Modeling and Control of an Electric Variable Valve Timing System

2013 ◽  
Vol 136 (2) ◽  
Author(s):  
Zhen Ren ◽  
Guoming G. Zhu
Keyword(s):  
Closed Loop ◽  
Control Strategies ◽  
Planetary Gear ◽  
Fast Response ◽  
Bench Test ◽  
Closed Loop Control ◽  
Variable Valve Timing ◽  
Valve Timing ◽  
Loop Control ◽  
Variable Valve

This paper presents a model of an electric variable valve timing (EVVT) system and its closed-loop control design with experimental validation. The studied EVVT uses a planetary gear system to control the engine cam timing. The main motivation of utilizing the EVVT system is its fast response time and the accurate timing control capability. This is critical for the combustion mode transition control between the spark ignition (SI) and homogeneous charge compression ignition (HCCI) combustion, where the engine cam timing needs to follow a desired trajectory to accurately control the engine charge and recompression process. A physics-based model was developed to study the characteristics of the EVVT system, and a control oriented EVVT model, with the same structure as the physics-based one, was obtained using closed-loop system identification. The closed-loop control strategies were developed to control the EVVT to follow a desired trajectory. Both simulation and bench test results are included.

EVALUATION OF CLOSED-LOOP CONTROL SYSTEM FOR RESTORING STANDING AND SITTING FUNCTIONS BY FUNCTIONAL ELECTRICAL STIMULATION

2005 ◽  
Vol 17 (01) ◽  
pp. 19-26 ◽  
Author(s):  
CHENG-LIANG LIU ◽  
CHUNG-HUANG YU ◽  
SHIH-CHING CHEN ◽  
CHANG-HUNG CHEN
Keyword(s):  
Electrical Stimulation ◽  
Functional Electrical Stimulation ◽  
Closed Loop ◽  
Spinal Cord Injuries ◽  
Control Method ◽  
Control Strategies ◽  
Evaluation Process ◽  
Closed Loop Control ◽  
Loop Control ◽  
Loop Control System

Functional electrical stimulation (FES) is a method for restoring the functional movements of paraplegic or patients with spinal cord injuries. However, the selection of parameters that control the restoration of standing up and sitting functions has not been extensively investigated. This work provides a method for choosing the four main items involved in evaluating the strategies for sit-stand-sit movements with the aid of a modified walker. The control method uses the arm-supported force and the angles of the legs as feedback signals to change the intensity of the electrical stimulation of the leg muscles. The control parameters, Ki and Kp, are vary for different control strategies. Four items are collected through questionnaires and used for evaluation. They are the maximum reactions of the two hands, the average reaction of the two hands, largest absolute angular velocity of the knee joints, and the sit-stand-sit duration time. The experimental data are normalized to facilitate comparison. Weighting factors are obtained and analyzed from questionnaires answered by experts and are added to evaluation process for manipulation. The results show that the best strategy is the closed-loop control with parameters Ki=0.5 and Kp=0.

scholarly journals Neural Network-Based State Estimation for a Closed-Loop Control Strategy Applied to a Fed-Batch Bioreactor

Complexity ◽  
2017 ◽  
Vol 2017 ◽  
pp. 1-16 ◽  
Author(s):  
Santiago Rómoli ◽  
Mario Serrano ◽  
Francisco Rossomando ◽  
Jorge Vega ◽  
Oscar Ortiz ◽  
...  
Keyword(s):  
Neural Network ◽  
Closed Loop ◽  
Rbf Neural Network ◽  
Control Strategies ◽  
Tracking Error ◽  
Closed Loop Control ◽  
Online Information ◽  
Fed Batch ◽  
Loop Control ◽  
Batch Bioreactor

The lack of online information on some bioprocess variables and the presence of model and parametric uncertainties pose significant challenges to the design of efficient closed-loop control strategies. To address this issue, this work proposes an online state estimator based on a Radial Basis Function (RBF) neural network that operates in closed loop together with a control law derived on a linear algebra-based design strategy. The proposed methodology is applied to a class of nonlinear systems with three types of uncertainties: (i) time-varying parameters, (ii) uncertain nonlinearities, and (iii) unmodeled dynamics. To reduce the effect of uncertainties on the bioreactor, some integrators of the tracking error are introduced, which in turn allow the derivation of the proper control actions. This new control scheme guarantees that all signals are uniformly and ultimately bounded, and the tracking error converges to small values. The effectiveness of the proposed approach is illustrated on the basis of simulated experiments on a fed-batch bioreactor, and its performance is compared with two controllers available in the literature.

