OpenRTM-aist Case Study on Raspberry Pi

Introduction

Raspberry Pi is a single-board computer with an ARM processor developed by the Raspberry Pi Foundation in the UK.

The Raspberry Pi is very convenient because it runs normal Linux (Debian, Fedora, Arch Linux) and FreeBSD for ARM regardless of the size of the embedded board, and can also compile on the board. Currently, for the storage device, the SD card can be used. It is inexpensive and has a large capacity. Also, the main board price is very low, about 3,000 yen. Also, since basic I/O is provided and can be connected to various external devices, various applications such as robot control and measurement with sensors are conceivable.

Specifications

The appearance of one type of Raspberry Pi is shown below.

Raspberry Pi

The Raspberry Pi has three basic types (Model A, Model B, Model Zero), and there are multiple models for each basic type. Please refer to the following Wikipedia link for details.

From Wikipedia: http://en.wikipedia.org/wiki/Raspberry_Pi

The specifications of typical models are shown below.

CENTER:Specification
	3 Model B	3 Model B +	4 Model B (4G)
Target Price	$ 35	$ 35	$ 55
SoC	Broadcom BCM2837	Broadcom BCM2837B0	Broadcom BCM2711
CPU	ARM Cortex-A53 1.2GHz	ARM Coretex-A53 1.4GHz	ARM Coretex-A72 1.5GHz
GPU	Broadcom VideoCore IV		Broadcom VideoCore VI
Memory (SDRAM)	1GB (GPU sharing)		4GB (GPU sharing)
USB 2.0 port	4 (Integrated USB hub)	4	2
USB 3.0 port	CENTER:-		2
Video output	Composite RCA (PAL & NTSC), HDMI (rev 1.3 & 1.4), MIPI DSI		Composite RCA (PAL/NTSC), micro-HDMI (up to 4kp60) 2.0 x 2, MIPI DSI
Audio output	3.5mm jack, I2S, HDMI		3.5mm jack, I2S, micro HDMI
Storage	SD memory card / MMC / SDIO card slot
Network	10/100 Mbps Ethernet (RJ45)	Gigabit Ethernet over USB 2.0 (maximum throughput 300Mbps) (RJ45)	Gigabit Ethernet (RJ45)
Low-level peripherals	8 × GPIO, UART, I2C, SPI and two chip select, + 3.3V, + 5V, ground
Power supply	2.5A (12.5W)		3A (15W)
Power source	5V/microUSB or GPIO		5V/USB Type-C or GPIO
Size	85.0mm x 56.5mm	85.0mm x 56.0mm

See the above Wiki for more details.

Overview of this book

Using the I/O extension platform PiRT-Unit developed by AIST makes it possible to use external I/O relatively easily.

PiRT-Unit

OpenRTM-aist (C++, Python, Java) can also be compiled and executed on the board, so even though it is an embedded board, it can be used in almost the same way as a normal Linux PC development process.

This section describes how to build an environment for developing and executing RT components with OpenRTM-aist, know-how for convenient use, how to control mobile robots, and how to use I/O.

Application using Raspberry Pi or PiRT-Unit

RT-Component	154
RT-Middleware	35
Tools	23
Documentation	2

OpenRTM-aist