High RPM cleaning mechanism

This mechanism is part of our solar panel cleaning robot. We want to build a mechanism that is able to rotate a brush with more than 350 RPM using a brushed DC motor. The brush is approx 15 feet long and its weight is around 8 kg. The brush is made of a hollow square aluminum pipe having microfiber clothes mounted on it. It is expected by the freelancer to select a cost-effective motor(it must be 12v) and build a cost-effective mechanism to achieve this RPM. The system will be battery-operated and voltage, current and battery limitations(of battery) must be considered during motor selection and mechanism designing. Freelancers must consider the easy and cost-effective ways of fabricating of mechanisms for production.

Microfiber flap length: 10cm - 20cm
Operating voltage & current : 12v, 8amps

Note: more details can be provided as per the requirement.