Method for analyzing signal waveform and analyzing vehicle dynamic characteristic

• US 7,523,011 B2
• Filed: 09/26/2006
• Issued: 04/21/2009
• Est. Priority Date: 09/27/2005
• Status: Active Grant

• Current Assignee: Meidensha Corporation, Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Original Assignee: Meidensha Corporation, Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Inventors: Suzuki, Masahiko, Akiyama, Takao, Yoshida, Teruo, Sagiyama, Tatsuya, Funahashi, Yoichi
• Primary Examiner(s): Dunn; Drew A
• Assistant Examiner(s): VO, HIEN XUAN
• Application Number:
  US11/526,991
• Publication Number:
  US 20070071327A1
• Time in Patent Office: 938 Days
• Field of Search: 702/141, 702/119, 702/66, 702/190, 702/191, 702/189
• US Class Current: 702/141
• CPC Class Codes: G06F 18/00 Pattern recognition
• CPC Class Codes: G06F 2218/06 by applying a scale-space analysis, e.g. using wavelet analysis

Abstract

A signal waveform analysis method includes: determining a trend component of an object signal by applying a zero-phase filter to the object signal; determining an oscillatory component of the object signal by removing the trend component from the object signal; determining a wavelet scalogram by performing a wavelet analysis on the oscillatory component; and determining an oscillation period of the object signal with which the wavelet scalogram indicates a maximum. The signal waveform analysis method is employed to evaluate vehicle dynamic characteristics.

Claims

1. A signal waveform analysis method comprising:

determining a trend component of an object signal by applying a zero-phase filter to the object signal;

determining an oscillatory component of the object signal by removing the trend component from the object signal;

determining a wavelet scalogram by performing a wavelet analysis on the oscillatory component; and

determining an oscillation period of the object signal with which the wavelet scalogram indicates a maximum.

3. The signal waveform analysis method as claimed in claim 1, wherein the determining an oscillation period of the object signal is implemented by determining an oscillation period of the object signal for each time with which the wavelet scalogram indicates a maximum at the each time.

2. A signal waveform analysis method comprising:

determining a trend component of an object signal by approximating the object signal with an exponential function expression;

determining an oscillatory component of the object signal by removing the trend component from the object signal;

determining a wavelet scalogram by performing a wavelet analysis on the oscillatory component; and

determining an oscillation period of the object signal with which the wavelet scalogram indicates a maximum.

4. A computer readable medium storing a signal waveform analysis computer program comprising:

computer program code for determining a trend component of an object signal;

computer program code for determining an oscillatory component of the object signal by removing the trend component from the object signal;

computer program code for determining a wavelet scalogram by performing a wavelet analysis on the oscillatory component; and

computer program code for determining an oscillation period of the object signal with which the wavelet scalogram indicates a maximum.

5. The computer readable medium as claimed in claim 4, wherein the computer program code for determining a trend component of an object signal is implemented by one of computer program code for applying a zero-phase filter to the object signal and computer program code for approximating the object signal with an exponential function expression.

6. The computer readable medium as claimed in claim 4, wherein the computer program code for determining an oscillation period of the object signal is implemented by computer program code for determining an oscillation period of the object signal for each time with which the wavelet scalogram indicates a maximum at the each time.

7. A vehicle dynamic characteristic analysis method comprising:

determining a trend component of an object signal;

determining an oscillatory component of the object signal by removing the trend component from the object signal;

determining a wavelet scalogram by performing a wavelet analysis on the oscillatory component;

determining a dominant oscillation period as a scale parameter for each time with which the wavelet scalogram indicates a maximum at the each time;

determining in accordance with the dominant oscillation period a time when the object signal is maximum; and

determining a maximum and a minimum of the object signal within the dominant oscillation period.

8. The vehicle dynamic characteristic analysis method as claimed in claim 7, wherein the determining a trend component of an object signal is implemented by one of applying a zero-phase filter to the object signal and approximating the object signal with an exponential function expression.

9. The vehicle dynamic characteristic analysis method as claimed in claim 7, further comprising applying a zero-phase filter to the object signal before the determining a trend component of an object signal.

10. The vehicle dynamic characteristic analysis method as claimed in claim 7,

wherein the determining a dominant oscillation period is implemented by determining a dominant oscillation period as a scale parameter for each time with which the wavelet scalogram indicates a maximum at the each time with a band limitation on scale parameter, and

wherein the determining a maximum and a minimum of the object signal comprises:

determining a complex signal waveform by performing a wavelet inverse transformation of the wavelet scalogram;

extracting a real part from the complex signal waveform; and

determining a maximum and a minimum of the object signal within the dominant oscillation period in accordance with the real part.

11. A vehicle dynamic characteristic analysis method comprising:

determining a trend component of an object signal;

determining an oscillatory component of the object signal by removing the trend component from the object signal;

determining a wavelet scalogram by performing a wavelet analysis on the oscillatory component with a band limitation on scale parameter;

determining a complex signal waveform by performing a wavelet inverse transformation of the wavelet scalogram; and

obtaining a signal waveform envelope by determining the absolute value of the complex signal waveform.

