共查询到17条相似文献,搜索用时 171 毫秒
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高性能四足仿生机器人的设计要求驱动其关节运动的液压驱动单元具有良好的动态特性,但由于液压驱动单元工作参数摄动和其固有的复杂非线性,使得多数情况下液压驱动单元的控制性能受到制约.采用机理建模方法,针对四足机器人采用的一种对称阀控制对称缸的液压驱动单元结构,综合考虑控制器饱和特性、伺服阀压力-流量非线性、伺服缸活塞初始位置变化、库伦摩擦非线性等因素的影响,建立了液压驱动单元非线性数学模型,给出了其液压固有频率和阻尼比表达式;运用Matlab/Simulink软件系统搭建了其非线性仿真模型,在相同工况下,分析了不同控制器比例增益的液压驱动单元位移阶跃响应的仿真及试验结果,以验证仿真模型;并搭建了液压驱动单元性能测试试验台,通过仿真与试验分析,进一步研究了控制器比例增益、系统供油压力、液压驱动单元初始位移、负载力、负载质量、负载刚度对液压驱动单元动态特性的作用机理和影响规律.研究结果表明,建立的非线性数学模型准确、实用,且以上参数的改变均会对液压驱动单元位置控制特性产生不同程度的影响,其影响规律可为四足仿生机器人液压驱动单元控制器参数的在线优化奠定基础. 相似文献
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《液压气动与密封》2019,(8)
针对传统液压四足机器人电液伺服阀控缸系统的非线性、参数时变性、控制误差大等问题,提出了一种基于位置闭环控制的模型参考自适应控制算法。以液压四足机器人为研究背景,介绍了单腿整体结构及组成;然后,建立液压四足机器人电液伺服阀控缸控制系统模型、传递函数,并设计模型参考自适应控制器;最后,结合AMESim-MATLAB软件搭建四足机器人电液伺服阀控缸系统的控制模型,并对搭建好的测试平台进行实验。实验表明基于电液位置伺服系统的液压四足机器人阀控缸位置控制系统模型的合理性,阀控缸位置跟踪效果好、响应速度快、误差小、鲁棒性强,验证了所设计的位置闭环控制的模型参考自适应控制算法的可行性。 相似文献
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为缓解液压驱动足式机器人动态步态行走时着地瞬间足端冲击对机器人系统及其运动控制的影响,提出了一种基于关节运动规划的机器人柔顺着地控制方法。以液压驱动单腿跳跃机器人为研究对象,分析机器人足端着地冲量,通过选择合适的机器人着地姿态和减小机器人着地前足端速度实现机器人柔顺着地,为此在空中相进行余弦速度曲线关节运动轨迹规划,以及着地相进行余弦函数关节运动轨迹规划。将该方法分别应用于基于MATLAB/Simulink软件建立的仿真模型和试验样机进行单腿竖直跳跃控制实验,仿真和试验结果显示采用该方法的机器人跳跃控制消除了足端着地瞬间地面作用力在膝关节液压缸无杆腔形成的液压冲击,实验结果表明提出的基于关节运动规划的机器人柔顺着地控制方法合理可行。 相似文献
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液压腿足式机器人因其可承受大负载、具有更高的速度上限等优势被广泛应用于物资搬运、地形侦查等场景。伺服阀作为液压系统中的控制元件,与机器人作业过程的运动稳定性、地形适应性、节能等方面都存在着密切关联。目前腿足式机器人系统普遍应用喷嘴挡板式伺服阀,不同阀型号的选择往往只需要满足阀的频响、压力、流量等指标,并且伺服阀的数学模型也通常近似为低阶环节,这在设计中弱化了伺服阀对系统的影响。为探究不同结构伺服阀与控制系统最佳匹配问题,研究了增材制造旋转直驱式伺服阀在机器人位置控制系统中的性能,并将其与传统喷嘴式挡板阀作比较,分别建立其数学模型并在单腿试验台上完成实验验证。结果表明,在相同的流量压力需求下,应用旋转直驱阀的控制系统足端阶跃响应时间减少了14%,足端正弦轨迹跟踪误差减少了21%。 相似文献
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Force control compensation method with variable load stiffness and damping of the hydraulic drive unit force control system 总被引:1,自引:0,他引:1
Each joint of hydraulic drive quadruped robot is driven by the hydraulic drive unit (HDU), and the contacting between the robot foot end and the ground is complex and variable, which increases the difficulty of force control inevitably. In the recent years, although many scholars researched some control methods such as disturbance rejection control, parameter self-adaptive control, impedance control and so on, to improve the force control performance of HDU, the robustness of the force control still needs improving. Therefore, how to simulate the complex and variable load characteristics of the environment structure and how to ensure HDU having excellent force control performance with the complex and variable load characteristics are key issues to be solved in this paper. The force control system mathematic model of HDU is established by the mechanism modeling method, and the theoretical models of a novel force control compensation method and a load characteristics simulation method under different environment structures are derived, considering the dynamic characteristics of the load stiffness and the load damping under different environment structures. Then, simulation effects of the variable load stiffness and load damping under the step and sinusoidal load force are analyzed experimentally on the HDU force control performance test platform, which provides the foundation for the force control compensation experiment research. In addition, the optimized PID control parameters are designed to make the HDU have better force control performance with suitable load stiffness and load damping, under which the force control compensation method is introduced, and the robustness of the force control system with several constant load characteristics and the variable load characteristics respectively are comparatively analyzed by experiment. The research results indicate that if the load characteristics are known, the force control compensation method presented in this paper has positive compensation effects on the load characteristics variation, i.e., this method decreases the effects of the load characteristics variation on the force control performance and enhances the force control system robustness with the constant PID parameters, thereby, the online PID parameters tuning control method which is complex needs not be adopted. All the above research provides theoretical and experimental foundation for the force control method of the quadruped robot joints with high robustness. 相似文献
