Real-Time Workshop Research Articles

Predictive Control of Harmonic Drive in Automotive Application

This paper addresses the predictive control of the harmonic drive in an automotive application. The goal of the control was to provide good steering feel for the driver and satisfactory tracking performance in a steering system. The paper presents the dynamic model of the harmonic drive, a design framework and a two step algorithm for predictive controller design. The elaborated model predictive controller is similar to a cascade type controller with constraints in the performance function to ensure closed loop stability and a useful compromise between torque tracking and position tracking. The controller was developed and implemented in a real-time environment for rapid prototype design using Matlab, Simulink, Real-Time Workshop and dSPACE AutoBox hardware, then it was experimentally tuned for best steering feel and good tracking performance.

MATLAB-based rapid controller development platform for control applications

Embedded controllers are increasingly popular in industrial applications since designing flexible control modules over them can rapidly provide a finished product with a low manufacturing cost. Hence, rapid controller prototyping for embedded controller has been presented to resolve obstacles to developing controllers quickly. However, most proposed methods are prohibitively expensive and are restricted in the choice of software and hardware, thus, making them infeasible for engineering applications with the considerations of performance and cost. To solve the aforementioned problems, this study adopts MATLAB/Simulink with Real-Time Workshop as an effective means of producing a rapid controller development platform (RCDP), in which the controller model is built by the graphical drive modules, and is verified in Simulink, and the executable code correspondent to the controller model is then automatically generated and transferred to the target system for testing and verification. Experimental results indicate that the automatic generated code for third order controller with 1 ms sampling rate and actual position tracking in the X-Y table motion control can typically achieve the desired performance. Thus the proposed RCDP can effectively and practically save the development time of controller designs, particularly in the experimental course related to control theory in the education.

PC104 Based Low-cost Inertial/GPS Integrated Navigation Platform: Design and Experiments

The integration of Global Positioning System (GPS)/Inertial Navigation System (INS) has become very important in various navigation applications. In the last decade, with the rapid development of Micro Electro Mechanical Sensors (MEMS), great interest has been generated in low cost integrated GPS/INS applications. This paper presents a PC104 based low cost GPS/INS integrated navigation platform. The platform hardware consists of low cost inertial sensors and an assembly of various PC104 compatible peripherals, such as data acquisition card, GPS receiver, Ethernet card, mother board, graphic card, etc. The platform software including inertial/GPS data acquisition, inertial navigation calculation and integrated GPS/INS Kalman filter is implemented with Simulink, which can be directly loaded and processed in the PC104 mother board with the aid of Matlab Real-Time Workshop (RTW) utility. This platform is totally self-embedded and can be applied independently or as part of a system. Simulation and real data experiments have been performed to validate and evaluate the proposed design. A very low cost MEMS inertial sensor was utilized in the experiments. The reference is the navigation solution derived from a tactic grade Inertial Measurement Unit (IMU). Test results show that PC104 navigation platform delivers the integrated navigation solutions comparable to the reference solutions, which were calculated with a conventional laptop computer, however with less power consumptions, less system volume/complexity and much lower over-all costs. Moreover the platform hardware is compatible to various inertial sensors of different grades by configuring the related parameters in the system software.

A Matlab based framework for the real-time environment at FTU

In this paper we report on recent developments, based on The MathWorks’ Simulink and Real-Time Workshop (RTW) packages, aimed at obtaining a high level environment where a new control law can be easily modelled, simulated with the real-time constraints and then translated in the appropriate executable format. Using this tool, the control designer only needs to specify the control law in the Simulink graphical environment. The arising model is then automatically translated in C code, integrated with control system code and simulated in real-time using the data from the Frascati Tokamak Upgrade (FTU) data base archive. All the necessary steps to adapt the RTW scripts and the control system code to the new simulation/validation environment will be illustrated in this paper. Moreover, we will report on some experimental tests where the actual experiment is compared with the simulations provided by the proposed environment.

