Enhancement of the Accuracy of the Modified (P–ω) Method Through the Implementation of a Nonlinear Robust Observer

2005 ◽  
Author(s):  
G. A. Kfoury ◽  
N. G. Chalhoub ◽  
N. A. Henein ◽  
W. Bryzik
Keyword(s):  
Internal Combustion Engines ◽  
Sliding Mode ◽  
Angular Displacement ◽  
Digital Simulation ◽  
Friction Torque ◽  
Original Version ◽  
State Variables ◽  
Connecting Rod ◽  
Simulation Results ◽  
Elastic Modes

The original version of the (P–ω) method is a model-based approach developed for determining the instantaneous friction torque in internal combustion engines. This scheme requires measurements of the cylinder gas pressure, the engine load torque, the crankshaft angular displacement and its time derivatives. The effects of the higher order dynamics of the crank-slider mechanism on the measured angular motion of the crankshaft have caused the (P–ω) method to yield erroneous results, especially, at high engine speeds. To alleviate this problem, a nonlinear sliding mode observer has been developed herein to accurately estimate the rigid and flexible motions of the piston-assembly/connecting-rod/crankshaft mechanism of a single cylinder engine. The observer has been designed to yield a robust performance in the presence of disturbances and modeling imprecision. The digital simulation results, generated under transient conditions that represent a decrease in the engine speed, have illustrated the rapid convergence of the estimated state variables to the actual ones in the presence of both structured and unstructured uncertainties. Moreover, this study has proven that the use of the estimated rather than the measured angular displacement of the crankshaft and its time derivatives can significantly improve the accuracy of the (P–ω) method in determining the instantaneous engine friction torque. However, the effects of structural deformations of the crank-slider mechanism have rendered the original version of the (P–ω) method to be inapplicable at high engine speeds. This problem has been addressed herein by modifying the formulation of the (P–ω) method in order to account for the first two elastic modes of the crankshaft torsional vibration. The simulation results confirm the good performance of the modified (P–ω) method in determining the instantaneous friction torque at high engine speeds.

Development of a Robust Controller and Observer for the Control of a Single-Link Flexible Robotic Manipulator

2005 ◽  
Author(s):  
N. G. Chalhoub ◽  
G. A. Kfoury ◽  
B. A. Bazzi
Keyword(s):  
Sliding Mode ◽  
Angular Displacement ◽  
Robotic Manipulator ◽  
The State ◽  
Nonlinear Observer ◽  
State Variables ◽  
Elastic Mode ◽  
Single Link ◽  
Elastic Modes ◽  
Flexible Robotic Manipulator

A fuzzy-sliding mode controller (FSMC) has been developed in this study to control the rigid and flexible motions of a single-link robotic manipulator. Only the angular displacement at the base joint of the beam is assumed to be measured. Therefore, a robust nonlinear observer has been designed, based on the sliding mode methodology, to accurately estimate the state variables in the presence of both structured and unstructured uncertainties. Both the controller and the observer account for the first elastic mode of the beam in their design. The dynamic model, used in assessing the performance of the closed-loop system, considers the first two elastic modes of the beam. The second elastic mode is included in order to investigate the effects of the higher order dynamics on the overall performance of the system. The digital simulations demonstrate the capability of the observer in yielding accurate estimates of the state variables in the presence of modeling inaccuracies. Furthermore, they serve to prove the viability of using the observer to provide on-line estimates of the state variables for the computation of the control signals. The simulation results illustrate robust performances of the controller and the observer in controlling the rigid and flexible motions of the single-link robot in the presence of both structured and unstructured uncertainties.

scholarly journals A Unified Anti-Windup Technique for Fuzzy and Sliding Mode Controllers

2015 ◽  
Vol 10 (6) ◽  
pp. 83 ◽  
Author(s):  
Radu Emil Precup ◽  
Marius L. Tomescu ◽  
Emil M. Petriu
Keyword(s):  
State Feedback ◽  
Position Control ◽  
Fuzzy Controller ◽  
Sliding Mode ◽  
Digital Simulation ◽  
The State ◽  
Sliding Mode Controllers ◽  
Hydraulic Servo ◽  
Back Calculation ◽  
Simulation Results

This paper proposes the unified treatment of an anti-windup technique for fuzzy and sliding mode controllers. A back-calculation and tracking anti-windup scheme is proposed in order to prevent the zero error integrator wind-up in the structures of state feedback fuzzy controllers and sliding mode controllers. The state feedback sliding mode controllers are based on the state feedback-based computation of the switching variable. An example that copes with the position control of an electro-hydraulic servo-system is presented. The conclusions are pointed out on the basis of digital simulation results for the state feedback fuzzy controller.

