Output feedback control of electro-hydraulic asymmetric cylinder system with disturbances rejection     

Yunfei Wang  Jiyun Zhao  Haigang Ding  He Zhang 《Journal of The Franklin Institute》2021,358(3):1839-1859

To achieve accurate position control of electro-hydraulic asymmetric cylinder system with only available displacement signal, an output feedback controller is proposed in this paper. The dynamic model of the system is expressed as a Brunovsky form, which helps to estimate the system states and simplify the controller structure. Then Levant differentiator is introduced to estimate the position, velocity and acceleration of the asymmetric cylinder system based on the output signal, which can reduce the impact of measurement noise compared to the means of calculating the time derivative of the displacement signal directly. Besides, a high gain disturbance observer is designed to reject the lumped disturbance rejection of the system including parameter uncertainty, modelling error and external disturbance. Moreover, a sliding mode surface is introduced to the controller design and a robust item with continuous function is applied to compensate for estimation errors. According to Lyapunov theory, the developed output controller is pledged to be stable that can realize disturbance rejection control as well as backstepping-free control. Furthermore, a large-size asymmetric cylinder experimental rig is set up to simulate practical applications environment. Comparative experimental results reveal the validity and potential practical meaning of the developed control approach.  相似文献   

Partial-state feedback adaptive stabilization for a class of nonlinear systems with uncertainties     

Yan Zhao  Jiangbo Yu 《Journal of The Franklin Institute》2021,358(9):4807-4821

This paper studies the adaptive asymptotically stabilizing control problem for a class of uncertain nonlinear systems by the partial-state feedback. The input-to-state stability (ISS) is used to describe the dynamic uncertainties, and a novel Nussbaum function is resorted to counteract the unknown identical control directions. The damping terms with the estimates of unknown disturbance bounds are inserted in control design to handle the nonvanishing external disturbances. It can be seen that all signals in closed-loop are bounded and the system states converge to zero asymptotically in spite of the uncertainties. Finally, a simulation example is introduced to show the effectiveness of the presented control scheme.  相似文献   

Robust finite-time sliding mode control for discrete-time singular system with time-varying delays     

Yinghong Zhao  Yangfan Liu  Yuechao Ma 《Journal of The Franklin Institute》2021,358(9):4848-4863

This paper explores the finite-time bounded issue for discrete-time singular time-varying delay system via sliding mode control method. A suitable discrete-time sliding mode control law is constructed to drive the state trajectories onto the specified sliding surface in a given finite time interval. Meanwhile, sufficient conditions for finite-time bounded to the closed-loop delayed system are provided in both reaching phase and sliding motion phase. In addition, the finite-time sliding mode controller gain matrix can be solved by using the linear matrix inequalities approach. Finally, three numerical examples are illustrated to demonstrate the superiority and practicability of presented results.  相似文献   

高职图书馆组织网络文献资源的切入点     

赵飞  王羿泉  梁伟 《包头职业技术学院学报》2018,(2):93-96

从高职院校图书馆组织网络文献现实状况入手,指出对于网络全文数据库高职图书馆缺乏网络文献组织技术手段,对于组织开放获取资源没有积极性的问题.分析高职图书馆开展网络文献组织的好处有以下几个方面,跨库统一检索平台可以有效将图书馆现有文献组织成一个整体,开放获取文献可以缓解图书馆经费压力,组织网络文献可以缓解读者信息过载.并指出高职院校图书馆网络文献组织工作切入点有图书馆现有网络资源组织统一检索平,组织开放获取资源向读者推广使用,接受虚拟馆藏文献概念,积极参与网络文献资源建设.  相似文献   

滇西抗战历史文化研究的价值意义、基础与路径     

赵周  侯兴华 《保山学院学报》2018,(1):37-41

滇西抗战历史文化厚重深邃,蕴含着重要的现实意义和学术价值,值得深入挖掘和研究,是我们主动服务教学与科学研究,特别是重点学科建设,服务滇西区域经济社会发展和积极融入国家"一带一路"战略的重要路径,也是实现特色资源、特色服务和特色发展的重要渠道.滇西抗战历史文化研究需要以高纬度、深层次、立体式和多视阈的方式,全面推进,研究方向应该包括理论研究与实证研究两方面,主要内容可涉及滇西抗战地位作用、旅游资源开发利用、民族精神与爱国主义教育、资料的收集整理等.  相似文献   

运动处方结合电刺激防治去势大鼠骨质疏松的实验研究     

谢江涛  赵廷刚 《成都体育学院学报》2011,37(3)

目的:探讨非药物手段(适宜健骨运动处方与电刺激联合作用)对绝经后骨质疏松的影响.方法:将40只去势大鼠分为骨质疏松模型组(OVX)和实验干预组,干预组含运动组(EX)、电刺激组(ES)、运动结合电刺激组(EX+ES)、假手术组(SHAM 组);对其进行60天的实验干预;测试实验前后的体重和股骨的生物力学指标等的变化情况.结果:OVX组体重、股骨的材料力学和结构力学指标上均出现明显异常,实验干预组的多数指标均优于(OVX组),在骨的最大载荷、破断载荷、弹性模量、极限强度指标上,EX+ES组与OVX组存在极其显著性差异(P＜O.01).结论:适宜健身运动与低频电刺激联合作用对骨质疏松的影响是促进成骨细胞的代谢,减少破骨细胞分泌和阻止骨丢失,可作为一种非药物方法防治绝经后骨质疏松症.  相似文献   

河南省大中型企业职工体育管理机制现状及对策研究     

赵玉娟 《福建体育科技》2011,30(2):11-13

通过对河南省大中型企业职工体育管理机构和内容的研究,分析企业职工体育管理存在的主要问题,提出企业职工体育管理的对策。  相似文献   

精巧的扳指     

杨波  赵智军 《收藏》2011,(1):93-94

扳指古称“碟（she）”,有骨制、角制和玉制的。可能是由于玉较易保存的缘故,考古发现中只有玉碟出现。我国已知最早的一件谍是出自商代晚期王妃妇好墓中,现存于中国社科院考古研究所。该镍表面呈淡绿色,有少部分的淡褐色沁斑,一侧高2．7厘米,一侧高3．8厘米,形似半截壶嘴,中空,可套入拇指。背面下部有一条横向的浅槽,槽由窄而宽。  相似文献   

最后的九华堂珍藏     

赵榆 《收藏》2011,(8):62-66

最近,我从香港九华堂刘少旅先生后人处,看到一批九华堂珍藏的张大千先生和张善抒先生的作品,不由让我联想起与刘少旅先生及其长子刘滦交往的往事。  相似文献   

对乒乓球专项学生腕膝关节损伤的调查与研究     

倪钊  桂文亮 《体育科技》2011,32(3):56-59

乒乓球运动是技战能主导类隔网对抗性项目,易致腕膝关节损伤。运用文献综述法和问卷调查法等研究方法,对华中师范大学体育学院乒乓球专项学生腕膝关节发生运动损伤的次数、时间、原因、伤后急救处理措施、恢复正常运动水平所需时长以及伤后对运动能力、心理的影响等方面进行调查分析,并针对这些问题提出相应的建议和预防措施,为乒乓球运动损伤的预防和处理提供理论参考。  相似文献