SMC Controller Research Articles

Robust Backstepping Sliding Mode Control and Observer-based Fault Estimation for a Quadrotor UAV

This study gives the mathematic model of a quadrotor unmanned aerial vehicle (UAV) and then proposes a robust nonlinear controller which combines the sliding-mode control technique and the backstepping control technique. To achieve Cartesian position trajectory tracking capability, the construction of the controller can be divided into two stages: a regular SMC controller for attitude subsystem (inner loop) is first developed to guarantee fast convergence rapidity of Euler angles and the backstepping technique is applied to the position loop until desired attitudes are obtained and then the ultimate control laws. The stability of the closed-loop system is guaranteed by stabilizing each of the subsystems step by step and the robustness of the controller against model uncertainty and external disturbances is investigated. In addition, an adaptive observer-based fault estimation scheme is also considered for taking off mode. Simulations are conducted to demonstrate the effectiveness of the designed robust nonlinear controller and the fault estimation scheme.

Optimal intelligent control for a variable-speed wind turbine using general regression neural network and adaptive PSO algorithm

In this paper, a robust optimal general regression neural network sliding mode GRNNSM controller is designed for a variable speed wind turbine VSWT. The main objective of the controller is to optimise the energy captured from the wind. Sliding mode control SMC approach emerges as an especially suitable option to deal with a VSWT. However, for large uncertain systems, the SMC produces chattering problems due to the higher needed switching gain. In order to guarantee the wind power capture optimisation without any chattering problems, this study propose to combine the SMC with the general regression neural network GRNN based on adaptive particle swarm optimisation APSO algorithm. The GRNN is used for the prediction of uncertain model part and hence enable a lower switching gain to be used for compensating only the prediction errors. The APSO algorithm with efficient global search is used to train the weights of GRNN in order to improve the network performance in terms of the speed of convergence and error level. The stability is shown by the Lyapunov theory and the control action used did not exhibit any chattering behaviour. The effectiveness of the designed method is illustrated in simulations by the comparison with traditional SMC.

Optimal Genetic-sliding Mode Control of VSC-HVDC Transmission Systems

This paper deals with the design of a hybrid optimal Genetic-Sliding Mode Control (GA-SMC) approach for VSC- HVDC transmission systems for improving the system's dynamic stability over a wide range of operating conditions considering different parameter variations and disturbances. For this purpose, a comprehensive state of the art of the VSC-HVDC stabilization dilemma is discussed. The nonlinear VSC-HVDC model is developed. The problem of de- signing a nonlinear feedback control scheme via two control strategies is addressed seeking a better performance. For ensuring robustness and chattering free behavior, the conventional SMC (C-SMC) scheme is realized using a boundary layer hyperbolic tangent function for the sliding surface. Then, the Genetic Algorithm (GA) is employed for determining the optimal gains for such SMC methodology forming a modified nonlinear GA-SMC control in order to conveniently stabilize the system end enhance its performance. The simulation results verify the enhanced performance of the VSC-HVDC transmission system controlled by SMC alone compared to the proposed optimal GA-SMC control. The comparative dynamic behavior analysis for both SMC and GA-SMC control schemes are presented.

LabVIEW Based pH Control of a Waste Water Treatment Prototype Plant by Incorporating PID,SMC and DSMC Controllers

LabVIEW Based pH Control of a Waste Water Treatment Prototype Plant by Incorporating PID,SMC and DSMC Controllers

English

This paper presents a new direct torque control (DTC) strategy for BLDC motor based on speed behaviour of PI and SMC based DTC of BLDC motor. In conventional direct torque controlled BLDC motor drive, there is usually undesired torque and flux ripple. So tuning PI parameters(Kp, Ki) are essential to DTC system to improve the performance of the system. PI controller is widely used in motor control system due to the simple control structure. In conventional PI controller, the performance of the motor may cause unexpected torque disturbances. To overcome the problems with PI controllers, in this paper, sliding mode controller is proposed to resolve the speed tracking problem for DTC of BLDC motor drive. The simulation results of DTC of BLDC motor drive with PI & SMC controllers are compared in the MATLAB/simulink environment.

