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[Sticky] B-robot EVO. OFF ROAD version

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350a26dd49eb55d3494500240423a207?s=80&d=mm&r=g
(@robotn1)
Member Admin
Joined: 5 years ago
Posts: 727
Topic starter  

It has been easy to modify the original B-robot EVO adding new Off-road wheels (regular 83 mm diameter RC buggy wheels, quite easy to get and inexpensive).

More info at: http://jjrobots.com/the-b-robot-evo-goes-off-road/

Enjoy it!
JJRobots TEAM


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1a042a675fa2180f0ff4702fe297c4db?s=80&d=mm&r=g
(@sasa999)
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Joined: 6 years ago
Posts: 107
 

Nice upgrade! How do you attach/fasten wheel to motor shaft? Any photos?


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350a26dd49eb55d3494500240423a207?s=80&d=mm&r=g
(@robotn1)
Member Admin
Joined: 5 years ago
Posts: 727
Topic starter  

Nice upgrade! How do you attach/fasten wheel to motor shaft? Any photos?

We have modelled a simple NUT for the motor´s axis
You only have to press it as a top after placing the wheel on the axis.
Photos below:

And the STL model attached to this text


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ef9841d50cb12db99fa2af10af0d9f10?s=80&d=mm&r=g
(@ing-lucian)
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Joined: 5 years ago
Posts: 9
 

very nice, congratulations


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84fac8fcf7e1324de44bbd744a7182f8?s=80&d=mm&r=g
 Jeff
(@akajefm)
Member Customer
Joined: 4 years ago
Posts: 8
 

I’ve fitted some buggy tires onto the Brobot EVO 2.
Here they are, they work well.
https://www.amainhobbies.com/aka-chain-link-1-8-buggy-premounted-tires-2-yellow-medium-long-wear-aka14017zry/p441289?v=450505&utm_source=transactional_email&utm_medium=e-mail&utm_campaign=order_complete&utm_cid=1273550&utm_content=%2faka-chain-link-1-8-buggy-premounted-tires-2-yellow-medium-long-wear-aka14017zry%2fp450505

Used a wheel mount from a Tetrix kit with a 3d printed adapter.

But as far as the code goes, it seems to work better with the original code as opposed to the “offroad code” linked to above. Any ideas? On the new code I could rarely get it to stand up without stalling the motors.


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350a26dd49eb55d3494500240423a207?s=80&d=mm&r=g
(@robotn1)
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Joined: 5 years ago
Posts: 727
Topic starter  

The behaviour will depend (a lot) on the Wheels diameter and the new centre of gravity.
We are about to upload a new code for the B-robot EVO 2 (now it is easier to stand up).
Can you let us know the wheel diameter and if you are using the regular 6xAA battery holder or any other power source (LiPO…)


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84fac8fcf7e1324de44bbd744a7182f8?s=80&d=mm&r=g
 Jeff
(@akajefm)
Member Customer
Joined: 4 years ago
Posts: 8
 

We are about to upload a new code for the B-robot EVO 2 (now it is easier to stand up).
Can you let us know the wheel diameter and if you are using the regular 6xAA battery holder or any other power source (LiPO…)

Neat, I look forward to trying it. subscribed.
These AKA wheels from the link above measure as:
83.4mm (3.28 in) hub diameter
112.4mm (4.42 in) tire diameter

I’m using the six AA holder that came with the robot and I use NIMH.
Only changes are a GoPro mount (no GoPro while testing), USB cable (easier to program) and some tiewraps.


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350a26dd49eb55d3494500240423a207?s=80&d=mm&r=g
(@robotn1)
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Joined: 5 years ago
Posts: 727
Topic starter  

Testing the new code! (potato quality video attached)
The Offroad version was tested after the race and adjusting the control PID parameters…


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127b7bfe9e1e74a5737be21327a956f4?s=80&d=mm&r=g
(@nikola-wan)
Member Moderator
Joined: 3 years ago
Posts: 13
 

I purchased this pair of APEX wheels with tires on EBAY for $20.

