Hardware (AutoNOMOS Model v2)
“AutoNOMOS Mini v2” is a model vehicle (scale 1:10) developed for educational purposes. The car can be controlled using a cellular phone or can be programmed to drive in fully autonomous mode. The main computer is an Odroid board (XU4 64GB) running Ubuntu Linux and the Robotic Operating System (ROS) on top. The chassis of the vehicle comes from the model-car building community. The vehicle has been motorized with a RC540 brushed motor. Steering is done through a servo motor HS-645MG. See the figures for details of the assembled units.
Figure 1: Top view of the hardware components
Electronics and sensors are arranged in two layers. Fig 1 shows the lower layer, Fig. 2 the assembled car. The sensors in the vehicle are a rotating laser scanner (RPLIDAR A2 360) which provides detection of obstacles around the vehicle. A Kinect-type stereoscopic system (Intel RealSense SR300), as well as a fish-eye video camera (ELP 1080p) pointed to the ceiling, have been mounted on top of the car’s body. The Kinect sensor provides a cloud of 3D points that can be used to detect obstacles. The video camera in the Kinect-type sensor can be used to detect the lane and objects in front of the car. The camera pointed to the ceiling can be used to identify markers, providing in this way a simulation of a GPS navigation unit, so that the car can localize indoors. The Odroid board is the main computer. The sensors are either connected through the 2 USB 3.0 ports to the Odroid board or directly to Odroid's USB 3.0 ports.
Figure 2: Side wiew of the assembled units
The car has 2 LED stripes (WS2812b) at the front and rear side for simulating car's head and tail lights, as well as blinkers and break lights. The engine and servo motor plus the LED stripes are connected to a custom control board (https://github.com/nerdmaennchen/motorcontroller-hw), which was developed at the Free University of Berlin. The control board is connected via USB with the Odroid and provides a firmware to control the motors and LEDs. At Fig. 3 you can see, how the motors are connected to this board. An additional board, the MPU6050, provides measurements from accelerometers and gyroscopes, that can be used to complement the odometry and also to measure the vehicle’s rotation. The MPU6050 is controlled by an Arduino Nano board through the I2C pin. The Arduino Nano board is connected to the Odroid by USB.
Figure 3: Motor connections
Figure 4: Electronic Modules and interconnections
Figure 5: The tree of interconnections
Make sure that a 14,8V battery is connected. With the silver power button you can turn the car on and off. When the button is pressed down it is turned on and should glow green. If it doesn't power on make sure a fuse is engaged into the "FUSE" socket (a FLINK 4,0A fuse can be used). If the Odroid doesn't boot make also sure that an eMMC card with the necessary software installed is inserted and the switch on Odroid is in eMMC mode.
Figure 5: Button to activate power supply via 14.8V battery.