A novel fully-integrated miniature six-axis force/torque sensor

This paper presents a new designed miniature six DOF （degree of freedom） force/torque sensor. This sensor is fully integrated with a micro DSP （digital signal processor）, so all the signal conditioning, A/D, decoupling, digital-signals serial output are performed in the sensor. Some experimental results are presented to demonstrate the capability of the proposed design. Finally, a neural network was used for decoupling the interacting signals, compared with the conventional method using the inverse matrix, this new method is more accurate.

Optimal design and experiment research of an orthogonal-parallel six-axis force/torque sensor

A novel orthogonal-parallel six-axis force/torque sensor is studied based on a modified Stewart platform architecture,and the optimal design and experiment research of the sensor are discussed.Firstly,the model of orthogonal parallel six-axis force/torque sensor based on improved Stewart platform architecture and its static mathematical model are proposed.Secondly,according to the actual working condition of the sensor,the sensor is optimized and the optimal solution is obtained.Then,the experimental prototype and calibration system is developed.Finally,the superiority of the sensor structure and the effectiveness of the optimization method are verified by calibration experiments.The results of the proposed method are useful for the further research and application of the orthogonal-parallel six-axis force/torque sensor.

Development and Calibration of a Hyperstatic Six-component Force/Torque Sensor

The six-component force/torque sensor has become one kind of the most important sensors with the ability of measuring all the external forces and torques. A novel hyperstatic six-component force/torque sensor based on the Stewart platform structure, which can be used for the force measurement of the robot wrist, is proposed, and its structural optimal design, finite element analysis and calibration experimentation is presented. The characteristic of the sensor structure is analyzed in comparison with the traditional Stewart platform-based sensor. The mathematical expression of the sensor＇s force mapping matrix is introduced. The condition number and generalized amplifying coefficient defined by singular values of force Jacobian matrix are used to evaluate the performances of isotropy and sensitivity of the sensor respectively. The optimal design of the sensor structure is performed with the objective of achieving high measurement sensitivity and good isotropy. The sensor prototype is fabricated, and the static and dynamic characteristics of the sensor are analyzed with finite element analysis software package ANSYS. The calibration device is manufactured, and the data acquisition and processing system is developed. The theoretical and experimental study of the static calibration of the sensor prototype is carried out. The results of simulation analysis and calibration experimentation prove the feasibility of the hyperstatic sensor structure, and the contents of this paper possess theoretical significance and engineering value for the further research and practical application of the six-component force sensor.

Force/Moment Isotropy of 8/4-4 Parallel Six-Axis Force Sensor Based on Performance Atlases

A six-axis force sensor with parallel 8/4-4 structure is introduced and its measurement principle is analyzed.Based on condition numbers of Jacobian matrix spectral norm of the sensor,the relationship between the force and moment isotropy and some structural parameters is deduced.Orthogonal test methods are used to determine the degree of primary and secondary factors that have significant effect on sensor characteristics.Furthermore,the relationship between each performance index and the structural parameters of the sensor is analyzed by the method of the atlas,which lays a foundation for structural optimization design of the force sensor.

Dynamic analysis of double-layer and pre-stressed multi-limb six-axis force sensor

In order to adapt to the specific task, the six-axis dynamic contact force between end-effectors of intelligent robots and working condition needs to be perceived. Therefore, the dynamic property of six-axis force sensor which is installed on the end-effectors of intelligent robots will have influence on the veracity of detection and judgment to working environment contact force by intelligent robots directly. In this paper, dynamic analysis to double-layer and pre-stressed multi-limb six-axis force sensor is conducted. First, the structure of the sensor is introduced, and the limb number is confirmed by introducing the related definitions of convex analysis. Then, based on vibration of multiple-degree-of-freedom system, a mechanical vibration simplified model of double-layer and pre-stressed multiple limb six-axis force sensor is set up. After that, movement differential equations of sensor and the response of analytical expression are deduced, and the movement differential equations is solved. Finally, taking the double-layer and pre-stressed seven limb six-axis force sensor as an example, numerical calculation and simulation of deriving result is conducted, which verify the correctness and feasibility of the theoretical analysis.

Miniature 6-axis force/torque sensor for force feedback in robot-assisted minimally invasive surgery

In order to restore force sensation to robot-assisted minimally invasive surgery(RMIS),design and performance evaluation of a miniature 6-axis force/torque sensor for force feedback is presented.Based on the resistive sensing method,a flexural-hinged Stewart platform is designed as the flexible structure,and a straightforward optimization method considering the force and sensitivity isotropy of the sensor is proposed to determine geometric parameters which are best suited for the given external loads.The accuracy of this method is preliminarily discussed by finite element methods(FEMs).The sensor prototype is fabricated with the development of the electronic system.Calibration and dynamic loading tests for this sensor prototype are carried out.The working ranges of this sensor prototype are 30 N and 300 N·mm,and resolutions are 0.08 N in radial directions,0.25 N in axial direction,and 2.4 N·mm in rotational directions.It also exhibits a good capability for a typical dynamic force sensing at a frequency close to the normal heart rate of an adult.The sensor is compatible with surgical instruments for force feedback in RMIS.

