Robust adaptive control for a MEMS vibratory gyroscope

This paper presents an adaptive sliding mode controller for a microelectromechanical systems (MEMS) vibratory z-axis gyroscope. The proposed adaptive sliding mode controller can real-time estimate the angular velocity and the damping and stiffness coefficients. The stability of the closed-loop system can be guaranteed with the proposed adaptive sliding mode control strategy. The numerical simulation for MEMS gyroscope is investigated to show the effectiveness of the proposed control scheme. It is shown that the proposed adaptive sliding mode control scheme offers several advantages such as real-time estimation of gyroscope parameters and large robustness to parameter variations and external disturbance.     

A novel adaptive sliding mode control with application to MEMS gyroscope

This paper presents a new adaptive sliding mode controller for MEMS gyroscope; an adaptive tracking controller with a proportional and integral sliding surface is proposed. The adaptive sliding mode control algorithm can estimate the angular velocity and the damping and stiffness coefficients in real time. A proportional and integral sliding surface, instead of a conventional sliding surface is adopted. An adaptive sliding mode controller that incorporates both matched and unmatched uncertainties and disturbances is derived and the stability of the closed-loop system is established. The numerical simulation is presented to verify the effectiveness of the proposed control scheme. It is shown that the proposed adaptive sliding mode control scheme offers several advantages such as the consistent estimation of gyroscope parameters including angular velocity and large robustness to parameter variations and external disturbances.     

Sliding mode control of a simulated MEMS gyroscope

The microelectromechanical systems (MEMS) are penetrating more and more into measurement and control problems because of their small size, low cost, and low power consumption. The vibrating gyroscope is one of those MEMS devices that will have a significant impact on the stability control systems in transportation industry. This paper studies the design and control of a vibrating gyroscope. The device has been constructed in a Pro-E environment and its model has been simulated in the finite-element domain in order to approximate its dynamic characteristics with a lumped model. A model reference adaptive feedback controller and the sliding mode controller have been considered to guarantee the stability of the device. It is shown that the sliding mode controller of the vibrating proof mass results in a better estimate of the unknown angular velocity than that of the model reference adaptive feedback controller.     

防抱制动系统参数自适应滑模变结构控制器的研究

首先针对具有参数不确定性的二阶非线性系统提出了自适应滑模变结构的控制算法 ,该算法的基本思想是用自适应策略来估计不确定系统的参数 ,根据估计出的参数值 ,来设计滑模控制器 ,优点是无须事先已知不确定参数的边界 ,并且由于在自适应变结构控制采用了消颤措施 (增加了消颤项 ) ,能削弱常规滑模控制所引起的颤振现象 ,也能提高单纯的自适应控制的鲁棒性能。而后将这一控制策略应用于防抱死制动系统 (ABS)的研究中 ,设计了防抱死制动系统的自适应滑模变结构控制器 ,通过计算机仿真 ,验证了该控制方案在 ABS应用中的可行性和有效性     

随机振动机械臂的自适应鲁棒滑模控制

为了解决存在外部不确定随机干扰情况下机械臂的高精度轨迹跟踪问题,提出了一种自适应鲁棒滑模控制方法,并用Lyapunov稳定性定理证明了其闭环系统的稳定性。采用饱和函数取代控制器中的符号函数,有效消除了控制器的抖振现象。仿真结果证明：与传统的PID控制器相比,提出的自适应鲁棒滑模控制器具有更高的鲁棒性、稳定性和精度。     

四旋翼飞行器的自适应鲁棒滑模控制器设计

针对四旋翼欠驱动系统的姿态控制问题,提出一种自适应鲁棒滑模控制方法。对四旋翼系统实现了双环控制,内环为姿态控制,外环为位置控制。根据牛顿-欧拉方程建立了四旋翼系统的动力学模型,针对系统中的外部扰动和参数摄动等不确定性因素,设计了基于Lyapunov稳定控制算法,内环使用自适应鲁棒滑模控制;外环使用鲁棒控制。仿真和实验表明所提控制策略对外界扰动和模型的不确定性具有较强的鲁棒性。     

Parameter estimation and interval type-2 fuzzy sliding mode control of a z-axis MEMS gyroscope

This paper reports a hybrid intelligent controller for application in single axis MEMS vibratory gyroscopes. First, unknown parameters of a micro gyroscope including unknown time varying angular velocity are estimated online via normalized continuous time least mean squares algorithm. Then, an additional interval type-2 fuzzy sliding mode control is incorporated in order to match the resonant frequencies and to compensate for undesired mechanical couplings. The main advantage of this control strategy is its robustness to parameters uncertainty, external disturbance and measurement noise. Consistent estimation of parameters is guaranteed and stability of the closed-loop system is proved via the Lyapunov stability theorem. Finally, numerical simulation is done in order to validate the effectiveness of the proposed method, both for a constant and time-varying angular rate.     