scholarly journals Control of Flexible Manipulator Systems

1996 ◽  
Vol 210 (2) ◽  
pp. 113-130 ◽  
Author(s):  
M O Tokhi ◽  
A K M Azad
Keyword(s):  
Closed Loop ◽  
Control Strategies ◽  
Open Loop ◽  
Flexible Manipulator ◽  
Closed Loop Control ◽  
Loop Control ◽  
Acceleration Feedback ◽  
Low Pass ◽  
Input Torque ◽  
Collocated Control

This paper presents an investigation into the development of open-loop and closed-loop control strategies for flexible manipulator systems. Shaped torque inputs, including Gaussian-shaped and low-pass (Butter-worth and elliptic) filtered input torque functions, are developed and used in an open-loop configuration and their performance studied in comparison to a bang-bang input torque through experimentation on a single-link flexible manipulator system. Closed-loop control strategies that use both collocated (hub angle and hub velocity) and non-collocated (end-point acceleration) feedback are then proposed. A collocated proportional and derivative (PD) control is first developed and its performance studied through experimentation. The collocated control is then extended to incorporate, additionally, non-collocated feedback through a proportional integral derivative (PID) configuration. The performance of the hybrid collocated and non-collocated control strategy thus developed is studied through experimentation. Experimental results verifying the performance of the developed control strategies are presented and discussed.

Trajektorienbasierte Strategie für die Regelung des Tiefziehprozesses während des Hubes*/Trajectory-based closed loop control for controlling deep-drawing process

2016 ◽  
Vol 106 (10) ◽  
pp. 684-689
Author(s):  
M. Prof. Liewald ◽  
M. Barthau ◽  
S. Braun
Keyword(s):  
Deep Drawing ◽  
Closed Loop ◽  
Control Strategies ◽  
Closed Loop Control ◽  
Drawing Process ◽  
Control Loop ◽  
Deep Drawing Process ◽  
Loop Control ◽  
Control Intervention ◽  
Measurement Devices

Am IFU der Universität Stuttgart wurde ein Regelkreis für das Tiefziehen entwickelt, welcher einen regelnden Eingriff in den Tiefziehvorgang während des Hubes erlaubt. Die Umsetzung dieses Regelungskonzeptes erfolgte mittels eines Ziehwerkzeugs, das an eine vereinfachte Geometrie eines PKW-Vorderkotflügels angelehnt ist. Beschrieben werden die messtechnische Ausstattung des Versuchswerkzeugs, der Aufbau des Regelkreises und die Entwicklung der Regelstrategie. Des Weiteren werden die Ergebnisse der Simulation sowie der ersten Versuche dargestellt.   At IFU, University of Stuttgart a control loop for deep-drawing process, with control intervention during deep-drawing stroke was developed. The closed-loop control was demonstrated on a fender shaped geometry. Described are the measurement devices, design of the closed-loop and the featured control strategies. Results of simulation and sensitivity analysis are also shown.

Integrated System Identification and Control Design for an IC Engine Variable Valve Timing System

2010 ◽  
Author(s):  
Zhen Ren ◽  
Guoming G. Zhu
Keyword(s):  
System Identification ◽  
Closed Loop ◽  
Test Bench ◽  
Open Loop ◽  
Integrated System ◽  
Variable Valve Timing ◽  
Valve Timing ◽  
Closed Loop System ◽  
Variable Valve ◽  
And Control

This paper applies integrated system modeling and control design process to a continuously variable valve timing (VVT) actuator system that has different control input and cam position feedback sample rates. Due to high cam shaft torque disturbance and high actuator open-loop gain, it is fairly difficult to maintain the cam phase at the desired constant level with an open-loop controller. As a result, multirate closed-loop system identification is a necessity. For this study, multirate closed-loop system identification, PRBS q-Markov Cover, was used for obtaining linearized system models at different engine operational conditions; and the output covariance constraint (OCC) controller, an H2 controller, was designed based upon the identified model and evaluated on the VVT test bench. Performances of the designed OCC controller was compared with those of the baseline PI controller on the test bench. Results show that the OCC controller uses less control effort and has less overshoot than those of PI ones.

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