Proportional-Integral Sliding Mode Control for Trajectory Tracking and Vibration Control of a Flexible Single Link Manipulator

This paper presents investigations into the development of a Proportional-Integral Sliding Mode Control (PI-SMC) for trajectory tracking and vibration control of a flexible single link manipulator. The motor at the single rotating joint is the control actuator. Two SMC control laws are reviewed. The classical discontinuous control based on the signum function and a modified control law where the servomotor output voltage depends on the instantaneous values of the states. The selection of the discontinuity gain is reviewed for exact model (certain case) as well as when the parameter variations are present (uncertain case). To prove the reaching condition, we use the Lyapunov stability criteria. It is proven that this design is equivalent to a full state feedback with its steady state motion constrained to the sliding hyper-surfaces. Simulation results of the response of the flexible manipulator with both controllers are presented. The performances of the control schemes are examined for input tracking capability, level of vibration reduction and time response specifications. A comparative assessment of both control techniques shows the effectiveness of the second control law and its invariance to so-called matched uncertainty.

Adaptive fuzzy controller with self-tuning fuzzy sliding-mode compensation for position control of an electro-hydraulic displacement-controlled system

The electro-hydraulic displacement-controlled system EHDCS performs specific non-linear and time-varying characteristics such that an exact model-based controller is complicated to be realized and the servo control is difficult to be implemented. In this study, the design method and experimental implementation of an adaptive fuzzy controller with self-tuning fuzzy sliding-mode compensation AFC-STFSMC are proposed which has on-line tuning ability for dealing with the system time-varying and non-linear uncertain behaviours for adjusting the control rule parameters. This control strategy employs the adaptive fuzzy approximation technique to design the equivalent controller of the conventional sliding-mode control SMC. Furthermore, the fuzzy sliding-mode control scheme with self-tuning ability is introduced to compensate the approximation error of the equivalent controller for improving the control performance. The proposed AFC-STFSMC scheme can design the sliding-mode controller with no requirement of the system dynamic model, be free from chattering, be stable tracking control performance, and be robust to uncertainties. Moreover, the stability proof of the proposed scheme using Lyapunov method is presented. The experimental results of the position control and the path control in EHDCS with different strokes and external disturbance forces show that the proposed AFC-STFSMC approach can achieve excellent control performance and robustness with regard to parameter variations and external disturbance.

Fuzzy sliding mode control for the two-link robot

This paper presents the fuzzy logic combined with the sliding mode FSMC to design a robust controller for the two-link robot system. The sliding mode control SMC can be used for a nonlinear system with small uncertainties. However, for complex nonlinear systems, the uncertainties are large and produce higher amplitude of chattering due to the higher switching gain. In this work, the nominal model of the robot is assumed known and the fuzzy logic is used to approximate only the unknown dynamic parts of the system, which are incorporated in the so called equivalent control. A small gain robust control term is added to remove the fuzzy approximation error. The simulation results show the effectiveness of the proposed method.

An innovative power regulation method applied for wireless magnetic-energy transportation

An innovative power regulation design and realization is proposed for wireless micro-power transmission. The proposed power regulation method is employed to regulate the power intensity transmitted by magnetic flux transmitter, based on distance change and angle misalignment between transmitter and receiver. Therefore, not only the power transmitted by magnetic flux transmitter is adjustable, but also consistent power received by locomotive devices can be achieved. Firstly, by Faraday’s law and Kirchhoff’s circuit law, the dynamic equation for proposed wireless power transmission is constructed. The distance change and angle misalignment between transmitter and receiver are also considered to reflect the influence on power received by micro-devices. In order to ensure that the power received by receiver is consistent at various locations along an ellipse trajectory, the sliding mode controller is synthesized to regulate the power transmitted by the magnetic energy source. In addition, the sliding mode estimator is also employed so that not only the system states can be estimated, but also the cost for sensors and the physical size of secondary side can be much reduced. By intensive simulation, no matter which distance and misalignment angle between transmitter and receiver is present, stable and consistent power at receiver can be achieved. Finally, the test rig for wireless micro-power transmission is constructed for performance verification. The experimental result shows that the constant power at receiver can be obtained if the SMC controller is applied to regulate the output power by transmitter.

