Berlin-based mechanical engineer Patrick Hallek has created an excellent omnidirectional self-driving robot known as Forki, which is designed around the Raspberry Pi, sensors, and a set of Mecanum wheels that can turn on a dime.
“Forki is a proof of concept for logistics robots that digitalize and automate warehouses in a scalable and affordable way. It was designed to develop and test software for industrial robots. Forki can already move autonomously in unknown environments and calculate, update, and depart certain routes.”
Under the hood, Forki is outfitted with four 60mm Mecanum wheels, four 12V DC metal gear reducer motors (130 RPM), a pair of L298N Dual H Bridge DC stepper motor driver modules, a 72.V battery, and an LM2596 DC-DC converter. Driving the robot is a Raspberry Pi 3 B/B+, four HC-SR04 ultrasonic sensors, and four Decawave DWM1001 ultra-wideband sensors, all packed within a 3D-printed shell.
Those sensors are the key for autonomous navigation, as the ultrasonic sensors use high-pitched sound waves to measure object distance, while the ultra-wideband sensors provide extremely accurate indoor positioning with a ToF (Time of Flight) down to 10cm. These, of course, need to be calibrated using a series of anchors (or receivers) and a corresponding tag connected to the Raspberry Pi via USB serial communication.
Hallek has uploaded a detailed walkthrough of the Forki build process that covers several parts — including getting the necessary hardware and materials, files needed for the 3D-printed pieces, and the code required to get the robot up and running on his Medium project page.