Low-level Software Research Articles

Mechatronic Design of a Four Wheel Steering Mobile Robot with Fault-Tolerant Odometry Feedback

In this paper, the mechatronics design of a four wheel steered mobile robot is discussed in detail. Mechanical structure and electrical interfaces are presented. Low-level software architecture based on embedded pc-based control is designed that enables the robot to operate its eight independent actuators synchronously. Kinematics models are elaborated, and it is shown that how mechanical structure of the robot affects kinematics and the feedback. Based on kinematics models, a fault tolerant wheel odometry is proposed to make the feedback robust to practical wheel odometry faults during the solution of forward kinematics. Real-time implementation of presented to support the the efficacy of proposed methods.

A control and automation system for wave basins

This paper presents the new active absorption wave basin, named Hydrodynamic Calibrator (HC), constructed at the University of São Paulo (USP), in the Laboratory facilities of the Numerical Offshore Tank (TPN). The square (14m×14m) tank is able to generate and absorb waves from 0.5Hz to 2.0Hz, by means of 148 active hinged flap wave makers. An independent mechanical system drives each flap by means of a 1HP servo-motor and a ball-screw based transmission system. A customized ultrasonic wave probe is installed in each flap, and is responsible for measuring wave elevation in the flap. A complex automation architecture was implemented, with three Programmable Logic Computers (PLCs), and a low-level software is responsible for all the interlocks and maintenance functions of the tank. Furthermore, all the control algorithms for the generation and absorption are implemented using higher level software (MATLAB®/Simulink block diagrams). These algorithms calculate the motions of the wave makers both to generate and absorb the required wave field by taking into account the layout of the flaps and the limits of wave generation. The experimental transfer function that relates the flap amplitude to the wave elevation amplitude is used for the calculation of the motion of each flap. This paper describes the main features of the tank, followed by a detailed presentation of the whole automation system. It includes the measuring devices, signal conditioning, PLC and network architecture, real-time and synchronizing software and motor control loop. Finally, a validation of the whole automation system is presented, by means of the experimental analysis of the transfer function of the waves generated and the calculation of all the delays introduced by the automation system.

Research on the Parametric Design of Involute Helical Gear Based on Pro/Program

Involute helical gear has advantages of larger overlap coefficient, steady transmission, lower impact and noise, higher load bearing capacity, longer life, so it is widely used in machinery, mining, metallurgy, aerospace and other fields. However, due to the involute helical gear tooth profile shape is more complex, and some low-level CAD software is difficult to directly generate a three-dimensional helical gear tooth profile. According to involute helical gear formation principle, this paper presents an effective method to establish the three-dimensional model for involute helical gear .In this paper, a parametric design method of realizing involute helical gear 3D model by using Pro/E modeling functions and Pro/Program programming is discussed. This method can enable designers to obtain helical gear 3D solid model quickly and accurately by inputting a little geometry characteristic parameters. It can also enables designers quickly update design based on the existing 3D gear model, so as to improve the design efficiency.

Special issue: software maintenance and reengineering (CSMR 2011)

Special issue: software maintenance and reengineering (CSMR 2011)

Introduction to the Special Issue on HRI System Studies

Human-Robot Interaction (HRI) systems are often realized through a complex integration of relevant state-of-the-art algorithms, low-level software and robotic hardware. As such, advances in techniques and approaches for integrating components into a robotic system are essential to advance the field. To develop such techniques and systems requires one to address real-world challenges, particularly those arising from the complex nature of human-robot interaction embedded in a dynamic social and/or task environment. This special issue focuses on the concept of systems, highlighting the importance of building actual HRI systems to validate and drive the science and technology in the field.

Process Algebra as a Common Framework for Hardware/Software Coverification

This letter presents the practical issues concerning late and insufficient verification of low-level software on hardware platforms developed by our industrial partner. To overcome these issues, we propose a coverification platform based on process algebra. The descriptions of hardware and software, and their interface are translated into a common process-algebraic platform, and formal verification techniques are used to check the conformance of the two descriptions. We present the results of our first attempt towards this goal, discuss the lessons learned, and present the road-map for future research.