Global Robust Terminal Sliding Mode Control for PMLSM Servo System

Permanent Magnet Linear Synchronous Motor (P MLSM was hard to control with traditional control strategy for parameters variation and external load disturbance, a global robust terminal sliding mode control (GRTSMC) was designed for PMLSM servo system, the sliding mode surface function was designed, the robust sliding mode control law was deduced and the stability was proved by Lyapunov theory. With the mathematical models of PMLSM, the simulation was taken with traditional PID control, SMC control and GRTSMC control proposed in this paper, the robust performance be found with GRTSMC control when motor parameters and external load changed, the efficiency and advantages of this robust control strategy was successfully demonstrated.

RBF Neural Network of Sliding Mode Control for Time-Varying 2-DOF Parallel Manipulator System

This paper presents a radial basis function (RBF) neural network control scheme for manipulators with actuator nonlinearities. The control scheme consists of a time-varying sliding mode control (TVSMC) and an RBF neural network compensator. Since the actuator nonlinearities are usually included in the manipulator driving motor, a compensator using RBF network is proposed to estimate the actuator nonlinearities and their upper boundaries. Subsequently, an RBF neural network controller that requires neither the evaluation of off-line dynamical model nor the time-consuming training process is given. In addition, Barbalat Lemma is introduced to help prove the stability of the closed control system. Considering the SMC controller and the RBF network compensator as the whole control scheme, the closed-loop system is proved to be uniformly ultimately bounded. The whole scheme provides a general procedure to control the manipulators with actuator nonlinearities. Simulation results verify the effectiveness of the designed scheme and the theoretical discussion.

Adaptive Fuzzy SMC Control for Nonlinear System of Dual Arm Robot

In this paper, a stable adaptive fuzzy sliding mode controller is developed for a class of MIMO nonlinear systems. Fuzzy logic system is designed to estimate the unknown function. Parameter adaptive laws and robustifying control terms are derived based on Lyapunov theory, and boudedness of signals in the closed-loop system can be guaranteed. The proposed controllers were used in trajectory control of right arm of dual arm robot. The results indicate that the proposed controller has satisfying tracking performance with robust characteristics.

Sliding Mode Load torque Observer based effective disturbance rejection for a 3-Phase BLDC drive

controller (SMC) controller has been proposed for the outer loop speed control of the 3-Phase Brushless DC(BLDC) motor drive. The robust hysteresis controller is employed to control the inner loop current performance of the drive. The developed SMC control scheme is simulated on MATLAB/SIMULINK platform under varying load torque disturbances up to the rated torque capability and the variable speed performance of the drive is tested. A sliding mode based load torque observer has also been designed for implementation of the scheme on real time basis. The efficient load torque rejection capabilities of the developed control scheme using the sliding mode load torque observer is then compared with a Proportional Integral (PI) based controller.

Control System Design of Automatic Feeding Machine

The research of the control system of automatic feeding machine in the present paper can be applied in different mechanical designs – from simple key-press input of cycling days, multiple time intervals and the feeding amount to setting steps of numbers of stepping motor via the control of SMC by time setting. This not only realizes the objective of “fixed-time” and “fixed-quantity” feeding, but also solves the problems of serious leaking, high failure rate, and loud noises during the process of using warehouse-type feeding machines, which brings favorable economic and social benefits for enterprises.