Unmanned Vehicle Controller Design, Evaluation and Implementation: From MATLAB to Printed Circuit Board

A detailed step-by-step approach is presented to optimize, standardize, and automate the process of unmanned vehicle controller design, evaluation, validation and verification, followed by actual hardware controller implementation on the vehicle. The proposed approach follows the standard practice to utilize MATLAB/SIMULINK and related toolboxes as the design framework. Controller design in MATLAB/SIMULINK is followed by automatic conversion from MATLAB to code generation and optimization for particular types of processors using Real-Time Workshop, and C to Assembly language conversion to produce assembly code for a target microcontroller. Considering Unmanned Aerial Vehicles, fixed or rotary wing ones, X-Plane is used to verify, validate and optimize controllers before actual testing on an unmanned vehicle and actual implementation on a chip and printed circuit board. Sample designs demonstrate the applicability of the proposed method.

DSP-Based Real-Time Implementation of a Hybrid $H \infty$ Adaptive Fuzzy Tracking Controller for Servo-Motor Drives

An embedded hybrid Hinfin adaptive fuzzy control structure is implemented for trajectory tracking control of a brushless servo drive system. The control structure employs a fuzzy logic controller incorporating an Hinfin tracking controller via an acceleration feedback signal. The fuzzy logic controller is equipped with an adaptive-law-based Lyapunov synthesis approach to compensate for system uncertainty and random changes in the external load acting on the drive system. The proposed control structure is experimentally verified on a state-of-the-art dSPACE DS1104 digital signal processor (DSP)-based data acquisition and control system in a laboratory 1-hp brushless drive system. The controllers are first designed in Simulink. Then, the Real-Time Workshop is used to automatically generate optimized C code for real-time applications. Afterward, the interface between MATLAB/Simulink and the dSPACE DS 1104 allows the control algorithm to run on the hardware processor of the DSP. The result is a powerful testbed for the rapid design and implementation of the hybrid tracking controllers for a wide variety of operating conditions. Experimental results are provided to verify the effectiveness of the proposed controller. Considerable improvement in the performance generated by the hybrid controller is compared with the traditional Hinfin controller

Real Time Implementation Of A Matched Filter For Radar Applications Based On Wave Digital Filters

AbstractBased on the theory of wave digital filters (WDFs), new model is derived to representmatched filter for radar applications, derived from lumped/distributed laddernetworks. This model contains lumped elements and commensurate transmissionlines. This paper also introduced a real-time implementation of the proposed model.We will demonstrate that this approach can be implemented in real time, althoughwith this prototype the frequencies are too low for practical radar applications. Thereal-time implementation is performed based on input/output data acquisition cardusing MATLAB, SIMULINK toolbox, Real-Time Workshop (RTW) toolbox andReal-Time Windows target (RTWT) toolbox. In addition, real-time windows targetrequires the Watcom C/C++ compiler.

Introduction to digital signal processing and filter design

Preface. 1. Introduction. 1.1 Introduction. 1.2 Application of DSP. 1.3 Discrete-Time Signals. 1.4 History of Filter Design. 1.5 Analog and Digital Signal Processing. 1.6 Summary. Problems. References. 2. Time-Domain Analysis and z Transform. 2.1 A Linear, Time-Invariant System. 2.2 z Transform Theory. 2.3 Using z Transform to Solve Difference Equations. 2.4 Solving Difference Equations Using the Classical Method. 2.5 z Transform Method Revisited. 2.6 Convolution Revisited. 2.7 A Model from Other Models. 2.8 Stability. 2.9 Solution Using MATLAB Functions. 2.10 Summary. Problems. References. 3. Frequency-Domain Analysis. 3.1 Introduction. 3.2 Theory of Sampling. 3.3 DTFT and IDTFT. 3.4 DTFT of Unit Step Sequence. 3.5 Use of MATLAB to Compute DTFT. 3.6 DTFS and DFT. 3.7 Fast Fourier Transform. 3.8 Use of MATLAB to Compute DFT and IDFT. 3.9 Summary/ Problems. References. 4. Infinite Impulse Response Filters. 4.1 Introduction. 4.2 Magnitude Approximation of Analog Filters. 4.3 Analog Frequency Transformations. 4.4 Digital Filters. 4.5 Impulse-Invariant Transformation. 4.6 Bilinear Transformation. 4.7 Digital Spectral Transformation. 4.8 Allpass Filters. 4.9 IIR Filter Design Using MATLAB. 4.10 Yule-Walker Approximation. 4.11 Summary. Problems. References. 5. Finite Impulse Response Filters. 5.1 Introduction. 5.2 Linear Phase Fir Filters. 5.3 Fourier Series Method Modified by Windows. 5.4 Design of Windowed FIR Filter Using MATLAB. 5.5 Equiripple Linear Phase FIR Filters. 5.6 Design of Equiripple FIR Filters Using MATLAB. 5.7 Frequency Sampling Method. 5.8 Summary. Problems. References. 6. Filter Realizations. 6.1 Introduction. 6.2 FIR Filter Realizations. 6.3 IIR Filter Realizations. 6.4 Allpass Filters in Parallel. 6.5 Realization of FIR and IIR Filters Using MATLAB. 6.6 Summary. Problems. References. 7. Quantized Filter Analysis. 7.1 Introduction. 7.2 Filter Design-Analysis Tool. 7.3 Quantized Filter Analysis. 7.4 Binary Numbers and Arithmetic. 7.5 Quantization Analysis of IIR Filters. 7.6 Quantization Analyis of FIR Filters. 7.7 Summary. Problems. References. 8. Hardware Design Using DSP Chips. 8.1 Introduction. 8.2 Simulink and Real-Time Workshop. 8.3 Design Preliminaries. 8.4 Code Generation. 8.5 Code Composer Studio. 8.6 Simulator and Emulator. 8.7 Conclusion. References. 9. MATLAB Primer. 9.1 Introduction. 9.2 Signal Processing Toolbox. References. Index.

