共查询到18条相似文献,搜索用时 156 毫秒
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针对超声驱动电源在不同共振频率跟踪(RFT)方案下存在的频率搜索范围小、跟踪进程长、软硬件设计复杂等问题,研究了基于集成芯片的频率跟踪方案。该方案以集成芯片为核心,结合逻辑控制及其外围接口电路,实现了压电换能器在毫秒量级的频率智能跟踪。此外,还设计了一种输出频率范围可调的VCO电路,来搭配使用频率跟踪模块;以匹配电路的电压放大倍数和换能器电流为目标函数计算出匹配参数。最后基于频率跟踪模块实现了小型化、低成本的超声驱动电源,验证了基于集成芯片的频率跟踪方案,所设计的电源拥有27KHz~29KHz频率搜索范围,0.5Hz的频率跟踪精度,实验结果表明,其能在3.5ms左右完成频率搜索和跟踪的进程。 相似文献
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基于阻抗匹配的超声手术刀频率跟踪方法研究 总被引:1,自引:0,他引:1
随着科技的发展,超声手术刀在医疗上的运用越来越广泛。在实际应用中,为了让超声手术刀的换能器能尽可能高效率地将电能转换成机械能,利用并联阻抗匹配实现了超声手术刀的阻抗匹配,让超声手术刀的换能器呈现纯阻抗,从而使换能器的输出功率最大,并且减少了换能器的发热,延长了使用寿命。另外超声手术刀的换能器在使用过程中,换能器的各项参数会随着温度以及环境等发生改变,因此设计了一种针对换能器的谐振频率进行变频的频率跟踪方法,通过对电流和电压的相位差进行跟踪,然后送入到FPGA进行运算,得到一个相位差,当相位发生偏差的时候,则采用一个变频公式调整输出频率,从而达到频率跟踪的效果。通过实际验证,所设计的超声手术刀阻抗匹配和频率跟踪方法可以很好地实现在不同负载下的频率自动跟踪,并且运行可靠。 相似文献
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分析了谐振微加速度计闭环驱动控制的要求,并根据要求建立了幅度和频率自适应控制的双闭环驱动分析模型.鉴于系统的高阶非线性,采用近似平均法分析了系统的稳态平衡点和稳定条件.对基于锁相技术的频率跟踪环,得到了环路频率稳定跟踪的积分控制器临界条件.对基于自动增益的幅度控制环,分析表明在没有PI控制器时不能实现恒幅振动,在引入PI控制器后,振动幅度与品质因数和频率无关;同时,较小的直流参考电压能实现同样大的振幅.仿真结果有效的验证了上述结论,理论分析和仿真有助于驱动电路的设计和调试. 相似文献
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本文针对超声波细胞粉碎机在实际应用中易出现频率失锁、频率跟踪不精确的现象,通过对锁相式自动频率跟踪方法的分析与研究,提出一种采用数控移相电路实现跟踪频率自动微调的方法,可以较好地解决超声波细胞粉碎机频率失锁及频率跟踪不精确的问题,通过锁相环频率跟踪电路的设计,频率自动跟踪软件设计,以及频率跟踪电路实验测试和分析加以论述... 相似文献
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频率跟踪电路是超声系统中的重要组成电路,文章介绍了频率自动跟踪原理,分析了实现频率自动跟踪所选取的方案,对于几种典型的频率跟踪电路进行了分析说明,并提出电路应用中需注意之处。 相似文献
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Rong-Jong Wai Jeng-Dao Lee 《IEEE transactions on systems, man, and cybernetics. Part B, Cybernetics》2004,34(5):2100-2111
Since the dynamic characteristics of a linear piezoelectric ceramic motor (LPCM) are highly nonlinear and time varying, it is difficult to design a suitable motor drive and position controller that realizes accurate position control at all time. This study investigates a double-inductance double-capacitance (LLCC) resonant driving circuit and a sliding-mode fuzzy-neural-network control (SMFNNC) system for the motion control of an LPCM. First, the motor structure and LLCC driving circuit of an LPCM are introduced. The LLCC resonant inverter is designed to operate at an optimal switching frequency such that the output voltage will not be influenced by the variation of quality factor. Moreover, a SMFNNC system is designed to achieve favorable tracking performance without precise dynamic models being controlled. All adaptive learning algorithms in the SMFNNC system are derived in the sense of Lyapunov stability analysis, so that system-tracking stability can be guaranteed in the closed-loop system. The effectiveness of the proposed driving circuit and control system is verified by experimental results. 相似文献
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介绍了一种用ZnO薄膜作为压电层的硅微压电式超声换能器(PMUT).该硅微压电换能器的振动基膜采用LPCVD制作的氮化硅薄膜和PECVD制作的二氧化硅形成的复合振动膜结构.文中运用有限元方法对该硅微压电换能器的结构进行了模拟和计算,并进行了预应力对硅微换能器共振频率的影响的分析.实验测得硅微压电式换能器的共振频率为71.36 kHz.本文还使用该硅微超声换能器在油中进行了初步的共振频率点收发信号的实验,接收实验测得信号峰峰值为9 mV左右,发射实验标准水听器接收信号峰峰值为0.8 mV左右. 相似文献
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Hayato Osaki Takefumi Kanda Shoki Ofuji Norihisa Seno Koichi Suzumori Takahiro Ukida 《Advanced Robotics》2018,32(9):500-510
