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Third-order point contact approach for five-axis sculptured surface machining using non-ball-end tools (Ⅰ): Third-order approximation of tool envelope surface

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science China(Technological sciences) 2010年第8期53卷 1904-1912页

作者： zhu limin1, ding han2 & XIONG YouLun2.1 {1. key laboratory of Mechanical System and Vibration, Shanghai Jiao Tong university, Shanghai 200240, China 2 {1. key laboratory of digital manufacturing equipment and technology, huazhong university of science and technology, wuhan 430074, China 1. state {1. {1. of Mechanical System and Vibration Shanghai Jiao Tong University Shanghai 200240 China2. State Key Laboratory of Digital Manufacturing Equipment and Technology Huazhong University of Science and Technology Wuhan 430074 China

In this paper, the geometric properties of a pair of line contact surfaces are investigated. Then, based on the observation that the cutter envelope surface contacts with the cutter surface and design surface along the characteristic curve and cutter contact (CC) path, respectively, a mathematical model describing the third-order approximation of the cutter envelope surface according to just one given cutter location (CL) is developed. It is shown that at the CC point both the normal curvature of the normal section of the cutter envelope surface and its derivative with respect to the arc length of the normal section can be determined by those of the cutter surface and design surface. This model characterizes the intrinsic relationship among the cutter surface, cutter envelope surface and design surface in the neighborhood of the CC point, and yields the mathematical foundation for optimally approximating the cutter envelope surface to the design surface by adjusting the cutter location.

关键词： five-axis NC machining rotary cutter cutter envelope surface normal curvature third-order point contact

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Cross-coupled controller design for triaxial motion systems based on second-order contour error estimation

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science China(Technological sciences) 2015年第7期58卷 1209-1217页

作者： ZHAO Huan zhu {1. ding han state {1. {1. of digital manufacturing equipment and technology Huazhong University of Science and Technology state {1. {1. of Mechanical System and Vibration Shanghai Jiao Tong University

The cross-coupled control(CCC)is widely applied to reduce contour errors in contour-following *** such situation,the contour error estimation plays an important ***,the linear or second-order estimation approach is adopted for biaxial motion systems,whereas only linear approach is available for triaxial *** this paper,the second-order contour error estimation,which was presented in our previous work,is utilized to determine the variable CCC gains for motion control systems with three *** integrated stable motion control strategy,which combines the feedforward,feedback and CCC controllers,is developed for multiaxis CNC *** results on a triaxial platform indicate that the CCC scheme based on the second-order estimation,compared with that based on the linear one,significantly reduces the contour error even in the conditions of high tracking feedrate and small radius of curvature.

关键词： cross-coupled controller contour error cross-coupled gains triaxial motion system computer numerical control (CNC)

Response Sensitivity Analysis of the Dynamic Milling Process Based on the Numerical Integration Method

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Chinese Journal of Mechanical Engineering 2012年第5期25卷 940-946页

作者： ding Ye {1. limin ZhanG Xiaojian ding han state {1. {1. of Mechanical System and Vibration Shanghai Jiao Tong University Shanghai 200240 China state {1. {1. of digital manufacturing equipment and technology Huazhong University of Science and Technology Wuhan 430074 China

As one of the bases of gradient-based optimization algorithms, sensitivity analysis is usually required to calculate the derivatives of the system response with respect to the machining parameters. The most widely used approaches for sensitivity analysis are based on time-consuming numerical methods, such as finite difference methods. This paper presents a semi-analytical method for calculation of the sensitivity of the stability boundary in milling. After transforming the delay-differential equation with time-periodic coefficients governing the dynamic milling process into the integral form, the Floquet transition matrix is constructed by using the numerical integration method. Then, the analytical expressions of derivatives of the Floquet transition matrix with respect to the machining parameters are obtained. Thereafter, the classical analytical expression of the sensitivity of matrix eigenvalues is employed to calculate the sensitivity of the stability lobe diagram. The two-degree-of-freedom milling example illustrates the accuracy and efficiency of the proposed method. Compared with the existing methods, the unique merit of the proposed method is that it can be used for analytically computing the sensitivity of the stability boundary in milling, without employing any finite difference methods. Therefore, the high accuracy and high efficiency are both achieved. The proposed method can serve as an effective tool for machining parameter optimization and uncertainty analysis in high-speed milling.

