Performance analysis of mechanical vibration suppression control system for motor drives with elastic load based on frequency response

The bifurcation theory is applied to bifurcations and accompanying jump phenomena which appear in the frequency response of nonlinear feedback control systems. It is also shown by a numerical example that such complicated structures exist in the frequency response of a simple nonlinear feedback control system.

Integrative modeling and simulation analysis of 11kW squirrel-cage asynchronous motor and vector control system have been done in the paper. Integrative model deals with the coupling effect between the motor and its control system, and analyzes system dynamic response. At the same time, the motor transient electromagnetic field performance has been acquired in the integrative simulation with slip frequency vector control strategy. Furthermore, the simulation results of integrative model are compared with that of non-integrative model, including control system circuit model and motor physical model without precise control strategy. The integrative model considers not only the motor external control strategy but also motor internal electromagnetic field performance and response with the control strategy. In addition, integrative modeling and simulation realizes coupling simulation analysis of squirrel-cage asynchronous motor and control system in system perspective and component perspective as well, which could effectively help us do the precise analysis of system performance.

In recent years, control system reliability has received much attention with increase of situations where computer-controlled systems such as robot control systems are used. In order to improve reliability, control systems need to have abilities to detect a fault (fault detection) and to maintain stability and control performance (fault tolerance). In this paper, we address the vibration suppression control of a one-link flexible arm robot. Vibration suppression is realized by an additional feedback of a strain gauge sensor attached to the arm besides motor position. However, a sensor fault (e.g., disconnection) may degrade the control performance and make the control system unstable at its worst. In this paper, we propose a fault tolerant control system for strain gauge sensor fault. The proposed control system has a strain gauge sensor signal observer based on the reaction force observer and detects the fault by monitoring the estimation error. After fault detection, the proposed control system exchanges the faulty sensor signal for the estimated one and switches to a fault mode controller so as to maintain the stability and the control performance. We apply the proposed control system to the vibration suppression control system of a one-link flexible arm robot and confirm the effectiveness of the proposed control system by some experiments.

Midcourse Space Experiment attitude system performance for gyro disabled operations

Magnethoreological-fluid (MR-fluid) actuators are consider as as suitable instruments in rehabilitation trainings so that they are passive actuators. Passive actuators will not generate force by themselves. Only when external force acts on them, they generate reaction force. Considering these properties, passive actuators are stable actuators and appropriate for the human society because they would be little risk for humans when they are loss of control. In past, the author has proposed robust velocity constraint control, in which nonlinear term of MR fluids are compensated. This research uses the control system and measures frequency responses. In the constructed system, bandwidth of velocity constraint control can be investigated, and quantitative performance evaluation of rehabilitation trainings using MR-fluid actuators is expected in the future.

Study on the radial vibration of a new type of composite piezoelectric transducer

Distributed control systems are crucial for regulating manufacturing processes by controlling field devices. Delays in device operation can significantly impact the time response of the process control system, affecting overall stability. To enhance network performance and process time response, it is essential to study the inherent delays of field and network devices. This paper examines process control loops involving a 3-layered network based on the OSI model’s physical, network, and application layers. The proposed networked control system assesses time delays within and between field devices configured through these layers, which are essential for control loops, including open, closed, and cascade loops. Analyzing these time delays enables effective control loop configuration, improving the process control time response and overall stability.

Verification of safety critical and control systems of Nuclear Power Plants using Petri nets

The Data Time Flow Simulator (DTF) has been developed at the AIT Austrian Institute of Technology in the course of the EU ARTEMIS Project POLLUX which is related to the design of electronic control systems for the next generation of electric vehicles. In previous work, we have introduced a generic approach for performance analysis of vehicle electronic control systems using the DTF. The main issue of this paper is to demonstrate the practicability of this design methodology by means of a specific use case, namely the performance analysis of a vehicle control system for an electric city car, designed using inputs from different POLLUX project partners from the automotive industry.

The increasing complexity associated with many modern engineering applications, including autonomous robot guidance and navigation, process control in sensor-rich environments, and control of biological systems, has far-reaching implications for control system design. As an example, reactive, embedded software systems, interacting among themselves and remote users over communication networks, introduce a whole new set of system-level challenges, and classic control design objectives such as stability, performance, and robustness are being complemented with a number of new questions. These include the cost of hardware implementation, measured for example not only by computational requirements such as speed and memory, but also by communication requirements such as available communication bandwidth. Moreover, the complexity associated with specifying the control procedures and with verifying the behavior of the closed-loop system increasingly plays a fundamental role, especially in safety-critical control systems arising in energy and transportation networks, and in medical applications.

