气动伺服系统同步控制实验台的研究

气动同步控制是同步控制研究领域的关键问题。本文主要以气动同步控制试验台为研究对象，对该气动系统的基本特性和气动伺服系统的双缸位置同步控制问题进行研究，提出双层滑模变结构控制同步控制策略，进行双缸位置跟踪控制的实验研究。实验结果表明，提出的新型控制方法在双缸跟踪控制精度和抗干扰能力方面都十分有效。     

自适应同步控制策略在3-PRR平面并联机构中的应用

本文以三自由度P—R—R型平面并联机构为研究对象,建立系统的动力学模型,结合同步控制和自适应控制两种控制方法的优缺点,提出了一种新颖的控制方法,称为自适应同步控制,用来提高并联机构不确定参数的跟踪精度。通过用自适应同步控制策略对被控对象进行控制仿真,其结果表明,自适应同步控制方法的跟踪效果好,精度高,系统误差小,可以满足并联机构控制的要求,能够解决机构的轨迹跟踪问题,证实了自适应同步控制策略的正确性和有效性。     

双直线电机驱动的龙门移动式加工中心H∞鲁棒自适应控制

对数控龙门移动式镗铣加工中心速度同步控制提出了一种新的H∞鲁棒自适应控制方法。用有死区和投影校正的递推最小二乘辨识算法对被控对象参数在线辨识，用H∞鲁棒控制算法对调节器参数在线求解，使系统在未知有界扰动、参数变化和未建模动态等不确定性因素同时存在时，对调节器参数进行自动整定，以保证速度同步控制的鲁棒性。仿真实验结果表明该方案控制效果好，鲁棒性强，可满足速度同步控制要求。     

基于模糊PID控制的直流电机同步控制系统

为了更好地解决过程自动化领域多电机同步控制问题,以直流电机同步控制为研究对象,根据直流电机参数建立了控制系统数学模型,分析了采用传统PID方式控制电机同步系统而存在的问题,将模糊控制与传统PID控制相结合,设计出了模糊PID控制器。数值仿真及实验结果表明,该方案鲁棒性优良,响应快速,动态过程中同步误差小,能够较好地满足被控对象对高精度同步控制的要求。所开发的模糊PID控制软硬件系统在相应的实验平台上获得了较好的控制效果。     

块状食品枕式包装机多轴同步控制

以多伺服枕式食品包装机为研究对象,分析了多伺服枕式包装机结构以及工作原理。基于径向基神经网络 PID 控制方法设计了一种多电机偏差耦合同步控制方法,通过 PID 补偿器实现电机的同步控制,并详细介绍了控制器的设计方法。最后对该同步控制方法进行了计算机仿真,仿真结果表明,该控制方法能够快速实现多电机同步控制,在干扰的情况下也能够快速再次稳定。该控制方法可以较大地提高食品包装的精度,提高食品包装质量。     

基于交叉耦合式控制的马达行走同步性研究

探讨了交叉耦合式马达同步控制的可行性。介绍了交叉耦合式的同步控制原理，搭建相应的同步控制数学模型，构建传递函数框图。通过在整机上进行实验，分析交叉耦合式控制在空载和带载两种情况下马达的转速响应曲线、左右马达转速误差曲线，得出结论，交叉耦合式控制马达具有较好的同步性，但会牺牲一定的响应时间，可根据实际情况选择不同控制策略。     

多缸调平系统模糊相邻耦合同步控制研究

针对调平系统的多液压缸同步控制研究,提出了一种基于模糊相邻耦合的控制方法。首先对调平系统受力及多缸控制系统进行分析,建立控制对象的非线性数学模型。对相邻耦合控制器进行设计,使用补偿器将相邻两根液压缸位置同步误差融合到液压缸控制器中,对于难以通过常规方法精确获得的补偿系数,使用模糊PID控制算法获取。通过MATLAB仿真和实验对模糊相邻耦合的同步控制方法进行测试,并使用主从同步控制方法进行对比分析。结果表明,使用模糊相邻耦合同步控制时,四根液压缸误差波动较小,并且在液压缸加减速阶段能快速将误差降低,具有较好的同步控制性能。     

海洋风电吊装运输专用船液压同步控制系统研究

以海洋风电吊装运输专用船液压控制系统为研究对象,针对该船桩腿升降系统实际工况需要的同步升降,分析其液压系统的工作特性.分别应用泵控和阀控的控制方式,实现同步控制.利用仿真分析的方法对两种控制方式的特性进行比较,确定采用阀泵联控的控制方案,实现了大功率、动态特性好的同步控制.     