关键词： milling stability sensitivity of the stability boundary numerical integration method

Numerical Robust Stability Estimation in Milling Process

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Chinese Journal of Mechanical Engineering 2012年第5期25卷 953-959页

作者： ZhanG Xiaoming {1. limin ding han XIONG Youlun state {1. {1. of digital manufacturing equipment and technology Huazhong University of Science and Technology Wuhan 430074 China state {1. {1. of Mechanical System and Vibration Shanghai Jiao Tong University Shanghai 200240 China

The conventional prediction of milling stability has been extensively studied based on the assumptions that the milling process dynamics is time invariant. However, nominal cutting parameters cannot guarantee the stability of milling process at the shop floor level since there exists many uncertain factors in a practical manufacturing environment. This paper proposes a novel numerical method to estimate the upper and lower bounds of Lobe diagram, which is used to predict the milling stability in a robust way by taking into account the uncertain parameters of milling system. Time finite element method, a milling stability theory is adopted as the conventional deterministic model. The uncertain dynamics parameters are dealt with by the non-probabilistic model in which the parameters with uncertainties are assumed to be bounded and there is no need for probabilistic distribution densities functions. By doing so, interval instead of deterministic stability Lobe is obtained, which guarantees the stability of milling process in an uncertain milling environment, In the simulations, the upper and lower bounds of Lobe diagram obtained by the c{1.ges of modal parameters of spindle-tool system and cutting coefficients are given, respectively. The simulation results show that the proposed method is effective and can obtain satisfying bounds of Lobe diagrams. The proposed method is helpful for researchers at shop floor to making decision on machining parameters selection.

关键词： robust stability estimation sensitivity analysis interval arithmetic decision making

Milling stability analysis using the spectral method

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science China(Technological sciences) 2011年第12期54卷 3130-3136页

作者： ding Ye {1. limin ZhanG XiaoJian ding han state {1. {1. of Mechanical System and Vibration Shanghai Jiao Tong University Shanghai 200240 China state {1. {1. of digital manufacturing equipment and technology Huazhong University of Science and Technology Wuhan 430074 China

This paper focuses on the development of an efficient semi-analytical solution of chatter stability in milling based on the spectral method for integral equations. The time-periodic dynamics of the milling process taking the regenerative effect into account is formulated as a delayed differential equation with time-periodic coefficients, and then reformulated as a form of integral equation. On the basis of one tooth period being divided into a series of subintervals, the barycentric Lagrange interpolation polynomials are employed to approximate the state term and the delay term in the integral equation, respectively, while the Gaussian quadrature method is utilized to approximate the integral tenn. Thereafter, the Floquet transition matrix within the tooth period is constructed to predict the chatter stability accor{1. to Floquet theory. Experimental-validated one-degree-of-freedom and two-degree-of-freedom milling examples are used to verify the proposed algorithm, and compared with existing algorithms, it has the advantages of high rate of convergence and high computational efficiency.

关键词： milling stability delayed differential equation integral equation spectral method Floquet theory

Kinematic generation of ruled surface based on rational motion of point-line

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science China(Technological sciences) 2012年第1期55卷 62-71页

作者： ZhanG XiaoMing {1. limin ding han XIONG YouLun state {1. {1. of digital manufacturing equipment and technology Huazhong University of Science and Technology Wuhan 430074 China state {1. {1. of Mechanical System and Vibration Shanghai Jiao Tong University Shanghai 200240 China

This paper studies representation of rigid combination of a directed line and a reference point on it （here referred to as a ＂point-line＂） using dual quatemions. The geometric problem of rational ruled surface design is viewed as the kinematic prob- lem of rational point-line motion design. By using the screw theory in kinematics, mappings from the spaces of lines and point-lines in Euclidean three-dimensional space into the hyperplanes in dual quaternion space are constructed, respectively. The problem of rational point-line motion design is then converted to that of projective Bezier or B-spline image curve design in hyperplane of dual quatemions. This kinematic method can unify the geometric design of ruled surfaces and tool path generation for five-axis numerical control （NC） machining.