2P1-K13 OpenRTM-aistとTECS(TOPPERS Embedded Component System)の連携(RTミドルウェアとオープンシステム)

A component-based software development is widely applied to solve software complexity and maintainability problems. The TECS which is a ・・type of static component system for ITRON OS is suitable for low level software systems that require real-time capability and stability, whereas the RT-component framework is appropriate to various system integrations, since it has high flexibility and re-usability. Integrating TECS and RT-component provides flexibility and expandability to the TECS as well as stability to the RT-component, so that it makes possible to construct a flexible and stable system. In this paper methods to integrate TECS and RT-component are considered, and some examples are discussed.

CREATING THE DISPLACEMENT MAPPED LOW-LEVEL MESH AND ITS APPLICATION FOR CG SOFTWARE

In this paper, we propose a new method for creating the displacement map to restore the detailed geometry from the low-level base mesh. The displacement mapping actually changes the surface geometry with the displacement information. Recent CG software can treat the displacement mapping for increasing the accuracy of the surface. We convert the displacement map to the color image that is mapped to the low-level mesh in order to utilize the displacement map by existing CG software. Because displacement information is in image format, we can compress the displacement information by any image compression technique. The load for creating the three-dimensional scene is reduced by using such a low-level mesh which has the displacement information. We obtain the displacement information by finding the point on the input mesh corresponding to the point on the base mesh. The corresponding point is calculated by using the barycentric coordinate of the parameterized mesh. Because the mesh parameterization creates one-to-one mapping between the input mesh and the base mesh, we can avoid the problems that are caused by the traditional ray-triangle intersection method. For demonstration, we restore the detailed surface from our result by using the Blender 2.44.

A Split-Crank Bicycle Ergometer Uses Servomotors to Provide Programmable Pedal Forces for Studies in Human Biomechanics

This paper presents a novel computer-controlled bicycle ergometer, the TiltCycle, for use in human biomechanics studies of locomotion. The TiltCycle has a tilting (reclining) seat and backboard, a split pedal crankshaft to isolate the left and right loads to the feet of the pedaler, and two belt-driven, computer-controlled motors to provide assistance or resistance loads independently to each crank. Sensors measure the kinematics and force production of the legs to calculate work performed, and the system allows for goniometric and electromyography signals to be recorded. The technical description presented includes the mechanical design, low-level software and control algorithms, system identification and validation test results.

Software model checking without source code

We present a framework, called air, for verifying safety properties of assembly language programs via software model checking. air extends the applicability of predicate abstraction and counterexample guided abstraction refinement to the automated verification of low-level software. By working at the assembly level, air allows verification of programs for which source code is unavailable—such as legacy and COTS software—and programs that use features—such as pointers, structures, and object-orientation—that are problematic for source-level software verification tools. In addition, air makes no assumptions about the underlying compiler technology. We have implemented a prototype of air and present encouraging results on several non-trivial examples.

Component-Based Software Development Framework for 3rd Party Logistics Business

This paper suggests a component-based software development framework for 3rd party logistics (3PL) business. This framework integrates two engineering methodologies in order to identify the most reusable software components that can be used in several types of 3PL business models. UML (Unified Modeling Language) is used to design lower-level software components and DEMO (Design and Engineering Methodology for Organization), one of the business engineering methodologies based on the communication theory, is used to identify core business processes for 3PL business models. By using the methodologies, we develop a 3PL management solution by applying the framework into a C2C type of 3PL business model, specifically the door-to-door (D2D) service.

The Planck-LFI Radiometer Electronics Box Assembly

The Radiometer Electronics Box Assembly (REBA) is the control and data processing on board computer of the Low Frequency Instrument (LFI) of the Planck mission (ESA).The REBA was designed and built incorporating state of the art processors, communication interfaces and real time operating system software in order to meet the scientific performance of the LFI.We present a technical summary of the REBA, including a physical, functional,electrical, mechanical and thermal description.Aspects of the design and development, the assembly, the integration and theverification of the equipment are provided. A brief description of the LFI onboard software is given including the Low-Level Software and the mainfunctionalities and architecture of the Application Software. The compressormodule, which has been developed as an independent product, later integrated inthe application, is also described in this paper.Two identical engineering models EM and AVM, the engineering qualification modelEQM, the flight model FM and flight spare have been manufactured andtested. Low-level and Application software have been developed.Verification activities demonstrated that the REBA hardware and software fulfilall the specifications and perform as required for flight operation.

