四旋翼无人机设计与滑模控制仿真

随着近些年自然灾害的频繁发生,四旋翼飞行器搜救设备得到越来越广泛的应用。首先介绍四旋翼飞行系统的总体设计架构,然后针对地面坐标系与集体坐标系建立了四轴飞行器的动态模型,同时为得到良好的响应速度、控制稳定度与鲁棒性,应用滑模变结构控制理论设计了飞行器的控制算法。最后通过仿真数据对相同条件下的PID控制器与该控制器对比,证明该控制器的强鲁棒性和控制稳定性满足项目任务需求。     

基于滑模控制的四旋翼飞行器控制器设计

基于四旋翼飞行器的结构和飞行原理,本文建立了其飞行动力学数学模型,并采用反馈线性化原理对该模型进行精确线性化;同时,本文采用基于趋近律的滑模变结构控制方法,进行飞行控制器设计,并用simulink对设计的控制器进行仿真,实现了四旋翼飞行器的定高悬停控制,提高了其飞行性能和鲁棒性。     

四旋翼飞行器双环条件积分滑模控制

针对存在阵风干扰及未建模特性下的四旋翼飞行器轨迹跟踪控制,基于非线性滑模控制技术,结合条件积分思想及Lyapunov稳定性理论设计了一种位姿双环条件积分滑模控制器.在获得四旋翼非线性动力学模型后对其进行线性化,简化被控对象数学模型,提高控制器设计效率.利用条件积分滑模控制律设计了位置环和姿态环的轨迹跟踪控制器,实现了控...     

基于广义逆和滑模的欠驱动无人艇跟踪控制

针对具有非对角惯性矩阵和阻尼矩阵的欠驱动无人水面艇(USV)进行了轨迹跟踪控制方法的研究,提出了基于广义动态逆和滑模变结构理论的控制器,实现了闭环系统全局渐近稳定。同时,通过引入动态尺度逆克服动态广义逆可能导致的系统奇异,通过扰动零投影矩阵来避免零投影矩阵的不可逆问题。最后,通过Matlab/Simulink仿真证明了本文方法的有效性。     

欠驱动柔性机械臂的动力学建模与控制

针对欠驱动柔性机械臂建模、控制困难的问题,文中采用在第一关节安装轻质弹簧的方法来表示机械臂的柔性,从而得到柔性臂的简化模型。将其应用到两连杆欠驱动柔性机械臂中,建立欠驱动柔性机械臂的系统模型,并利用拉格朗日函数法,对该系统进行动力学建模。同时通过构造基于系统能量和驱动杆状态的李雅普诺夫函数,设计该欠驱动柔性机械臂系统的控制律。最后,使用Matlab对该系统及所设计的控制律进行数值仿真。仿真结果表明,所构建的动力学模型以及设计的控制规则具有良好的有效性,且同时具备响应速度快、控制输入小的优点。     

基于观测器的四旋翼飞行器自适应滑模姿态控制

针对存在建模不确定性和外部干扰时四旋翼飞行器的姿态控制问题,提出一种基于观测器的自适应滑模控制算法。在建立四旋翼飞行器姿态误差动力学模型的基础上,通过全局渐近收敛观测器获取系统的未知状态反馈量,利用自适应滑模控制抑制系统的不确定性和干扰,构建一种基于观测器的自适应滑模姿态控制器。基于Lyapunov的稳定性分析表明,该方法的跟踪误差是一致最终有界的。数值仿真实验结果表明,与现有滑模控制方法相比,所提方法具有更好的姿态跟踪性能和较高的抗干扰鲁棒性,能有效保证飞行器的姿态跟踪控制性能。     

