# Experiment Investigation of Bistable Vibration Energy Harvesting with Random Wave Environment
## 2 Materials  
### Bistable Vibration Harvesting System on the Random Wave  
In order to generate the stochastic resonance phenomena, the existence of the random noise input signal, the periodic excitation force and the nonlinear bistable system are mentioned as three requirements. In this study, the experimental system of bistable vibration in the random wave environment shown in Figure 1 is devised.  
As shown in Figure 1, the experimental system consists of three parts: a water tank, a random wave generator, and a bistable vibration model body. It is fixed to the bottom of the tank using an elastic plate under the vibration model body in the center of the water tank,and the vibration model body consists of a wooden box that floats halfway on the water surface. In the vibration model body, in order to cause the phenomenon of probabilistic resonance, a mini shaker with periodic exciting force is set up.  
In order to realize vibratory power generation, a piezoelectric element is stuck near the root of a cantilever beam, and the vibration generating voltage can be obtained from a piezoelectric element that is bent and deformed along with the vibration of the vibration model.  
In order to generate a random exciting force by the waves, it is connected to the vibration model body and the elastic plate under the vibration model body by the rubber plate. On the other hand, in order to generate a random wave, a wave generator is installed on the left side of the water tank. It is fixed to the bottom of the water tank by the pin connecting element of the rotation free under the wave making plate. It is connected to the shaking table by the link mechanism on the wave-making board, and the amplifier and the signal generator are installed at the end of the shaking table.  
In order to verify the amplification effect and the vibration generation performance by the stochastic resonance using the bistable vibration power generation system in the random wave environment shown in Figure 1, an experimental apparatus and a measuring system shown in Figure 2 were developed.  
Figure 1: The diagram of experimental settings of bistable vibration power generation system in random wave environment.  
Figure 2: The experimental equipment and measurement system for bistable vibration power generation system in random wave environment.  
The measurement system shown in Figure 2 is used, and the verification experiment is carried out according to the following procedure. Firstly, a random excitation signal is generated from the signal generator and sent to the amplifier, and the random excitation signal amplified by the amplifier is sent to the shaking table. The wave generator is vibrated by the shaking table, and random waves are generated on the surface of the water in the water tank. The stochastic resonance is generated in the vibration model by shaking the shaking table from the mini shaking table.  
In addition, in order to measure the response vibration displacement of the vibration model in the center of the water tank and the voltage generated by the vibration generated by the piezoelectric element, the measurement marks are pasted on the mass block and support point, respectively. In the measurement, the measurement marker's motion locus is recorded using the high-speed camera, the tracking software is used, and the vibration displacement data of the mass block and support point can be produced. The output lead of the piezoelectric element is directly connected to the data logger to record the voltage signal of the oscillatory power generation using the data logger.