Development of a Robust Nonlinear Observer for a Single-Link Flexible Manipulator

2004 ◽  
Author(s):  
Nabil G. Chalhoub ◽  
Giscard A. Kfoury
Keyword(s):  
Sliding Mode ◽  
Initial Conditions ◽  
The State ◽  
Observer Design ◽  
Nonlinear Observer ◽  
Flexible Manipulator ◽  
State Variables ◽  
State Equations ◽  
On Line ◽  
Simulation Results

Accurate measurements of all the state variables of a given system are often not available due to the high cost of sensors, the lack of space to mount the transducers or the hostile environment in which the sensors must be located. The purpose of this study is to design a robust sliding mode observer that is capable of accurately estimating the state variables of the system in the presence of disturbances and model uncertainties. It should be emphasized that the proposed observer design can handle state equations expressed in the general form. The performance of the nonlinear observer is assessed herein by examining its capability of predicting the rigid and flexible motions of a compliant beam that is connected to a revolute joint. The simulation results demonstrate the ability of the observer in accurately estimating the state variables of the system in the presence of structured uncertainties and under different initial conditions between the observer and the plant. Moreover, they illustrate the deterioration in the performance of the observer when subjected to unstructured uncertainties of the system. Furthermore, the nonlinear observer was successfully implemented to provide on-line estimates of the state variables for two model-based controllers. The simulation results show minimal deterioration in the closed-loop response of the system stemming from the usage of estimated rather than exact state variables in the computation of the control signals.

Friction fault diagnosis and fault tolerant control for electronic throttles with sliding mode and adaptive RBF estimator

2021 ◽  
pp. 095965182110125
Author(s):  
Shoutao Li ◽  
Yiran Shi ◽  
Yujia Zhai ◽  
Shuangxin Wang ◽  
Yantao Tian ◽  
...  
Keyword(s):  
Fault Diagnosis ◽  
Internal Combustion Engines ◽  
Fault Tolerant ◽  
Sliding Mode ◽  
Fault Tolerant Control ◽  
Friction Torque ◽  
System Stability ◽  
Physical Parameters ◽  
Nonlinear Dynamic Model ◽  
Simulink Model

The change of throttle viscous and coulomb frictions often cause inaccuracy or malfunction in electronic throttles, and lead to degradation of reliability of vehicles with internal combustion engines. A fault detection fault tolerant control scheme is proposed in this work to tackle the problem. A nonlinear dynamic model is derived for the throttle. A disturbance observer is designed based on the model to diagnose the fault, and a sliding mode control combined with an adaptive neural network estimator is developed for fault tolerant control. The system stability is ensured after the fault occurs and the throttle position tracking is maintained by the applied Lyapunov method. A Simulink model is developed for the throttle with real physical parameters to evaluate the performance. Abrupt and incipient changes are simulated in the throttle friction torque and the simulation results show that the developed method is effective in fault diagnosis and fault tolerant control.

