Control method for ventilated supercavitating vehicle considering planing avoidance and stability

2018 ◽  
Vol 233 (3) ◽  
pp. 957-968
Author(s):  
Seonhong Kim ◽  
Nakwan Kim
Keyword(s):  
Control Method ◽  
Ventilation System ◽  
Stability Loss ◽  
Vehicle Stability ◽  
Control Input ◽  
Supercavitating Vehicle ◽  
Additional Control ◽  
Avoidance Control ◽  
And Performance ◽  
Stability Issues

In this study, we focus on realizing planing avoidance control for a ventilated supercavitating vehicle while considering stability issues. A ventilated supercavitating vehicle can control the size of a cavity by blowing gas into the cavity. By controlling the cavity size, planing can be prevented in advance. However, the vehicle loses its stability because of the growth of the cavity. Additional control input is determined to prevent “stability loss” based on linear stability analysis while considering ventilation system dynamics. The proposed controllers are applied to a supercavitating vehicle model, and numerical simulations are performed to analyze the physical feasibility and performance of the designed controllers. The results show that the proposed control methods can maintain vehicle stability during maneuvering operations and can eliminate planing.

Design of Controls to Attenuate Loads in the Controls Advanced Research Turbine

2004 ◽  
Vol 126 (4) ◽  
pp. 1083-1091 ◽  
Author(s):  
Alan D. Wright ◽  
Mark J. Balas
Keyword(s):  
Wind Speed ◽  
Wind Turbines ◽  
Control Method ◽  
Maximum Energy ◽  
Drive Train ◽  
Control Input ◽  
Pitch Control ◽  
Additional Control ◽  
Bending Modes ◽  
Turbine Speed

The wind industry seeks to design wind turbines to maximize energy production and increase fatigue life. To achieve this goal, we must design wind turbines to extract maximum energy and reduce component and system loads. This paper applies modern state-space control design methods to a two-bladed teetering-hub upwind machine located at the National Wind Technology Center. The design objective is to regulate turbine speed in region 3 (above rated wind speed) and enhance damping in several low-damped flexible modes of the turbine. The controls approach is based on the Disturbance Accommodating Control method and provides accountability for wind-speed disturbances. First, controls are designed with the single control input rotor collective pitch to stabilize the first drive-train torsion as well as the tower first fore-aft bending modes. Generator torque is then incorporated as an additional control input. This reduces some of the demand placed on the rotor collective pitch control system and enhances first drive train torsion mode damping. Individual blade pitch control is then used to attenuate wind disturbances having spatial variation over the rotor and effectively reduces blade flap deflections caused by wind shear.

Enhancing Vehicle Stability Through Model Predictive Control

2009 ◽  
Author(s):  
Craig E. Beal ◽  
J. Christian Gerdes
Keyword(s):  
Stability Control ◽  
Vehicle Stability ◽  
Control Input ◽  
Severe Injuries ◽  
Convex Optimization Problem ◽  
Control Approach ◽  
Vehicle Stability Control ◽  
Additional Control ◽  
Finite Time Horizon ◽  
Automotive Crashes

Vehicle stability control systems have been widely and accurately cited as a significant influence in reducing the rate of severe injuries and fatalities in automotive crashes. However, these systems are purely reactive, providing additional control input only after undesired vehicle behavior is sensed. This paper presents a new approach to controlling the motion of a vehicle in highly dynamic situations. This approach solves a convex optimization problem over a finite time horizon to predict and prevent these hazardous situations. Thus, the controller determines input that simultaneously tracks the driver’s intended trajectory while preventing tire saturation. Simulation results are presented to demonstrate the efficacy of this control approach.

