Height Control in Laser Cladding Using Adaptive Sliding Mode Technique: Theory and Experiment

2010 ◽  
Vol 132 (4) ◽  
Author(s):  
Meysar Zeinali ◽  
Amir Khajepour
Keyword(s):  
Laser Cladding ◽  
Closed Loop ◽  
Sliding Mode ◽  
Adaptive Sliding Mode Control ◽  
Feedback Signal ◽  
Complex Nature ◽  
Control Input ◽  
Image Processing Algorithm ◽  
Adaptive Sliding Mode ◽  
Laser Cladding Process

A closed-loop control of the laser cladding process is desired due to difficulties encountered in depositing a layer with acceptable quality from both geometrical and metallurgical point of views. One of the main parameters to achieve the desired geometry in laser cladding process is the height of the deposited layers. In this paper, a real-time measurement and control of the clad height is presented. Due to complex nature of the process and presence of uncertainties, a robust and adaptive sliding mode control is proposed and implemented to control the clad height. The velocity of the substrate is used as a control input while the molten pool height, which is obtained using a charge-coupled device (CCD) camera and an image processing algorithm is used as a feedback signal. Stability of the controller is proven in the presence of time-varying uncertainties and the performance of the closed-loop system is validated by simulation and experiments. The experimental results are promising and show that the geometrical accuracy of the deposited layers can be improved significantly.

Geometry Control of the Deposited Layer in a Nonplanar Laser Cladding Process Using a Variable Structure Controller

2008 ◽  
Vol 130 (3) ◽  
Author(s):  
Alireza Fathi ◽  
Amir Khajepour ◽  
Mohammad Durali ◽  
Ehsan Toyserkani
Keyword(s):  
Laser Cladding ◽  
Closed Loop ◽  
Least Squares Method ◽  
Sliding Mode ◽  
Scanning Speed ◽  
Recursive Least Squares ◽  
Hammerstein Model ◽  
Model Parameters ◽  
Control Input ◽  
Laser Cladding Process

This paper presents a closed-loop laser cladding process used in nonplanar deposition of desired metallic materials. In the proposed system, the deposited layer geometry is continuously controlled via a sliding mode controller (SMC). The controller, which uses the scanning speed as the control input, is designed based on a parametric Hammerstein model. The model is a parametric dynamic model with several unknown parameters, which are identified experimentally using the recursive least squares method. The designed SMC is robust to all model parameters’ uncertainties and disturbances. The results showed that the tracking accuracy improves and the chattering effect reduces if an integrator on the scanning speed is added to the controller. It was observed that this addition decreases the response speed. The performance of the proposed controllers was verified through the fabrication of several parts made of SS303-L. This verification indicates that the developed closed-loop laser cladding process can reduce stair-step effects as well as production time in rapid prototyping of functional parts created with the adaptive slicing technique.

Adaptive type-2 fuzzy sliding mode control of steer-by-wire systems with event-triggered communication

2021 ◽  
pp. 095440702199539
Author(s):  
Bingxin Ma ◽  
Yongfu Wang
Keyword(s):  
Sliding Mode Control ◽  
Closed Loop ◽  
Sliding Mode ◽  
Adaptive Sliding Mode Control ◽  
Control Input ◽  
Time Varying ◽  
Adaptive Sliding Mode ◽  
Mode Control ◽  
Event Triggered

The steering-by-wire (SbW) system is one of the main subsystems of automatic vehicles, realizing the steering control of autonomous vehicles. This paper proposes an event-triggered adaptive sliding mode control for the SbW system subject to the uncertain nonlinearity, time-varying disturbance, and limited communication resources. Firstly, an event-triggered nested adaptive sliding mode control is proposed for SbW systems. The uncertain nonlinearity is approximated by the interval type-2 fuzzy logic system (IT2 FLS). The time-varying disturbance, modeling error, and event-triggering error can be offset by robust terms of sliding mode control. The key advantage is that the high-frequency switching of sliding mode control only appears on the time derivate of control input without increasing the input-output relative degree of closed-loop SbW systems, such that the chattering phenomenon can be eliminated. Finally, theoretical analysis shows that the practical finite-time stability of the closed-loop SbW system can be achieved, and communication resources in the controller-to-actuator channels can be saved while avoiding the Zeno-behavior. Numerical simulations and experiments are given to evaluate the effectiveness of the proposed method.

