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1、計算機仿真（龍格庫塔方法）的軟件 VB 設計與實現(xiàn)
Dim a(0 To 10) As Single, b(0 To 10) As Single, c(0 To 10) As Single, d(0 To 10) As Single
Dim e(0 To 10) As Single, h(0 To 10) As Single, p(0 To 10) As Single, q(0 To 10) As Single
Dim n1 As Byte, n2 As Byte n1 表示的是 y
的階數(shù) ,n2 表示的是輸入函數(shù)的階數(shù)
Dim i As Integer
Dim f(0 To 2
2、000) As Single f(m)=y, 也就是各個時刻 的y值
Dim X0(0 To 12) As Single, X1(0 To 12) As Single
Dim dt As Single, u As Single dt 為采樣周期 ,u 為輸入
Dim q1 As Single, p1 As Single, h1 As Single, e1 As Single
Dim b0(0 To 10) As Single, bn(-4 To 10) As Single
Dim m As Integer
Dim max As Single
Private Sub Combo1_
3、Click()
n1 表示的是 y 的階數(shù)
n1 = Combo1.ListIndex + 1
For i = n1 + 1 To 8
Text1(i).Visible = False
Label1(i).Visible = False
Label9(i).Visible = False Next
For i = 0 To n1
Text1(i).Visible = True
Label1(i).Visible = True
Label9(i).Visible = True Next
Combo2.Clear
Combo2.Text = " 請選擇輸出 u 的最大階數(shù)
4、"
For i = 0 To n1
Combo2.AddItem ((i) & " 階 ")
Next
End Sub
n2 表示的是輸入函數(shù)的階數(shù)
Private Sub Combo2_Click() n2 = Combo2.ListIndex For i = n2 + 1 To 8
Text2(i).Visible = False
Label2(i).Visible = False
Label10(i).Visible = False Next For i = 0 To n2
Text2(i).Visible = True
Label2(i).Visible = Tr
5、ue
Label10(i).Visible = True Next
End Sub
Private Sub Calculate_Click()
dt = Val(Text3.Text) dt 是采樣周期
u = Val(Text4.Text)
n1 = Combo1.ListIndex + 1
If n1 = 0 Then 對付忘記選擇最高階數(shù)時的情況
Call MsgBox(" 請選擇階數(shù)！ ", 48, " 未選擇階數(shù) ")
Exit Sub
End If
For i = 0 To 12 設X0的初值都是0,且i大于8，這一點很重要!
X0(i) = 0
Next
6、
For i = 0 To n1 - 1
a(i)b(i)c(i)d(i) 等等都是計算的中間
a(i) = -Val(Text1(i).Text) / Val(Text1(n1).Text) 變量
Next
For i = 0 To n2
b0(i) = Val(Text2(i).Text) / Val(Text1(n1).Text) Next
If Combo3.ListIndex = 1 Then
n1 = n1 + 1
For i = n1 - 1 To 1 Step -1 a(i) = a(i - 1)
Next
a(0) = 0
End If
For i
7、= -4 To -1
bn(i) = 0
Next
b(0) = a(0) * a(n1 - 1)
For i = 1 To n1 - 1
b(i) = a(i - 1) + a(i) * a(n1 - 1)
Next
c(0) = a(0) * b(n1 - 1)
For i = 1 To n1 - 1
c(i) = b(i - 1) + a(i) * b(n1 - 1)
Next
d(0) = a(0) * c(n1 - 1)
For i = 1 To n1 - 1
d(i) = c(i - 1) + a(i) * c(n1 - 1)
Next
For i =
8、 0 To n1 - 1
e(i) = dt * a(i) + dt * dt / 2 * b(i) + dt * dt * dt / 6 * c(i) + dt * dt * dt * dt / 24 * d(i) h(i) = dt * dt / 2 * a(i) + dt * dt * dt / 6 * b(i) + dt * dt * dt * dt / 24 * c(i) p(i) = dt * dt * dt / 6 * a(i) + dt * dt * dt * dt / 24 * b(i)
q(i) = dt * dt * dt * dt / 24 * a(i)
Next
9、
If n2 = 0 Then
n2 為 0 和不為 0 的公式是不一樣的，表示輸入函數(shù) u 為 n2 階
b0(0) = Val(Text2(0).Text) / Val(Text1(n1).Text)
m = 1
Do
q1 = 0: p1 = 0: h1 = 0: e1 = 0
For i = 0 To n1 - 1 這些個也是中間變量
q1 = q1 + q(i) * X0(i + 1)
p1 = p1 + p(i) * X0(i + 1)
h1 = h1 + h(i) * X0(i + 1)
e1 = e1 + e(i) * X0(i + 1)
Next
F
10、or i = 1 To n1
X1(i) = X0(i) + dt * X0(i + 1) + dt * dt / 2 * X0(i + 2) + dt * dt * dt / 6 * X0(i + 3) + dt * dt * dt * dt / 24 * X0(i + 4)
Next
X1(n1) = X1(n1) + e1 + (dt + dt * dt / 2 * a(n1 - 1) + dt * dt * dt / 6 * b(n1 - 1) + dt * dt *
dt * dt / 24 * c(n1 - 1)) * b0(0) * u
If n1 >= 4 Then
11、
X1(n1 - 3) = X1(n1 - 3) + q1 + dt * dt * dt * dt / 24 * b0(0) * u
X1(n1 - 2) = X1(n1 - 2) + p1 + (dt * dt * dt / 6 + dt * dt * dt * dt / 24 * a(n1 - 1)) * b0(0) * u