A New Model-Free Stability-Based Cognitive Control Method

2014 ◽  
Author(s):  
Xi Nowak ◽  
Dirk Söffker
Keyword(s):  
Control Method ◽  
Mimo System ◽  
Equilibrium Points ◽  
Optimization Method ◽  
Control Input ◽  
Adaptive Stabilization ◽  
Whole Process ◽  
Model Free ◽  
Stabilization Control ◽  
And Performance

This contribution considers a new realization of the cognitive stabilizer, which is an adaptive stabilization control method based on a cognition-based framework. It is assumed, that the model of the system to be controlled is unknown. Only the knowledge about the system inputs, outputs, and equilibrium points are the preliminaries assumed within this approach. A new improved realization of the cognitive stabilizer is designed in this contribution using 1) a neural network estimating suitable inputs according to the desired outputs, 2) Lyapunov stability criterion according to a certain Lyapunov function, and 3) an optimization method to determine the desired system outputs with respect to the system energy. The proposed cognitive stabilizer is able to stabilize an unknown nonlinear MIMO system at arbitrary equilibrium point of it. Suitable control input can be designed automatically to guarantee the stability of motion of the system during the whole process although the changing of the system behavior or the environment. Numerical examples are shown to demonstrate the successful application and performance of this method.

An Analytical Transient Tire Model

2001 ◽  
Vol 29 (2) ◽  
pp. 108-132 ◽  
Author(s):  
A. Ghazi Zadeh ◽  
A. Fahim
Keyword(s):  
Transient Behavior ◽  
Stability Control ◽  
Vehicle Stability ◽  
Tire Model ◽  
Steering Angle ◽  
First Order ◽  
Vehicle Stability Control ◽  
Proposed Model ◽  
Depth Study ◽  
And Performance

Abstract The dynamics of a vehicle's tires is a major contributor to the vehicle stability, control, and performance. A better understanding of the handling performance and lateral stability of the vehicle can be achieved by an in-depth study of the transient behavior of the tire. In this article, the transient response of the tire to a steering angle input is examined and an analytical second order tire model is proposed. This model provides a means for a better understanding of the transient behavior of the tire. The proposed model is also applied to a vehicle model and its performance is compared with a first order tire model.

scholarly journals A 4-DOF Upper Limb Exoskeleton for Physical Assistance: Design, Modeling, Control and Performance Evaluation

2021 ◽  
Vol 11 (13) ◽  
pp. 5865
Author(s):  
Muhammad Ahsan Gull ◽  
Mikkel Thoegersen ◽  
Stefan Hein Bengtson ◽  
Mostafa Mohammadi ◽  
Lotte N. S. Andreasen Struijk ◽  
...  
Keyword(s):  
Upper Limb ◽  
Tracking Control ◽  
Degrees Of Freedom ◽  
Control Method ◽  
Mechanical Design ◽  
Trajectory Tracking Control ◽  
Upper Limb Exoskeleton ◽  
And Performance ◽  
Physically Disabled People ◽  
Human Upper Limb

Wheelchair mounted upper limb exoskeletons offer an alternative way to support disabled individuals in their activities of daily living (ADL). Key challenges in exoskeleton technology include innovative mechanical design and implementation of a control method that can assure a safe and comfortable interaction between the human upper limb and exoskeleton. In this article, we present a mechanical design of a four degrees of freedom (DOF) wheelchair mounted upper limb exoskeleton. The design takes advantage of non-backdrivable mechanism that can hold the output position without energy consumption and provide assistance to the completely paralyzed users. Moreover, a PD-based trajectory tracking control is implemented to enhance the performance of human exoskeleton system for two different tasks. Preliminary results are provided to show the effectiveness and reliability of using the proposed design for physically disabled people.

scholarly journals Observer-based robust integral of the sign of the error control of class I of underactuated mechanical systems: Theory and real-time experiments

2021 ◽  
pp. 014233122110313
Author(s):  
Afef Hfaiedh ◽  
Ahmed Chemori ◽  
Afef Abdelkrim
Keyword(s):  
Real Time ◽  
Error Control ◽  
Degrees Of Freedom ◽  
Sliding Mode ◽  
Mechanical Systems ◽  
Class I ◽  
Control Input ◽  
Underactuated Mechanical Systems ◽  
Control Scheme ◽  
And Performance

