Three-Dimensional Conjugate Tooth Surface Design and Contact Analysis of Harmonic Drive with Double-Circular-Arc Tooth Profle

A three-dimensional conjugate tooth surface design method for Harmonic Drive with a double-circular-arc tooth profle is proposed. The radial deformation function of the fexspline (FS), obtained through Finite Element (FE) analysis, is incorporated into the kinematics model. By analyzing the FS tooth enveloping process, the optimization of the overlapping conjugate tooth profle is achieved. By utilizing the hobbing process, the three-dimensional machinable tooth surface of FS can be acquired. Utilizing the coning deformation of the FS, simulations are conducted to analyze the multi-section assembly and meshing motion of the machinable tooth surface. The FE method is utilized to analyze and compare the loaded contact characteristics. Results demonstrate that the proposed design method can achieve an internal gear pair consisting of a circular spline with a spur gear tooth surface and the FS with a machinable tooth surface. With the rated torque, approximately 24% of the FS teeth are engaged in meshing, and more than 4/5 of the tooth surface in the axial direction carries the load. The contact patterns, maximum contact pressure, and transmission error of the machinable tooth surface are 227.2%, 40.67%, and 71.24% of those on the spur gear tooth surface, respectively. It clearly demonstrates exceptional transmission performance.

STUDY ON SENSOR-BASED CONTROL METHOD FOR HARMONIC DRIVE SYSTEM

A new type of robust traje ctory tracking control for harmonic using joint torque sensor and joint acceleration sensor information is concerned with.Joint torque sensor information is used to compensate the uncertainty of link and load parameters. Joint acceleration feedback control will enhace the robustness of the driving system, resist the dynamic uncertainties and disturbing torque acted on the joint axis within definite bandwidth, improve the joint tracking performance, and resist the vibration of the load side of the harmonic drive system. Experimental studies are carried out and comparison of several controllers , such as PD and sensor- based control, the experimental results clearly illustrate the effectiveness of the proposed methods.

Tooth Position and Deformation of Flexspline Assembled with Cam in Harmonic Drive Based on Force Analysis

Deformation of the flexspline is the basis of analyzing tooth trajectory and designing tooth profile.Considering the tooth influence on the position of equivalent neutral layer,a piecewise method for calculating the deformation of flexspline assembled with a cam wave generator is presented in this paper.Firstly,a mechanic model of a ring of uniform thickness in contact with a rigid cam is established.The displacements of the ring inside and outside an unknown wrapping angle are determined by the geometric constraints of the cam profile and the equilibrium rela-tionship,respectively.Meanwhile,the wrapping angle is solved according to the boundary conditions.The assembly forces are derived to investigate the circumferential elongation and strain.Then,considering the tooth effects on the neutral layer of flexspline,the tooth is positioned on the equivalent neutral layer,which is the non-elongation layer within one gear pitch but offset from the geometric mid-layer.The equivalent neutral layer is positioned by the empirical formula of the offset ratio,which is summarized by the orthogonal simulation on finite element models of racks.Finally,finite element models of a ring-shaped and a cup-shaped flexspline assembled with elliptical cam are established to verify the effectiveness and accuracy of the piecewise method.The results show that,compared with the geometric method,the tooth positioning deviation calculated by the piecewise method can be reduced by about 70%with a more accurate deformation description from the geometric condition and mechanic condition inside and outside the wrapping angle.

Impulse Controller Design of a Harmonic Drive System with Friction

A friction model was established for impulse control design in a precision control system. First, the physical characteristics of the impulse in momentum, such as motion and energy, were analyzed and formulated. Then, experimental response to a new pulse with two harmonic expansions was studied. The first harmonic is the main pulse to drive the arm, and the second harmonic has two functions： its first half helps the main pulse eliminate the dead zone, and its second half, a negative pulse, stops the arm motion quickly. Finally, an impulse feedback controller was developed. Comparison between simulation and experiments shows the effectiveness of the proposed controller.

