These are two experimental platforms each with four-wheel drive. The one on the left uses a more conventional system of tank steering in which the motors on each side are wired in parallel and steering is controlled by varying the speed of both motors on each side.
The one on the right is using mecanum wheels and each motor is driven independently. This platform is capable of being driven sideways, as well as turning on the spot, forward and backwards and diagonally.
In their base configuration, they only operate in remote control mode, using a PS3 bluetooth controller to provide basic directional instructions, and using an ESP32 D1 R32, an Arduino Uno lookalike board, to provide the intelligence.
The robots are powered by rechargeable battery packs in a now familiar configuration using L298D controllers. A voltmeter is included on the battery pack holder to indicate battery charge state.
Software and additional information is held on github