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针对液压四足机器人结构布局混乱、能量损失大及控制策略复杂等问题,从机器人整机、液压系统和控制策略3个角度分析了液压四足机器人的研究现状。首先,对各团队的机器人进行介绍,指出国内外的技术差距;然后,从动力来源、系统类型、液压回路和伺服执行元件4个方面对液压系统的主要2大构成分别阐述,着重介绍了以节能为目的的阀控系统和集成化、一体化的伺服执行器;接着概述了主流的几种控制策略,并分析各自的优缺点;最后,指出液压四足机器人的发展方向将集中在高速高压化、轻量化、节能降噪以及先进的控制算法,以实现液压四足机器人的高动态性能和行业应用。 相似文献
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《机械工程学报(英文版)》2015,(5)
The previous sensitivity analysis researches are not accurate enough and also have the limited reference value, because those mathematical models are relatively simple and the change of the load and the initial displacement changes of the piston are ignored, even experiment verification is not conducted. Therefore, in view of deficiencies above, a nonlinear mathematical model is established in this paper, including dynamic characteristics of servo valve, nonlinear characteristics of pressure-flow, initial displacement of servo cylinder piston and friction nonlinearity. The transfer function block diagram is built for the hydraulic drive unit closed loop position control, as well as the state equations. Through deriving the time-varying coefficient items matrix and time-varying free items matrix of sensitivity equations respectively, the expression of sensitivity equations based on the nonlinear mathematical model are obtained. According to structure parameters of hydraulic drive unit, working parameters, fluid transmission characteristics and measured friction-velocity curves, the simulation analysis of hydraulic drive unit is completed on the MATLAB/Simulink simulation platform with the displacement step 2 mm, 5 mm and 10 mm, respectively. The simulation results indicate that the developed nonlinear mathematical model is sufficient by comparing the characteristic curves of experimental step response and simulation step response under different constant load. Then, the sensitivity function time-history curves of seventeen parameters are obtained, basing on each state vector time-history curve of step response characteristic. The maximum value of displacement variation percentage and the sum of displacement variation absolute values in the sampling time are both taken as sensitivity indexes. The sensitivity indexes values above are calculated and shown visually in histograms under different working conditions, and change rules are analyzed. Then the sensitivity indexes values of four measurable parameters, such as supply pressure, proportional gain, initial position of servo cylinder piston and load force, are verified experimentally on test platform of hydraulic drive unit, and the experimental research shows that the sensitivity analysis results obtained through simulation are approximate to the test results. This research indicates each parameter sensitivity characteristics of hydraulic drive unit, the performance-affected main parameters and secondary parameters are got under different working conditions, which will provide the theoretical foundation for the control compensation and structure optimization of hydraulic drive unit. 相似文献
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液压驱动单元(Hydraulic drive unit,HDU)是液压驱动型足式机器人常用的关节驱动器,具有集成度高、功率密度大等特性。机器人顶层规划后,需依靠其完成具体动作,实现机器人的行走、对角小跑、奔跑等步态。HDU所受外负载会随机器人腾空相和着地相频繁大幅变化,严重影响系统性能。若HDU具备高性能基于力的阻抗控制,则可有效减小机器人在运动过程中足地接触时的碰撞力,保证机器人运动的平稳性。为提高基于力的阻抗控制系统的抗外扰动能力,研究一种前馈抗扰控制(Feedforward disturbance rejection control,FDRC)。介绍HDU基于力的阻抗控制系统及其数学模型,推导其非线性状态空间表达式。针对系统的外扰动推导等价输入矩阵,设计前馈抗扰控制器,并估算伺服阀流量系数。利用HDU性能测试试验台,针对不同工况和典型信号进行试验。试验结果表明,FDRC可大幅提高HDU基于力的阻抗控制系统的抗外扰动能力,且工况适应性良好。该控制方法可降低外扰动对液压驱动型机器人的影响,提高机器人的适应性。 相似文献
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以电液伺服比例阀控非对称液压缸同步系统为研究对象,通过详细分析,建立了同步系统的数学模型,采用Matlab的Simulink模块对系统的动态特性进行仿真分析,并利用AMESim和Simulink软件对双缸同步液压系统进行了基于PID控制的联合仿真,仿真结果表明,将电液伺服比例阀应用于同步控制,系统响应快,控制精度高,经济性好,可应用于工程实际。 相似文献
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基于传统液压缸伺服系统建模参数的复杂性、不确定性、以及系统的时变性等问题,提出了一种基于MATLAB-AMESim的液压缸位置伺服系统辨识方法。该文以组成足式机器人驱动单元的液压缸为研究对象,简单介绍了液压缸的组成结构及工作原理;其次建立液压缸控制系统模型、传递函数,阐述了液压缸伺服系统辨识方法原理和基本过程;最后,通过MATLAB-AMESim软件搭建单缸位置伺服系统进行系统辨识仿真,将仿真结果与实际液压缸位置伺服系统测试结果进行对比。实验表明基于MATLAB-AMESim的液压缸位置伺服系统辨识仿真具有良好的实用性,验证了系统模型辨识方法的有效性。 相似文献