The combined usage of a Gyro and Accelerometer

A new explanatory article have appeared on the ITE Project wiki. It provides mathematical background for linking together Gyro and Accelerometer readings in order to determine the robot's 3D motion trajectory.

Navigation Module - Mathematical Background

Stereo vision camera system

Here is a camera module for ITE. Two fast web cameras Philips 2050nc (up to 90 FPS @ 640x480, 6 FPS @ 1600x1200, 20 FPS @ 800x600), with very low-noise images is a good/cheap choice for computer vision. Both cameras are mounted on pitch aluminium plate connected to a geared stepper motor MP35EA (12V, 92mA, 4-Phase bipolar, gear ratio 1:85, torque = 0.4 kg*cm = 5.6 oz-in). The inter-lens distance is 0.12 m = 4.725 in) - picture on the left. Since the right camera is rotated by 180°, the software rotation of captured images is required. 

 

The test platform (right picture) can also perform rotation by the vertical axis (stepper motor, bipolar, 24V, 0.5A). Since there is no slip ring for USB cameras' data transfer, the expected yaw angle is ±230-270° (some experiments required), the horizontal rotation angle is -85°..+110° (0° - horizontal line).

All my control boards are designed for a closed loop control (feedback angle is measured by optical sensor and corrections applied after each motor step if required). The pitch rotation motor does not have a secondary shaft, so the feedback wheel will be mounted on a plate's output shaft and a sensor will be mounted from the side. Bottom motor has a secondary shaft, so encoder wheel is mounted thru the special shaft coupling (on picture below the wheel is not yet installed).

I will describe a sensor system in details in next posts, when demonstrating a camera movement control and a video capture. Below there is a mounting place for a sensor (optical interrupter TCST1103/1202).

I'm planning to publish here run tests of my application (OpenCV+Qt) for image capture and disparity map generation within 4 weeks.
Currently I'm busy on programming (upgrading) my parallel neural network application (also using GPU /w OpenCL). I will post results and an application here about it within two weeks.

ITE::System modules scheme

Preliminary design of ITE's components interconnection.

Currently I have only a 180W DC-ATX power supply, but I will be able to add more power later (by parallel usage of several DC/DC converters). I have the only motion motor control module currently in alpha-stage, but it's working well. The control system's data storage will use one HDD (for archiving data, a lot of space is required) and one SSD (for system - Linux). Similar installation showed the successful start up with Windows XP as primary OS. A mid-end GPU (180 W peak approx.) will be used for computationally intense highly parallel computer vision tasks and image processing (preferably OpenCL-based). Computer vision tasks are foreseen to have better (computing power)/(consumed electric power) ratio on GPU as compared to multicore CPU. Also, near real-time image processing will probably show up as hard-to-implement.

ITE robot project:: Beginning

Currently I'm involved in development of a rover-kind robot project and hope that I'll be able to publish it's photos soon. I will write a small annotation for the beginning.
Few years before, I've decided to apply my knowledge of MCU in practice. I've made a lot of small testing devices, and the best way to achieve higher skills was to start development of large robotic project. Popular Martian rover robots have captured my interest of making something similar. So, I've decided to construct large 6-wheeled robot with highly advanced artificial intelligence. Using normal PC boards will result in low-cost computing power, so the robot must be large enough to contain it. Also there must be enough space for capatitive batteries. I assume normal operation time, without solar charging, should be 5-7 hours. Here is a photo of ITE for the beginning (top view):The codename ITE stands for Intellectual Terrain Explorer. Later I will write something about schemes and modules of ITE. On photo you can see plastic packs with red batteries inside - these are Li-Ion modules 22.2V each, composed from laptop batteries of 11.1 V. All these six packs (three of them are under the motherboard) can provide up to 645 W*h of energy (up to 7-8 hours uptime to total discharge). Each wheel of rover can be driven and rotated separately with the help of total 12 motors (6+6 for turning/running). You can see a turning DC motor already attached on the left bottom corner of picture. The entire armature of the robot is made from Titan - this will guarantee a low weight and high strength (if properly welded). Currently in physical construction and design one mechanical engeneer involved, who gives me advices when I'm making modules and electronics.
I hope to involve more people to this project, because it is going to be open-source solution.
P.S.: The rover project was started nearly in October-November 2008.


More technical info about design will be available later. I will try to post here as regular as possible.