Control Strategies for Semi-Active Lorry Suspensions

1996 ◽  
Vol 210 (2) ◽  
pp. 161-178 ◽  
Author(s):  
D Cebon ◽  
F H Besinger ◽  
D J Cole
Keyword(s):  
Linear Models ◽  
Control Strategies ◽  
Power Input ◽  
Optimum Level ◽  
Passive Damping ◽  
Control Laws ◽  
Body Acceleration ◽  
Performance Improvements ◽  
Full State Feedback ◽  
Active Damper

The optimum level of passive damping for minimizing the root mean square (r.m.s.) dynamic tyre force and r.m.s. body acceleration of a heavy vehicle is determined by testing a damper in a ‘hardware-in-the-loop’ (HiL) test rig. Two different control strategies [‘modified skyhook damping’ (MSD), and linear optimal control with full state feedback (FSF)] are investigated theoretically using linear models, and suspension force control laws are derived. These control laws, along with simple ‘on–off’ control, are then tested experimentally using a prototype semi-active damper which is controlled so as to follow the demanded force, except when power input is required. The achievable performance improvements are compared and differences between the linear theory, computer simulations and experimental performance are discussed. It is found that using FSF control, r.m.s. body acceleration and r.m.s. tyre force can be reduced simultaneously by 28 and 21 per cent of their values for optimal passive damping.

Control of Suspensions for Vehicles With Flexible Bodies—Part I: Active Suspensions

1996 ◽  
Vol 118 (3) ◽  
pp. 508-517 ◽  
Author(s):  
Aleksander Hac´ ◽  
Iljoong Youn ◽  
Hsien H. Chen
Keyword(s):  
Rigid Body ◽  
Output Feedback ◽  
Control Strategies ◽  
The Body ◽  
Vehicle Body ◽  
Structural Vibrations ◽  
Control Laws ◽  
Modal Damping ◽  
Rigid Body Model ◽  
Full State Feedback

In this paper, two classes of control strategies for active suspension are developed. The purpose of control is to reduce structural vibrations of the body without compromising traditional control objectives. In the first approach, the control laws for the suspension forces are synthesized to enhance modal damping in the structural modes. In the second approach, a separate proof-mass actuator mounted on the vehicle body is used to suppress structural vibrations, while suspension controllers based on a rigid-body model are utilized. The results of simulation demonstrate that with both methods significant reductions in structural vibrations can be achieved without sacrificing other aspects of performance, provided that modal variables for the body beaming modes are available for feedback. To simplify the implementation, suboptimal decentralized controllers using state and subsequently output feedback are developed, which are obtained by taking advantage of the separation between the natural frequencies of the rigid-body and the structural modes. For both control methods, output feedback, including the modal variables for the body beaming modes, results in performances that are close to those obtained for a full state feedback.

Control of flexible manipulators: A survey

Robotica ◽  
2004 ◽  
Vol 22 (5) ◽  
pp. 533-545 ◽  
Author(s):  
M. Benosman ◽  
G. Le Vey
Keyword(s):  
Linear Models ◽  
Control Strategies ◽  
Research Area ◽  
Future Research ◽  
Complex Nature ◽  
Open Problems ◽  
Complex Models ◽  
The Many ◽  
The One ◽  
Flexible Arms

A survey of the field of control for flexible multi-link robots is presented. This research area has drawn great attention during the last two decades, and seems to be somewhat less “attractive” now, due to the many satisfactory results already obtained, but also because of the complex nature of the remaining open problems. Thus it seems that the time has come to try to deliver a sort of “state of the art” on this subject, although an exhaustive one is out of scope here, because of the great amount of publications. Instead, we survey the most salient progresses – in our opinion – approximately during the last decade, that are representative of the essential different ideas in the field. We proceed along with the exposition of material coming from about 119 included references. We do not pretend to deeply present each of the methods quoted hereafter; however, our goal is to briefly introduce most of the existing methods and to refer the interested reader to more detailed presentations for each scheme. To begin with, a now well-established classification of the flexible arms control goals is given. It is followed by a presentation of different control strategies, indicating in each case whether the approach deals with the one-link case, which can be successfully treated via linear models, or with the multi-link case which necessitates nonlinear, more complex, models. Some possible issues for future research are given in conclusion.

