Research On Testing Method Of Force Testing System Characteristic

The dynamic characteristics of the applied stress testing system need to be tested in the load detection of vehicles on the expressway,on-line weight detection and control of products on the packaging production line,and so on.In this paper,the dynamic characteristics of the force testing system to be tested are tested and analyzed.Considering the characteristics of the actual test system,a force test system consisting of resistance strain force sensor,measurement amplifier circuit and high-pass filter circuit is built in this paper.The non-periodic triangular wave force signal is used as the excitation signal,and the response signal of the force test system is collected synchronously.The excitation and response data are processed by deconvolution method,and the impulse response function of the system is solved numerically.Among them,the aperiodic triangular wave is realized by 8-bit DAC controlled by MCU,the force signal is generated by power amplifier circuit driving electric exciter,and the response data is collected by 10-bit ADC in MCU and sent to PC through serial port.The upper computer part is real-time displayed by response data acquisition interface designed by MATLAB GUI.The main contents of this paper are as follows: Firstly,the impulse response function of the system is simulated by means of MATLAB and Altium Designer 2009 for the first-order passive low-pass and second-order passive band-pass network model,and compared with the theoretical impulse response function,the feasibility of solving the impulse response function by discrete iteration algorithm is verified;Secondly,the elements of the force generator are measured.The test analysis mainly includes changing AC power amplifier circuit to DC power amplifier circuit and determining input excitation force signal by theoretical analysis and experimental test of electric exciter.Thirdly,testing and analysis of each unit of the force test system to be tested,mainly including theoretical analysis and experimental test of the gain and common mode suppression ability of the amplifier circuit.The static and dynamic characteristics of the resistance strain force sensor are tested,and the frequency characteristics of the high-pass filter circuit are deduced theoretically and tested experimentally.Fourthly,the response signal is collected by using 10-bit ADC in the chip,and sent to the host computer through the serial port.Fifthly,the data acquisition interface of the response to be measured is designed by using MATLAB GUI.Real-time display of response data is realized,and the data is stored after acquisition for subsequent solution of impulse response function.Finally,the input force signal obtained from theoretical analysis and the collected response data are solved by deconvolution algorithm.Through testing,the impulse response function is solved numerically by means of discrete iteration algorithm,and then the corresponding amplitude-frequency characteristic curve is obtained by Fourier transform to frequency domain,and the system bandwidth is analyzed.The lower cut-off frequency range can be roughly determined;because the excitation signal does not contain high-frequency components,the upper cut-off frequency can not be tested.