scholarly journals Sensorless adaptive sliding mode position control for piezoelectric actuators with charge leakage

2019 ◽  
Vol 31 (1) ◽  
pp. 40-52
Author(s):  
Davood Soleymanzadeh ◽  
Hamed Ghafarirad ◽  
Mohammad Zareinejad
Keyword(s):  
Closed Loop ◽  
Position Control ◽  
Sliding Mode ◽  
Piezoelectric Actuators ◽  
Position Estimation ◽  
Adaptive Sliding Mode Control ◽  
Control Procedure ◽  
Loop Control ◽  
Precise Position ◽  
Adaptive Sliding Mode

Position control of piezoelectric actuators is greatly affected by nonlinearities such as hysteresis and creep. Therefore, precise position sensors must be utilized which have high cost and complicated structures in micro scales. Charge-based position estimation is an alternative method which resorts to piezoelectric linear charge-position property to estimate the actuator position, but in low-impedance actuators, there is a charge leakage caused by actuator internal resistance which deteriorates the position estimation and closed-loop control performance. In this article, the leakage is considered as a sensor fault. Therefore, a combination of charge measurement method and an appropriate observer is designed to detect and isolate the mentioned fault and estimate the actuator position properly. In addition, an adaptive sliding mode control procedure is proposed for trajectory tracking in the presence of estimated states. The required analysis is carried out to guarantee the closed-loop stability. Finally, experimental results show the effectiveness of the proposed method.

Adaptive Sliding Mode Control of Servo System

2014 ◽  
Vol 556-562 ◽  
pp. 2466-2469
Author(s):  
Yue Fei Wu ◽  
Da Wei Ma ◽  
Gui Gao Le
Keyword(s):  
Sliding Mode Control ◽  
Sliding Mode ◽  
Servo System ◽  
Lyapunov Theory ◽  
Adaptive Sliding Mode Control ◽  
Switching Function ◽  
Control Input ◽  
Adaptive Sliding Mode ◽  
Mode Control ◽  
Chebyshev Neural Network

A novel adaptive sliding mode control is proposed to guarantee high precision and robustness of servo system of rocket launcher. An improved PID switching function is designed to smooth control input, meanwhile Chebyshev neural network is adopted to identify the system’s Jacobian information, and parameters of controller can be acquired by self-tuning law which can be derived by Lyapunov theory. Simulation results show the control input is chattering-free, and both load disturbance and parameter perturbation can be compensated.

Adaptive Sliding Mode Control for Spacecraft Proximity Operations

2014 ◽  
Vol 644-650 ◽  
pp. 571-577
Author(s):  
Yue Chi ◽  
Wei Huo
Keyword(s):  
Closed Loop ◽  
Sliding Mode ◽  
Adaptive Sliding Mode Control ◽  
Closed Loop System ◽  
Model Uncertainties ◽  
External Disturbances ◽  
Precision Control ◽  
Proximity Operations ◽  
Adaptive Sliding Mode ◽  
Adaptive Sliding Mode Controller

The high precision control problem of a pursuer spacecraft approaching a space target in proximity missions is investigated in this paper. By choosing proper sliding mode surfaces, a novel adaptive sliding mode controller is presented in presence of model uncertainties and unknown external disturbances. It is proved that the relative position and attitude errors of the closed-loop system asymptotically converge to zero. The validity of the proposed control strategy is demonstrated by numerical simulation results.

scholarly journals Adaptive Sliding Mode Control Based on Uncertainty and Disturbance Estimator

2014 ◽  
Vol 2014 ◽  
pp. 1-10 ◽  
Author(s):  
Yue Zhu ◽  
Sihong Zhu
Keyword(s):  
Nonlinear Systems ◽  
Sliding Mode Control ◽  
Closed Loop ◽  
Sliding Mode ◽  
Adaptive Sliding Mode Control ◽  
External Disturbances ◽  
Adaptive Sliding Mode ◽  
Mode Control ◽  
Closed Loop Systems ◽  
Disturbance Estimator

