got 3 re-programmed TZ-85s to control my motors and a Turnigy Nano-Tech 5Ahr 5S1P (18.5V) battery to power it all. I'm planning on rewriting the program for the bottom TZ-85A to turn it into a servo to protect the linear actuator. Its all controlled by an Orange RX 710 and a Specktrum DX5e (not pictured). Also not pictured is the LED power on light which I'm still playing with.
Is that something you would consider making open source? Could be very useful!I'm planning on rewriting the program for the bottom TZ-85A to turn it into a servo
Agreed, potentially interested!
Looks like this is going to be a nice build, like the shaft adapters!
I would also be interested in a such a program!
So no pressure right?
The main obstacle to writing my own TZ-85A code is that no one has reverse engineered a schematic and I don't know which pins are used for what. The ATMega8 has 24 usable GPIO pins and I would have thought that only 11 would be needed for the brushless controller (3 high fet channels, 3 low fet channels, 3 sensors, 1 temp sensor and 1 RC channel) but as far as I can tell they're nearly all used! I was getting copies of the RC signal in on 3 pins which included the serial input/output pins (which has given me a separate idea).
I eventually settled on PORTC Pin 2 as it seemed like it could be the sensor pin for the unused phase, so here's a teaser shot for the TZ-85A servo:
Time for another update!
I've ordered the Aluminium Chassis a week ago and it was due to be delivered on Thursday, unfortunately there was a minor delay and I managed to pick it up last night (Friday). I spent a good chunk of that evening drilling hole for bolts and tapping the threads in the bulkheads. The end result looks rather cool if I say so myself!
Some of the TIG welding has gone in a bit wonky so I'm planning to face some of the bulkheads off a little to get them back to that mythical 90 degrees.
I also ordered the 4mm Hardox front, side and rear armour a week ago and I'm expecting that to be finished around Wednesday next week and I'm hoping I'll actually have it in my hands by Friday. The 5mm polycarbonate top and bottom panels have been delivered and I'm planning to get them CNC drilled & routed so they should drop into place nice and clean.
I've been having some problems laying out the flipper arm and I think I may have to get a custom arm fabricated. This is going to considerably add to the cost and time to completion but hopefully will look awesome.
I had set myself rough deadline of 10th April at the start of March, I knew it would be very ambitious target but it did prompt me into ordering the chassis and armour. I'm expecting to be at least a week late at this point but I will have a robot!
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