Computation of the Instantaneous Frictional Losses of Internal Combustion Engine Components

2010 ◽  
Author(s):  
Giscard A. Kfoury ◽  
Nabil G. Chalhoub
Keyword(s):  
Inverse Dynamics ◽  
Sliding Mode ◽  
Combustion Engine ◽  
Digital Simulation ◽  
Equations Of Motion ◽  
Internal Combustion ◽  
State Variables ◽  
Ic Engine ◽  
Frictional Losses ◽  
Engine Components

An inverse dynamics scheme, based on a detailed differential-algebraic model of the crank-slider mechanism of a single cylinder internal combustion (IC) engine, is developed for the computation of the instantaneous frictional losses of engine components. The proposed approach requires accurate measurements of the independent and superfluous coordinates of the crank-slider mechanism as well as their time derivatives. This was achieved by implementing a sliding mode observer, previously developed by the authors, to provide the required estimates of the state variables. The aforementioned observer is suitable for use with differential-algebraic nonlinear equations of motion and was shown to be robust to both modeling imprecision and external disturbances. The digital simulation results show the capability of the combined inverse dynamics scheme with the observer in producing good estimates of the instantaneous frictional losses of the various engine components.

Speed regulation control of tractors’ new dual-flow transmission system based on slip rate resistance classification

2021 ◽  
pp. 095440702110105
Author(s):  
Guang Xia ◽  
Yan Xia ◽  
Xiwen Tang ◽  
Linfeng Zhao ◽  
Baoqun Sun
Keyword(s):  
Control Strategy ◽  
Control Algorithm ◽  
Production Efficiency ◽  
Sliding Mode ◽  
Slip Rate ◽  
Speed Control ◽  
Working Environment ◽  
Vehicle Speed ◽  
Speed Change ◽  
Simulation Results

Fluctuations in operation resistance during the operating process lead to reduced efficiency in tractor production. To address this problem, the project team independently developed and designed a new type of hydraulic mechanical continuously variable transmission (HMCVT). Based on introducing the mechanical structure and transmission principle of the HMCVT system, the priority of slip rate control and vehicle speed control is determined by classifying the slip rate. In the process of vehicle speed control, the driving mode of HMCVT system suitable for the current resistance state is determined by classifying the operation resistance. The speed change rule under HMT and HST modes is formulated with the goal of the highest production efficiency, and the displacement ratio adjustment surfaces under HMT and HST modes are determined. A sliding mode control algorithm based on feedforward compensation is proposed to address the problem that the oil pressure fluctuation has influences on the adjustment accuracy of hydraulic pump displacement. The simulation results of Simulink show that this algorithm can not only accurately follow the expected signal changes, but has better tracking stability than traditional PID control algorithm. The HMCVT system and speed control strategy models were built, and simulation results show that the speed control strategy can restrict the slip rate of driving wheels within the allowable range when load or road conditions change. When the tractor speed is lower than the lower limit of the high-efficiency speed range, the speed change law formulated in this paper can improve the tractor speed faster than the traditional rule, and effectively ensure the production efficiency. The research results are of great significance for improving tractor’s adaptability to complex and changeable working environment and promoting agricultural production efficiency.

Comprehensive Analysis for Influence of Controllable Damper Time Delay on Semi-Active Suspension Control Strategies

2017 ◽  
Vol 139 (3) ◽  
Author(s):  
Yechen Qin ◽  
Feng Zhao ◽  
Zhenfeng Wang ◽  
Liang Gu ◽  
Mingming Dong
Keyword(s):  
Time Delay ◽  
Dynamic Characteristics ◽  
Ride Comfort ◽  
Hybrid Control ◽  
Sliding Mode ◽  
Control Strategies ◽  
Active Suspension ◽  
Test System ◽  
Suspension Control ◽  
Simulation Results

This paper presents a comprehensive comparison and analysis for the effect of time delay on the five most representative semi-active suspension control strategies, and refers to four unsolved problems related to semi-active suspension performance and delay mechanism that existed. Dynamic characteristics of a commercially available continuous damping control (CDC) damper were first studied, and a material test system (MTS) load frame was used to depict the velocity-force map for a CDC damper. Both inverse and boundary models were developed to determine dynamic characteristics of the damper. In addition, in order for an improper damper delay of the form t+τ to be corrected, a delay mechanism of controllable damper was discussed in detail. Numerical simulation for five control strategies, i.e., modified skyhook control SC, hybrid control (HC), COC, model reference sliding mode control (MRSMC), and integrated error neuro control (IENC), with three different time delays: 5 ms, 10 ms, and 15 ms was performed. Simulation results displayed that by changing control weights/variables, performance of all five control strategies varied from being ride comfort oriented to being road handling oriented. Furthermore, increase in delay time resulted in deterioration of both ride comfort and road handling. Specifically, ride comfort was affected more than road handling. The answers to all four questions were finally provided according to simulation results.

