Study On Low-broadband Characteristics And Application Of Multi-dof Piezoelectric Composite Vibrator

At present,the Internet of Things(Io T)technology has been widely used in various industries.Wireless sensor network technology has played a vital role in the development of the Internet of Things technology,but the difficulty of battery replacement has become one of the reasons that restrict the further effective development of wireless sensor network and even Internet of things technology.At home and abroad,various energy harvesting schemes have been proposed in response to this problem,such as solar energy,wind energy,and mechanical energy.Among them,piezoelectric energy harvesting technology with mechanical energy-electricity conversion as its core has stood out because of its simple structure and high conversion efficiency.However,current low-power wireless sensors that use piezoelectric energy harvesting technology as a self-powered part need to be further studied due to their narrow coverage frequency and low output energy.Therefore,this article abandons the traditional single-degree-of-freedom piezoelectric vibrator with a narrow output frequency band,and chooses a multi-degree-of-freedom piezoelectric vibrator based on Timoshenko beam theory.And on this basis,combined with the application requirements of the actual construction machine attitude angle detection,the lowbroadband characteristics and application performance of the multi-degree-of-freedom piezoelectric composite vibrator were studied in turn.The main research contents are as follows:(1)Mechanism analysis of multi-degree-of-freedom piezoelectric acquisition.The key theoretical basis of piezoelectric energy acquisition was introduced and expounded,the dynamic model and piezoelectric coupling model of L-type piezoelectric vibrator with multiple degrees of freedom were analyzed and established,the key influencing parameters that affect the piezoelectric energy conversion effect were obtained.(2)Study on Low-Bandwidth Characteristics of Multi-degree-of-freedom Piezoelectric Compound Oscillator.The rationality of setting parameters of material,load and boundary condition in finite element method is verified by analysis.The effects of load,material and size parameters on the energy acquisition effect of multidof piezoelectric vibrators were studied and the optimal parameters were determined.Six simplified layouts of different layouts were proposed and analyzed and the optimal layout structure was obtained.The low-bandwidth characteristics of compact and noncompact piezoelectric composite vibrators were proposed and studied.Compared with traditional piezoelectric composite vibrators of the same size,the advantages of multidegree-of-freedom piezoelectric composite vibrators in low-bandwidth characteristics were determined.(3)Complete the hardware and software design and development of piezoelectric energy harvesting node and low-power wireless sensor node.Analyze the application requirements of self-powered wireless sensors at this stage and complete the hardware and software design of piezoelectric energy harvesting nodes and low-power wireless sensor nodes.(4)The theoretical and application properties of the compact piezoelectric composite oscillator were verified by experiments.The vibration energy acquisition test bed and the construction machinery application measurement test platform were built.The key parameter influence rule verification test,low broadband characteristic test and application test of compact piezoelectric composite vibrator were completed respectively.The results show that the influence of key parameters and the multidegree-of-freedom piezoelectric composite vibrator test results were generally consistent with the simulation analysis results.And there are some differences in the amplitude and bandwidth due to the inevitable friction loss in the actual installation and the ideal environment in the theoretical simulation analysis.Practical results the waiting time in the first frequency range of the piezoelectric composite oscillator is 53 s,the waiting time in the second frequency range is 76 s,and the waiting time in the third frequency range is 96s.