串联双非对称液压缸同步控制方案分析

本文针对驱动风洞尾撑系统偏航角的串联双非对称液压缸的同步控制问题，提出了几种同步控制方案并进行了分析，同时指出要使系统达到较好的动、静态性能应采用共反馈同步误差校正或主／辅控制单边校正同步控制方案     

深井钻机绞车多电机主从同步控制设计

随着钻井深度不断地加深,大功率、高性能的绞车呈逐年增长趋势。大功率的绞车就必须采用多电机同步驱动,解决好多电机同步控制关键就是找到一种新的控制方法来消除或减小多电机之间转矩差值。针对这个问题,以7000 m变频钻机为研究对象,借鉴了国内在多电机控制方面的各种方案对比,找出更适合绞车多电机同步控制方法 -主从同步控制。解决好多电机同步性的问题,为未来超深井钻机绞车的研制奠定科学依据。     

Research on back- pressure compensation characteristics of a pilot-assisted load control valve applied in overrunning load hydraulic systems

This paper reports the research of proportion flow control with back-pressure compensation feature on an LCV (load control valve). The back-pressure compensation feature means when back-pressure rises, flow of the LCV can be unchanged or lower. The back-pressure compensation feature is very important to the safety of the system, because high back-pressure will make the main valve open larger and lowering speed be undesired faster. In this paper, static equilibrium equations of LCV were established and influence relationship of back-pressure and other parameters was derived. In addition, back-pressure influence was simulated, based on above analysis a preliminary optimization scheme was proposed and tested. After that, the method of back-pressure compensation was proposed and has been verified by simulation. Finally, an LCV with back-pressure compensation feature was tested on the test rig. Experiment data validates that the main flow of the LCV with back-pressure compensation method was lower under a higher back-pressure and the pilot pressure control region was unchanged.     

基于Internet的网络化控制系统设计及控制研究

对于基于Internet的网络化控制系统,由于其网络延时具有随机、长时滞特性,使得控制系统稳定性和动态性能很差。本文基于离散的状态反馈网络化控制系统,提出了一种基于对象模型的多步预测补偿方法,通过在执行器端设置消息缓冲的办法实现时滞补偿的策略。基于Socket技术,应用LabWindows/CVI,采用以上时滞补偿方法设计了基于Internet的液位过程控制系统。实时跟踪控制实验和抗外部扰动实验结果结果表明,本文所提时滞补偿策略有效可行,能够很好地提高网络控制系统的动态性能。     

迭代控制在动态电压恢复器控制策略中的应用

根据动态电压恢复器(DVR)控制系统设计的要求,提出了基于迭代控制的前馈控制方法.经仿真实验验证,该方法可在稳态下较好的补偿谐波电压,提高了DVR控制系统的动态响应速度.     

复合前馈补偿的超磁致伸缩执行器精密伺服控制

研究了一种内嵌超磁致伸缩执行器(GMA)的智能镗削装置,针对GMA迟滞非线性,给出了一种基于复合前馈补偿的精密伺服控制方法。简要介绍了经典Preisach迟滞数值模型的实现方法,给出了一种基于迭代的迟滞非线性补偿方法以避免直接求取Preisach逆模型。讨论了迭代算法的实现步骤,验证了算法的可行性。分析了异圆销孔的镗削加工特点,在迭代补偿的基础上设计了重复控制补偿器,并结合两种补偿方法,给出了一种基于复合前馈补偿的PID控制方法,最后通过实验检验了方法的有效性。实验结果表明:在开环情况下,所给的迭代算法可以将GMA的迟滞非线性由补偿前的-15.7%~+11.8%减小到-4.6%~+5.2%,而基于复合前馈补偿的PID控制则可将误差进一步减小到±1 μm以内。实验表明,迭代补偿算法是有效的,该算法在补偿迟滞非线性的同时可避免直接求取Preisach逆模型,而基于复合前馈补偿的PID控制方法还可进一步提高GMA的控制精度。     

Ultra-precision nano-structure fabrication by amplitude control sculpturing method in elliptical vibration cutting

This paper studies the nano-structure fabrication on hardened steel by means of elliptical vibration cutting equipped with the ultra-precision amplitude control sculpturing method. Machining performance of the amplitude control sculpturing method is investigated, and the limitation in nano-scale machining is explored. In this proposed method, machinable part geometry is essentially restricted by vibration conditions and tool geometry. In addition, a considerable error between the amplitude command and the envelope of the tool trajectory is generated when the slope of the machining part geometry becomes steep. To overcome this error, a compensation method for the amplitude control command is proposed. In order to clarify the machining performance of the proposed technology, a series of analytical and experimental investigations are conducted. Furthermore, by applying the proposed command compensation method, nano-structures with a large ratio of structure height to wave length are machined accurately. The proposed sculpturing method is subsequently applied to the machining of nano-textured grooves and a three-dimensional grid surface, which verifies the feasibility of the proposed amplitude control sculpturing method.     

