lunedì 30 giugno 2014

System architecture

NOTE: this post is a revision of an older one to reflect last changes on Geduino

On this post the general architecture of Geduino will be explosed in order to show how each component works and communicate with other ones.

Geduino is based on UDOO board, a mini PC with quad core processor (Freescale IMx6) and a micro controller (SAMx8). UDOO provide an Arduino compatible pinout (the same as Arduino Due) that can be connected to SAMx8 (in this case it will works exactly as an Arduino Due) or to IMx6 CPU. SAMx8 and IMx6 will communicate between them using UART.

Other hardware component:
- PING))) sensors from Parallax. Ping sensors will be connected and controlled by the SAMx8 micro controller and their goal is to provide a secure and fast obstacle avoidance system;
- the RPLidar from RoboPeak, connected using UART pins to the IMx6. The RPLidar will provide laser scan data and it is the  core information source for the SLAM algorithm;
- the MD25 and EMG30 motor, connected using UART to SAMx8 micro controller. The motor will move Geduino and provide odometry information to SLAM algorithm;
- the MPU9150 from Sparkfun, connected using I2C to SAMx8 micro controller. This is a complete IMU that provide orientation information to SLAM algorithm in order to increase its accuracy.

Furthermore two other hardware board are used:
- the power board: attached to power source (LiPo battery or AC adapter) it provide stable power (5V or 12V) to all other components. In order to preserve the LiPo battery life the power board send to SAMx8 the current voltage of the battery;
- the shield board: this is a shield which pinout is Arduino Due compatible. Almost all hardware components will be connected to this shield. It include all systems (voltage level converter, configuration jumpers...) needed for hardware communication.

Last, but not the least, the 7" LCD touch screen, a standard UDOO optional that will provide a GUI to interact with Geduino.

Construction: part two

NOTE: this is a quite old post and in latest revision some construction details maybe changed

To build up the upper plate of the robot I use the same technics used for lower plate. The upper plate must have the supporting mount for LCD panel. This mount was cut from an aluminum sheet and it is composed by the rear mount and the from mask.
For aesthetics reason the front mask was decorated with a black glue paper.

Finally the two plates mounted with the LCD and UDOO connected and powered.

mercoledì 18 giugno 2014

Construction: part one

NOTE: this is a quite old post and in latest revision some construction details maybe changed

It's time to build the bottom plate of Geduino.

Before to start this task I print the bottom plate design, using CAD software, on A3 sheet with 1:1 scale factor. I glued this sheet on a 400x500 mm plate made of fiber glass is a sandwich between two sheets of carbon fiber.

I start cutting the plate using a Proxxon small driller ( Using this tool was quite easy to cut the plate: the only problematic parts was the slot for wheels (specially the rounded corner).

After cut the plate is time to drill it. This task must be done with high precision in order to match mounting for motors, boards and sensors.

Using the same Proxxon tool with a grinder I finish the border of the cut plate to make it smother. After this task the glued paper and the protection film from the plate can be removed.

Here the final result with motors, wheel  and board mounted.