Torque estimation for robotic joint with harmonic drive transmission based on system dynamic characteristics

In the applications of joint control and robot movement,the joint torque estimation has been treated as an effective technique and widely used.Researches are made to analyze the kinematic and compliance model of the robot joint with harmonic drive to acquire high precision torque output.Through analyzing the structures of the harmonic drive and experiment apparatus,a scheme of the proposed joint torque estimation method based on both the dynamic characteristics and unscented Kalman filter(UKF)is designed and built.Based on research and scheme,torque estimation methods in view of only harmonic drive compliance model and compliance model with the Kalman filter are simulated as guidance and reference to promote the research on the torque estimation technique.Finally,a promoted torque estimation method depending on both harmonic drive compliance model and UKF is designed,and simulation results compared with the measurements of a commercial torque sensor,have verified the effectiveness of the proposed method.

Safety and Performance of Harmonic®HD 1000i Shears in Thoracoscopic Procedures: A Retrospective Study

Background: Ultrasonic energy devices are utilized for transection, incision, and hemostasis in traditional open and laparoscopic procedures. The Harmonic HD 1000i Shears, designed to deliver a precise amount of thermal energy during tissue transection and vessel sealing, has been utilized in many specialties. This study aimed to confirm real-world safety and performance of the Harmonic device in two thoracoscopic procedures: lobectomy and segmentectomy. Methods: The primary endpoint of this retrospective, observational, single-arm study was rate of post-operative blood transfusions related to study device or procedure. Secondary endpoints included occurrence of intra- and post-operative adverse events (AEs) or complications device- or procedure-related, and rate of required additional hemostatic measures. Adults included those who underwent thoracoscopic lobectomy or segmentectomy where HD 1000i shears were used while excluding those where additional advanced energy devices were used. The study was conducted at Severance Hospital, Yonsei University Health System, South Korea from May 1, 2018, to November 30, 2020. Results: Subjects included n = 766 lobectomies (mean age 63.79, 52% male) and n = 215 segmentectomies (mean age 63.19, 54% male). Estimated blood loss was 50 mL (0 min, 3200 max) and 20 mL (0 min, 800 max), intraoperative transfusion rate 0.001% and 0%, intraoperative complication/AE rate 1% and 2%, and post-operative complication/AE rate 9% and 4% in the lobectomy and segmentectomy groups, respectively. Median operative times were 108 min. (35 min, 395 max) for lobectomies and 105 min. (32 min, 574 max) for segmentectomies. Conclusion: Given the low rate of blood loss and intra- and post-operative complication/AE rates, HD 1000i can be used confidently for thoracoscopic pulmonary resection in adults.

The research of load spectrum between flexible gear and wave generator of harmonic drive

The harmonic drive is a kind of gear transmission that uses wave generator to produce controllable soft round elastic deformation and engages with rigid gear to transmit motion and power. The load distribution on the surface of the flexible gear and wave generator is an important parameter of studying the deformation of flexible gear and flexible bearing outside the wave generator and is also a necessary condition for studying the fatigue damage of flexible gear under alternating load. In this paper, a 3D model of 32-type 80：1 harmonic drive is build. Based on the generalized Hooke law, a hypothesis of load distribution which is proved to be validity by using finite element simulation is proposed on the interface of flexible gear and wave generator. On this base, the mathematic model and the quantitative calculation formula of the load distribution on the surface of the flexible gear and wave generator are proposed which provide a basis for the dynamic analysis and the fatigue damage of harmonic gear drive.