基于滑模与控制分配的六旋翼飞行器容错控制

针对六旋翼飞行器的执行机构失效故障, 提出一种基于滑模和控制分配方法的容错控制方案; 采用了分层设计结构, 将基本控制律设计与控制分配律分为两个独立的部分, 针对系统建模不确定性与外界干扰, 设计滑模控制律, 提高了系统的鲁棒性, 运用控制分配方法, 在飞行器发生失效故障甚至卡死故障时, 在线调解控制分配矩阵, 减小故障机构对整体飞行性能的影响。仿真结果验证了所提容错控制的正确性和有效性。     

欠驱动系统Pendubot的模糊控制策略

本文针对欠驱动Pendubot机器人系统，提出一种简单可靠的摇起及平衡控制策略。通过利用模糊控制及全状态反馈控制技术来分别设计摇起控制器及平衡控制器，其中模糊摇起控制器的设计使得系统的摇起可靠性得到大大的加强，并缩短了响应时间，两个控制器的转换通过转换装置实现。最后的仿真结果验证了算法的有效性。     

一类非线性系统的模糊神经网络全局滑模控制

文中针对一类非线性系统提出了一种基于模糊神经网络的全局滑模控制策略。设计了模糊神经全局滑模函数,并根据Lyapunov稳定性理论设计出控制器和自适应律。文中以三相并联型有源电力滤波器为实例在MATLAB平台上进行了仿真实验,电网电流谐波畸变率由24. 71%降低到1. 6%,表明所提出的方案具有很好的补偿性能。     

四旋翼直升机的滑模控制研究

四旋翼直升机因其优良特性,在军事和民用领域均有广阔的应用前景。为确保其安全稳定飞行,针对周口师范学院自主研制的四旋翼直升机,结合其结构及动力学原理,考虑非匹配不确定性因素的影响,对三自由度四旋翼直升机进行建模。采用线性矩阵不等式技术进行变结构滑模控制系统设计,仿真结果表明,该系统抗参变能力较强,直升机的飞行姿态基本满足控制要求。     

Event-triggered type-2 fuzzy-based sliding mode control for steer-by-wire systems

This paper proposes an event-triggered higher-order sliding mode control for steer-by-wire (SbW) systems subject to limited communication resources and uncertain nonlinearity. First, an interval type-2 fuzzy logic system (IT2 FLS) is adopted to approximate the uncertain nonlinearities. A fuzzy-based state observer is developed to estimate unavailable states of the extended SbW system. Then, to save communication resources and eliminate chattering, an event-triggered higher-order sliding mode control is proposed for the SbW system. The key advantage is that the proposed control scheme can offset the observation error and the event-triggering error. After that, the practical finite-time stability of the closed-loop SbW system is proved in the framework of the Lyapunov theory. Finally, numerical simulations and vehicle experiments are given to evaluate the effectiveness and superiority of the proposed scheme.     

基于自治水下机器人纵向运动的滑模定深控制

针对自治水下机器人(AUV)的控制特点,建立了AUV纵向运动的动力模型,采用高阶滑模非线性控制的方法,并运用计算机仿真的手段进行了验证,仿真结果显示了该系统具有良好的控制性能,有效地消除了滑模控制的抖振,对外部扰动具有较强的鲁棒性。     

滑模控制策略在具有不确定性的混沌系统同步中的应用

根据滑模控制原理求取混沌同步控制形式，利用扩张状态观测器对系统信息进行渐进估计，得到物理可实现的同步控制策略，以此实现具有不确定性混沌系统的同步。以Duffing和VanderPol系统为例进行仿真，效果良好。     

High-gain observer-based integral sliding mode tracking control for heavy vehicle electro-hydraulic servo steering systems

The electro-hydraulic servo steering system (EHSSS) is the key element to determine the handling and stability of heavy vehicles. Accurate steering control is challenged due to its complicated structure and a wide range of steering loads. In this paper, an output feedback integral sliding mode control (ISMC) method based on high-gain observer is proposed to solve this issue. First, a new Hurwitz matrix design method is presented for EHSSS with non-chain integrator, in order to prove the convergence of the observer error dynamics. Then, the Lyapunov stability of the observer-based controller is verified. Finally, a test bench is established to experimentally validate the proposed method's effectiveness through multiple test scenarios. The results show the tracking error of the proposed method is significantly smaller than PI and similar to full-state feedback integral sliding mode controller. This paper provides a valuable reference for high-gain observer-based nonlinear control applied to a typical electro-hydraulic servo steering system.     