In this paper, the control problem of a class I of underactuated mechanical systems (UMSs) is addressed. The considered class includes nonlinear UMSs with two degrees of freedom and one control input. Firstly, we propose the design of a robust integral of the sign of the error (RISE) control law, adequate for this special class. Based on a change of coordinates, the dynamics is transformed into a strict-feedback (SF) form. A Lyapunov-based technique is then employed to prove the asymptotic stability of the resulting closed-loop system. Numerical simulation results show the robustness and performance of the original RISE toward parametric uncertainties and disturbance rejection. A comparative study with a conventional sliding mode control reveals a significant robustness improvement with the proposed original RISE controller. However, in real-time experiments, the amplification of the measurement noise is a major problem. It has an impact on the behaviour of the motor and reduces the performance of the system. To deal with this issue, we propose to estimate the velocity using the robust Levant differentiator instead of the numerical derivative. Real-time experiments were performed on the testbed of the inertia wheel inverted pendulum to demonstrate the relevance of the proposed observer-based RISE control scheme. The obtained real-time experimental results and the obtained evaluation indices show clearly a better performance of the proposed observer-based RISE approach compared to the sliding mode and the original RISE controllers.

A Computational Analysis of Flow Field in Twin-Track Subway Tunnel to Improve Air Quality

2013 ◽  
Vol 319 ◽  
pp. 599-604
Author(s):  
Makhsuda Juraeva ◽  
Kyung Jin Ryu ◽  
Sang Hyun Jeong ◽  
Dong Joo Song
Keyword(s):  
Air Quality ◽  
Computational Model ◽  
Stokes Equations ◽  
Ventilation System ◽  
Three Dimensional ◽  
Aerodynamic Characteristics ◽  
Navier Stokes ◽  
Subway Tunnel ◽  
Air Supply ◽  
And Performance

A computational model of existing Seoul subway tunnelwas analyzed in this research. The computational model was comprised of one natural ventilationshaft, two mechanical ventilationshafts, one mechanical airsupply, a twin-track tunnel, and a train. Understanding the flow pattern of the train-induced airflow in the tunnel was necessary to improve ventilation performance. The research objective wasto improve the air quality in the tunnel by investigating train-induced airflow in the twin-track subway tunnel numerically. The numerical analysis characterized the aerodynamic behavior and performance of the ventilation system by solving three-dimensional turbulent Reynolds-averaged Navier-Stokes equations. ANSYS CFX software was used for the computations. The ventilation and aerodynamic characteristics in the tunnel were investigated by analyzing the mass flowrateat the exits of the ventilation mechanicalshafts. As the train passed the mechanical ventilation shafts, the amount of discharged-air in the ventilationshafts decreased rapidly. The air at the exits of the ventilation shafts was gradually recovered with time, after the train passed the ventilation shafts. The developed mechanical air-supply for discharging dusty air and supplying clean airwas investigated.The computational results showed that the developed mechanical air-supplycould improve the air quality in the tunnel.

scholarly journals A Framework of Cloud Model Similarity-Based Quality Control Method in Data-Driven Production Process

2020 ◽  
Vol 2020 ◽  
pp. 1-10
Author(s):  
Sheng Hu ◽  
Shuanjun Song ◽  
Wenhui Liu
Keyword(s):  
Quality Control ◽  
Production Process ◽  
Control Method ◽  
Cloud Model ◽  
Data Driven ◽  
Monitoring Method ◽  
Control Approach ◽  
Acceptable Method ◽  
And Performance ◽  
Model Similarity

Considering the problem that the process quality state is difficult to analyze and monitor under manufacturing big data, this paper proposed a data cloud model similarity-based quality fluctuation monitoring method in data-driven production process. Firstly, the randomness of state fluctuation is characterized by entropy and hyperentropy features. Then, the cloud pool drive model between quality fluctuation monitoring parameters is built. On this basis, cloud model similarity degree from the perspective of maximum fluctuation border is defined and calculated to realize the process state analysis and monitoring. Finally, the experiment is conducted to verify the adaptability and performance of the cloud model similarity-based quality control approach, and the results indicate that the proposed approach is a feasible and acceptable method to solve the process fluctuation monitoring and quality stability analysis in the production process.

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