Vision For Robotic

The ability of a robot to sense its environment is a prerequisite for any decision making. Robots have traditionally used mainly range sensors such as sonars and laser range finders. However, camera and processing technology has recently advanced to the point where modern robots are increasingly equipped with vision-based sensors.

Indeed on the AIBO, the camera is the main source of sensory information, and as such, we placed a strong emphasis on the vision component of our team. Since computer vision is a current area of active research, there is not yet any perfect solution. As such, our vision module has undergone continual development over the course of this multi-year project. This lecture focusses on the progress made during our first year as an example of what can be done relatively quickly. During that time, the vision reached a sufficient level to support all of the localization and behavior achievements described in the rest of this lecture. Our progress since the first year is detailed in our 2004 and 2005 team technical reports , as well as a series of research papers Our vision module processes the images taken by the CMOS camera located on the AIBO. The module identifies colors in order to recognize objects, which are then used to localize the robot and to plan its operation.

Our visual processing is done using the established procedure of color segmentation followed by object recognition. Color segmentation is the process of classifying each pixel in an input image as belonging to one of a number of predefined color classes based on the knowledge of the ground truth on a few training images. Though the fundamental methods employed in this module have been applied previously (both in RoboCup and in other domains), it has been built from scratch like all the other modules in our team. Hence, the implementation details provided are our own solutions to the problems we faced along the way.

We have drawn some of the ideas from the previous technical reports of CMU [89]andUNSW[9]. This module can be broadly divided into two stages: (i) low-level vision, where the color segmentation and region building operations are performed and (ii) high-level vision, wherein object recognition is accomplished and the position and bearing of the various objects in the visual field are determined.

Robotics technology has recently advanced to the point of being widely accessible for relatively low-budget research, as well as for graduate, undergraduate, and even secondary and primary school education. However, for most interesting robot platforms, there remains a substantial learning curve or “ramp-up cost” to learning enough about the robot to be able to use it effectively. This learning curve cannot be easily eliminated with published curricula or how- to guides, both because the robots tend to be fairly complex and idiosyncratic, and, more importantly, because robot technology is advancing rapidly, oftenmaking previous years’models obsolete as quickly as competent educational guides can be created.

Operating System for Embedded systems

Embedded systems can have anything between a complex real-time operating system, such as Linux, or just the application program with no operating system, whatsoever. It all depends on the intended application area. For the Eye- Con controller, we developed our own operating system RoBIOS (Robot Basic Input Output System), which is a very lean real-time operating system that provides a monitor program as user interface, system functions (including multithreading, semaphores, timers), plus a comprehensive device driver library for all kinds of robotics and embedded systems applications. This includes serial/parallel communication, DC motors, servos, various sensors, graphics/text output, and input buttons.

 The RoBIOS monitor program starts at power-up and provides a comprehensive control interface to download and run programs, load and store programs in flash-ROM, test system components, and to set a number of system parameters. An additional system component, independent of RoBIOS, is the Hardware Description Table (HDT, see Appendix C), which serves as a userconfigurable hardware abstraction layer [Kasper et al. 2000], [Bräunl 2001]. RoBIOS is a software package that resides in the flash-ROM of the controller and acts on the one hand as a basic multithreaded operating system and on the other hand as a large library of user functions and drivers to interface all on-board and off-board devices available for the EyeCon controller. RoBIOS offers a comprehensive user interface which will be displayed on the integrated LCD after start-up. Here the user can download, store, and execute programs, change system settings, and test any connected hardware that has been registered in the HDT

Pprogram are shown in photo. Hardware access from both the monitor program and the user program is through RoBIOS library functions. Also, the monitor program deals with downloading of application program files, storing/ retrieving programs to/from ROM, etc.

The RoBIOS operating system and the associated HDT both reside in the controller’s flash-ROM, but they come from separate binary files and can be downloaded independently. This allows updating of the RoBIOS operating system without having to reconfigure the HDT and vice versa. Together the two binaries occupy the first 128KB of the flash-ROM; the remaining 384KB are used to store up to three user programs with a maximum size of 128KB each

Since RoBIOS is continuously being enhanced and new features and drivers are being added, the growing RoBIOS image is stored in compressed form in ROM. User programs may also be compressed with utility srec2bin before downloading. At start-up, a bootstrap loader transfers the compressed RoBIOS
from ROM to an uncompressed version in RAM. In a similar way, RoBIOS unpacks each user program when copying from ROM to RAM before execution.

