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基于气浮原理的多维力标定方法及系统的研究

Research on Multi-axis Force Calibration Method and System Based on the Flotation Principle

【作者】 黄斌

【导师】 余晓芬;

【作者基本信息】 合肥工业大学 , 精密仪器及机械, 2012, 博士

【摘要】 三维柔性触觉触感器标定时对加载方式有其特殊要求。以砝码加载为代表的开环加载标定方式操作较为繁琐,加载装置中的误差直接传递到加载力中,加载精度难以提高;采用六维力或三维力传感器实时测量标定力的闭环加载标定方式操作简便,加载精度不受加载装置误差的影响,但加载精度受制于六维力/三维力传感器的测量精度。基于六维力测量的柔性触觉传感器标定方案的关键技术难点在于六维力测量精度。鉴于现有的六维力传感器测量精度难以满足柔性触觉阵列传感器标定精度的要求,本文在研究柔性触觉阵列传感器的标定方法中,提出了一种旨在避免多维力测量时维间耦合、提高测量精度的气浮式测力思想:通过测量喷嘴——浮板机构中气流参数来测量浮板上的作用力的大小,在理论研究的基础上设计了一种可用于柔性触觉传感器标定的气浮式六维力测力平台样机,理论研究与实验结果表明,气浮式六维力测力平台具有很高的测量精度,从而使得基于六维力测量的柔性触觉阵列传感器标定方案得以实现。论文主要内容以及创新性工作有以下几个方面:(1)分析了柔性触觉传感器标定的特殊要求以及普通加载装置误差,针对高精度的柔性触觉阵列传感器,提出了基于气浮式六维力测量的柔性触觉阵列传感器标定方案;(2)对压力式喷嘴浮板机构的基本理论进行了较为系统的研究,建立了喷嘴-浮板机构数学模型,研制了喷嘴-浮板机构实验装置,实验验证了理论研究的正确性;(3)用FLUENT软件仿真分析了喷嘴节流孔直径、承压腔直径和深度、喷嘴外径以及不同气膜厚度和供气压力对喷嘴-浮板机构静特性的影响规律,并根据仿真数据对喷嘴结构尺寸提出了优化设计方案;(4)设计了一种气浮式六维力测力平台,研究得出了气浮式六维力测力平台的数学模型,研制了气浮式六维力测力平台样机;(5)提出了基于浮板重力加载的气浮式六维力测量平台标定方法,解决了气浮式六维力测量平台的标定难题。本文经过实验得出以下结论:气浮式测力平台测力时不存在维间耦合现象,符合理论预期;空间力测量的误差为:力的大小误差<0.2%,力的方向误差<0.5°,力的作用点误差≤±0.05毫米,满足柔性触觉阵列传感器标定的要求。气浮式测力方法及气浮式六维力传感器,其意义并不仅限于解决了柔性触觉传感器标定问题。作为一种新型测力方法,气浮测力在多维力测量领域具有独特应用前景,尤其是气浮式多维力测量方法在测量精度上的突破,对许多相关领域具有重要意义,本文研究的成果对各种气浮式多维力传感器的设计具有普遍应用价值。

【Abstract】 Three-dimensional flexible tactile sensor has its own special requirements for loading method when it is calibrated. The open-loop load calibration method represented by weight load is more complicated to operate. The loading device error is directly delivered to the load force, which leading to the load accuracy is difficult to improve; it is easy to operate in real-time measurement of calibration force for closed-loop load calibration method by using six-axis force/three-axis force sensor, and the load accuracy is only subject to the accuracy of six-axis force/three-axis force sensor which isn’t affected by the loading device error.The difficulty of flexible tactile sensor calibration based on six-axis force is the measurement accuracy of six-axis force. In view of the existing six-axis force sensor measurement accuracy is difficult to meet the calibration accuracy requirements of flexible tactile sensor array, this paper presents a flotation-type force measurement thought which designed to avoid coupling between the dimension and improve easurement accuracy in multi-axis measurements:the force on the floating plate could be measured by measuring the gas parameters of nozzle-floating plate mechanism, and designs a prototype of flotation-type six-axis force measurement platform that can calibrate the three-dimensional flexible tactile sensor. Theoretical studies and experimental results show that flotation-type six-axis force measurement platform has a high measurement accuracy, so the three-dimensional flexible tactile sensor calibration based on six-axis force can be achieved.The main content and innovative work of the paper is in the following areas:(1) the special requirement of flexible tactile sensor calibration and loading device error is analyzed, a program of flexible tactile sensor array calibration based on flotation-type six-axis force measurement is proposed in connection with high-precision flexible tactile sensor array;(2) a systematic study on the basic theory of the pressure nozzle-floating plate mechanism is carried out, a mathematical model of nozzle-floating plate mechanism is established, an experimental device of nozzle-floating plate mechanism is developed, and the experiments verify the correctness of the theoretical study;(3) The affect of nozzle orifice diameter, the diameter and the depth of the pressure chamber, nozzle diameter and gas film thickness and gas pressure on the static characteristics of the nozzle-floating plate mechanism is analyzed with Fluent software simulation, and an optimization scheme of nozzle structure size is proposed according to the simulation data;(4)a flotation-type six-axis force measurement platform is designed and made, a mathematical model of nozzle-floating plate mechanism platform is researched;(5)a calibration method of flotation-type six-axis force measurement based on gravity load of floating plate and the calibration problem of flotation-type six-axis force measurement platform is solved. In this paper, we draw the following conclusions:flotation-type force measurement platform contains no coupling between the dimension which is consistent with theoretical expectations; the space force measurement error is:the size of the force error <0.2%, direction of the force error <0.5°, Point error of the force≤±0.05mm, and they meet the calibration requirements of flexible tactile sensor array.The significance of flotation force measurement methods and flotation-type six-axis force sensor is not limited to solve the problem of three-dimensional flexible tactile sensor calibration. As a new force measurement approach, flotation force measurement has a unique prospect in the field of multi-axis force measurement, The breakthrough of the flotation-type multi-dimensional force measurement on the measurement accuracy has a significance on many related fields.The results of research have a universal application on a variety of flotation multidimensional force sensor design.

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