大行程柔顺并联机构的系统创成与控制方法研究

Compliant mechanisms can generate ultra-high resolution and repeatability for the high precision positioning system, which is significantly applied in the ultra-precision manufacturing engineering and the micro-nano engineering. However, those mechanisms can not contribute a wide motion range simultaneously due to the limited deformation of flexible joints, which can not satisfy the demands of the trans-scale high-precisoin positioning. Based on the superelasticity of the functional material, i.e. the shape memory alloy, the conceptual design of novel ultra-wide range compliant mechanisms is proposed in this reseach, which can output macro stroke and micro precision simultaneously. The proposed concept will be widely utilized in the precision positioning, the micro-nano manufacturing and assembly etc. Several key research issues are involved in this proposed research, i.e. the mathematics modeling, charactersistics analysis and multi-objective optimization of the wide range compliant mechanisms based on the superelasticity effect of the shape memory alloy; system modelling calibration and absolute accuracy compensation strategy of the wide range compliant mechanisms based on the enhanced pseudo-rigid-body model; controller design and synthesis of the wide range compliant mechanisms based on sub-workspace division and robust gain scheduling control; active vibration suspension and vibration suspension optimization of the proposed system based on flexible piezoelectric patches. This research proposal is attempting to solve several critical scientific issues and technique bottlenecks which will provide detailed references and solid fundamentals to the research of novel high precision actuation/transmission machinery with "structure-sensing-control" integration features.

柔顺机构能够提供极高的运动分辨力和重复定位精度，在超精密制造/微纳工程中有着极为重要的应用，但受到柔顺关节变形量的限制，无法提供大运动行程，难以满足跨尺度的高精度定位的系统需求。本课题将利用形状记忆合金的超弹性效应，提出超大行程柔顺机构的概念设计，使得柔顺机构能够同时实现宏观的行程和微观的精度，在精密定位、微纳工程等领域将具有十分广阔的应用前景。本课题的主要关键技术涉及：形状记忆合金超弹性效应下柔顺机构模型表述、特性分析与多目标结构优化；基于改进的伪刚体模型的大行程柔顺机构系统模型修正与绝对定位精度补偿；基于子空间划分与鲁棒变增益控制的大行程柔顺机构控制器设计与综合；基于柔性压电陶瓷片的柔顺机构主动抑振与抑振优化等问题。本课题研究内容能够解决目前柔顺机构的若干瓶颈问题，将为新型精密驱动/传动机械的"结构-传感-控制"一体化的研究，提供详实的科学依据和技术基础。

高精度传动技术是现代高端精密装备的重要支撑性技术。传统柔顺并联机构由于受到柔性铰链转角范围的限制，仅能提供微米级的工作空间。为了解决这一问题，本课题开展了大行程柔性铰链及其所构建而成的平面柔顺并联机构的关键技术研究。对大行程柔顺铰链的结构设计、力学建模、性能分析，柔顺并联机构的系统设计、闭环轨迹跟踪控制等方面进行了深入分析，实现了平面柔顺并联机构在大范围内的高精度运动。基于形状记忆合金（SMA）材料的超弹性特性，设计了一种新型大行程切口型柔性铰链。采用Brinson本构模型描述了SMA材料超弹性过程中的应力-应变关系，通过单轴拉伸实验获得了SMA材料的本构参数。基于非线性梁理论和Brinson本构模型建立了几何非线性和材料非线性条件下的超弹性柔性铰链的末端变形模型。采用有限元分析和实验验证了超弹性柔性铰链变形模型的准确性。分析了超弹性柔性铰链的几何参数、切口形式对其变形特性的影响。为了获得综合转动性能最优的柔性铰链，采用非支配遗传算法NSGA-II对大行程柔性铰链的结构参数进行了多目标优化。同时以规则工作空间内的全局条件数为指标对平面3-PRR并联机构的构型参数进行了优化。利用优化得到的大行程柔性铰链的几何参数和并联机构的构型参数，设计并建立了一套大行程3-PRR柔顺并联机构。提出了一种基于有限时间扰动观测器的积分滑模控制算法，提高了直线超声电机位移平台的轨迹跟踪性能。为了消除大行程柔顺并联机构运动过程中不确定因素的影响，提出了一种基于扰动观测器的逆运动学轨迹跟踪控制策略，通过轨迹跟踪实验验证所设计的轨迹跟踪算法的有效性和大行程柔顺并联机构的运动性能。