ON MODEL PREDICTIVE CONTROL OF QUASI-RESONANT CONVERTERS

2009 ◽  
Vol 18 (07) ◽  
pp. 1167-1183 ◽  
Author(s):  
FARZAD TAHAMI ◽  
MEHDI EBAD
Keyword(s):  
Model Predictive Control ◽  
Predictive Control ◽  
Linear Models ◽  
Control Strategies ◽  
Sampling Interval ◽  
Control Synthesis ◽  
Resonant Converters ◽  
Control Input ◽  
Model Approximation ◽  
Dynamic Matrix

In this paper, different model predictive control synthesis frameworks are examined for DC–DC quasi-resonant converters in order to achieve stability and desired performance. The performances of model predictive control strategies which make use of different forms of linearized models are compared. These linear models are ranging from a simple fixed model, linearized about a reference steady state to a weighted sum of different local models called multi model predictive control. A more complicated choice is represented by the extended dynamic matrix control in which the control input is determined based on the local linear model approximation of the system that is updated during each sampling interval, by making use of a nonlinear model. In this paper, by using and comparing these methods, a new control scheme for quasi-resonant converters is described. The proposed control strategy is applied to a typical half-wave zero-current switching QRC. Simulation results show an excellent transient response and a good tracking for a wide operating range and uncertainties in modeling.

Stability of a Class of Piezoelectric State-Switching Methods

2000 ◽  
Author(s):  
Andrew J. Kurdila ◽  
William W. Clark ◽  
Weijian Wang ◽  
Dwayne E. McDaniel
Keyword(s):  
Lyapunov Functions ◽  
Closed Loop ◽  
Control Strategies ◽  
Short Circuit ◽  
Open Circuit ◽  
Hybrid Dynamical Systems ◽  
Multiple Lyapunov Functions ◽  
Control Laws ◽  
State Switching ◽  
The Stability

Abstract Experimental and anecdotal evidences have shown that state-switched control strategies for piezoelectric actuators can be advantageous. However, most discussions of the stability of these systems has relied on heuristic, or physically motivated, arguments. In this paper, we show that recent open-circuit/short-circuit state-switching control laws can be viewed as hybrid dynamical systems of Witsenhausen type. Within this framework, the closed-loop stability of OC/SC switching is rigorously established using the method of multiple Lyapunov functions.

scholarly journals Experimental Analysis of a Novel Double Damper System with Semi-Active Control

Electronics ◽  
2020 ◽  
Vol 9 (9) ◽  
pp. 1518
Author(s):  
Anish Gorantiwar ◽  
Rajvardhan Nalawade ◽  
Arash Nouri ◽  
Saied Taheri
Keyword(s):  
Control Algorithm ◽  
Performance Metrics ◽  
Control Strategies ◽  
Normal Load ◽  
Data Acquisition System ◽  
Test Rig ◽  
Strong Basis ◽  
Acceleration Data ◽  
Separate Control ◽  
Active Damper

An experimental study was conducted to compare the performance of an in-house built novel double semi-active damper against a conventional semi-active single damper. Different performance metrics were analyzed, and the performance of the two dampers was evaluated based on these metrics. A Hybrid Skyhook–Groundhook control algorithm was developed and implemented on the variable orifice double damper. The semi-active single damper is governed via two separate control strategies, namely—Skyhook and Groundhook control, respectively. The effectiveness of each algorithm is better understood by adding a normal load on top of the Shock Dyno, thus modifying it to act as a quarter car test rig. The sprung and unsprung acceleration data are collected via the accelerometers mounted on the Shock Dyno through a Data Acquisition System. The results obtained from this experiment provide a strong basis that the semi-active double damper performs better in terms of the comfort cost than that of the commercial semi-active single dampers.

