【作者】 姜斌；

【导师】 刘晓论； 杨志刚；

【作者基本信息】 吉林大学 ， 机械设计及理论， 2009， 博士

【摘要】 振动送料器在自动加工与装配等领域有着重要应用。目前的驱动方式有电磁式与压电式,传统的电磁振动送料器,电磁干扰严重,近年出现了压电振动方式,解决了电磁干扰问题,但振幅较大,对微小物体的整列性能及输送稳定性还不理想。这两类振动送料器的工作频率在50-300Hz之间,噪音大,在要求高清洁、低噪声的生产场合,使用上受到限制。超声波振动的传统应用为电学与声学领域,超声波马达的成功开发应用证明了它在机械驱动领域的应用前景。本文提出以超声波振动代替传统方式驱动振动送料器工作,是超声波振动在这一领域的新的应用。提出利用声频以外的高频超声振动来消除送料时振动噪音的方法,利用超声振动振幅更小的特点,提高对轻薄细小物料输送的平稳性和整列性能。本文提出以压电超声换能器为振动源,通过合理的机械结构形成超声波振动对送料器的驱动,使料盘表面获得的运动叠加或合成以形成椭圆运动,从而具备推动与之接触物料移动的能力。具体工作包括:设计了超声波振动送料的原理样机,对超声波振动送料器的驱动部件-压电超声换能器的设计方法进行了理论分析,对结构参数进行了设计计算,利用ANSYS软件分析了振动模态,对基本参数进行了测试。综合考虑超声波振动送料器构件形状、重量、空间位置及其交互关系与耦合影响,建立超声波振动驱动过程的运动学与动力学模型,通过理论分析、数值运算和有限元分析,获得力学、结构参数对驱动性能的影响规律;研究超声波驱动状态下物料与料盘表面之间的相互作用规律,获取料盘表面椭圆运动的形成机理,取得超声波送料机构动力学参数与结构优化设计方法。对超声波振动送料器的谐振特性进行了分析,提出了谐振频率的跟踪方法,在此基础上,根据超声波振动送料器的特点,设计了驱动电路。搭建了集相位检测、信号处理与反馈控制等功能于一体的超声波振动送料器专用控制器,从而保证了送料器协调、稳定地工作,提高了对物料的输送质量与效率。对超声波振动送料器的性能进行了测试研究,验证了理论与仿真分析所得出的结论,验证了结构设计的方法。研究与测试结果表明,超声波振动送料的输送稳定性和整列性能相比于现有送料方式更佳,噪音更小,同时总结了工况变化对送料器输送性能的影响规律。从理论与试验两方面说明以超声波振动驱动送料器工作是可行的。更多还原

