Hallo Stanley,

first, nice to have a Chinese in this forum. Warm welcome!

You must have a good ground point in your robot. Best, next to battery. If you have several batteries connect 0V of them with very short and big wires together. Your ground star point should sit at the biggest battery, means that one, where most current is flowing out.
If you have components which must have a ground connection (0V) connect them by separate thick and short wires to this ground point. All these ground wires look like a star, with the central ground point in center. That's meant by star point grounding.

This methode helps you, to keep voltage drop of big or noisy currents away from sensitive electronics. Star point grounding is real essential.

Connect metall enclosure with one big and short wire also to this ground star point. Everything made of metall, not having any contact to circuitry should be grounded in that way. Then, all this metallic parts have ground potenial and cannot be the source of interference or act like an antenna. Capacitive stray coupling is heavily minimzed.

Also, your mcu would benefit from an additional metallic enclosure, which should be connected with shortest wire (!) to 0V of mcu circuitry. If you cannot use something like that, even a sheet of steel, copper or aluminium foil, having some contact to 0V of mcu circuit will help.

This is meant by grounding and shielding. Most problems can be avoided or fixed by these measures.

Good luck,
Kai