Development and Control of a Robotic Exoskeleton for Shoulder, Elbow and Forearm Movement Assistance

World health organization reports, annually more than 15 million people worldwide suffer a stroke and cardiovascular disease, among which 85% of stroke patients incur acute arm impairment, and 40% of victims are chronically impaired or permanently disabled. This results a burden on the families, communities and to the country as well. Rehabilitation programs are the main way to promote functional recovery in these individuals. Since the number of such cases is constantly growing and that the duration of treatment is long, an intelligent robot could significantly contribute to the success of these programs. We therefore developed a new 5DoFs robotic exoskeleton named MARSE-5 motion assistive robotic-exoskeleton for superior extremity that supposed to be worn on the lateral side of upper arm to rehabilitate and ease the shoulder, elbow and forearm movements. This paper focused on the design, modeling, development and control of the proposed MARSE-5. To control the exoskeleton, a nonlinear sliding mode control SMC technique was employed. In experiments, trajectory tracking that corresponds to typical passive rehabilitation exercises was carried out. Experimental results reveal that the controller is able to maneuver the MARSE-5 efficiently to track the desired trajectories.

Longevity of organic layers of vertical flow ponds for sulfate reduction in treating mine drainages in South Korea

This study was carried out to evaluate longevity of available organic materials used for sulfate-reducing bacteria (SRB) activity in vertical flow ponds (VFPs) to treat mine drainage in South Korea. Spent mushroom compost samples (SMC) were tested as substrates in VFPs and analyzed for total organic carbon in VFPs, and were collected to analyze total organic carbon (TOC), T-N, T-P, K, metals and residual cellulose to check the longevity assessment. Chemical analysis revealed that the average contents of Fe, Al and Mn in SMC of VFPs were 19,907, 32,137 and 434 mg/kg, respectively. The contents of Fe and Al in SMC of VFPs were much higher than those of the unused SMC (control), but to the contrary, those of Mn showed a reversed tendency. Average TOC content of the controls was 64.19% but in one of the VFP substrates was as low as 15.92%. This might be resulted from SRB consumed the available organic carbon in SMC as VFPs system aged. Contents of T-N in VFPs tended to decrease as VFPs aged. The residual cellulose ranged from 3.88 to 6.72% (g/g). There existed a negative relationship between residual cellulose contents and ages of VFPs. Assuming that SMC in all VFPs had similar compositions when the VFPs were initially established, trend analysis predicted that the amount of carbon source for SRB might be available for 12-15 years further, depending on VFPs.

Sliding mode control for a class of nonlinear discrete-time networked systems with multiple stochastic communication delays

In this article, a sliding mode control problem is studied for a class of uncertain nonlinear networked systems with multiple communication delays. A sequence of stochastic variables obeying Bernoulli distribution is applied in the system model to describe the randomly occurring communication delays. The discrete-time system considered is also subject to parameter uncertainties and state-dependent stochastic disturbances. A novel discrete switching function is proposed to facilitate the sliding mode controller design. The sufficient conditions are derived by means of the linear matrix inequality (LMI) approach. It is shown that the system dynamics in the specified sliding surface is robustly exponentially stable in the mean square if two LMIs with an equality constraint are feasible. A discrete-time SMC controller is designed that is capable of guaranteeing the discrete-time sliding-mode reaching condition of the specified sliding surface. Finally, a simulation example is given to show the effectiveness of the proposed method.

BAS/BSCR12 Proteomic analysis of smooth muscle cells derived from carotid plaque shows differences between symptomatic and asymptomatic plaques

RationaleSmooth muscle cells (SMC) are key players in atherosclerotic disease. The proteome of SMC in human carotid disease and its relationship with plaque-related symptomatology are still ill defined.MethodologyCarotid endarterectomy specimens...