This paper presents an original adaptive sliding mode control strategy for a class of nonlinear systems on the basis of uncertainty and disturbance estimator. The nonlinear systems can be with parametric uncertainties as well as unmatched uncertainties and external disturbances. The novel adaptive sliding mode control has several advantages over traditional sliding mode control method. Firstly, discontinuous sign function does not exist in the proposed adaptive sliding mode controller, and it is not replaced by saturation function or similar approximation functions as well. Therefore, chattering is avoided in essence, and the chattering avoidance is not at the cost of reducing the robustness of the closed-loop systems. Secondly, the uncertainties do not need to satisfy matching condition and the bounds of uncertainties are not required to be unknown. Thirdly, it is proved that the closed-loop systems have robustness to parameter uncertainties as well as unmatched model uncertainties and external disturbances. The robust stability is analyzed from a second-order linear time invariant system to a nonlinear system gradually. Simulation on a pendulum system with motor dynamics verifies the effectiveness of the proposed method.

scholarly journals Output Feedback Adaptive Sliding Mode Control Design for a Plate Heat Exchanger

2018 ◽  
Vol 21 (4) ◽  
pp. 549-555
Author(s):  
Shibly Ahmed Al-samarraie ◽  
Luma F. Ali
Keyword(s):  
Heat Exchanger ◽  
Cold Water ◽  
Sliding Mode ◽  
Time Derivative ◽  
Hot Water ◽  
Adaptive Sliding Mode Control ◽  
Sliding Mode Controller ◽  
Control Input ◽  
Adaptive Sliding Mode ◽  
Adaptation Law

The heat exchanger is a device used to transfer heat energy between two fluids, hot and cold. In this work, an output feedback adaptive sliding mode controller is designed to control the temperature of the outlet cold water for plate heat exchanger. The discontinuous gain value of the sliding mode controller is adapted according to a certain adaptation law, where the only information required is the measurement of the outlet cold temperature. A sliding mode differentiator was design to estimate time derivative of outlet hot water temperature. Two constraints which imposed on the volumetric flow rate of the hot water (control input) were considered within the rules of the proposed adaptation law in this work. These are the control input is positive only and has a maximum value. For constructing the sliding variable, the outlet hot water temperature and its time derivative are required. The maximum allowable desired outlet cold water has been estimated as function of heat exchanger parameters and maximum control input. The simulation results demonstrate the performance of the proposed adaptive sliding mode control where the outlet cold water was forced to follow desired temperature equal to . Additionally, the robustness of the proposed controller was tested for the case where the cold inlet temperature is not constant. The results reveal the robustness of the proposed controller.

scholarly journals Adaptive Sliding Mode Control Based on Equivalence Principle and Its Application to Chaos Control in a Seven-Dimensional Power System

2020 ◽  
Vol 2020 ◽  
pp. 1-13 ◽  
Author(s):  
Jiangbin Wang ◽  
Ling Liu ◽  
Chongxin Liu ◽  
Xiaoteng Li
Keyword(s):  
Sliding Mode Control ◽  
Power System ◽  
Design Process ◽  
Equivalence Principle ◽  
Sliding Mode ◽  
Chaotic Oscillation ◽  
Adaptive Sliding Mode Control ◽  
Adaptive Sliding Mode ◽  
Mode Control ◽  
Control Scheme

The main purpose of the paper is to control chaotic oscillation in a complex seven-dimensional power system model. Firstly, in view that there are many assumptions in the design process of existing adaptive controllers, an adaptive sliding mode control scheme is proposed for the controlled system based on equivalence principle by combining fixed-time control and adaptive control with sliding mode control. The prominent advantage of the proposed adaptive sliding mode control scheme lies in that its design process breaks through many existing assumption conditions. Then, chaotic oscillation behavior of a seven-dimensional power system is analyzed by using bifurcation and phase diagrams, and the proposed strategy is adopted to control chaotic oscillation in the power system. Finally, the effectiveness and robustness of the designed adaptive sliding mode chaos controllers are verified by simulation.

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