Design and calibration of spoke piezoelectric six-dimensional force/torque sensor for space manipulator

The large manipulator outside the space cabin is a multi-degree of freedom actuator for space operations.In order to realize the automatic control and flexible operation of the space manipulator,a novel spoke structure piezoelectric six-dimensional force/torque sensor with redundancy ability,high stiffness and good decoupling performance is innovatively proposed.Based on the deformation coordination relationship,the redundancy measurement mechanism is revealed.The mathematical models of the sensor with and without branch fault are established respectively.The finite element model is established to verify the feasibility of structure and redundancy measuring principle of the sensor.Depending on the theoretical analysis and simulation analysis,the prototype of the sensor is developed.Static and dynamic calibration experiments are carried out.The actual output voltage signal of the six-dimensional force/torque sensor is collected to establish the equation between the standard input applied load and the actual output voltage signal.Based on ant colony optimized BP algorithm,performance indexes of the sensor with and without branch fault are analyzed respectively.The experimental results show that the spoke piezoelectric sixdimensional force/torque sensor with the eight-point support structure has good accuracy and reliability.Meanwhile,it has strong decoupling characteristic that can effectively shield the coupling between dimensions.The nonlinear errors and maximum interference errors of decoupled data with and without branch faults are less than 1% and 2%,respectively.The natural frequency of the sixdimensional force sensor can reach 2856.45 Hz and has good dynamic characteristics.The research content lays a theoretical and experimental foundation for the design,development and application of the new six-dimensional force/torque sensors with redundancy.Meanwhile,it will significantly improve the research level in this field,and provide a strong guarantee for the smooth implementation of force feedback control of the space station manipulator project.

Ground demonstration system based on in-orbit assembly oriented manipulator flexible force control

To eliminate the load weight limit of carrier rockets and reduce the burden on support structures,in-orbit assembly is a key technology to make design of scattering a large diameter telescope into submirror modules,which requires smooth operation of assembly robots,and flexible force control technology is necessary. A ground demonstration system is presented for in-orbit assembly focusing on flexible force control. A six-dimensional force/torque sensor and its data acquisition system are used to compensate for gravity. For translation and rotation,an algorithm for flexible control is proposed. A ground transportation demonstration verifies accuracy and smoothness of flexible force control,and the transportation and assembly task is completed automatically. The proposed system is suitable for the development of in-orbit assembly robots.

用于高精度电动钻孔器的复合力传感器设计

设计了一种用于高精度电动钻孔器的复合力传感器,能够为电动钻孔器的转速及进给速度的自动调节提供准确有效的反馈判断参数。传感器安装在电动钻孔器的驱动轴和钻头之间,能够将钻头受到的扭矩和沿轴线方向的阻力实时反馈给控制机构。传感器的旋转轴和弹性体采用一体式结构,通过力学计算确定了其应变与扭矩和轴向阻力成近似线性关系;利用有限元方法分析了弹性体的应变分布、扭力和阻力之间的相互影响和极限形变;通过实验,得到了传感器的解耦矩阵。实践表明,传感器扭矩信号的灵敏度可达2.6 mV·V^(-1),综合测量误差≤0.5%,阻力信号的灵敏度可达2.2 mV·V^(-1),综合测量误差≤2%。传感器安装在电动钻孔器上,能够将扭矩信息和阻力信息实时反馈给控制机构,有助于电动钻孔器及时和准确地对转速和进给速度进行主动调节。

一种基于TMR技术的力矩传感器设计

针对电助力自行车的动态力矩测量,设计一种基于穿隧磁阻(Tunneling Magneto Resistive,TMR)的一维力/力矩的检测系统以及一种无线数能同传系统,用于测量人体在骑行过程中,施加在中轴上的力矩,并实现力矩传感器信号的多级放大以及信号采集软件和硬件的设计。应用控制器局域网络(Controller Area Network,CAN)总线接口与外部上层控制器通信,实时计算和传递电助力自行车骑行过程中的力矩信号。实验结果证明,该传感系统能够完成脚底踩踏力矩信息的实时采集、计算与通信。