Fuzzy sliding mode control for a class of piezoelectric system with a sliding mode state estimator

A new fuzzy sliding mode hysteresis compensating control strategy for a kind of typical piezoelectric system (PES) is proposed in this paper. Firstly, a typical nonlinear dynamic model of the PES is introduced. In order to compensate the hysteresis of the PES, an ideal linear hysteretic model is introduced by analyzing the characteristic of dynamic hysteretic model. Then, the ideal hysteretic model is transformed into an expected linear model by multiplying a slope conversion factor which can be obtained by experiment. Further, the sliding mode control principle is constructed to calculate the hysteretic compensating control law, which can guarantee the practical hysteretic characteristic to reach the expected linear output feature. Consider the unmeasured hysteresis output of the PES, we further design a sliding mode estimator to estimate the hysteretic part’s output. Finally, we derive the adaptive law of the fuzzy sliding mode controller, and demonstrate its stability through Lyapunov stability theory. The simulation results show the validity of the sliding mode compensator for this kind of nonlinear dynamic model of PES.     

Enhanced fuzzy sliding mode controller for active suspension systems

We proposed a fuzzy sliding mode controller (FSMC) to control an active suspension system and evaluated its control performance. The FSMC employed the error of the sprung mass position and the error change to establish a sliding surface, and then introduced the sliding surface and the change of the sliding surface as input variables of a traditional fuzzy controller (TFC) in controlling the suspension system. However, no substantial improvement in the ride comfort could be obtained with the FSMC relative to the TFC because the dynamic effect of the sprung mass acceleration from the bouncing tire during tire rotation was not eliminated. We have developed an enhanced fuzzy sliding mode controller (EFSMC) that maintained not only the original FSMC property but also introduced an assisted FSMC to address and compensate for this problem, and to enhance the road-holding capability of the vehicle. The assisted FSMC differs from the original FSMC only in using the sprung mass acceleration instead of the sprung mass position as a variable of the controller design. The EFSMC exhibits better control performance than either the TFC or the FSMC, in suppressing the acceleration of the vehicle body to improve the ride quality, and in reducing the tire deflection to increase the road-holding ability of a car, as confirmed by experimental results.     

Adaptive incremental sliding mode control for a robot manipulator

An adaptive incremental sliding mode control (AISMC) scheme for a robot manipulator is presented in this paper. Firstly, an incremental backstepping (IBS) controller is designed using time-delay estimation (TDE) to reduce dependence on the mathematical model. After substituting IBS controller into the nonlinear system, a linear system w.r.t. tracking errors is obtained while TDE error is the disturbance. Then, the AISMC scheme, including a nominal controller and an SMC, is developed for the resulted linear system to improve control performance. According to the equivalent control method, the SMC in the AISMC scheme is to handle TDE error. To receive optimal control performance at the sliding manifold, an LQR controller is selected as the nominal controller. The SMC is designed based on positive semi-definite barrier function (PSDBF) since it prevents switching gains from being over/under-estimated, and two practical problems are addressed in this paper: A new PSDBF is designed and conservative (large) setting bounds affecting tracking precision and/or system stability are avoided; An improved PSDBF based SMC is developed where the PSDBF and an adaptive parameter are used simultaneously to regulate switching gains, and the system is still stable when sliding variable occasionally exceeds the predefined vicinity. Moreover, finite-time convergence property of the sliding variable is strictly analyzed. Finally, real-time experiments are conducted to verify the effectiveness of the proposed control method.