scholarly journals Risk factors for intradomiciliary infestation by the Chagas disease vector Triatoma dimidiatain Jutiapa, Guatemala

2009 ◽  
Vol 25 (suppl 1) ◽  
pp. S83-S92 ◽  
Author(s):  
Dulce Maria Bustamante ◽  
Carlota Monroy ◽  
Sandy Pineda ◽  
Antonieta Rodas ◽  
Xochitl Castro ◽  
...  
Keyword(s):  
Risk Factors ◽  
Socioeconomic Status ◽  
Chagas Disease ◽  
Linear Models ◽  
Control Strategies ◽  
Chi Square ◽  
Disease Vector ◽  
Log Linear ◽  
Chi Square Analysis

Seventeen variables were evaluated as possible risk factors for the intradomiciliary infestation with Triatoma dimidiata in 644 houses in Jutiapa, Guatemala. During 2004 the houses were assessed for vector presence and evaluated for hygiene, cluttering, material comfort, construction conditions and number of inhabitants, among other factors. Chi-square analysis detected significant associations between vector presence and eight variables related to domestic sanitary and construction conditions. Log-linear models showed that regardless of the age of the house, the odds of vector presence were 4.3 and 10 times lower in houses with a good socioeconomic status compared with poor and very poor houses respectively. Log-linear models also pointed to a greater chance of vector presence when walls lacked plastering (3.85 times) or walls had low quality-incomplete plastering (4.56 times), compared with walls that were completely plastered. Control strategies against T. dimidiata should include the introduction of better-quality but inexpensive plastering formulations and better sanitation practices should also be promoted among the population. Such control strategies should not only reduce or eliminate infestation, but also prevent vector reinfestation.

Solar Hybrid Combined Cycle Performance Prediction: Influence of GT Model and Spool Arrangement

2012 ◽  
Author(s):  
G. Barigozzi ◽  
G. Bonetti ◽  
G. Franchini ◽  
A. Perdichizzi ◽  
S. Ravelli
Keyword(s):  
Gas Turbine ◽  
Performance Prediction ◽  
Gas Turbines ◽  
Control Strategies ◽  
Rankine Cycle ◽  
Simulation Method ◽  
Power Input ◽  
Combined Cycle ◽  
Cycle Performance ◽  
Solar Field

A modeling procedure was developed to simulate design and off-design operation of Hybrid Solar Gas Turbines in a combined cycle (CC) configuration. The system includes an heliostat field, a receiver and a commercial gas turbine interfaced with a conventional steam Rankine cycle. Solar power input is integrated in the GT combustor by natural gas. Advanced commercial software tools were combined together to get design and off-design performance prediction: TRNSYS® was used to model the solar field and the receiver while the gas turbine and steam cycle simulations were performed by means of Thermoflex®. Three GT models were considered, in the 35–45 MWe range: a single shaft engine (Siemens SGT800) and two two-shaft engines (the heavy-duty GT Siemens SGT750 and the aero derivative GE LM6000 PF). This in order to assess the influence of different GT spool arrangements and control strategies on GT solarization. The simulation method provided an accurate modeling of the daily solar hybrid CC behavior to be compared against the standard CC. The effects of solarization were estimated in terms of electric power and efficiency reduction, fossil fuel saving and solar energy to electricity conversion efficiency.

scholarly journals Control strategies for the Fokker−Planck equation

2018 ◽  
Vol 24 (2) ◽  
pp. 741-763 ◽  
Author(s):  
Tobias Breiten ◽  
Karl Kunisch ◽  
Laurent Pfeiffer
Keyword(s):  
Closed Loop ◽  
Control Strategies ◽  
Planck Equation ◽  
Control Laws ◽  
Closed Loop Systems ◽  
Associated Solutions ◽  
Fokker Planck Equation ◽  
Speed Up ◽  
Double Well Potential ◽  
Fokker Planck