Sliding mode controller with modified sliding function for DC-DC Buck Converter

This article presents design of Sliding Mode Controller with proportional integral type sliding function for DC-DC Buck Converter for the controlled power supply. The converter with conventional sliding mode controller results in a steady state error in load voltage. The proposed modified sliding function improves the steady state and dynamic performance of the Convertor and facilitates better choices of controller tuning parameters. The conditions for existence of sliding modes for proposed control scheme are derived. The stability of the closed loop system with proposed sliding mode control is proved and improvement in steady state performance is exemplified. The idea of adaptive tuning for the proposed controller to compensate load variations is outlined. The comparative study of conventional and proposed control strategy is presented. The efficacy of the proposed strategy is endowed by the simulation and experimental results.     

基于优化自适应阈值的非线性机电系统传感器 故障检测和主动容错控制

针对具有参数不确定性和传感器故障的非线性机电系统,提出一种基于优化自适应阈值和故障重构策略的主动容错控制方法。首先,利用线性分式变换理论对存在参数不确定性的非线性机电系统进行建模,并提出基于粒子群优化算法的优化自适应阈值以提高参数不确定条件下的故障检测性能。其次,通过解析冗余关系推导出系统的动力学方程,并提出一种基于递归终端滑模的跟踪控制策略,以实现系统健康状态下的负载位置跟踪。当系统发生故障时,构建自适应滑模观测器进行传感器故障重构,根据重构结果设计自适应主动容错控制律,并利用故障检测结果进行控制律的实时切换。实验结果表明,所提出的故障检测和主动容错控制方法能在0.06 s内准确的实现传感器故障检测和容错控制,验证了该方法的可行性。     

A new optimal sliding mode controller design using scalar sign function

This paper presents a new optimal sliding mode controller using the scalar sign function method. A smooth, continuous-time scalar sign function is used to replace the discontinuous switching function in the design of a sliding mode controller. The proposed sliding mode controller is designed using an optimal Linear Quadratic Regulator (LQR) approach. The sliding surface of the system is designed using stable eigenvectors and the scalar sign function. Controller simulations are compared with another existing optimal sliding mode controller. To test the effectiveness of the proposed controller, the controller is implemented on an aluminum beam with piezoceramic sensor and actuator for vibration control. This paper includes the control design and stability analysis of the new optimal sliding mode controller, followed by simulation and experimental results. The simulation and experimental results show that the proposed approach is very effective.     

Adaptive super-twisting sliding mode observer based robust backstepping sensorless speed control for IPMSM

This paper proposes a higher-order sliding mode observer based robust backstepping control to realize high-performance sensorless speed regulation for the interior permanent magnet synchronous motor (IPMSM). A new robust adaptive super-twisting higher-order sliding mode based observer is proposed to estimate the rotor position. The proposed observer has advantages of sliding chattering reduction and robustness against uncertainties. And, a new robust integral adaptive backstepping control with sliding mode actions is designed to achieve precise speed regulation. The uncertainties with unknown bounds can be stabilized by the sliding mode actions. And both transient and steady performance can be achieved by using the sliding mode and integral actions simultaneously. Then, a sensorless scheme is put forward to by combining the presented observer and the proposed controller. The stability of the observer and controller are verified. Simulation and experiment results validate the proposed approach.     

A modified model reference adaptive control with application to MEMS gyroscope

Micro electro-mechanical systems (MEMS) are increasingly being used in measurement and control problems due to their small size, low cost, and low power consumption. The vibrating gyroscope is a MEMS device that will have a significant impact on stability control systems in the transportation industry. This paper investigates the application of a modified model reference adaptive control for MEMS gyroscope. Using this adaptive control algorithm, an estimation of the angular velocity and the damping and stiffness coefficients in real time is easily computable. Changing the conventional model reference input makes it feasible to utilize a low pass filter to remove unwanted oscillations caused by high adaptation gain. This new adaptive control technique enables quick compensation for large changes in the system dynamics, providing consistent estimation of gyroscope parameters including angular velocity and large robustness to parameter variations and external disturbances. The asymptotic stability of the mentioned adaptive controller is guaranteed using the Lyapunov direct method. Numerical simulation is presented to verify the effectiveness of the proposed control scheme.     

Adaptive sliding mode current control with sliding mode disturbance observer for PMSM drives

This paper focuses on the current control of a permanent magnet synchronous motor (PMSM) for electric drives with model uncertainties and external disturbances. To improve the performance of the PMSM current loop in terms of the speed of response, tracking accuracy, and robustness, a hybrid control strategy is proposed by combining the adaptive sliding mode control and sliding mode disturbance observer (SMDO). An adaptive law is introduced in the sliding mode current controller to improve the dynamic response speed of the current loop and robustness of the PMSM drive system to the existing parameter variations. The SMDO is used as a compensator to restrain the external disturbances and reduce the sliding mode control gains. Experiments results demonstrate that the proposed control strategy can guarantee strong anti-disturbance capability of the PMSM drive system with improved current and speed-tracking performance.     

