23.7
Routh-Hurwitz 기준을 적용할 때 안정성 분석을 복잡하게 만드는 두 가지 특정 시나리오가 발생할 수 있습니다.
첫 번째 시나리오는 R…
Routh-Hurwitz 기준에서는 두 가지 뚜렷한 상황이 발생할 수 있습니다.
Routh 테이블의 첫 번째 열에 단수 0이 독점적으로 나타나면 0으로 나누기 문제가 발생합니다.
이 문제를 피하기 위해 일반적으로 엡실론과 같은 작은 숫자가 0을 대체합니다.
해석은 엡실론에 대한 기호를 가정하는 것으로 시작됩니다. 엡실론이 양수로 선택되면 부호 변경은 시스템이 오른쪽 반평면에 두 개의 극이 있어 불안정하다는 것을 나타냅니다. 마찬가지로, 음수를 선택하면 동일한 불안정성 결론에 도달하게 됩니다.
두 번째 시나리오는 전체 행이 0으로만 구성되는 경우에 발생합니다. 이것은 짝수 다항식이 원래 다항식의 인수임을 시사합니다.
보조 다항식은 0 행 위에 있는 행의 계수를 사용하여 형성됩니다. 이것은 미분되며, 이 도함수의 계수가 표의 0을 대체합니다.
또한 나머지 Routh 테이블을 구성하는 일반적인 방법이 구현됩니다.
짝수 다항식과 홀수 다항식은 별도로 표로 작성되며, 오른쪽 절반 평면 극점의 총 수는 짝수 및 홀수 다항식 표에서 발견된 극점의 합입니다.
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Q1: What happens when a singular zero appears in the first column of the Routh table?
A singular zero in the first column creates a division by zero problem. To resolve this, a small number called epsilon is substituted for the zero. The stability analysis then proceeds by assuming a sign for epsilon. Regardless of whether epsilon is positive or negative, the sign changes indicate the system is unstable with two poles in the right-half s-plane.
Q2: How do you handle an entire row of zeros in the Routh table?
When an entire row consists of zeros, it indicates an even polynomial is a factor of the original polynomial. An auxiliary polynomial is constructed using coefficients from the row above the zero row. This auxiliary polynomial is differentiated, and the derivative coefficients replace the zeros in the table. The standard Routh table construction then continues from this point.
Q3: What does the epsilon substitution method reveal about system stability?
The epsilon substitution method resolves division by zero issues when a singular zero appears in the Routh table's first column. By assuming epsilon as either positive or negative and observing sign changes, engineers can determine if the system is unstable. Both epsilon values lead to the same conclusion: two poles exist in the right-half s-plane, indicating instability.
Q4: How are even and odd polynomials analyzed separately in the Routh-Hurwitz criterion?
When an entire row of zeros appears, the original polynomial contains an even polynomial factor. Even and odd polynomials are tabulated separately using the auxiliary polynomial method. The total number of right-half s-plane poles is determined by summing the poles found in both the even and odd polynomial Routh tables, ensuring comprehensive stability analysis.
Q5: Why is the auxiliary polynomial method important for Routh-Hurwitz analysis?
The auxiliary polynomial method addresses the special case when an entire Routh table row contains zeros. By differentiating the auxiliary polynomial formed from the row above the zeros, engineers obtain coefficients that replace the zeros. This technique prevents misinterpretation of system stability and enables accurate identification of right-half s-plane poles for robust system design.
Q6: What are the two special cases that complicate Routh-Hurwitz stability analysis?
The first special case occurs when a singular zero appears in the Routh table's first column, requiring epsilon substitution. The second case arises when an entire row contains zeros, indicating an even polynomial factor. Both scenarios require specific handling techniques to avoid misinterpretation and ensure accurate determination of system stability and right-half s-plane pole locations.
Q7: How does the Routh-Hurwitz criterion determine if a system is stable or unstable?
The Routh-Hurwitz criterion analyzes sign changes in the first column of the Routh table to determine stability. When special cases like singular zeros or zero rows occur, specific techniques such as epsilon substitution or auxiliary polynomial differentiation are applied. The presence of sign changes indicates poles in the right-half s-plane, confirming the system is unstable and affecting transient and steady state response.