Decimal floating-point support on the IBM System z10 processor

The latest IBM zSeries® processor, the IBM System z10™ processor, provides hardware support for the decimal floating-point (DFP) facility that was introduced on the IBM System z9® processor. The z9® processor implements the facility with a mixture of low-level software and hardware assists. Recently, the IBM POWER6™ processor-based System p™ 570 server introduced a hardware implementation of the DFP facility. The latest zSeries processor includes a decimal floating-point unit based on the POWER6 processor DFP unit that has been enhanced to also support the traditional zSeries decimal fixed-point instruction set. This paper explains the hardware implementation to support both decimal fixed point and DFP and the new software support for the DFP facility, including IBM z/OS®, Java™ JIT, and C/C++ compilers, as well as support in IBM DB2® and middleware.

Synthesizing Behavioral Model of Event-Based Requirements

Problem Statement: in the software engineering field, satisfaction of user's requirements by software has been a matter of concern. Therefore, monitoring software behavior against user's high-level requirements has already received a considerable and significant attention. However, the gap between low-level software behavior and high-level requirements has put an obstacle in the way of monitoring. Approach: to overcome the obstacle, we presented a method to synthesize a behavioral model of the event-based requirements in three steps: (1) eliciting event-based requirements; (2) specifying the requirements in event-based formulae and (3) mapping the formulae into a behavioral model. Results: to show effectiveness of the method, it was applied to requirements of a safety critical system, called Railroad Crossing Control (RCC) one and a behavioral model was synthesized. The model was used to synthesize monitor of the RCC system. The monitor is responsible for surveillance of software behavior for preventing the collision between the train and some car at the junction of rail and road.Conclusions: we proposed a systematic method started from users' requirements elicitation and concluded with its behavioral specification. Focus of the method was on event-based real-time requirements which were stated by scenarios in a sequence of real-time interactions.

Achieving behavioral control with millisecond resolution in a high-level programming environment

The creation of psychophysical tasks for the behavioral neurosciences has generally relied upon low-level software running on a limited range of hardware. Despite the availability of software that allows the coding of behavioral tasks in high-level programming environments, many researchers are still reluctant to trust the temporal accuracy and resolution of programs running in such environments, especially when they run atop non-real-time operating systems. Thus, the creation of behavioral paradigms has been slowed by the intricacy of the coding required and their dissemination across labs has been hampered by the various types of hardware needed. However, we demonstrate here that, when proper measures are taken to handle the various sources of temporal error, accuracy can be achieved at the 1 ms time-scale that is relevant for the alignment of behavioral and neural events.

A theory of platform-dependent low-level software

The C language definition leaves the sizes and layouts of types partially unspecified. When a C program makes assumptions about type layout, its semantics is defined only on platforms (C compilers and the underlying hardware) on which those assumptions hold. Previous work on formalizing C-like languages has ignored this issue, either by assuming that programs do not make such assumptions or by assuming that all valid programs target only one platform. In the latter case, the platform's choices are hard-wired in the language semantics. In this paper, we present a practically-motivated model for a C-like language in which the memory layouts of types are left largely unspecified. The dynamic semantics is parameterized by a platform's layout policy and makes manifest the consequence of platform-dependent (i.e., unspecified) steps. A type-and-effect system produces a layout constraint: a logic formula encoding layout conditions under which the program is memory-safe. We prove that if a program type-checks, it is memory-safe on all platforms satisfying its constraint. Based on our theory, we have implemented a tool that discovers unportable layout assumptions in C programs. Our approach should generalize to other kinds of platform-dependent assumptions.

