Problem with Self-Balancing Robot in Ultimate 2.0 Kit


Built it according to the instructions provided by Makeblock.

It sort of works. After a very short period of going, that is to say balancing, back and forth, it lurches forwards or backwards and immediately falls over. It appears to be overcompensating for values on the x-axis or simply compensating when the x-axis tipping point is already past a point of no return. I hooked the build up to the mBlock software and read out values coming from the sensors: they appear OK.

Has anyone encountered this and if so found the cause and a fix?


The Ultimate 2.0 comes with three motors, could you check the labels on the motor if you are using two 25mm motors on the self-balancing robot please?


Thanks for your answer. We are in another time zone, so apologies for the late reply. And yes, the build uses the two identical 185RPM motors.

On our previous build, the Robotic Arm Robot, the robot felt a little sluggish - there was a lag between events and actions (but it was of course controlled remotely over bluetooth). If this has persisted, it could be that when the robot gains some momentum going back and forth, the sensor data from the gyro may be processed too slowly for the motors to compensate in time.

When I hold the robot in the air, however, and tilt it back and forth on the gyro’s x-axis, the motors spin slower towards the center of gravity and faster the more it tilts, before the motors stop at certain positive and negative values (when the program presumes it has tipped over). This all seems fine, which is why I am unsure how to proceed.

Do you have any suggestions as to what we can test?


Will it be possible for you to take a video to show how the self-balancing robot behaves please? It will be more straightforward for us to assist you.


Thank you. We’ll make the video. Give us a little time to organize that and I’ll post a link for you when it is done.



Has this issue been investigated or resolved?
The exact same issue happens to me as well.

It doesn’t balance for long before it falls over.
The distance it needs to correct itself gets bigger and bigger.
Some times it doesn’t balance at all.

I have doubled checked the build and it looks to be 100% the same as the instructions.



Hi Dforeman,

Could you take a picture to show your wiring connection on the slef-balancing robot?
Besides, please kindly take a video to show the behaves on the robot while you controlling it.


Apologies for not following up on this. Here’s a video of the behavior:


Hi HmmMaker,

Here I test the Ultimate robot in self-balance mode, it works properly.
For the current issue on your robot, please check the following points:

  1. Check if you have connected the motors to the correct motor ports. Please double check refer to the picture below.

  2. Screw the wheels to the shaft connectors tight;
    And screw the shaft connectors to the motor shafts tight with the headless screw M3*8.

  3. Check the power for the robot. What’s kind of batteries do you use?
    According to our test and research, it is suggested to use rechargeable Li-ion battery or rechargeable nickel-metal hydride, nickel-cadmium which can be bought from amazon or local shop. Or Alkaline battery with good quality like Energizer, DURACELL.



Here are a couple of videos and pics of the wiring. I have checked and I am using the correct motors and the build looks correct.

In the iOS App I am unable to drive it around due to it falling over all of the time.

As you can see it falls over more often than not.
I have installed the latest mblock on my PC and updated the firmware.


  1. The motor ports are connected as in the build illustration. Just to test, I swapped them around. It is obvious that the illustrated way they were connected is right.

  2. The wheels are tight.

  3. We use rechargeable NiCad batteries of good quality. They worked flawlessly on our previous build: the gripper arm.

I also swapped the sensor ports around. I previously took readouts from the sensors on the connected ports, and they were OK. Strangely, removing the proximity sensor entirely and connecting the gyro to port 7 results in the exact same behavior as shown in the video. I feel I have to look at the underlying code to get any further.

Since I build these with a 6-year-old who wants instant gratification, however, I think that it is time for us to move on to the catapult. That should create some robotic wreckage around the house and bring back the enthusiasm!

Many thanks for your help trying to resolve this issue.


Hi Dforeman & Dforeman,

How about try removing the two extra encoder motor drivers on port 3, 4 of MegaPi board.
Also, please make sure there is no wires touch the wheels on the robot.

When you start letting the robot balance by itself, please don’t let it go immediately, you can let it go when you feel it has adjusted itself enough (help it do the adjustment with your hands at beginning if necessary). Here is a video (this file only available for seven days) to you for reference.
According to the principle of the balance robot, if it is out of balance, he needs to speed up to adjust the balance. But when the speed is fast, his chances of success are diminished due to inertia.

Sometimes, the balance robot does not adjust its balance very well. But if your robots have never kept balance for several minutes, there is possibility of the problem on mechanical structure.
Could you please try totally disassemble the robot, the assemble it again according to the instructions.
As for the Gyro sensor and Ultrasonic sensor, it is better to keep the Gyro sensor connected to Port 6 and Ultrasonic sensor connected to Port 7.

Once still the same issue after re assemble it, may we have a video chat through skype to do further checking?



I quickly tried removing the 2 encoders and I adjusted the wheels to give more space between them and the motor as the screws were sometimes rubbing against the screws holding the motor.
On one attempt it stayed balanced a little bit longer (45 seconds) than before but it did keep falling over instantly as well and there was more falling over than balanced.

On the weekend I’ll rebuild it following the instructions you mentioned and will let you know.
Happy to do a skype to get it resolved if the rebuild doesn’t work.





I’ve rebuilt it from scratch following the instructions you linked to.
Initially I used the YouTube video which was the same as the step by instructions just harder to use.

After the rebuild the only part that i had different was the plastic rings. I had the 3mm not the 2mm.
I replace them with the 2mm rings and made sure everything was tight. I also used fresh batteries.

I put it on the ground and held onto it till it was balancing on its own. And it worked perfectly.
I was even able to drive it around. I left it balancing for 10 minutes and it stayed up. I tried several times and it was the same result every time.
I tried it with the two extra motor encoders plugged in as well and the same result. It was perfect.

Thanks so much for all of your help on this. Next time I’ll look for the step by step instructions instead of the youtube version. Pausing the video was a pain compared to scrolling down. Not sure if this was the difference…

Before I did the rebuild, I built the same balancing robot from the Ranger kit and it works even better.

I love the MakeBlock kits. They are so much fun!!!
I love that you are creating more models to build and have started creating tasks to complete an upload the results.

You are unique in this area. Keep up the good work!!!

Thanks again



Hi Dforeman,

Great Job! Glad to hear that you love our robots, we will continue to work hard to develop better products.


Hi, tech support! I am also having the same problem that HmmMaker had (robot falls over), but unfortunately, I cannot access the link you have offered, cause it expired after 7 days from posting. Could you please send the instructions again? That would be very helpful.



Hi! Could you please send me over the instructions from tech support? I cannot access the document now and I am having the same problem with my robot (falling off). Thanks!


I just used the instructions in this link and rebuilt from scratch making sure there is plenty of clearance around everything.


Hi mishoo,

That is just a video to show the normal performance of the balance robot. I have sent it to your email via pCloud transfer. You can refer to it.
While it is also highly suggested to double check the mechanical structure refer to the instruction which shared by Dforeman.


I am having the same type of problems as discussed above. The robot almost balances, but usually falls over. After reading all the ideas above, I realized the motors were wired to the wrong motor driver/encoder. When I swapped them (according to the instructions, the wires are suppossed to cross, left motor driver to right motor, etc., correct?), the problem became even worse. Either way, it does not balance. I used the instructions to build the robot. I am happy to send photos or video.
Please advise where I should start.