Abstract 5313: Reduction of S100A12 in Marfan Syndrome Aortic Smooth Muscle Cells Attenuates Inflammatory and Apoptotic Pathways

Marfan syndrome (MFS) is associated with thoracic aortic aneurysms. S100A12 has been associated with initiation of inflammatory pathways via activation of the receptor for advance glycation endproducts (RAGE) and is up regulated in smooth muscle cells of ruptured human coronary artery plaques. We tested the hypothesis that S100A12 is expressed in SMC in human aortic aneurysms of MFS, and that downregulation of S100A12 may suppress inflammatory and apoptosis pathways. Methods: Aortic tissue from a patient undergoing surgery for MFS aneurysm and control aortic tissue were compared and several cell lines of primary SMC’s were established. SMC that carry a mutation in the FBN-1 gene (Arg529Term) and control SMC were each transfected with siRNA-S100A12-GFP and siRNA-control-GFP. GFP positve SMC were isolated by FACS, followed by qRT-RCR using arrays for inflammation and apoptosis pathways (RT2 profiler PCR Array, SA Biosciences). Results: Immunohistochemistry of aortic tissue from MFS revealed expression of S100A12 in SMC, but not in SMC of control aortic tissue. S100A12 was expressed strongest in SMC near the focal areas of medial degeneration. Cultured SMC that carry the FBN-1 mutation strongly expressed S100A12 protein. S1090A12 expression was completely abolished by transfection with siRNA-S100A12-GFP construct but not with siRNA control-GFP construct. S100A12 reduction in FBN-1 mutant SMC suppressed at least two fold the mRNA of 80% of genes on the inflammation array and of 91% of the genes on the apoptosis array. The death receptor Fas, caspase 10 and effector caspases 3 and their substrate DFFA were probed using semi-quantitative immunoblotting. FBN-1 mutant SMC showed approximately 2-fold increase for Fas, and two fold increase in Casp3 and DFFA compared to control SMC. Treatment with Fas CH11 activating monoclonal antibody induced Casp3 approximately 12 fold in FBN-1 mutant SMC compared to a two fold induction in control SMC (p< 0.001). Reduction of S100A12 in FBN-1 mutant SMC reversed this pattern with s significant reduction in Fas, caspase 10 & 3, and DFFB. Summary: S100A12 is upregulated in SMC in thoracic aneurysms and reduction of S100A12 reduces Fas-mediated apoptosis in aortic SMC in MFS. This research has received full or partial funding support from the American Heart Association, Midwest Affiliate (Illinois, Indiana, Iowa, Kansas, Michigan, Minnesota, Missouri, Nebraska, North Dakota, South Dakota & Wisconsin).

Gait capacity affects cortical activation patterns related to speed control in the elderly

Functional decline in locomotion is common among the elderly, and the prevalence of gait disorders increases with age. Recently, increasing interest has been focused on the influence of age-related decline in brain function and neurological disorders such as dementia and Alzheimer's disease on gait capacity. However, the neural mechanisms underlying gait control in the elderly remain poorly understood. We examined whether cortical activation patterns associated with the control of gait speed were related to the walking capacity in elderly subjects. Fifteen healthy elderly subjects participated in the study (mean +/- SD 63 +/- 4). Using functional near-infrared spectroscopy, we measured the changes in the cortical oxygenated hemoglobin (oxyHb) while the subjects walked on a treadmill at low, moderate, and high speeds corresponding to 30, 50, and 70% intensity of work load in each subject. We found a greater increase in oxyHb in the left prefrontal cortex (PFC) and the supplementary motor area (SMA) during walking at 70% intensity than at 50 or 30%. The degree of medial sensorimotor cortex (mSMC) and SMA activations was correlated with the locomotor speed and cadence. Heart rate response was only related with left PFC activation. Furthermore, at the highest speed, the change in the PFC activation was greater in subjects with low gait capacity than in those with high gait capacity. Our results indicate that the left PFC, SMA, and SMC control gait speed, and that the involvement of the left PFC might depend on an age-related decline in gait capacity in the elderly.