A Fast Job Scheduling System for a Wide Range of Bioinformatic Applications

Bioinformatic tools are often used by researchers through interactive Web interfaces, resulting in a strong demand for computational resources. The tools are of different kind and range from simple, quick tasks, to complex analyses requiring minutes to hours of processing time and often longer than that. Batteries of computational nodes, such as those found in parallel clusters, provide a platform of choice for this application, especially when a relatively large number of concurrent requests is expected. Here, we describe a scheduling architecture operating at the application level, able to distribute jobs over a large number of hierarchically organized nodes. While not contrasting and peacefully living together with low-level scheduling software, the system takes advantage of tools, such as SQL servers, commonly used in Web applications, to produce low latency and performance which compares well and often surpasses that of more traditional, dedicated schedulers. The system provides the basic functionality necessary to node selection, task execution and service management and monitoring, and may combine loosely linked computational resources, such as those located in geographically distinct sites.

Service Management: An Interview with Alan Ganek

A new multiprocessor system-on-chip prototyping flow based on the Portable Operating System Interface (Posix) standard and a multiprocessor hardware platform lets you quickly prototype Posix-based applications. Modern MPSoCs (multiprocessor systems on chip) contain a huge amount of software and rely on complex hardware components. As application complexity grows, programmable multiprocessor platforms are becoming more desirable. In fact, chips with several processors (such as general purpose processors and digital signal processors) are emerging in the industry, either for low-end applications such as audio codec or high-end applications such as video encoders. Reconfigurable hardware platforms recently emerged as effective solutions to validate and prototype MPSoC designs early in a design flow. Such prototyping platforms make simultaneous hardware and software development possible and enable early software design and debugging,13 thus allowing for early software and hardware integration - which is the critical step in MPSoC system designs. Applications running on these new multiprocessor platforms usually require sophisticated multitasking operating systems to execute the system parts mapped to software. These operating systems provide a suitable abstraction, allowing easy development of application software.4 Using a standard API at this level makes this process even more effective and enhances software portability and reuse across different operating systems. However, the same portability doesn't apply from a hardware perspective, where changes to the underlying configurable hardware architecture are still seen as a major source of nonportability and usually lead to long, tedious redesign cycles. MPSoC designers have recently introduced the concept of hardware-dependent software (HdS) to tackle such strong coupling between hardware and software within the lower system software layers.1 Here, we describe our experience in MPSoC prototyping using a multiprocessor operating system kernel that implements the Portable Operating System Interface (Posix) API standard on top of a reconfigurable multiprocessor platform using the HdS concept. (We chose Posix as the API owing to its wide acceptance and availability in many runtime environments.5) Investigating the complexity of hardware and software integration in multiprocessor system design, a process still not completely mastered in MPSoC design flows, helped us understand the duality between the low-level software layer (HdS) and the underlying hardware platform in the context of MPSoC design.

Parallel Programming of Multi-processor SoC: A HW–SW Interface Perspective

For the design of classic computers the parallel programming concept is used to abstract HW/SW interfaces during high level specification of application software. The software is then adapted to existing multiprocessor platforms using a low level software layer that implements the programming model. Unlike classic computers, the design of heterogeneous MPSoC includes also building the processors and other kind of hardware components required to execute the software. In this case, the programming model hides both hard-ware and software refinements. This paper deals with parallel programming models to abstract both hardware and software interfaces in the case of heterogeneous MPSoC design. Different abstraction levels will be needed. For the long term, the use of higher level programming models will open new vistas for optimization and architecture exploration like CPU/RTOS tradeoffs.

A Component-Based Approach to the Design of Networked Control Systems

Component-based techniques revolve around composable, reusable software objects that shield the application level software from the details of the hardware and low-level software implementation and vice versa. Components provide many benefits that have led to their wide adoption it software and middleware developed for embedded systems: They are well-defined entities that can be replaced without affecting the rest of the systems, they can be developed and tested separately and integrated later, and they are reusable. Clearly such features are important for the design of large-scale complex systems more generally, beyond software architectures. We propose the use of a component approach to address embedded control problems. We outline a general coponent-based framework to embedded control aid show how it can be instantiated inspecific problems that arise in the control over/of sensor networks. Building on the middleware component framework developed under the European project RUNES, we develop a number of control-oriented components necessary for the implementation of control applications and design their integration. The paper provides the overview of the approach, discusses a real life application where the approach has been tested and outlines a number of specific control problems that arise in this application.