RBF神经滑模控制在永磁直线同步电机的应用研究

给出了神经网络学习算法和神经滑模控制器的具体设计思路,将滑模控制器的切换函数作为神经网络输入,以滑模控制器为网络输出,从而实现神经网络学习能力和滑模控制自适应切换能力有效结合,将神经滑模控制器应用于永磁直线同步电机伺服系统,通过仿真说明了其良好的跟踪特性和低速平稳性。     

Adaptive fast sliding mode fault tolerant control integrated with disturbance observer for spacecraft attitude stabilization system

In this paper, the problem of fault-tolerant control (FTC) for spacecraft attitude stabilization system with actuator fault and mismatched disturbance is investigated. A novel fault tolerant control strategy based on adaptive fast terminal sliding mode control (AFTSMC) is proposed. Firstly, a novel composite observer is proposed to estimate the disturbance, actuator efficiency factor and partial states of the system. By introducing a sliding mode observer, the bias actuator fault is reconstructed. Subsequently, in accordance with the estimated information, a novel sliding mode fault tolerant controller is designed. The proposed control scheme contains two compensators and two adaptive parameters to attenuate the mismatched disturbance, to compensate actuator fault, and to guarantee fast convergence of the system. Furthermore, the reachability of sliding motion is proved. The simulation results for the spacecraft system illustrate the effectiveness of the proposed method.     

An enhanced tracking control of marine surface vessels based on adaptive integral sliding mode control and disturbance observer

In this paper, a new control methodology is developed to enhance the tracking performance of fully actuated surface vessels based on an integrating between an adaptive integral sliding mode control (AISMC) and a disturbance observer (DO). First, an integral sliding mode control (ISMC), in which the backstepping control technique is used as the nominal controller, is designed for the system. The major features, i.e., benefits and drawbacks, of the ISMC are discussed thoroughly. Then, to enhance the tracking performance of the system, an adaptive technique and a new disturbance observer based on sliding mode technique are developed and integrated into the ISMC. The stability of the closed-loop system is proved based on Lyapunov criteria. Computer simulation is performed to illustrate the tracking performance of the proposed controller and compare with the existing controllers for the tracking control of a surface vessel. The simulation results demonstrate the superior performance of the proposed strategy.     

Rotation matrix based finite-time attitude synchronization control for spacecraft with external disturbances

This paper investigates the anti-unwinding finite-time attitude synchronization control problem for Spacecraft formation flying with external disturbances. Two finite-time controllers are designed based on rotation matrix and terminal sliding mode method. By designing a novel sliding mode surface, the first controller is developed when the upper bound of the external disturbances can be exactly known. However, this value is not always available in reality. In addition, the direct use of the upper bound of the external disturbances can result in the chattering problem. For the purpose of overcoming the disadvantage of the first controller, a modified control law is proposed, in which the adaptive law is applied to estimate the unknown value online. Theoretical analysis and numerical simulations are presented to demonstrate the validity of the proposed controllers.     

A fast converging robust controller using adaptive second order sliding mode

This paper proposes an adaptive second order sliding mode (SOSM) controller with a nonlinear sliding surface. The nonlinear sliding surface consists of a gain matrix having a variable damping ratio. Initially the sliding surface uses a low value of damping ratio to get a quick system response. As the closed loop system approaches the desired reference, the value of the damping ratio gets increased with an aim to reducing the overshoot and the settling time. The time derivative of the control signal is used to design the controller. The actual control input obtained by integrating the derivative control signal is smooth and chattering free. The adaptive tuning law used by the proposed controller eliminates the need of prior knowledge about the upper bound of system uncertainties. Simulation results demonstrate the effectiveness of the proposed control strategy.     

电液位置伺服系统自适应反演滑模控制

在六自由度并联运动平台运动控制中，可转化为对各个支链的运动控制，每条支链采用电液伺服运动系统。针对并联运动平台支链位置控制中存在的抗干扰和控制精度问题，提出了一种基于自适应反演滑模控制算法。该算法利用自适应控制策略，以此对系统的建模误差和外加干扰等不确定性进行估计，再结合反演滑模控制算法设计平台支链位置控制器，解决并联运动平台位置精确控制问题。仿真结果和试验表明，该控制策略能够很好的实现支链电液伺服运动快速、稳定、高精度位置控制，并对系统的外加干扰具有很强的鲁棒性和自适应性。