Let's Make Robots!

T'REX tank chassis

It's been a long time coming but the T'REX robot chassis is here!

I've just been testing the final product so I thought I would post a few photos of the new chassis. The chassis is aluminium with a black powder coating. The tracks and struts are zinc with a black anodized finish. The wheels are zinc with a chrome finish.

With a ground clearance of 70mm and a total height of 130mm this robot chassis can handle very rough terrain.  I've used counter sunk screws to ensure a smooth under carriage. This and the high clearance helps to prevent the chassis getting caught on objects. Hex head screws are used because they are harder to strip than phillips heads although you should not need to undo them.

The T'REX chassis has mounting holes for the T'REX controller which automatically detects RC, I2C and bluetooth control. There's a heap of room in the front for batteries and other controllers. An 11.1V (3S) 5000mAh or better LiPo is recommended.

 

Unfortunately we did not get the T'REX finished in time for Christmas but you can still pre-order them from Pome now. They will be ready by the end of November.

 

 

 

AttachmentSize
TREX_TANK_Instruction_Manual.pdf1.54 MB

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I'm using the T'rex controller, but I'm using my own code. Will have a look at your code and copy the pwm frequency part :)

Is there a recommended pwm frequency for the motors? I'm currently using the standard Arduino pwm frequency which is very low, can probably get more torque out of the motors with a higher pwm frequency?

What controller are you using? The T'REX controller defaults to 122Hz which gives a good combination of low noise, high torque. Going down to 31Hz will give you slightly higher torque again but it is not as smooth in some cases.

Have a look at my tutorial here: http://letsmakerobots.com/content/changing-pwm-frequencies-arduino-controllers

Part of the stock trex firmware changes the pwm frequency. The section that does it does list a few different settings all commented out so you can switch and choose frequency instead. I think on there it has some notes about which ones work well and their impact.

From mobile I can't check the files myself.

Up, down, north, south, it's all relative to your position in the universe.

I need to carry a load of about 3.5kg on this chassis, does it supports this weight?

Not unless you add additional suspension springs from an RC car. Out of the box it is only designed to carry some lithium batteries and control PCBs / camera / pant tilt etc.

Question below yours is relevant

You mean above!

No I mean below. Unless one has decided to invert the notion of whether something is above or below.