Real-time Code Generation Research Articles

A numeric derivation for fast regressive modeling of manipulator dynamics

We present Pseudo-Symbolic Dynamic Modeling (PSDM), a novel method of deriving the closed-form equations of motion of a serial kinematic chain, using base inertial parameters. PSDM is a numerical algorithm, yet allows for model simplification and pre-computation generally only possible using symbolic software. In PSDM, we characterize the form of the dynamic equations to build a set of functions guaranteed to form a linear basis for the inverse dynamics function of the manipulator. Then, a two-step numerical analysis is performed to reduce this set into a minimal dynamic model, in regressor form. PSDM offers a fast and procedural method of generating simplified dynamic models. Extensions to the algorithm allow for fast real-time code generation, forward dynamic modeling, and increased model efficiency through the elimination of minimally important model elements. The algorithm is benchmarked on common robot configurations and shown to be attractive for the dynamic modeling of up to 7-DOF manipulators, in terms of derivation time and real-time evaluation speed. Additionally, a MATLAB implementation of the algorithm has been developed and is made available for general use.

Model-based design of supervisory controllers for baggage handling systems

The complexity of airport baggage handling systems in combination with the required high level of robustness makes designing supervisory controllers for these systems a challenging task.We show how a state of the art, formal, model-based design framework has been successfully used for model-based design of supervisory controllers for an actual industrial baggage handling system, and for a real-time emulation model of an actual international airport.The high level modeling elements of the applied CIF model-based design framework allow the modeler to concentrate on implementing the baggage handling system design requirements, instead of programming PLC code. It also allows a modular and hierarchical design of the supervisory controller, and provides flexibility in adapting and extending the model. Validation of the controller and the uncontrolled plant by means of simulation and visualization made it possible to catch all modeling errors, leading to very short modeling, testing and error correction iteration loops.To the best of our knowledge, this is the first successful employment of formal, model-based design in the context of supervisory control for actual, industrial size baggage handling systems, that covers the entire development process from requirements up to and including validation, real-time PLC code generation and implementation.We give an overview of the model-based design framework, discuss several modeling issues, and analyze the results of the industrial applications. We do not go into full technical detail, due to nondisclosure agreements, but tell the story, and give lessons learned that we consider useful for practitioners.

A system-level FPGA design methodology for video applications with weakly-programmable hardware components

High-performance video applications with real-time requirements play an important role in diverse application fields and are often executed by advanced parallel processors or GPUs. For embedded scenarios with strict energy constraints such as automotive image processing, FPGAs represent a feasible power-efficient computer platform. Unfortunately, their hardware-driven design concept results in long development cycles and impedes their acceptance in industrial practice. Additionally, the verification of the FPGA's correctness and its performance figures are unavailable until a very late development stage, which is critical during design space exploration and the integration in complex embedded systems. Weakly-programmable architectures, supporting design and run-time reuse via flexible hardware components, represent a promising and efficient FPGA development approach. However, they currently lack suitable design and verification methodologies for real-time scenarios. Therefore, this paper proposes a system-level FPGA development concept for video applications with weakly-programmable hardware components. It combines rapid software prototyping with component-based FPGA design and advanced formal real-time analysis and code generation techniques. The presented approach enables an early verification of the application's correctness, including exact performance figures. It provides a software-level verification of weakly-programmable hardware components and an automated assembly of the final hardware design. The developed tools and their usability are demonstrated by a binarization and a dense block matching application, which represents a basic preprocessing step in automotive image processing for driver assistance systems. When compared to a hand-optimized variant, the generated hardware design achieves comparable performance and chip area figures without requiring significant hardware integration effort.

Research and Implementation Model Base System Platform Based on C MEX S-Function

Modeling and simulation is more and more widely applied in the development of the control system. It is very difficult to maintain and transplant that control system model is Complexity, dedicated and variability. To solve that problem this paper put forward research and implementation model base system platform based on C MEX S-Function. model base system platform contain model development ,model management ,and model storage and so on function. C MEX S-Function has some advantages that contain flexible, easy to transplant, run fast, real-time code generation and so on. So practices have proven that this base system platform can reduce development circle, reduce development cost, has model reusability and portability better, laid the foundation for embedded real-time code generation.

Design and digital implementation of voltage and current mode control for the quasi‐ Z ‐source converters

Two strategies of peak dc-link voltage control of the voltage-fed quasi-Z-source converters (qZSC) are analysed and compared. Different from the currently available literatures, the peak dc-link voltage is estimated by summing the two capacitor voltages of qZSC. The voltage mode and current mode controls are derived based on the fifth-order small-signal model of the quasi-Z-source network with inductive load. Both controllers are digitally implemented using a digital signal processor (DSP)-based direct digital design approach, where the real-time workshop is used for automatic real-time code generation for a TMS320F2808 DSP. Digital compensators are tuned using Bode diagram and discrete frequency response approaches with a graphical MATLAB/single-input single-output tool. The performances of the proposed control strategies are verified by the experimental results during start-up, input voltage and load disturbances.

A DSP-Based Dual Loop Digital Controller Design and Implementation of a High Power Boost Converter for Hybrid Electric Vehicles Applications

This paper presents a DSP based direct digital control design and implementation for a high power boost converter. A single loop and dual loop voltage control are digitally implemented and compared. The real time workshop (RTW) is used for automatic real-time code generation. Experimental results of a 20 kW boost converter based on the TMS320F2808 DSP during reference voltage changes, input voltage changes, and load disturbances are presented. The results show that the dual loop control achieves better steady state and transient performance than the single loop control. In addition, the experimental results validate the effectiveness of using the RTW for automatic code generation to speed up the system implementation.

