This is my half tracked vehicle. It is remote controlled by the PSP-NX-V3. In “normal” mode it is driven by one joystick, it has no differential but when turning, the back two motors go at different speeds, simulating a differential. When you hold down the R1 button, it goes into “two joystick” mode where the left and right joystick control the treads independently, great for getting around tight corners, the right joystick also controls the front wheels.
You can download the program here.
You can download the instructions here.
And the MLCad files here.
You can also see this on Rebrickable.