User programs and the operating system itself can run faster in RAM than in ROM, because of faster memory access times. Each operating system comprises machine-independent parts (for example
higher-level functions) and machine-dependent parts (for example device drivers for particular hardware components). Care has been taken to keep the machine-dependent part as small as possible, to be able to perform porting to a different hardware in the future at minimal cost.

Integrated Design Issues in Mechatronics System

The inherent concurrency or simultaneous engineering of the mechatronics approach relies heavily on the use of system modeling and simulation throughout the design and prototyping stages. Because the model will be used and altered by engineers from multiple disciplines, it is especially important that it be programmed in a visually intuitive environment. Such environments include block diagrams, flow charts, state transition diagrams, and bond graphs. In contrast to the more conventional programming languages such as Fortran, Visual Basic, C , and Pascal, the visual modeling environment requires little training due to its inherent intuitiveness. Today, the most widely used visual programming environment is the block diagram. This environment is extremely versatile, low in cost, and often includes a code generator option, which translates the block diagram into a C (or similar) high-level language suitable for target system implementation. Block diagrambased modeling and simulation packages are offered by many vendors, including MATRIXxTM, Easy5TM, SimulinkTM, Agilent VEETM, DASYLabTM, VisSimTM, and LabVIEWTM.

Mechatronics is a design philosophy: an integrating approach to engineering design. The primary factor in mechatronics is the involvement of these areas throughout the design process. Through a mechanism of simulating interdisciplinary ideas and techniques, mechatronics provides ideal conditions to raise the synergy, thereby providing a catalytic effect for the new solutions to technically complex situations. An important characteristic of mechatronic devices and systems is their built-in intelligence that results through a combination of precision in mechanical and electrical engineering, and real-time programming integrated into the design process. Mechatronics makes the combination of actuators, sensors, control systems, and computers in the design process possible.

Starting with basic design and progressing through the manufacturing phase, mechatronic design optimizes the parameters at each phase to produce a quality product in a short-cycle time. Mechatronics uses the control systems to provide a coherent framework of component interactions for system analysis. The integration within a mechatronic system is performed through the combination of hardware (components) and software (information processing).

• Hardware integration results from designing the mechatronic system as an overall system and bringing together the sensors, actuators, and microcomputers into the mechanical system.
• Software integration is primarily based on advanced control functions.

Figure 1-3 illustrates how the hardware and software integration takes place. It also shows how an additional contribution of the process knowledge and information processing is involved besides the feedback process.

FIGURE 1-3 GENERAL SCHEME OF HARDWARE AND SOFTWARE INTEGRATION

 

The first step in the focused development of mechatronic systems is to analyze the customer needs and the technical environment in which the system is integrated. Complex systems designed to solve problems tend to be a combination of mecahanical, electric, fluid power, and thermodynamic parts, with hardware in the digital and analog form, coordinated by complex software. Mechatronic systems gather data from their technical environment using sensors. The next step is to use elaborate modeling and description methods to cover all subtasks of this system in an integrated manner. This includes an effective description of the necessary interfaces between subsystems at an early stage. The data is processed and interpreted, thus leading to actions carried out by actuators. The advantages of mechatronic systems are shorter developmental cycles,
lower costs, and higher quality.

Mechatronic design supports the concepts of concurrent engineering.

In the designing of a mechatronic product, it is necessary that the knowledge and necessary information be coordinated amongst different expert groups. Concurrent engineering is a design approach in which the design and manufacture of a product are merged in a special way. It is the idea that people can do a better job if they cooperate to achieve a common goal. It has been influenced partly by the recognition that many of the high costs in manufacturing are decided at the product design stage itself. The characteristics of concurrent engineering are

• Better definition of the product without late changes.
• Design for manufacturing and assembly undertaken in the early design stage.
• Process on how the product development is well defined.
• Better cost estimates.
• Decrease in the barriers between design and manufacturing.

However, the lack of a common interface language has made the information exchange in concurrent engineering difficult. Successful implementation of concurrent engineering is possible by coordinating an adequate exchange of information and dealing with organizational barriers to crossfunctional cooperation. Using concurrent engineering principles as a guide, the designed product is likely to meet the basic requirements:

• High quality
• Robustness
• Low cost
• Time to market
• Customer satisfaction

The benefits that accrue due to the integration of concurrent engineering management strategy are greater productivity, higher quality, and reliability due to the introduction of an intelligent, selfcorrecting sensory and feedback system. The integration of sensors and control systems in a complex system reduces capital expenses, maintains a high degree of flexibility, and results in higher machine utilization.