12. A vehicle dynamic characteristic analysis method comprising:

determining a trend component of an object signal;

determining an oscillatory component of the object signal by removing the trend component from the object signal;

determining a wavelet scalogram by performing a wavelet analysis on the oscillatory component;

processing the wavelet scalogram with a filter having a frequency-gain characteristic at each time;

determining a complex signal waveform by performing a wavelet inverse transformation of the wavelet scalogram; and

obtaining the magnitude of a component emphasized by the filter by determining the absolute value of the complex signal waveform.

13. The vehicle dynamic characteristic analysis method as claimed in claim 12, further comprising determining a signal waveform of the emphasized component by extracting a real part from the complex signal waveform.

14. A vehicle dynamic characteristic analysis method comprising:

determining a trend component of an object signal;

determining an oscillatory component of the object signal by removing the trend component from the object signal;

determining a wavelet scalogram by performing a wavelet analysis on the oscillatory component;

determining a dominant oscillation period of the object signal at a trigger time;

determining an average of the object signal in accordance with the dominant oscillation period at the trigger time.

15. The vehicle dynamic characteristic analysis method as claimed in claim 14, wherein the determining an average of the object signal comprises:

determining a first average and a standard deviation of the object signal in accordance with the dominant oscillation period at the trigger time; and

determining a second average of the object signal before change in accordance with the first average and the standard deviation.

16. A computer readable medium storing a vehicle dynamic characteristic analysis computer program comprising:

computer program code for determining a trend component of an object signal;

computer program code for determining an oscillatory component of the object signal by removing the trend component from the object signal;

computer program code for determining a wavelet scalogram by performing a wavelet analysis on the oscillatory component;

computer program code for determining a dominant oscillation period as a scale parameter for each time with which the wavelet scalogram indicates a maximum at the each time;

computer program code for determining in accordance with the dominant oscillation period a time when the object signal is maximum; and

computer program code for determining a maximum and a minimum of the object signal within the dominant oscillation period.

17. The computer readable medium as claimed in claim 16, wherein the computer program code for determining a trend component of an object signal is implemented by one of computer program code for applying a zero-phase filter to the object signal and computer program code for approximating the object signal with an exponential function expression.

18. The computer readable medium as claimed in claim 16, wherein the vehicle dynamic characteristic analysis computer program further comprises computer program code for applying a zero-phase filter to the object signal before the determining a trend component of an object signal.

19. The computer readable medium as claimed in claim 16,

wherein the computer program code for determining a dominant oscillation period is implemented by computer program code for determining a dominant oscillation period as a scale parameter for each time with which the wavelet scalogram indicates a maximum at the each time with a band limitation on scale parameter, and

wherein the computer program code for determining a maximum and a minimum of the object signal comprises:

computer program code for determining a complex signal waveform by performing a wavelet inverse transformation of the wavelet scalogram;

computer program code for extracting a real part from the complex signal waveform; and

computer program code for determining a maximum and a minimum of the object signal within the dominant oscillation period in accordance with the real part.

20. A computer readable medium storing a vehicle dynamic characteristic analysis computer program comprising:

computer program code for determining a trend component of an object signal;

computer program code for determining an oscillatory component of the object signal by removing the trend component from the object signal;

computer program code for determining a wavelet scalogram by performing a wavelet analysis on the oscillatory component with a band limitation on scale parameter;

computer program code for determining a complex signal waveform by performing a wavelet inverse transformation of the wavelet scalogram; and

computer program code for obtaining a signal waveform envelope by determining the absolute value of the complex signal waveform.

21. A computer readable medium storing a vehicle dynamic characteristic analysis computer program comprising:

computer program code for determining a trend component of an object signal;

computer program code for determining an oscillatory component of the object signal by removing the trend component from the object signal;

computer program code for determining a wavelet scalogram by performing a wavelet analysis on the oscillatory component;

computer program code for processing the wavelet scalogram with a filter having a frequency-gain characteristic at each time;

computer program code for determining a complex signal waveform by performing a wavelet inverse transformation of the wavelet scalogram; and

computer program code for obtaining the magnitude of a component emphasized by the filter by determining the absolute value of the complex signal waveform.

22. A computer readable medium storing a vehicle dynamic characteristic analysis computer program comprising:

computer program code for determining a trend component of an object signal;

computer program code for determining an oscillatory component of the object signal by removing the trend component from the object signal;

computer program code for determining a wavelet scalogram by performing a wavelet analysis on the oscillatory component;

computer program code for processing the wavelet scalogram with a filter having a frequency-gain characteristic at each time;

computer program code for determining a complex signal waveform by performing a wavelet inverse transformation of the wavelet scalogram; and

computer program code for determining a signal waveform of the emphasized component by extracting a real part from the complex signal waveform.

23. A computer readable medium storing a vehicle dynamic characteristic analysis computer program comprising:

computer program code for determining a trend component of an object signal;

computer program code for determining an oscillatory component of the object signal by removing the trend component from the object signal;

computer program code for determining a wavelet scalogram by performing a wavelet analysis on the oscillatory component;

computer program code for determining a dominant oscillation period of the object signal at a trigger time; and

computer program code for determining an average of the object signal in accordance with the dominant oscillation period at the trigger time.

24. The computer readable medium as claimed in claim 23, wherein the computer program code for determining an average of the object signal comprises:

computer program code for determining a first average and a standard deviation of the object signal in accordance with the dominant oscillation period at the trigger time; and

computer program code for determining a second average of the object signal before change in accordance with the first average and the standard deviation.