X1(n1 - 1) = X1(n1 - 1) + h1 + (dt * dt / 2 + dt * dt * dt / 6 * a(n1 - 1) + dt * dt * dt * dt / 24 * b(n1 - 1)) * b0(0) * u
ElseIf
12、 n1 >= 3 Then
X1(n1 - 2) = X1(n1 - 2) + p1 + (dt * dt * dt / 6 + dt * dt * dt * dt / 24 * a(n1 - 1)) * b0(0) * u
X1(n1 - 1) = X1(n1 - 1) + h1 + (dt * dt / 2 + dt * dt * dt / 6 * a(n1 - 1) + dt * dt * dt * dt / 24 * b(n1 - 1)) * b0(0) * u
ElseIf n1 >= 2 Then
X1(n1 - 1) = X1(n1 - 1) + h1 + (dt * d
13、t / 2 + dt * dt * dt / 6 * a(n1 - 1) + dt * dt * dt * dt / 24 * b(n1 - 1)) * b0(0) * u
End If
f(m) = X1(1)
For i = 1 To n1
X0(i) = X1(i)
Next
m = m + 1
Loop Until m = 2000 循環(huán)計算 2000 次
Else
For i = (n2 + 1) To 10
b0(i) = 0
Next
For i = 0 To n1 - 1
bn(i) = b0(i) + b0(n1) * a(i)
Next
Do
14、
For i = 1 To n1
X1(i) = X0(i) + dt * X0(i + 1) + dt * dt / 2 * X0(i + 2) + dt * dt * dt / 6 * X0(i + 3) + dt * dt * dt * dt / 24 * X0(i + 4) + (h(n1 - i) * bn(n1 - 1) + p(n1 - i) * bn(n1 - 2) + q(n1 - i) * bn(n1
- 3)) * u
Next
For i = 1 To n1
X1(i) = X1(i) + e(n1 - i) * X0(1) + h(n1 - i) *
15、X0(2) + p(n1 - i) * X0(3) + q(n1 - i) * X0(4) + (dt * bn(n1 - i) + dt * dt / 2 * bn(n1 - 1 - i) + dt * dt * dt / 6 * bn(n1 - 2 - i) + dt * dt * dt * dt / 24 * bn(n1 - 3 - i)) * u
Next f(m) = X1(1)
For i = 1 To n1 X0(i) = X1(i)
Next
m = m + 1
Loop Until m = 2000
End If
max = f(1)
For m = 2 To
16、 1999
開始繪圖
If Abs(f(m)) > Abs(max) Then max = f(m)
End If
Next
If max > 0 Then
Picture1.Cls
Picture1.Scale (-20 * dt, 1.2 * max)-(2020 * dt, -0.05 * max)
Picture1.Line (0, 0)-(2002 * dt, 0)
Picture1.Line (0, 0)-(0, 1.18 * max)
Picture1.Line (2002 * dt, 0)-(1960 * dt, -0.025 * max)
Picture
17、1.Line (2002 * dt, 0)-(1960 * dt, 0.025 * max)
Picture1.Line (0, 1.18 * max)-(10 * dt, 1.1 * max)
Picture1.Line (0, 1.18 * max)-(-10 * dt, 1.1 * max)
Else
Picture1.Cls
Picture1.Scale (-5 * dt, 0.2 * Abs(max))-(2002 * dt, 1.2 * max)
Picture1.Line (0, 0)-(2002 * dt, 0)
Picture1.Line (0, 0)-
18、(0, 1.2 * max)
Picture1.Line (2002 * dt, 0)-(1900 * dt, 0.1 * max)
Picture1.Line (0, 1.2 * max)-(50 * dt, 1.1 * max)
End If
For m = 2 To 1999
Picture1.Line ((m - 1) * dt, f(m - 1))-(m * dt, f(m)), vbRed Next
If (f(1999) - f(1800)) < 0.00001 Then
Picture1.Line (0, f(1999))-(2000 * dt, f(199
19、9))
Picture1.CurrentX = 0
Picture1.CurrentY = f(1999) + 0.1 * max
Picturel.Print "y g =" & f(1999)
End If
If Combo3.ListIndex = 0 Then
Picture1.Line (0, f(1999))-(2000 * dt, f(1999))
Picture1.CurrentX = 0
Picture1.CurrentY = f(1999) + 0.1 * max
Picture1.Print "y g =" & f(1999)
Else
Pictu
20、re1.Line (0, 0)-(2000 * dt, u * 2000 * dt)
End If
End Sub
Private Sub Combo3_Click()
Text4.Visible = True
Label12.Visible = True
If Combo3.ListIndex = 0 Then
Label5.Caption ="請輸入階躍信號 u的系數(shù)：” Else
Label5.Caption = " 請輸入斜坡信號 u 的系數(shù)：
End If
End Sub
Private Sub dtxnzb_Click()
Dim y00 As Single
21、
Dim thigema As Single
Dim ts As Single
Dim ess As Single
If Combo3.List In dex = 0 Then
yOO = f(1999) thigema = max - y00 m = 2000
Do
Loop Un til Abs(f(m) - y00) >= (0.05 * yOO)
ts = m * dt
ess = u - y00
Framel.Visible =
=True
Label6.Capti on =
="超調(diào)量d
:"& thigema
Label7.Capti on =
="調(diào)節(jié)時間
ts:" & ts
Label8.Capti on =
="穩(wěn)態(tài)誤差
ess:" & ess
Else
Framel.Visible = True
Label6.Caption ="穩(wěn)態(tài)誤差 ess:" & (u * 1999 * dt - f(1999)) / (u * 1999 * dt) & "%"
End If
End Sub
計算機仿真龍格庫塔方法的軟件VB設計與實現(xiàn)