Harmonic Drive再添伺服马达减速器新产品

日本Harmonic Drive Systems日前在可将齿轮背隙(Backlash)控制在3分以下的伺服马达减速器“HPG系列”中，又增加了两款新产品。新推出的产品包括支持小容量马达(10～100W)的“型号11”和支持中容量马达(2k～15kW)的“型号65”。这样一来，HPG系列已达6种机型，可支持从10W到15kW的各种伺服马达。价格方面，型号11从44，300日元(约合人民币3400元)起，型号65从22万日元(约合人民币1．7万元)起。

Research on Influence Mechanism of Transmission Accuracy for Harmonic Drive Mechanism Considering Multi-factor Coupling

The influence mechanism of transmission accuracy for harmonic drive mechanism considering multi-factor coupling was studied. According to analysis of influence factors of transmission accuracy for harmonic drive mechanism, it was obtained that the transmission errors of harmonic drive mechanism include processing errors and installation errors. The transmission error is produced by eccentric vector, it directly affects the rotation angle of output shaft and it makes harmonic drive mechanism produce backlash. Then analyze the movement error caused by the rigid wheel machining error, the flexible wheel machining error, the assembly error of the rigid wheel and the flexible wheel, the wave generator component, and the comprehensive expression method of motion error generated by each error source was obtained. The performance test device of space drive mechanism was used to test, and the law of the transmission accuracy of harmonic drive mechanism with temperature, speed and assembly clearance was obtained. The test results show that the transmission accuracy of harmonic drive mechanism decreases with increasing temperature, and the speed has little effect on the transmission accuracy of harmonic drive mechanism;the assembly quality has a significant impact on harmonic drive accuracy.

考虑多源误差影响的谐波减速器传动误差建模与分析

为解决现有谐波减速器传动误差建模方法的不足,提出一种考虑装配误差、齿面误差的综合误差建模方法。该方法首先建立装配误差和齿面误差数学模型,并进行误差影响参数分析。其次,测量实验样机装配偏心量和歪斜角度,基于模型得到对应偏心误差、歪斜误差模型理论值,齿面加工误差幅值按一般加工工况大小代入模型,得到对应加工误差模型理论值;然后,分别进行500 h、1500 h、3000 h时长的磨损实验,磨损后进行齿面形貌扫描和数据分析,得到对应的齿面形貌参数,基于模型得到对应的磨损误差模型理论值。最后,综合考虑多源误差影响,设置3组同型号样机,进行传动误差实验。实验结果表明:考虑装配偏心、歪斜和齿面加工等影响因素,传动误差的实验测量值与模型理论值误差在1.7~3.3%之间;综合考虑装配偏心、歪斜、齿面加工、齿面磨损等影响因素,在磨损500 h、1500 h、3000 h后传动误差的实验测量值与模型理论值误差分别在-3.45~2.07%、-5.88~-2.94%、1.33~5.33%之间。

微半球陀螺交直流混合电压切换驱动方法研究

微半球谐振陀螺的标度因数受阻尼不均匀程度和幅值控制精度影响,保证陀螺结构高度对称性的同时,驱动模态幅值控制精度也尤为重要。针对常见一倍频、1/2倍频电压驱动方式存在同频驱动噪声干扰和补偿相位延时导致微半球谐振陀螺驱动模态幅值控制精度较低,标度因数稳定性不足等问题,由于起振后陀螺等效驱动形式变化,基于微谐振子电压驱动原理构建了稳幅阶段微谐振子动态振动模型,提出了一种用于稳幅阶段的同相位二倍频电压驱动方式,设计了一种用于陀螺模态控制的交直流混合电压切换驱动方法,避免了相位补偿和同频驱动引起的幅值波动干扰。最后经力平衡模式仿真试验对比验证,混合电压切换驱动方法下驱动模态幅值控制精度提升5.882%,陀螺仪标度因数稳定性提高6.625%。

谐波驱动系统Back-stepping滑模控制研究

针对谐波传动系统动力学模型中存在的柔性变形、摩擦和运动误差等非线性因素。为了提高系统的传动精度,针对系统非线性刚度和静态误差因素进行了建模,并提出了一种Back-stepping滑模控制方法。利用Lyapunov稳定性理论,证明了闭环系统的误差是一致有界的。仿真结果表明,与PID控制相比,采用Back-stepping滑模控制,系统传动误差曲线峰峰值减小66.63%;负载端角速率误差曲线峰峰值减小77.35%。Back-stepping滑模控制能有效地补偿系统传动误差,抑制其负载端的速度波动,提高了系统的传动精度。