A real-time control platform for rapid prototyping of induction motor vector control

This paper presents a real-time control platform developed for rapid prototyping of an induction motor (IM) vector control. Firstly, the control system is designed with the Simulink in the form of user-friendly block-diagrams. Next, c-codes are automatically generated from the block-diagrams with the real-time workshop. And lastly, an executable code, produced from the c-codes through a DSP c-compiler, is downloaded into a target DSP board. With this automatic programming scheme rapid prototyping is realized with the least low-level handwork programming. Presented control platform has been evaluated through the rapid prototyping of a voltage source inverter-fed IM driver and some experiments have been carried out to show its effectiveness.

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.

MODELING AND MOTION CONTROL OF ROBOTIC HAND FOR TELEMANIPULATION APPLICATION

This paper presents the process of a motion control system design and implementation for a teleminulation system. The robotic manipulator/hand is a nonlinear system with coupled effects among the joints. By applying the frequency response method, the nonlinear system is modeled as decoupled linear ones, in which each joint is controlled independently. The experimental results show the feasibility of the modeling process. Based on the obtained transfer function of each joint, the digital PID controllers are designed. The motion control system for the telemanipulation system is then implemented using the software package MATLAB, Simulink, Real Time Workshop, xPC Target and a C/C++ compiler, and the hardware I/O boards, amplifiers, etc. The presented developing procedure shows a convenient way to implement a real time robotic control system.

Concurrent models of computation for embedded software

The prevailing abstractions for software are better suited to the traditional problem of computation, namely transformation of data, than to the problems of embedded software. These abstractions have weak notions of concurrency and the passage of time, which are key elements of embedded software. Innovations such as nesC/TinyOS (developed for programming very small programmable sensor nodes called ‘motes’), Click (created to support the design of software-based network routers), Simulink with Real-Time Workshop (created for embedded control software) and Lustre/SCADE (created for safety-critical embedded software) offer abstractions that address some of these issues and differ significantly from the prevailing abstractions in software engineering. The paper surveys some of the abstractions that have been explored.

ADVANCED CONTROL ALGORITHMS + SIMULINK COMPATIBILITY + REAL-TIME OS = REX

This paper describes the structure and features of a new industrial control system called REX. During the system design, special attention was paid to the simulation facility of the control algorithms. The equivalent behavior of simulation and real-time control is guaranteed by a large function blocks library which is implemented for both Simulink and each target platform. REX is suitable for building real-time control systems of real, virtual and remote laboratories. REX does not utilize Real Time Workshop by The Mathworks.

