【作者】 王洪艳；

【导师】 赵克定；

【作者基本信息】 哈尔滨工业大学 ， 机械电子工程， 2008， 博士

【摘要】 气液联控伺服系统是将可压缩性小、粘度较大的液体介质引入到常规气压伺服系统中并进行控制而构成的一种新型的气、液介质复合控制系统。它将气体介质“柔”的特性与液体介质“刚”的特性融为一体,即保持了气动系统所具有的快速性的优点,又具有较好的刚度。此特点对于机器人的柔顺力控制非常有利,故此本课题针对气液联控伺服系统进行了柔顺力控制的研究。在查阅大量国内外相关文献的基础上,总结了气液联控伺服系统的发展背景及研究现状。对柔顺力控制的发展现状进行了分析,阐述了常用的柔顺力控制策略及其控制中的关键问题。通过对国内外相关研究的分析,确定了本文的主要研究方向。与其它气压伺服系统相比,PWM电-气开关/伺服系统具有更适用于连续控制及造价较低等优点,因此得到了广泛的应用。但PWM气压伺服系统具有严重非线性,建模困难,这就阻碍了它的发展。为此本文应用非线性PWM平均方法将原离散多输入模型转换为连续单输入模型,简化后的模型更有利于对系统的研究。阻抗控制能够实现位移与力的统一控制,是实现柔顺力控制的主要理论依据之一。论文将基于力和基于位置的阻抗控制方法分别应用于气液联控系统中,通过仿真分析两种阻抗控制性能及阻抗参数变化对系统控制性能的影响规律。由于基于位置的阻抗控制性能更好,更易于应用于柔顺力控制中,故此本文重点针对基于位置的阻抗控制进行研究。内环位置控制器的性能在一定程度上影响柔顺力控制的性能,为进一步提高系统性能,本文应用非线性控制理论对气液联控系统的状态方程进行了研究,提出了滑模变结构控制策略。根据相对阶的定义判断系统阶次,在此基础上设计了三阶滑模面变结构控制器,并对其进行了仿真研究。但该三阶滑模控制器所含参数复杂且相互之间耦合,控制效果并不理想。故此进行了滑模面的降阶,设计了二阶滑模面变结构控制器,并对其进行了仿真研究,仿真结果表明滑模变结构控制改善了系统的快速性,提高了系统的跟踪性能。柔顺力控制过程中,环境参数的已知与否对系统控制策略的选取有很大影响,并直接影响到控制的效果。本文将环境参数归纳为三种情况:环境参数已知时不变、环境参数未知时不变、环境参数未知时变。分别针对此三种情况提出了模糊阻抗控制方法、直接自适应控制方法、间接自适应控制等方法。实现了不同环境参数下的柔顺力控制。最后,搭建了气液联控柔顺力控制系统实验台,编制了计算机控制软件和完整的实验方案。通过对系统的仿真和实验研究证明,本文设计的实验系统和控制软件是成功的,阐述的理论和观点是正确的,设计的控制器是合理可行的。论文的研究为气液联控系统进一步应用到气动工业机器人的柔顺力控制中奠定了基础。更多还原

【Abstract】 Pneumatic hydraulic combination control (PHCC) servo system is a new-style composite control system, in which the liquid medium with low compressibility and high viscosity is led into a normal pneumatic servo system and controlled in closed-loop simultaneously. The system compounds the characteristic of“flexibility”in pneumatic system and“rigidity”in hydraulic system, and possesses the excellence of speediness and rigidity, which is good to compliant control of robot. So the paper research compliant control of PHCC servo system.After synthesizing numerous related literatures and reference materials at home and abroad, the research and development situation of pneumatic servo system in recent years is summed up. Then the development situation of compliant control is analyzed. The common control strategy and the key problem in compliant control are detailed.Compared with the other pneumatic servo system, the PWM electricity-pneumatic on/off servo system is applied broadly for its excellence of more fit to continuous control and low cost. But the serious nonlinearity and hard modeling prevented its development. So applied nonlinear PWM average method, the paper changes the model from disperse multi-input to the single-input, which advantaged research of the system.The unionize control of position and force can be realized by impedance control, which is one of main compliant force control theory. The paper introduces the method of impedance control, and applied the force-based impedance control and position-based impedance control respectively to PHCC servo system. Then analysis control performance and impedance parameter by the simulation of two kind impedance. For the better performance and easy application to compliant control, the paper emphases the research on the position-base impedance control.The performance of inner position controller influences the performance of compliant control. To improve the performance of system, the paper applied nonlinear control theory to research the state equation and put forward the variable structure control strategy. Based on the rank of system, which judge by define of relative rank, the three rank variable structure controller is designed. Then computer simulation is carried out. But the performance is not ideal because of the coupling of complex parameters. So the work of lower rank of sliding surface is developed and the two rank variable structure controller is designed. Then computer simulation is carried out, too. Simulation results indicate the speediness and tracking ability of the controller.In the process of compliant force control, the chose of control strategy is affected by the knowability of environment parameters and influent the performance of control. The paper reduces the situation of environment to three case: environment knowable, environment non-knowable and time invariant, environment non-knowable and time variant. Then the control method of fuzzy impedance control, direct adaptive control, and indirect adaptive control is designed respectively to the three situations, which realized the compliant force control in differ environment parameter situations.Finally, the pneumatic-hydraulic compliant force control system is build. the computer control software and the whole experiment scheme is put forward. The simulation and experiment results of system proved the designed experiment system and control software in this paper are successful, and the theories and views set forth are right, and the controller designed are reasonable and feasible.The research of paper established foundation of further application to compliant force control of pneumatic industry robots.更多还原