Go1 loose knee joints? Is it normal?

I am noticing that my go1 has 1-2 degrees of loose motion in the knee joints. It’s playing havoc with my custom walking controller.

I am trying to determine if this loose motion is normal or if I have a defective robot. It’s on every knee joint looks like it’s where the lever connects to the motor. It’s as off they forgot to put bushings on the connection or something.

If you have also seen this on your go1 let me. I want to know if it’s international or if I should open it up and fix it.

Aside from your custom controller does it exhibit this behavior when controlling via the remote? I would recommend not opening it up at this point. If you can provide some more detail we can work to get Unitree support to chime in on this issue. I have not experienced this before and if you have a brief video that you can post it would help us diagnose. Thanks.

The built in controller works fine as far as I can tell.

Here are a couple of video’s showing the issue:

I opened it up and the backlash is coming from the spur gears used in the thighs. Using low backlash gears or just changing the ratios of the planetary gears in the motors would resolve this. I did contact Unitree and they said they did not fix this in the go2.

Did Unitree give you any indication if the same gears are being used in Go2? I realize they mentioned they did not fix it, but was wondering if the same gear ratio exists.

The only other thing they said is they increased the strength of the joints.