MoDEST: From Model-driven design towards real-time code generation for embedded control systems

This paper presents a model-driven methodology and tool for Embedded Control System (ECS) design. This methodology defines a common metamodel that unifies the design steps and ensures the consistency of models along the design cycle. It uses an approach based, in one side, on the software components that increase models reusability to face the increasing complexity of ECS; in the other side, on the aspect-oriented paradigm that allows to model transversal real time properties to support models analysis and validation in the earliest steps of the design cycle. Our methodology supports the control and scheduling co-design in order to evaluate the performance and stability of ECS during their design. A tool called MoDEST implements this methodology and provides real-time code generation. It should help designers to choose the best scheduling that preserves the control performance and quality of the designed ECS.

Testing Performance and Reliability of Magnetic Suspension Controllers

The aim of this paper is to present an experiment realized with the support of magnetic levitation system equipped with additional electromagnet. This extra unit allows to realize more experiments including identification and control, diagnose the performance of the closed loop system and design controllers for single axis of the active magnetic bearing. The test rig consists of two electromagnets, distance and current sensors and ferromagnetic object. The system is controlled by the personal computer or embedded system. The MATLAB/Simulink software allows to perform identification, signal analysis, controller design and real-time code generation for the selected target. The experimental controllers reliability test under external pulse excitation is presented.

Using Real Time Workshop for rapid and reliable control implementation in the Frascati Tokamak Upgrade Feedback Control System running under RTAI-GNU/Linux

The Feedback Control System running at FTU has been recently ported from a commercial platform (based on LynxOS) to an open-source GNU/Linux-based RTAI-LXRT platform, thereby, obtaining significant performance and cost improvements. Based on the new open-source platform, it is now possible to experiment novel control strategies aimed at improving the robustness and accuracy of the feedback control. Nevertheless, the implementation of control ideas still requires a great deal of coding of the control algorithms that, if carried out manually, may be prone to coding errors, therefore time consuming both in the development phase and in the subsequent validation tests consisting of dedicated experiments carried out on FTU. In this paper, we report on recent developments based on Mathworks’ Simulink and Real Time Workshop (RTW) packages to obtain a user-friendly environment where the real time code implementing novel control algorithms can be easily generated, tested and validated. Thanks to this new tool, the control designer only needs to specify the block diagram of the control task (namely, a high level and functional description of the new algorithm under consideration) and the corresponding real time code generation and testing is completely automated without any need of dedicated experiments. In the paper, the necessary work carried out to adapt the Real Time Workshop to our RTAI-LXRT context will be illustrated. A necessary re-organization of the previous real time software, aimed at incorporating the code coming from the adapted RTW, will also be discussed. Moreover, we will report on a performance comparison between the code obtained using the automated RTW-based procedure and the hand-written C code, appropriately optimised; at the moment, a preliminary performance comparison consisting of dummy algorithms has shown that the code automatically generated from RTW is faster (about 30% up) than the manually written one. This preliminary result combined with the fact that the use of RTW eliminates the coding workload leads to the conclusion that this approach to control implementation grants significant advantages. According to the FTU experiment program, the actual deployment of the new tool is scheduled for the next experimental campaign.

Modelling of real-time constraints using SDL for embedded systems design

The use of SDL (Specification and Description Language)has arisen as a promising way of dealing with the increasing complexity of embedded real-time systems. However, SDL does not take into account non-functional aspects, such as the time requirements that are especially important in the context of real-time systems. Furthermore, the associated code generators do not integrate the management of temporal constraints. A real-time semantic extension to SDL for real-time systems modelling is proposed. The real-time profile is added to SDL in order to prepare the real-time code generation. To illustrate the proposal, an example of a speed regulator is presented.

The ORCCAD Architecture

The ORCCAD programming environment for robotic systems allows users to address automatic control laws in continuous time at the lower levels, and aspects of discrete-time logic at the higher lev els. ORCCAD provides tools of specification, formal verification, simulation, and real-time code generation integrated within a set of dedicated graphical interfaces. Basic robot actions, which are in trinsically hybrid entities, are handled by the ROBOT-TASK struc ture, which smartly interfaces aspects of continuous and discrete time. ROBOT-TASKS are further logically composed into more complex actions, ROBOT-PROCEDURES, through a dedicated lan guage. While system performance can be checked using simula tions, crucial properties such as deadlock avoidance, safety, and liveness can be formally verified at both levels. The approach is illustrated with an underwater inspection mission.

Automated Generation and Scheduling of ADA95 Hard Real-Time Control Code

This paper describes a development system for embedded real-time control, Descartes, which allows control algorithms to be entered in block diagram form which are then transformed to Ada95 executable code. The intention is to allow the design engineer to produce real-time software that will run on the controller hardware with minimal use of programming, which will be portable over the platforms on which Ada95 is supported, which has predictable real-time behaviour and which permits configuration on distributed platforms.

164 Automatic generation of real-time code using the beacon CAE environment

164 Automatic generation of real-time code using the beacon CAE environment

Predictable Parallel Real-time Code Generation

The design and implementation of controller software for embedded hard real-time applicatiions can prove to be a time consuming and error prone task. In order to create software with predictable execution times and real-time responses normally relies on low level coding and customisation for a particular processor. An extra dimension of difficulty is added if concurrency and parallelism is considered. Parallelism can be used to increase the controller throughput and to allow optimum real-time responses. The work presented in this paper focuses on a design and implementation system that attempts to address these problems by providing an environment that will automate the generation of parallel real-time control code. The paper describes the development system, gives an overview of the controller hardware platform and shows results from the prototype software system.

Predictable parallel real-time code generation

Predictable parallel real-time code generation