Using a projection-based decoupling of the Fokker−Planck equation, control strategies that allow to speed up the convergence to the stationary distribution are investigated. By means of an operator theoretic framework for a bilinear control system, two different feedback control laws are proposed. Projected Riccati and Lyapunov equations are derived and properties of the associated solutions are given. The well-posedness of the closed loop systems is shown and local and global stabilization results, respectively, are obtained. An essential tool in the construction of the controls is the choice of appropriate control shape functions. Results for a two dimensional double well potential illustrate the theoretical findings in a numerical setup.

The Effects of Nylon Polymer Threads on Strain-Loading Hysteresis Behavior of Supercoiled Polymer (SCP) Artificial Muscles

2019 ◽  
Author(s):  
Revanth Konda ◽  
Jun Zhang
Keyword(s):  
Thermal Activation ◽  
Experimental Validation ◽  
Linear Models ◽  
Artificial Muscle ◽  
Power Input ◽  
Artificial Muscles ◽  
Helical Spring ◽  
Spring Model ◽  
Actuation Mechanism ◽  
Proposed Model

Abstract Supercoiled polymers (SCP) actuator, as a recently discovered artificial muscle, has attracted a lot of attention as a compliant and compact actuation mechanism. SCP actuators can be fabricated from nylon polymer threads, and generates up to 20% strain under thermal activation. A common challenge, however, is to accurately and efficiently estimate the performance of SCP actuators considering their significant hysteresis among loading, strain, and power input. Previous studies adopted either linear models that failed to capture the hysteresis or phenomenological models that required tedious procedures for identification and implementation. In this paper, a physics-inspired model is presented to efficiently capture and estimate SCP actuators’ strain – loading hysteresis by analyzing the properties of nylon threads from which they are fabricated. The strains of SCP actuators are found to be linear to that of the nylon threads under the same loading conditions. An efficient approach is proposed to characterize and estimate the strain – loading hysteresis of SCP actuators fabricated with different numbers of nylon threads. A helical spring model is adopted to obtain the stiffness of SCP actuators with different configurations. Experimental validation involving two-ply, four-ply, and six-ply nylon threads and SCP actuators are provided to confirm the effectiveness of the proposed model.

scholarly journals Evaluation and planning of Chagas control activities using geospatial tools

2019 ◽  
Vol 14 (2) ◽  
Author(s):  
Diego Weinberg ◽  
Mario Lanfri ◽  
Carlos M. Scavuzzo ◽  
Marcelo Abril ◽  
Sofía Lanfri
Keyword(s):  
Rural Communities ◽  
Linear Models ◽  
Control Strategies ◽  
Public Health Problem ◽  
Spatiotemporal Analysis ◽  
Point Of View ◽  
Geographical Information ◽  
Triatoma Infestans ◽  
Spatiotemporal Pattern ◽  
History Of

Chagas continues to be a relevant public health problem in Latin America. In this work, we present a spatiotemporal analysis applied for the evaluation and planning of Chagas vector control strategies. We analysed the spatial distribution of the vector Triatoma infestans infestation related to ongoing control interventions cycles in rural communities near Añatuya, Santiago del Estero, Argentina. A geographical information system was developed for the spatial analysis obtaining, for each house, variables that describe the history of spraying and infestation at each time of interventions. Bi-dimensional histograms were used to describe the spatiotemporal pattern of these activities and peri-domestic infestation at the last intervention was modelled by a neural network model. We qualitatively evaluate control programmes considering the history of infestation and spraying from a spatiotemporal point of view, incorporating new ways of visualising this information. Predictions are based on novel, non-linear models and spatiotemporal indices, which should be useful for strategically allocating Chagas control resources in the future and thus help to better plan spraying strategies.

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