# Parametric and Experimental Modeling of Axial-Type Piezoelectric Energy Generator with Active Base
## 5 Experimental Probe
### The Principle of Operation of the Laboratory Test Setup LTS -01  
The process of measuring the frequency response of the oscillatory process of the PEG model and recording its output characteristics was as follows and is shown in Figure 10. On a personal computer (1), two programs were launched: (i) a program for recording voltage parameters on an E14-440D ADC/DAC module from L-Card (10) PowerGraph and (ii) a swept signal generation program with its own developed software [42]. The signal had a fixed output oscillation amplitude with a voltage of 2 V. The process of sweeping (enumerating) the signal was carried out by alternating the excited frequencies from 1 Hz to 1000 Hz. Excitation of each vibration frequency was carried out for 0.5 sec with a pause of 0.5 sec between the transition to another frequency, with a step between frequencies of 1 Hz. The signal could be transmitted via the audio path or USB channel to the AFG 3022B Tektronix signal generator (2), thereby being recorded or generated on it. The PowerGraph program allows high-quality recording and unloading of the measured signal voltage to the ADC module (10). The generated signal was fed through the current-carrying path to the electromagnetic forced oscillation exciter. Voltage was supplied from the oscillator of the sweeping frequency of the device with a stable amplitude and a linearly varying frequency. Figure 10: General view of laboratory test setup LTS -01 for studying the output parameters of PEG. 1—computer with monitor; 2—AFG 3022B Tektronix signal generator; 3—power amplifier LV-102; 4—electromagnetic vibrator VEB Robotron 11077; 5—vibrator working table for fixing the model; 6—RF603 optical linear displacement transducer; 7—optical sensor switching unit (6); 8—optical linear displacement transducer optoNCDT; 9—optical sensor switching unit (8); 10—external ADC/DAC E14-440D module; 11—bank of the active electric load resistance R1–R6 of the corresponding PEG elements; 12—the base of the investigated object; 13—matching path; 14—piezoelectric generator of axial type; 15—grounding path; 16—piezoelectric cylindrical type; 17—piezoelectric elements of the plate type; 18—tripods for mounting optical sensors. The AC voltage value was amplified by the power amplifier (3) and supplied to the vibrator (4); the resulting output voltage from the piezoelectric generator was loaded with AC electrical resistance and supplied to one of the ADC channels (10) of the external module. The values of these voltages were reproduced on the computer monitor screen (1) in the form of an amplitude-time characteristic (ATC). On the working Table 5 of the electromagnetic forced oscillation exciter VEB Robotron 11,077 (4), the investigated PEG sample of the axial type was fixed with a rigidly bolted connection. When voltage was applied to the vibrator (4), predetermined amplitude displacements occured in the vertical direction of the working Table 5. The vibration amplitude in a certain frequency range was linearly proportional to the vibration excitation frequency. The resulting vertical displacements of the working Table 5 set the PEG in motion. Mechanical vibrations of various parts of the generator generated voltage across all piezoelectric elements. The piezoelectric elements were connected to the grounding path (15) and in parallel with the active electric load resistance bank (11) of the corresponding rating. There were six piezoelectrics and, accordingly, each of them had its own individual electrical path. The voltage excited on the piezoelectric elements was recorded using the ADC module (10). Using the ADC module (10), the voltage values from the optical displacement sensors (6) and (8) were also recorded. Subsequent signal processing was performed by software using an external ADC/DAC E14-440 module from L-Card, a personal computer and PowerGraph software. Observation of the shape of the exciting signal and signals from the sensors was performed on the monitor screen and can be duplicated using a digital oscilloscope.