AbstractRobots composed of hydraulic actuators have been utilized in various fields and at disaster sites. However, the hydraulic control system for multiple-degree-of-freedom mechanisms is large because such systems require many control components. The purpose of this research was to develop a small hydraulic flow control valve. This paper describes the fabrication and evaluation of a small three-way valve by particle excitation using a piezoelectric transducer. This valve consists of two transducers and can switch the inlet and outlet ports by applying an AC voltage of different driving frequencies to each transducer because each transducer has different resonant frequencies. The flow rate was controlled by applying a voltage to the piezoelectric transducer. We evaluated the vibration characteristics of the fabricated three-way valve. The vibration velocity exhibited peaks at 120 and 155 kHz for the inlet and outlet port, respectively, and that of each transducer increased with the applied voltage. Therefore, this three-way valve can switch the opening port by changing the driving frequencies and continuously controlling the flow rate. As a result, we have succeeded in driving the novel small three-way valve. 相似文献
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H. H. Hansen 《Structural and Multidisciplinary Optimization》1997,14(2-3):150-157
An ultrasonic transducer, consisting of two piezoelectric ceramic disks and two resonance rods, is optimized with respect to the shape of the two resonance rods in order to maximize the amplitude of the vibrating tip. The mathematical model is presented and a finite element model of the transducer is set up. Harmonic analysis (forced vibration) is used for calculation of resonance frequency, vibration mode, amplitude and phase. The resulting optimal shape is presented. The numerical analysis shows that the new design improves the amplitude 4.0 times. The improved transducer has been tested against the standard transducer and experiments show good agreement with theoretical results. A special design of the ultrasonic transducer for sonar applications has also been investigated. Applications of the improved ultrasonic transducer are more efficient transducers in high energy applications such as ultrasonic welding, drilling, disruption, cleaning, and sonar and underwater communication. 相似文献
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《Advanced Robotics》2013,27(3-4):277-290
A smooth impact drive mechanism (SIDM) is a unique piezoelectric actuator that is widely used as a camera focusing mechanism, cell phone lens movement mechanism, etc. This principle enables a compact driving mechanism; however, it cannot generate high-speed movement because a soft-type multilayered piezoelectric transducer (PZT) is utilized at off-resonant movement. This paper proposes a resonant-type SIDM actuator driven with hard-type PZTs to realize high-speed and powerful operation. The fundamental principle is also based on the conventional SIDM; therefore, a saw-shaped movement is required. To generate a high-power ultrasonic output, two Langevin transducers are adopted instead of a soft-type multilayered PZT. One Langevin transducer was a stator and the other was slider whose tip was adhered to a carbon fiber reinforced plastic (CFRP) rod. The CFRP rod was connected to the stator transducer with the frictional force. To obtain quasi-saw-shaped vibration, the longitudinal vibration for each Langevin transducer was excited and these movements were added at the connection point at the CFRP rod. In order to combine these vibration modes, the lengths of the stator and slider Langevin transducers were designed to make the resonant frequencies ratio to be 1:2. By using the proposed principle, the slider Langevin transducer was successfully driven with the speed of 0.11 m/s and the output force was 1.8 N with no load. 相似文献