关键词： line space point-line space rational motion dual quaternion hyperplane ruled surface generation

Tool path generation and simulation of dynamic cutting process for five-axis NC machining

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Chinese science Bulletin 2010年第30期55卷 3408-3418页

作者： ding {1. BI QingZhen zhu limin XIONG YouLun state {1. {1. of digital manufacturing equipment and technology Huazhong University of Science and Technology Wuhan 430074 China state {1. {1. of Mechanical System and Vibration Shanghai Jiao Tong University Shanghai 200240 China

Five-axis NC machining provides a valid and efficient way to manufacture the mechanical parts with complex shapes,which are widely used in aerospace,energy and national defense industries. Its {1. innovations have attracted much attention in recent years. In this paper,the {1.-of-the-art techniques for five-axis machining process planning are summarized and the challenging problems are analyzed from the perspectives of tool path generation,integrated geometric/mechanistic simulation and machining stability analysis. The recent progresses in accessibility-based tool orientation optimization,cutter location (CL) planning for line contact and three-order point contact machining,shape control of cutter envelope surface and milling stability prediction are introduced in detail. Finally,the emerging trends and future challenges are briefly discussed.

关键词：五轴数控加工刀具轨迹生成五轴联动过程仿真动态切削形状复杂技术创新稳定性分析

On time-domain methods for milling stability analysis

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Chinese science Bulletin 2012年第31期57卷 4336-4345页

作者： ding {1. ding Ye zhu limin state {1. {1. of digital manufacturing equipment and technology Huazhong University of Science and Technology Wuhan 430074China state {1. {1. of Mechanical System and Vibration Shanghai.liao Tong UniversityShanghai 200240China

As a basic and advanced machining technique,the high-speed milling process plays an important role in realizing the goal of high performance *** the viewpoint of machining dynamics,obtaining chatter-free machining parameters is a prerequisite to guaranteeing machining accuracy and improving machining *** paper gives an overview on recent progress in time domain semi-analytical methods for chatter stability analysis of milling *** state of art methods of milling stability prediction in milling processes and their applications are introduced in *** bottlenecks involved are analyzed,and potential solutions are ***,a brief prospect on future works is presented.

关键词：铣削过程时域方法稳定性分析定性分析方法加工技术稳定性预测加工精度加工参数

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Pneumatic and tendon actuation coupled muti-mode actuators for soft robots with broad force and speed range

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science China(Technological sciences) 2022年第9期65卷 2156-2169页

作者： zhu JiaQi PU MengHao CHEN {1. XU Yi ding {1. WU ZhiGang state {1. {1. of digital manufacturing equipment and technology Huazhong University of Science and TechnologyWuhan 430074China

Broad output force and speed ranges are highly desired for actuators to endow soft robots with high performance,thereby increasing the range of tasks they can ***,limited by their low structural stiffness and single actuation method,most of the existed soft actuators are still difficult to achieve a broad force and speed range with a relatively compact body ***,we propose a pneumatic and tendon actuation coupled soft actuator(PTCSA)with multiple actuation modes,mainly composing of a multi-joint thermoplastic polyurethanes(TPU)-made skeleton sealed in a film *** TPU skeleton with certain structural stiffness combined with soft joints allows PTCSA to output small force and respond rapidly under pneumatic actuation,as well as output high force and flexibly regulate response speed under tendon actuation,therefore achieving a broad force and speed range with a compact *** multiple modes constructed from the two actuation methods with different force and speed properties can cover diverse application *** demonstrate its performance,PTCSA is further used to construct a soft robotic arm(with a maximum lifting speed of 1.8°/s and can easily lift a load of 200 g),an inchworm-inspired wheel-footed soft robot(moves at a high speed of {1.3 cm/s when unload or pulls a load of 300 g forward),and a soft gripper(can grasp diverse objects,from 0.1.g potato chips to an 850 g roll of Sn-0.7 Cu wire,from a high-speed moving tennis ball to an upright pen).This work indicates the potential of combining multiple complementary actuation methods to improve the force and speed range of soft actuators,and may provide inspiration for related research.

关键词： soft actuator tendon actuation pneumatic actuation broad force and speed range multiple modes