My APEX wheels

Here are the specs for my wheels:

– Apex RC Products 1/8 Off-Road Buggy Black Star Wheels / Attack Tires #6041
– This auction is for 2 wheels / tires.
– These are very good off-road tires for any of the 1/8 buggy. Foam inserts are included with these tires.
– These are pre-mounted and pre-glued
– Tire Diameter/Height: 117.5mm
– Tire Width: 40.5mm
– Wheel Diameter: 83mm
– Wheel Hex: 17mm
– Offset: 0

I also attached my 17mm nut STL file.

I am using the 6xAA battery holder with Alkaline batteries.

Monty


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350a26dd49eb55d3494500240423a207?s=80&d=mm&r=g
(@robotn1)
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Joined: 5 years ago
Posts: 727
Topic starter  

Thanks for this Monty. Got a pair
😀


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127b7bfe9e1e74a5737be21327a956f4?s=80&d=mm&r=g
(@nikola-wan)
Member Moderator
Joined: 3 years ago
Posts: 13
 

Thanks for this Monty. Got a pair
😀

I am still having intermittent issues with my kit:
– bot just falls over while driving straight
– intermittent bot won’t power up

I have followed the B-Robot recent thread, where it was suggested to check the IMU, shield and Leonardo solder joints. I have reflowed the IMU, shield IMU i2c connections, and checked the Leonardo solder connections. It appears my issue is similar to the other post – if I just touch the IMU cable – I can sometimes get the bot working for a while, but if it falls over – it may not respond (arm doesn’t work, and if I pick it up the motors don’t spin to balance the bot again).

Monty


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350a26dd49eb55d3494500240423a207?s=80&d=mm&r=g
(@robotn1)
Member Admin
Joined: 5 years ago
Posts: 727
Topic starter  

It is probably a IMU problem. If the robot suddenly falls that means:
1) low battery (discarded)
2) Incorrect angle value coming from the IMU: cable disconnected/ faulty IMU
I will stick with the second option as you have already indicated that the B-robot sometimes does not power up.
Please check the IMU headers (back face) are not touching the metallic case of the WIFI module. If you want you can solder the i2c cables to the IMU. Alternative: let us know a delivery address and we will send you a replacement of the IMU


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127b7bfe9e1e74a5737be21327a956f4?s=80&d=mm&r=g
(@nikola-wan)
Member Moderator
Joined: 3 years ago
Posts: 13
 

It is probably a IMU problem. If the robot suddenly falls that means:
1) low battery (discarded)
2) Incorrect angle value coming from the IMU: cable disconnected/ faulty IMU
I will stick with the second option as you have already indicated that the B-robot sometimes does not power up.
Please check the IMU headers (back face) are not touching the metallic case of the WIFI module. If you want you can solder the i2c cables to the IMU. Alternative: let us know a delivery address and we will send you a replacement of the IMU

Thanks – I sent PM with my shipping address for a replacement IMU (and cable too)

Monty


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93dd108e8288522c69ed87b154778bae?s=80&d=mm&r=g
(@dcpowered)
Member Customer
Joined: 3 years ago
Posts: 40
 

I just installed off-road wheels on my slightly modified B-Robot EVO 2 chassis which has been widened from the original to allow space for a second servo (if you want to try my modified chassis: https://www.thingiverse.com/thing:2858220 ). The added benefits of wider wheels are more stability and also since the wheels are securely fixed to the motor shaft with hex coupling, the robot motion is more accurate in a straight line and also when steering. 🙂

In case some of you might be interested, i bought them from aliexpress – a pair for about USD 10, currently available in 3 different colours. Search for “83mm RC wheel” and select “5mm Extended Hexagonal Coupling”, as that’s the diameter of the stepper motor shaft. BTW, 83mm is the diameter for off-road wheels recommended by JJrobots but maybe other ‘slightly’ different sizes could also work without having to modify the code. But with 83mm wheels, the robot balances and can be controlled without any issues.


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350a26dd49eb55d3494500240423a207?s=80&d=mm&r=g
(@robotn1)
Member Admin
Joined: 5 years ago
Posts: 727
Topic starter  

Wow! Upload a video or link a youtube video. We really want to see it rolling!


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