【作者】 肖才伟；

【导师】 程凯；

【作者基本信息】 哈尔滨工业大学 ， 机械制造及其自动化， 2014， 博士

【摘要】 为了提高超精密切削加工的零件表面质量，高效稳定的获得完整一致面形精度的大尺寸表面的零部件，切削刀具在加工过程中的实时状态起着至关重要的作用。刀具所受切削力、切削温度、刀具磨损等直接影响零件加工精度、表面质量、刀具的寿命和加工效率，而刀具的磨损和破损甚至直接破坏加工工件表面完整性，因此，对刀具加工过程中的状态监测与控制就显得非常必要。并且尽量减小刀具磨损，延长刀具的寿命，以进一步突破刀具对超精密加工难加工材料和大尺寸表面的尺寸和行程限制，因此，需要赋予切削刀具系统相应的功能集成。本课题针对超精密加工对刀具实时监测和加工能力的需求，提出了智能切削刀具系统概念，其基本思想是刀具系统执行切削加工同时具有感知切削力的能力，以实时监测刀具加工状态，并且可根据加工的需要进行振动辅助切削加工，并通过超声振动加工提高切削质量，延长刀具寿命，提高刀具对难加工材料的加工能力。本文首先根据智能切削刀具系统的基本思想和设计原则，建立智能切削刀具系统等效物理模型，分析三向作用力下压电梁的应力分布规律；建立感知单元的应力分布大小与作用力的关系。根据压电梁的弯曲振动激励方式，对梁的端面质点振动轨迹合成进行分析，建立端面质点的振动轨迹方程，为智能切削刀具的感知和振动系统结构设计奠定理论基础。为了实现三向切削力的测量和解耦，提出了一种切削力感知式智能切削刀具构型，通过集成刀杆中的微小三向切削力测量系统，融合微小三向切削力测量系统和刀具于一体，实现精密切削过程中微小三向切削力的自主实时监测。通过建立智能切削刀具等效压电悬臂梁模型，建立了感知单元输出电荷与三向切削力的耦合关系，通过感知单元组合实现三向切削力的解耦；详细推导了各向切削力作用下，各感知单元的电荷分布情况，并建立了三向切削力与四个压电传感单元输出电荷之间的映射关系，建立了三向切削力与感知单元输出电荷的感知解耦方程。通过标定测试对感知式智能切削刀具的感知解耦算法进行修正，建立了修正后的解耦方程。为了测试和评估设计研制出的切削力感知式智能切削刀具，首先基于LabVIEW程序搭建集成三向切削力解耦算法的测试软件平台，实现切削力的实时测量。通过切削实验进行灵敏度的静态标定，建立各向切削力与感知单元输出电压的关系，实现三向切削力的精确感知解耦。分析结构参数对灵敏度和刚度的影响规律，对智能切削刀具的总体综合性能进行评价。最后通过对比切削实验验证了切削力感知式智能切削刀具解耦方法正确性和刀具结构设计的有效性。为了进一步提高切削力感知式智能切削刀具的刚度、灵敏度和实用性，提出一种改进优化的切削力感知式智能切削刀具，通过改变了感知段横截面的构型和感知单元的安装方式和可转位刀具的设计显著的提高了该智能切削刀具的实用性；建立了感知系统刚度和电荷灵敏度的分析模型，对感知段横截面的构型和感知单元的安装方式进行优化改进设计，分析了感知段横截面的尺寸参数与刚度和灵敏度之间的关系，实现了主切削力最小0.1N的感知能力。为了提高金刚石超精密切削加工能力，减小刀具磨损，延长刀具的使用寿命，提出并研制了一种超声振动感知式智能切削刀具。主要具有两个方面的功能：一是超声振动加工能力；二是实现振动切削过程的实时监测。根据压电梁的弯曲振动激励方法，采用两向弯曲振动模态实现超声椭圆轨迹合成，并根据梁的端面质点振动规律和振动感知原理，对超声振动感知式智能切削刀具进行原理分析和结构设计。基于超声振动感知式的智能切削刀具的振动特性和输出力系数分析，对刀具系统结构参数进行设计。通过对刀具的振动特性和感知特性进行测试，评价振动刀具系统振动频率和振幅及其温度特性，确定刀具的合理使用激励参数和感知能力；并对振动感知式刀具进行切削力的静态标定试验，建立输出电压与切削力的关系，实现振动切削过程的监测。最后对端面振动切削过程进行分析，分析切削工艺参数对切削过程的影响，通过对比试验验证超声振动感知式智能切削刀具的超声振动切削加工能力和实时感知功能。更多还原