压磁效应及其在传感器中的应用

铁磁性材料受到机械力的作用时 ,它的内部产生应变 ,导致导磁率发生变化 ,产生压磁效应。利用压磁效应可以开发出各种压磁式传感器 ,包括压磁式非接触扭矩传感器 ,压磁式非晶带加速度传感器和压磁式压力传感器等。文章重点介绍上述传感器的原理 。

平板式压电六维力/力矩传感器的研制

针对弹性体式六维力/力矩传感器存在的技术瓶颈,提出了一种新型平板式压电六维力/力矩传感器。首先,介绍了传感器的结构和工作原理,提出了两种石英晶片组布置方案。然后,推导了两种布置方案的传感器的数学模型,并建立了有限元模型,仿真得到了两种结构传感器输出的电荷灵敏度、维间干扰、固有频率等重要参数,确定了石英晶片组相对合理的布置方式。最后,对传感器进行了静态和动态标定。研究结果表明:传感器结构简单合理、仿真分析方法和数学模型正确,固有频率>25 kHz,使用退耦矩阵后传感器的维间干扰<3%,基本满足传感器的设计指标。

基于六维力传感器的工业机器人末端负载受力感知研究

针对工业机器人末端负载与外界环境接触力的感知需求,在机器人法兰与负载之间设置六维力传感器,并研究一套标定与计算方法,综合考虑负载重力作用、传感器零点、机器人安装倾角等因素,利用不少于3个机器人姿态下的力传感器数据,可求得传感器零点、机器人安装倾角、负载重力大小、负载重心坐标等参数,进一步可消除传感器零点及负载重力对受力感知的影响,精确得到机器人末端负载所受的外部作用力与力矩.实验得到对于重量从320 N到1 917 N的负载,在静态条件下,感知外力的误差在负载重力的0.28%以内,感知外力矩的误差在负载对传感器力矩的0.59%以内.

基于Stewart平台的六维力/力矩传感器各向同性的解析研究

对基于 Stewart平台的六维力 /力矩传感器的雅可比矩阵进行了解析推导 ,用解析的方式求出它的奇异值。并对基于矩阵谱范数的条件数进行了研究 ,得到传感器的各向同性与其结构尺寸间的解析关系 。

面向应用需求的力/力矩传感器技术发展动向

本文论述了面向应用需求的力/力矩传感器发展现状和趋势,从机器人学、特种机器人及机器人化机器几个方面讨论了力传感器研究的现状和应用需求,并指出力传感技术发展的总趋势为利用新材料、新工艺实现微型化、集成化,利用新原理、新方法实现更多种类的信息获取,再辅以先进的信息处理技术提高传感器的各项技术指标,以适应更广泛的应用需求。

五维力测力平台的研制

介绍了一种 5维力测力平台的原理 ,结构以及硬件设计和软件功能 ,这种结构的 5维力具有精度高 ,频响好的特性。

串并联微动机构的运动学分析

本文提出了一种新颖的用于微动操作的“串并联”机构，利用矢量运算的方法，简便地分析了它的运动学特性，阐述了此机构的一些特点，并根据讨论的结果，设计出了微操作手的样机．

应变式扭矩传感器的设计研究

扭矩传感器应用广泛,对其研究十分必要。针对典型弹性元件理论分析的基础上,提出了5种应变式扭矩传感器的实现形式,并对其应变、变形及扭振固有频率进行了理论研究,分别建立了对应的力学模型。依据所建立的力学模型,以扭转变形最小为目标函数,进行了弹性元件几何尺寸的优化设计,并分析了不同形式的扭矩传感器性能差异。最后,设计了一种应变式扭矩传感器,并对其进行了有限元仿真,仿真结果很好地验证了所建立的力学模型。故所建立的力学模型可以较好地解决应变式扭矩传感器的设计计算问题。

集成式五维微力/力矩传感器的研究

五维微力 /力矩传感器应用于微装配机器人操作末端的微力觉感知 ,能够同时测量三个方向的微力Fx、Fy、Fz 和两个方向的微力矩Mx 和My;测力量程± 1N ,测力矩量程± 0 .0 5N·m ;放大电路集成在传感器的本体中。应用力学理论对本体进行理论分析 ,推导出计算公式 ,求出本体的应变 ;并采用有限元分析软件进行仿真 ,分析应变 。

一种二维力/扭矩传感器的设计

针对用于测试旋转型行波超声电机工作状态下定子、转子摩擦力／力矩的特殊要求，并利用有限元法对传感器进行了结构优化，设计了组合式二维传感器，该传感器的一维测量法向正压力；另一维测量扭矩。法向力的量程为0-200N，准确度为0．09％；扭矩的量程为0-2N·m，准确度为0．41％。满足了试验要求。