Empowering the business analyst for on demand computing

The tools, methods, and techniques used to create business architecture are often quite different from those used in developing software architecture. This “impedance mismatch” or gap is aggravated by volatile business requirements that need to be satisfied in operational systems. Bridging this gap not only allows a more seamless transition and faster time to market, but also enables and empowers business analysts to contribute their deep subject matter expertise at many phases of the software-development life cycle, a critical aid in fruitful application development. This paper presents a case study of a project with the U.S. Patent and Trademark Office (USPTO), which explored the potential for reducing duplication of effort among patent offices by sharing work products. IBM provided an innovative method to support the analysis, the “business compiler,” a tool that implements Grammar-oriented Object Design (GOOD). GOOD is a method for creating and maintaining dynamically reconfigurable software architectures driven by business-process architectures. The business compiler was used to capture business processes within real-time workshops for various lines of business and create an executable simulation of the processes used.

04/00750 Technology and control for hydraulic manipulators: Measson, Y. et al. Fusion Engineering and Design, 2003, 69, (1–4), 129–134

An optimal-tuning nonlinear PID controller design strategy is proposed for hydraulic systems. After an analysis of these systems, an analytic physical dynamical model with dead-zone nonlinearity is derived. A nonlinear PID control scheme with the inverse of the dead zone is introduced to overcome the dead zone in the hydraulic systems. An optimal PID controller is designed to satisfy some desired time-domain performance requirements. Using an estimated process model, the optimal-tuning PID control provides optimal PID parameters even when the process dynamics are time variant. This strategy is implemented in an environment composed of dSPACE, MATLAB, SIMULINK and Real-Time Workshop. The performance of the controller is demonstrated on a hydraulic position control test rig.

Session summary

The first session in the 12th International Real-Time Ada Workshop was a summary of the new core language features that are proposed for the Amendment to Ada that is scheduled for 2005.

Self-Tuning Control: Laboratory Real - Time Education

The combination of the automatic control theory courses and practical implementation of the designed controller algorithms in real-time conditions is very important for training of the control engineers. This contribution presents a MATLAB-Toolbox for design, simulation verification and especially real-time implementation of single input - single output (SISO) discrete self-tuning controllers. The proposed adaptive controllers what are included into a Toolbox can be divided into three groups. The first group covers PID adaptive algorithms using traditional Ziegler-Nichols method for the setting of the controller parameters, the second group of described controllers is based on the pole placement design and the third group contains the controllers derived on the other approaches (dead-beat, minimum variance etc.). The controllers are implemented as an encapsulated SIMULINK blocks and thus allows users simple integration into existing SIMULINK schemas. The process of developing real-time applications using MATLAB Real-Time Workshop and several control courses is also presented. The MATLAB-Toolbox is very successfully used in Adaptive Control Course in education practice for design and verification of self-tuning control systems in real-time. It is suitable for design and verification of the industrial controllers, too. The MATLAB-Toolbox is available free of charge at Internet site - http://www.utb.cz/stctool/.

Rapid Controller Prototyping with Matlab/Simulink and Linux

This paper presents a Rapid Controller Prototyping System based on Matlab, Simulink and the Real-Time Workshop toolbox. Executable code is automatically generated for Linux RTAI, a hard real-time extension of the Linux Operating System. The produced code runs as a kernel module on a standard PC with the modification of the Linux Operating System.This environment can be used in a teaching laboratory to quickly implement real-time controllers. Students have the possibility to follow all the phases of the controller design within a unique environment (analysis, design, simulation, implementation) and can concentrate on the design aspects without having to deal with programming issues.Some applications are presented to demonstrate the capabilities and the performance of this environment.

The real-time position control of a pneumatic system with rapid prototyping approach

In this study, MATLAB and Simulink Real-Time Workshop© are used for developing real-time design and evaluating control algorithm because of their code flexibility and rapid prototyping features. The conventional PID algorithm performs to control the position of the pneumatic system. Optimal controller parameters are found experimentally under different working scenarios with the rapid prototyping approach in the real time.

Implementation of DSP Algorithms Using High-Level Approach

In most cases, Digital Signal Processing (DSP) algorithms are nowadays implemented using the classical way, that can be denoted as a low-level implementation. With this technique, mathematical equations are directly rewritten into a source code and then compiled into an executable. This approach however requires good knowledge of the signal processor and programming itself. This disadvantages can be overcome using another method called the high-level implementation, which uses for executable generation the Matlab and its capability of executable generation from Simulink models. A simulink model is converted by Real-Time Workshop into an executable file for a signal processor.