【Abstract】 To meet the requirements of high-efficiency, high-accuracy and high-reliability machining processes, especially for cutting difficult-to-machining materials, the cutting tools play a crucial role to obtain components with stable high-quality and high accuracy integrity surface. Tool wear and breakage directly affect the quality of the surface on processed components, it is necessary to monitor and control the condition for cutting tools during processing. It is needed to provide the cutting tools system more functions in order to breakthrough the materials and size limits in processing difficult-to-process materials and the large dimension surface, as well as to reduce the tools wear, extend tools working life. This project proposed a smart cutting tool system, aiming at the demands of real-time condition monitoring and multi-function for cutting tools. The basic idea is the ability of real-time cutting force monitoring the cutting tools has during processing, and the system also has the ability with vibration assisted processing according to the demands for the processing. The processing quality could be increased, the working life could be extended and the processing ability of the diamond cutting tool could be improved through ulrasonic vibration machining.This dissertation first established the equivalent physical model-piezoelectric beam for the cutting tool system based on the basic thought and design principles of smart cutting tool systems, and analyzed the stress distribution rules under the applied three directions of force. It analyzed the combined vibration path of end face mass points of the beam according to the exciting type of bending vibration of the piezoelectric beam, thus established the vibration path function of the end face mass points of the beam, and provided basis theoretical instruction for the design of the sensing principles of the smart cutting tool and the design of the vibration system.To achieve measurment and decoupling three components cutting force, it proposed a model of cutting force sensing smart cutting tool, through the tool-bar integrated micro three directional forces measuring system, merged the micro three directional forces measuring system with the cutting tool into one component, achieved the autonomously real-time monitoring of the micro three direction forces. Through building the equivalent piezoelectric cantilever beam of the smart cutting tool, established the coupling relations between output charge of the sensing elements and the three components cutting forces, and achieved decoupling through the combination of sensing elements. Deducted the charge distribution of each sensing element in detail under applied cutting forces in each direction, and established the mapping relation between three cutting force components with the output charge of the four piezoelectric sensing elements, and thus established the decoupled sensing equation of the three components cutting forces and sensing elements output charge. Corrected the decoupled sensing equation of the sensing type smart cutting tool through calibration test, thus obtained the corrected decoupled equation.In order to test and evaluate the designed cutting force sensing smart cutting tool, first the LabVIEW program is used to establish test platform of the three direction cutting force decoupling algorithm, to realize the real-time measuring if cutting force. Through cutting experiment to statically calibrate the sensitivity, realized the accurately decoupling of the three direction cutting force, and then comprehensively evaluate the performance of the smart cutting tool, analyzed the affecting rules of the structural parameters. And finally the feasibility of the decoupling method the design of the smart cutting tool is validated through comparative experiments.In order to further enhance the stiffness, sensitivity and practicability of the cutting force sensing smart cutting tool, an improved cutting force sensing smart cutting tool was proposed, by changing the type of cross surface in sensing section, the assembly type of sensing elements, and the design of the index-able carbide insert cutting tool, improve the practicability of the smart cutting tool. Established the stiffness and charge sensitivity analyzing model of the sensing system, optimize design the type of cross surface in sensing section and the assembly type of sensing elements, analyzed the dimension parameters of the cross surface in the sensing section and the relation between stiffness and sensitivity, realized sensing ability of minimal0.1N for the main cutting force.To improve the processing ability of the diamond ultra-precision machining, decrease cutting tool wear, extend the cutting tool working life, proposed and investigated an ultrasonic vibration type sensing smart cutting tool, which characterizes two aspects: elliptical ultrasonic vibration processing, and real-time monitoring of vibration machining process. According to excitation method of bending vibration of the piezoelectric beam, adopted the bi-directional bending vibration mode to realize the elliptical path forming, and based on vibration principles of the end surface mass points and the vibration sensing principles, designed the structure of the ultrasonic vibration sensing smart cutting tool. And on the basis on the analyze of the vibration performance of equal cross surface, analyze the vibration performance of the smart cutting tool system, and determined the structural parameters of the cutting tool, then deduced the output force coefficients.In order to improve the vibration output performance, the size of the piezoelectric elements should locate in the field between the vibration nodes of cutting tool side surface. Through the vibration and sensitivity test, evaluated the vibration frequency, amplitude and temperature characteristics, and determined the proper excitation parameter and sensing ability. Calibrated the vibration sensing cutting tool, and obtain the relation between the output voltage and the cutting force, realized the monitoring of vibration processing. Finally, it analyzed the machining process of the cross surface, and the influence of process parameters to the machining. The ultrasonic processing ability and real-time sensing capability of the ultrasonic vibration sensing smart cutting tool are validated through comparison experiments.更多还原