一种应用于半桥拓扑的斜率补偿电路

针对在峰值电流控制模式下半桥型开关电源存在次谐波振荡的问题,提出一种新型斜率补偿电路。该斜率补偿电路由少量外围常用器件构成,其补偿深度可由外围器件参数进行调节,与开关驱动信号完全保持同步。基于LTspice搭建斜率补偿电路的仿真模型,仿真结果表明,该电路补偿效果良好。样机实测结果也验证了该斜率补偿电路的有效性。所提电路适用于选择峰值电流模式但电源管理芯片内部没有斜率补偿电路的应用场合。

Optimization and experimental research on a new-type short cylindrical cup-shaped harmonic reducer

In order to obtain a new-type short cylindrical cup-shaped flexspline that can be applied to space mechanisms,the APDL language of ANSYS software was employed to develop a parameterized equivalent contact model between a flexspline and a wave generator. The validity of the parameterized equivalent contact model was verified by comparing the results of the analytic value of the contact model and the value calculated by the theoretical formula. The curvilinear trend of stress was obtained by changing the structural parameter of the flexspline. Based on the curvilinear trend of stress,multi-objective optimizations of key structural parameters were achieved. Flexspline,wave generator,and circular spline of a new 32-type short cylindrical cup-shaped harmonic reducer were designed and manufactured. A performance test bench to carry out tests on the harmonic reducer was designed. Contrast experiments were implemented to determine the efficiency of the new 32-type short cylindrical cup-shaped harmonic reducer and the conventional 32-type harmonic reducer under different conditions. The experimental results reveal that there is approximately equality in terms of efficiency between the new 32-type short cylindrical cup-shaped harmonic reducer and the conventional 32-type harmonic reducer. The volume of the flexspline of the new 32-type short cylindrical cup-shaped harmonic reducer is reduced by approximately 30% through multi-objective optimization. When the new 32-type short cylindrical cup-shaped harmonic reducer is used on the wheel of a rover prototype,the mass of the wheel hub is decreased by 0.42 kg. Test analysis of wheel motion verifies that the new 32-type short cylindrical cup-shaped harmonic reducer can meet the requirements regarding bearing capacity and efficiency.

基于有向图的强化学习自动驾驶轨迹预测

轨迹预测作为自动驾驶中的重要组成部分,旨在对车辆进行行驶估计,以便车辆根据行驶估计进行路径规划,从而做出安全准确的决策。首先,为提升车辆轨迹预测精度,采用有向图方法构建高清驾驶场景地图,有向图方法将地图信息矢量化,以便有效提取地图拓扑结构;其次,采用生成对抗模仿学习(GAIL)通过生成器与判别器的对抗博弈学习数据集驾驶策略,从而根据当前状态采取对应驾驶行为;最后,通过采样遍历得到多模态预测轨迹方案。在nuScenes运动预测数据集上进行仿真,量化结果显示相比于其他方法,K=5时,最小最终位移误差MinFDE_(5)提高了10.8%;K=10时,最小最终位移误差MinFDE_(10)提高了17.53%,最小平均位移误差MinADE_(10)提高了9.52%,失误率MissRate_(10)减少了28.26%。评估结果表明:生成的轨迹多模态符合场景基本结构,且准确度得到提高。

谐波减速器动力学特性与建模研究进展

谐波减速器具有相对质量低、结构紧和价格低廉等优点,广泛应用于空间机械臂关节设计.然而,谐波减速器的运动误差、刚度和摩擦3种动力学特性阻碍了空间机械臂关节指向精度、运动稳定度等性能指标的提升.为改善空间机械臂关节性能,国内外学者针对谐波减速器的运动误差、刚度和摩擦3种动力学特性开展了试验研究和机理分析,并建立了数学模型.本文从试验、机理和建模3个角度出发,系统论述关于谐波减速器的运动误差、刚度和摩擦3种动力学特性的最新研究成果,总结分析谐波减速器动力学特性和建模研究所面临的挑战以及未来发展的方向.

