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151.
针对现有非线性控制方案的一些瓶颈问题,从线性控制的角度出发,开展了一种用于WMR的线性二次型最优控制方法设计的研究.首先,基于WMR的运动学模型采用动态反馈线性化技术将非线性运动学模型转化为线性模型;然后,选取跟踪误差及误差收敛速度作为设计指标;同时考虑实现渐进跟踪,针对不同形式的参考轨迹,根据内模原理对控制器模态进行扩展,利用线性模型设计基于内模扩展LQ最优轨迹跟踪控制器;最后通过动态反馈反变换得到实际控制器.此外,通过将此方法的控制效果与几种经典方法进行仿真比对,说明了此方法对于跟踪的精确性和快速性上有较大优势. 相似文献
152.
《International Journal of Hydrogen Energy》2020,45(58):33925-33938
The accurate control of automotive fuel cell oxygen excess ratio (OER) is necessary to improve system efficiency and service life. To this end, an anti-disturbance control driven by a feedback linearization model predictive control (MPC)-based cascade scheme is proposed. It considers strong nonlinear coupling and disturbance injection of fuel cell oxygen supply. A six-order nonlinear fuel cell oxygen feeding model is presented. It is further formulated using an extended state observer to rapidly reconstruct the OER, to overcome the slow response and interference errors of sensor measurements. In the proposed cascade control, the outer loop is the anti-disturbance control which is used to realize the optimized OER tracking and the inner loop via the feedback linearization to linearize the oxygen feeding behaviors conducts MPC to regulate the air compressor output mass flow. The feedback linearization demonstrates a robust tracking performance of nonlinear outputs, and the integral absolute error of anti-disturbance control is 0.3021 lower than that of PI control under a custom test condition. Finally, the numerical validation on a hybrid driving cycle indicates that the proposed cascade control can regulate the fuel cell OER with an average absolute error of 0.02313 in the high air compressor operation efficiency zone. 相似文献
153.
This study deals with the quartic autocatalysis of homogeneous–heterogeneous chemical reaction that occurs in the bioconvective flow of micropolar nanofluid between two horizontally parallel plates. The quartic autocatalysis is found to be more effective than cubic autocatalysis since the concentration of the homogeneous species is substantially high. The upper plate is assumed to be in motion and the lower plate is kept stationary. Such a flow of micropolar fluid finds application in the pharmaceutical industry, microbial enhanced oil recovery, hydrodynamical machines, chemical processing, and so forth. The governing equations for this flow are in the form of the partial differential equation and their corresponding similarity transformation is obtained through Lie group analysis. The governing equations are further transformed to coupled nonlinear differential equations that are linearized through the Successive linearization method and are solved using the Chebyshev Collocation method. The effects of various parameters, such as micropolar coupling parameter, spin gradient parameter, reaction rates, and so forth, are analyzed. It is observed that the fluid flows with a greater velocity away from the channel walls, whereas near the channel walls the velocity decreases with an increase in the coupling parameter. Furthermore, the spin parameter increases the spin gradient viscosity that reduces the microrotation of particles that further decreases the microrotation profile. 相似文献
154.
155.
As a form of hybrid multi-energy systems, the integrated energy system contains different forms of energy such as power, thermal, and gas which meet the load of various energy forms. Focusing mainly on model building and optimal operation of the integrated energy system, in this paper, the dist-flow method is applied to quickly calculate the power flow and the gas system model is built by the analogy of the power system model. In addition, the piecewise linearization method is applied to solve the quadratic Weymouth gas flow equation, and the alternating direction method of multipliers (ADMM) method is applied to narrow the optimal results of each subsystem at the coupling point. The entire system reaches its optimal operation through multiple iterations. The power-thermal-gas integrated energy system used in the case study includes an IEEE-33 bus power system, a Belgian 20 node natural gas system, and a six node thermal system. Simulation-based calculations and comparison of the results under different scenarios prove that the power-thermal-gas integrated energy system enhances the flexibility and stability of the system as well as reducing system operating costs to some extent. 相似文献
156.
高比例的新能源和直流负载的接入给配电网带来了全新的挑战,随着基于电压源换流器(voltage source converter,VSC)的换流技术不断发展,交直流混合配电网因其能够为分布式电源提供高效经济的接入方式而得到了越来越广泛的应用。提出了一种含有分布式电源、储能和VSC的交直流混合配电网运行优化模型,该模型以配网购电成本、弃风弃光成本、网损成本和储能日运行维护成本之和构成的系统综合运行成本最小为目标,优化配网购电量、VSC的功率和储能的充放电策略。针对该混合整数非线性模型带来的求解困难的问题,提出了一种考虑网损的线性化方法对模型进行线性化处理,该方法没有网架拓扑形式的限制,具有更广泛的适用性。最后,在改造的13节点算例中验证了所提方法的有效性和准确性。 相似文献
157.
In this paper we experimentally characterize friction in an astronomical telescope and introduce a new model for capturing the observed behavior of friction in both the micro and macro displacement regimes of motion. The model is a modification of the LuGre model and is developed for velocity reversal systems like an astronomical telescope. The proposed model is represented with a pair of masses separated by a linear spring. This model is then employed to synthesize a feedback linearizable controller for the system. The simulation results for the proposed friction model in open loop are presented and validated with the experimental results. The stability aspects of the closed loop system with the modified friction model is then investigated. For estimating the unmeasurable states of the system used in feedback linearization, we discuss the observability of the system with the new model for friction. 相似文献
158.
In this paper the attitude control of a spacecraft simulator using Reaction Wheels (RW) as the actuators is investigated. The main goal of the current study is to bring the RWs to the rest at the end of the maneuver without angular velocity measurement. A modified feedback linearization controller is applied by considering the Euler angles of the simulator as the output and the RWs angular momentums as the internal state variables. The stability of the proposed controller and the internal dynamics is analyzed using Lyapunov theory. Two modified sliding mode observers are designed to estimate the angular velocities of the spacecraft attitude control subsystem simulator. The proposed observers do not use the control input and the detailed knowledge of the model and thus it can be implemented easily. The global stability of the system is proved. The proposed controller and observers are finally evaluated numerically and experimentally on an attitude spacecraft simulator. 相似文献
159.
研究了带躯干双足机器人平面稳定行走控制问题。改进传统的弹簧-质点模型,得到带躯干的双足机器人模型,通过控制髋关节施加力矩和改变弹簧腿的刚度,使得系统收敛到期望步态。针对系统模型的非线性和强耦合特征,采用反馈线性化方法将系统的动力学模型转化成线性系统,采用PD控制和P控制对机器人的躯干倾角和髋关节轨迹进行整体控制。在理论分析的基础上,对控制方法进行了数值仿真研究。仿真结果表明：该文采用的反馈线性化和变刚度控制方法可以实现带躯干双足机器人的稳定行走;与基于时间轨迹的控制方法相比,该文基于空间轨迹的控制器对各种外力干扰具有良好的抵抗能力;控制器对躯干的倾角变化具有适应性;当模型不确定时控制器表现出优异的鲁棒性。 相似文献
160.
This paper is concerned with the problem of finite-time stability analysis of uncertain discrete-time Networked Control Systems (NCSs) with varying communication delays in a random fashion. Both measurement and actuation delays are modeled by two independent Bernoulli distributed white sequences. A dynamic output feedback controller is designed to realize finite time control for this class of NCSs with prescribed performance level. An iterative algorithm is developed to compute the controller's parameters by means of the Cone Complementarity Linearization Method (CCLM). The validity and feasibility of the proposed stability criterion are confirmed via numerical simulation examples. 相似文献