基于多层模糊控制的交叉耦合补偿方法的研究及应用

采用交叉耦合控制能有效地提高复杂曲面轮廓精度,但是传统的交叉耦合控制需要一个确定的数学模型,而且对于大于3轴的多轴交叉耦合控制,由于建模非常困难等原因,现有的研究成果比较少。在加工复杂轮廓时,由于各个轴之间的耦合强度是不同的,所以在前人研究的基础上提出基于多层模糊的交叉耦合补偿方法。该方法根据各个轴之间耦合关系的强弱对耦合层次进行划分,然后设计多层耦合控制器,对实时的轮廓误差进行补偿,更符合实际控制系统的组合规律,所以综合的控制性能更高。最终,将该方法在四轴联动对称加工机床上进行实验研究。     

Integrated control strategy for CVT powertrains with consideration of vehicle drivability

During shift,power flow is not interrupted in powertrains equipped with continuously variable transmission(CVT).When hard acceleration is commanded,engine speed will flare and corresponding torque will be consumed,which leads to a drop in vehicle drive torque and also the vehicle acceleration.This is the reason why CVT vehicles have poor drivability during hard acceleration maneuver.Conventional method such as torque compensation doesn’t always work due to the limited backup torque of engine.According to this,means to evaluate the drivability of CVT vehicles are studied,affect factors of drivability are analyzed in detail.Hard acceleration process of CVT vehicle is studied by theoretical analysis,based on which engine torque and ratio change rate of CVT are identified as two key control parameters that decide the drivability of CVT vehicles during hard acceleration maneuver.Therefore,a control strategy based on restricting the change rate of CVT ratio together with torque compensation is proposed,and two different algorithms to establish the limitation of ratio change rate are proposed.These two algorithms are simulated and compared with each other,results indicate that drop of vehicle acceleration is eliminated evidently by limit the change rate of CVT ratio,but small ratio change rate also results in a longer time to finish the accelerate process,an algorithm to decide a proper ratio change rate is needed in order to tune these different characteristics.In order to get better control effects,a new fuzzy logic based algorithm is proposed to decide a proper ratio change rate during kick down conditions,simulation and experiment results indicate that,the amount of vehicle acceleration decrease is reduced from about 1 m/s2 to almost 0,in the mean time the accelerate process only delayed for about 0.3 s.The proposed control strategy and algorithm can effectively tune the characteristics of CVT equipped vehicle during kick down conditions.     

Force control compensation method with variable load stiffness and damping of the hydraulic drive unit force control system

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.     

Realization of direct flow control with load pressure compensation on a load control valve applied in overrunning load hydraulic systems

This paper presents the realization of direct proportional flow control with load pressure compensation feature on a LCV (load control valve). Proportional flow control performance means the flow through the LCV is proportional to the pilot pressure in the control stroke. Proportional flow control decides the overrunning load lowering speed control performance of the whole system. The load pressure compensation feature means when the load pressure is too high, the flow of the LCV can be restricted about the maximum rated flow. The load pressure compensation feature is important to the safety of the system. That is because large flow means undesired fast lowering speed, which will cause accident in applications, especially those large mass overrunning load systems. In this paper, the flow control performance was simulated and the parameter relationship of the orifices was derived, which is the base for the optimizing of the compensation orifice. In addition, load pressure compensation feature was simulated and the compensation orifice size was optimized. Finally, an LCV built according to above methods was tested on a test rig. Experiment data validates the methods presented and the realization of direct flow control with load pressure compensation feature gives guidance for the direct flow control performance development of other valves.     

Adaptive robust motion trajectory tracking control of pneumatic cylinders with LuGre model-based friction compensation

Friction compensation is particularly important for motion trajectory tracking control of pneumatic cylinders at low speed movement. However, most of the existing model-based friction compensation schemes use simple classical models, which are not enough to address applications with high-accuracy position requirements. Furthermore, the friction force in the cylinder is time-varying, and there exist rather severe unmodelled dynamics and unknown disturbances in the pneumatic system. To deal with these problems effectively, an adaptive robust controller with LuGre model-based dynamic friction compensation is constructed. The proposed controller employs on-line recursive least squares estimation（RLSE） to reduce the extent of parametric uncertainties, and utilizes the sliding mode control method to attenuate the effects of parameter estimation errors, unmodelled dynamics and disturbances. In addition, in order to realize LuGre model-based friction compensation, the modified dual-observer structure for estimating immeasurable friction internal state is developed. Therefore, a prescribed motion tracking transient performance and final tracking accuracy can be guaranteed. Since the system model uncertainties are unmatched, the recursive backstepping design technology is applied. In order to solve the conflicts between the sliding mode control design and the adaptive control design, the projection mapping is used to condition the RLSE algorithm so that the parameter estimates are kept within a known bounded convex set. Finally, the proposed controller is tested for tracking sinusoidal trajectories and smooth square trajectory under different loads and sudden disturbance. The testing results demonstrate that the achievable performance of the proposed controller is excellent and is much better than most other studies in literature. Especially when a 0.5 Hz sinusoidal trajectory is tracked, the maximum tracking error is 0.96 mm and the average tracking error is 0.45 mm. This paper constructs an adaptive robust controller