【Abstract】 The traditional electromagnetic vibration feeder is restricted to the production occasions of high cleaning and low noise due to unfavorable factors, such as serious magnetic interference, severe work noisy and so on. One of the most effective solutions to reduce the noise is to adopt the drive mode except sonic vibrations; while the most radical solution to solve the magnetic interference problem is a non-magnetic drive mode. And the piezoelectric actuation is precisely meeting the above requirements.The ultrasonic vibration feeder developed in this paper is under the support of Chinese Natural Science Foundation program“The driving mechanisim and study of ultrasonic vibration feeder”, and national 863 program“The research and development of vertical-driven-piezoelectric feeder”. Because of ultrasonic actuation traditionally applied to the electrical and acoustic fields, its mechanical drive capability was known only in recent years. Ultrasonic motor is a successful example of ultrasound-driven applications, and current study of ultrasonic actuation is focused on motor direction yet. So ultrasonic vibration to the feed can be seen as further development and application of ultrasound-driven capability, which through reasonable structure form ultrasonic vibration to drive the system, so that the surface of feed plate’s movements are superimposed or combined and finally form elliptical motion, enabling it to promote the materials contacting with them continuous movement, it is active exploration of ultrasonic actuation technology in handling material direction.1. The research purpose of ultrasonic feederAs an indispensable part of production line, automatic feeding device determines the pros and cons of automated production processes to a large extent and thus we call high requirements on its structure, noise, working principle, delivery precision. Because of vibration is vibration feeders’intrinsic properties during its work, the only way to reduce noise is to adopt the drive mode except sonic vibrations, and the use of ultrasonic vibration may be the best choice to solve this problem. Ultrasonic Piezoelectric vibration feeder is more quiet, lower altitude ,smooth delivery, lower electro-magnetic interference, better array performance, lower prices, faster response speed than the traditional electro-magnetic and low frequency Piezoelectric vibration feeder, it’s what the current vibration feeder can not match.2. Design of piezoelectric transducerUltrasonic transducer has many different types according to vibration mode, the direction of stretching vibration and piezoelectric conversion mode, depending on the different applications, we choose a different structure of piezoelectric vibrator, and they have their own features respectively. This article discusses the basic technical theory of the vibration mode of ultrasonic transducer, and in accordance with relevant analysis and calculation, we select the piezoelectric ultrasonic transducer of bolt-type fastening of the vertical vibration mode; design and calculate its structural parameters; analyze the transducer vibration mode by ANSYS software; test the resonant frequency and impedance of the designed transducer by precision impedance analyzer and measured the end amplitude of the transducer by experiments. The results of principle analysis and experimental verification tells us that the ultrasonic piezoelectric transducer can meet the design requirements of ultrasonic feeders in the regard of the operating frequency, electromechanical conversion efficiency, transmission power, the output amplitude and so on.3. The modeling and simulation of kinetics, kinematics of ultrasonic feederIn this paper, we present a new type of ultrasonic vibration feeder prototype and determine the vibration of the basic structure of the feed device; based on the analysis of the structure of ultrasonic vibration to the feeding mode to enhance the driving capacity, we focuses on the effects of the materials and the structure of the major components to ultrasonic feeder. Through the establishment of ultrasonic feeder’s mechanical model and the analysis of the system’s dynamic part, we obtain the mathematical relationship between the natural frequency and vibration frequency of the system. We established ultrasonic vibrating feeding system’s dynamics model, analyzed the relationship between the natural frequency and vibration frequency by ANSYS software and carry out the kinetic analysis to guide the structural design of the various components, manufacture and the assembly of the ultrasound feeder prototype. Through the establishment of differential equations of motion of materials, the analysis of the conditions how material can slip and jump in feed tray, the scope of the working abilities of the feeder can be determined. Through the establishment of kinematics mathematical model of material conveyor, the analysis of the formation mechanism of elliptical motion, the analysis of the trajectories of the feed tray particle using ANSYS software, we verified the works of ultrasonic vibration feeder. Through the analyses and experiments of drag reduction mechanism of ultrasonic suspension, the establishment of the relevant motion equations, we analyzed the affect of drag-reducing on the ultrasonic suspension feeder’s drives capacity.4. The structural design and specificity analysis of ultrasonic feederOn the basis of the above mathematical analysis and FEM simulation, the design of base, feed tray, support parts and flexible connecting piece were optimized. The performance parameters of the various parts of the ultrasonic feeder were determined and the ultrasonic feeder’s structure was further optimized on the basis of the assembly, approach and cross-experiment. Through the establishment of equivalent circuit of the system, the resonant characteristics of the system were analyzed and calculated. On the basis of the test of the relationship between ultrasonic feeder’s resonant frequency and impedance characteristics by various methods, we obtained ultrasonic vibration feeder’s impedance phase characteristic values under the state of resonance, further more the new method of using direct phase method to track the resonant frequency ultrasound was proposed. Through the establishment of mathematical model of ultrasonic feeder, the impedance matching meaning, matching methods and performance were studied and based on comparing several matching methods, the impedance matching program was determined.5. The design of ultrasonic piezoelectric digital controllerBy the works of ultrasonic feeders, only under the resonant state, ultrasonic feeders performs good transmission capacity. Since factors like material quality in feed tray changes, the resonant frequency of ultrasonic feeders is shifted. Therefore, the drive power of ultrasonic feeder needs to have the ability to track its resonant frequency. Based on the above analysis of the feeder, a dedicated digital drive power was designed for the ultrasonic feeder, which uses DSP as control core, uses inverter topology and uses transformer-isolated output. We have modeled and analyzed the topology structure of the main circuit, designed the circuit of resonant frequency tracking and control and the control software, conducted a test and performance analysis on the drive power.6. The research on the performance of the ultrasonic feederA prototype of a new ultrasonic feeder has been made, and has done some experiments. The results showed that ultrasonic feeder has the ability to make feed tray promote materials continuous moving by the longitudinal vibration of ultrasonic transducer, and under the resonant state can get the best transmission capacity. Experiments show that when working frequency is 15.3 kHz, spring thickness is 5mm, the conveyor speed of metal sheets of diameter of 3mm can get up to 6mm per second, at the same time, as the piezoelectric ultrasonic-based driven mode, the possibility of electromagnetic interference and noise was eliminated theoretically. It has been proved that, the ultrasonic feeder is able to form elliptical motion of elastic surface body, thus obtains capabilities to promote material movement with a well-designed structure which synthesizes one or more ultrasonic vibrations on an elastomer to make them vibrate in accordance with a plan mode. And frequency-tracking experiment proved that, under the changing conditions, ultrasonic feeder could work stably in the vicinity of the resonant frequency with the drive power automatically tracking the changing resonant frequency.更多还原