A novel robust finite-time tracking control of uncertain robotic manipulators with disturbances

2020 ◽  
pp. 107754632098244
Author(s):  
Hamid Razmjooei ◽  
Mohammad Hossein Shafiei ◽  
Elahe Abdi ◽  
Chenguang Yang
Keyword(s):  
Finite Time ◽  
Control Method ◽  
Sliding Mode ◽  
Robotic Manipulators ◽  
Sliding Mode Controller ◽  
Time Varying ◽  
State Variables ◽  
Terminal Sliding Mode ◽  
Control Laws ◽  
Finite Time Boundedness

In this article, an innovative technique to design a robust finite-time state feedback controller for a class of uncertain robotic manipulators is proposed. This controller aims to converge the state variables of the system to a small bound around the origin in a finite time. The main innovation of this article is transforming the model of an uncertain robotic manipulator into a new time-varying form to achieve the finite-time boundedness criteria using asymptotic stability methods. First, based on prior knowledge about the upper bound of uncertainties and disturbances, an innovative finite-time sliding mode controller is designed. Then, the innovative finite-time sliding mode controller is developed for finite-time tracking of time-varying reference signals by the outputs of the system. Finally, the efficiency of the proposed control laws is illustrated for serial robotic manipulators with any number of links through numerical simulations, and it is compared with the nonsingular terminal sliding mode control method as one of the most powerful finite-time techniques.

CONTROLLING THE UNCERTAIN MULTI-SCROLL CRITICAL CHAOTIC SYSTEM WITH INPUT NONLINEAR USING SLIDING MODE CONTROL

2009 ◽  
Vol 23 (16) ◽  
pp. 2021-2034 ◽  
Author(s):  
XINGYUAN WANG ◽  
DA LIN ◽  
ZHANJIE WANG
Keyword(s):  
Chaotic System ◽  
Sliding Mode ◽  
Equilibrium Points ◽  
Dead Zone ◽  
Variable Structure ◽  
Sliding Mode Controller ◽  
Global Stabilization ◽  
Structure Control ◽  
Control Scheme ◽  
Simulation Results

In this paper, control of the uncertain multi-scroll critical chaotic system is studied. According to variable structure control theory, we design the sliding mode controller of the uncertain multi-scroll critical chaotic system, which contains sector nonlinearity and dead zone inputs. For an arbitrarily given equilibrium point of the uncertain multi-scroll chaotic system, we achieve global stabilization for the equilibrium points. Particularly, a class of proportional integral (PI) switching surface is introduced for determining the convergence rate. Furthermore, the proposed control scheme can be extended to complex multi-scroll networks. Finally, simulation results are presented to demonstrate the effectiveness of the proposed control scheme.

scholarly journals Active Sliding Mode for Synchronization of a Wide Class of Four-Dimensional Fractional-Order Chaotic Systems

2014 ◽  
Vol 2014 ◽  
pp. 1-11 ◽  
Author(s):  
Bin Wang ◽  
Yuangui Zhou ◽  
Jianyi Xue ◽  
Delan Zhu
Keyword(s):  
Sliding Mode Control ◽  
Fractional Order ◽  
Wide Class ◽  
Stability Theory ◽  
Chaotic Systems ◽  
Sliding Mode ◽  
Order System ◽  
Fractional Order Calculus ◽  
Simulation Results ◽  
The Stability

We focus on the synchronization of a wide class of four-dimensional (4-D) chaotic systems. Firstly, based on the stability theory in fractional-order calculus and sliding mode control, a new method is derived to make the synchronization of a wide class of fractional-order chaotic systems. Furthermore, the method guarantees the synchronization between an integer-order system and a fraction-order system and the synchronization between two fractional-order chaotic systems with different orders. Finally, three examples are presented to illustrate the effectiveness of the proposed scheme and simulation results are given to demonstrate the effectiveness of the proposed method.

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