Resonant direct and converse magnetoelectric (ME) effects have been investigated experimentally and theoretically in FeGa/PZT/FeGa sandwich laminate composites under the same electric and magnetic bias conditions. Resonant direct ME effect (DME) occurs at antiresonance frequency while resonant converse ME effect (CME) occurs at resonance frequency. The antiresonance and resonance frequencies have close but different values under identical bias conditions. The magnitudes of resonant effective ME coefficients for direct and converse ME effects are also not equal. A model was developed to describe the frequency response of DME and CME in laminate composite, which was in good agreement with experimental results.

Delamination identification is very important for structural health monitoring of composite laminated structures. In the present study, a two-step delamination identification method using resonant and anti-resonant frequency changes is proposed. The present method can identify the location of delamination and the size nondestructively. As a preparation for delamination identification of a CFRP laminated beam, the beam is divided into two domains. At the first step, the delaminated domain is identified using the anti-resonant frequency changes. At the second step, the delamination location and the size are identified in the delaminated domain using the resonant frequency changes. Delamination identifications of CFRP cantilever beams are conducted using both FEM analysis data and experimental data. As a result, effectiveness of the present method is shown.

A novel approach is provided for the analysis of multi-loop control systems by a digital computer introducing operational arrays, in which all the instructions are given through the data input. Changing parameters for optimisation purposes or the introducing of additional networks becomes a matter of changing the operational array in the data, leaving the main programme untouched. Although the method is general, only the frequency response of a control system is considered, but at the same time the way has been left open to expand the method as experience reveals the need for further facilities, i.e. root locus, time response, etc. The programme has been written in Algol, but the basic flow diagram can be easily converted into any other language. Whatever the language is, the programme provides the necessary software design facilities translated into control engineering terms in a readily usable computational form.

This paper presents performance comparison of a novel hybrid control algorithm and a Positive Position Feedback (PPF) control law for vibration suppression with low energy consumption. The proposed hybrid control method combines a bang-bang active controller with a PPF control law and results in a significant reduction of actuation energy requirement due to its ability to switch the actuation voltage source between external power supply and PPF feedback controller. Experimental results show that a single mode vibration control system using this proposed hybrid controller consumes 46% less power compared to the traditional PPF control system to give the same settling time. Experiments also reveal that substantial nonlinearity exists in the piezoelectric constant of the transducer, especially under high voltage actuation. The voltage dependent behavior of electromechanical coupling coefficient is identified empirically and represented by a curve fit expression. A real time adaptive control algorithm is developed to account for the voltage dependent behavior of the coupling coefficient and the simulation results are validated experimentally.

We review practical case studies of a developing method of highly reliable real-time embedded control systems using a CPU model-based hardware/software co-simulation. We take an approach that enables us to fully simulate a virtual mechanical control system including a mechatronics plant, microcontroller hardware, and object code level software. This full virtual system approach simulates control system behavior, especially that of the microcontroller hardware and software. It enables design space exploration of microarchitecture, control design validation, robustness evaluation of the system, software optimization before components design. It also avoids potential problems. The advantage of this work is that it comprises all the components in a typical control system, enabling the designers to analyze effects from different domains, for example mechanical analysis of behavior due to differences in controller microarchitecture. To further improve system design, evaluation and analysis, we implemented an integrated behavior analyzer in the development environment. This analyzer can graphically display the processor behavior during the simulation without affecting simulation results such as task level CPU load, interrupt statistics, and the software variable transition chart. It also provides useful information on the system behavior. This virtual system analysis does not require software modification, does not change the control timing, and does not require any processing power from the target microcontroller. Therefore this method is suitable for real-time embedded control system design, in particular automotive control system design that requires a high level of reliability, robustness, quality, and safety. In this study, a Renesas SH-2A microcontroller model was developed on a CoMET™platform from VaST Systems Technology. An electronic throttle control (ETC) system and an engine control system were chosen to prove this concept. The electronic throttle body (ETB) model on the Saber® simulator from Synopsys® and the engine model on MATLAB®/Simulink®simulator from MathWorks can be simulated with the SH-2A model using a newly developed co-simulation interface between MATLAB®/Simulink® and CoMET™. Though the SH-2A chip was being developed as the project was being executed, we were able to complete the OSEK OS development, control software design, and verification of the entire system using the virtual environment. After releasing a working sample chip in a later stage of the project, we found that such software could run on both actual ETC system and engine control system without critical problem. This demonstrates that our models and simulation environment are sufficiently credible and trustworthy.