HEAT-SPINNING TECHNOLOGY OF HARMONIC GEAR-CLOSED FLEXSPLINE

Based on the experiments,heatspinning forming technology of the closed flexspline is studied and forming area and the laws of variations under the different technological parameters are gained.The semifinished flexspline products which can meet the quality demands have been successfully applied by matching the optimum technological parameters in the forming area.The research results create the conditions for spreading and applying the harmonic drive.

EMA摩擦前馈补偿的模糊自抗扰控制方法研究

针对谐波减速器伺服传动系统中摩擦对位置跟踪精度的影响,提出非线性摩擦建模及前馈补偿的方法,并结合模糊自抗扰控制器提高系统的控制精度。首先,给出机电执行器中永磁同步电机的数学模型,构建了谐波减速器的动力学模型,推导了摩擦力矩和转矩电流的关系。通过小波+卡尔曼联合滤波的方式获取了不同转速下对应的转矩电流,采用3次高斯拟合的方式得到了转速与转矩电流的函数关系。然后,根据自抗扰控制与模糊控制原理制定模糊规则,设计了模糊自抗扰控制器;根据拟合的数学函数在模糊自抗扰控制器中加入前馈补偿,抑制谐波减速器中非线性摩擦,提高系统控制精度。最后,通过实验与PI控制方式进行比较,实验结果表明,使用摩擦前馈补偿的模糊自抗扰控制方法较PI控制方法,在空载状态、负载状态下位置跟踪误差的均方根值减少了约180、176。

双圆弧谐波齿廓设计方法

针对双圆弧齿廓参数表征量多、圆弧尺度与设计参数关联度低的不足,提出一种根据柔轮齿与刚轮齿的相对运动特征设计双圆弧谐波齿廓的方法.首先,根据工况参数与柔轮中线变形曲线函数特征,分别在固定刚轮与固定柔轮两种形式下分析柔轮齿廓公切点的运动轨迹,提取其最大切向位移量作为齿顶圆弧的参数特征,并建立齿顶齿廓连续共轭条件及设计公切点倾角;在此基础上,根据给定的齿厚比与分度圆,分析切向位移量系数与公切线倾角对共轭啮合区间的影响,并结合连续共轭条件遴选合理的齿廓重要参数.其次,结合算例分析了传动比分别为80和100时柔轮齿与刚轮齿的啮合状态及性能,结果显示共轭齿廓能够实现连续啮合且不存在干涉.最后,结合有限元仿真校验齿廓啮合特性,结果表明:共轭存在角度为68.31°、单侧共轭齿对数为37对、啮合侧隙最大值小于10µm,有限元仿真与数值算例分析结果基本吻合,验证了本文设计方法的有效性.

基于Ansys带式输送机驱动装置架动态特性分析

带式输送机驱动电动机加载简谐激励即疲劳载荷时会引起疲劳破坏,当电动机激励频率接近驱动装置架的固有频率时系统会发生共振,而共振会引起冲击载荷甚至影响系统的安全运行。文中分析了振动对机架的影响,结合SolidWorks对驱动装置架进行建模,利用Ansys对驱动装置架进行静力学和动力学分析。通过对机架进行模态分析发现电动机支架连接处扭转和弯曲较大,优化改进了机架结构并进行谐响应分析,得到位移-频率响应曲线和应力-频率响应曲线,改进后的机架增加了固有频率并满足设备使用要求,为大型带式输送机驱动装置架开发设计提供了理论参考。