Redesign of electronic circuit and firmware

I need a replacement for a motor control board (see attached details) that is used in a pool cleaning robot, as there are no spares available. I want a complete working replacement, which will mean researching the commands coming from the control panel to the board and the firmware held on the microcontroller. Alternatively, a complete controller and board can be proposed, which will provide the same basic facilities. These are to make random walk for cleaning and a facility to remove the robot for cleaning the basket.