Double Pendulum

x1[t_] := R1*Sin[\[Theta]1[t]]
y1[t_] := (-R1)*Cos[\[Theta]1[t]]
x2[t_] := R1*Sin[\[Theta]1[t]] + R2*Sin[\[Theta]2[t]]
y2[t_] := (-R1)*Cos[\[Theta]1[t]] - R2*Cos[\[Theta]2[t]]
v1[t_] := Sqrt[D[x1[t], t]^2 + D[y1[t], t]^2]
v2[t_] := Sqrt[D[x2[t], t]^2 + D[y2[t], t]^2]

T1[t_] := (1/2)*m1*v1[t]^2
T2[t_] := (1/2)*m2*v2[t]^2
U[t_] := m1*g*y1[t] + m2*g*y2[t]
L[t_] := T1[t] + T2[t] - U[t]

Simplify[D[LB[t], \[Theta]1B[t]] == D[D[LB[t], Derivative[1][\[Theta]1B][t]], t]]; 
Simplify[D[LB[t], \[Theta]2B[t]] == D[D[LB[t], Derivative[1][\[Theta]2B][t]], t]]; 

\[Theta]10 = Pi/2; 
\[Theta]1d0 = 0; 
\[Theta]20 = Pi/2; 
\[Theta]2d0 = 0; 

g = 9.8; 
R1 = 0.7; 
R2 = 0.7; 
m1 = 1; 
m2 = 1; 

sols = 
  NDSolve[
   {R1*(g*m1*Sin[\[Theta]1[t]] + g*m2*Sin[\[Theta]1[t]] + 
     m2*R2*Sin[\[Theta]1[t] - \[Theta]2[t]]*Derivative[1][\[Theta]2][t]^2 + 
     (m1 + m2)*R1*Derivative[2][\[Theta]1][t] + 
     m2*R2*Cos[\[Theta]1[t] - \[Theta]2[t]]*Derivative[2][\[Theta]2][t]) == 0, 
    m2*R2*(g*Sin[\[Theta]2[t]] - R1*Sin[\[Theta]1[t] - 
      \[Theta]2[t]]*Derivative[1][\[Theta]1][t]^2 + R1*Cos[\[Theta]1[t] - 
      \[Theta]2[t]]*Derivative[2][\[Theta]1][t] + R2*Derivative[2][\[Theta]2][t]) == 0, 
    \[Theta]1[0] == \[Theta]10, 
    Derivative[1][\[Theta]1][0] == \[Theta]1d0, 
    \[Theta]2[0] == \[Theta]20, 
    Derivative[1][\[Theta]2][0] == \[Theta]2d0
   }, 
   {\[Theta]1, Derivative[1][\[Theta]1], Derivative[2][\[Theta]1], 
    \[Theta]2, Derivative[1][\[Theta]2], Derivative[2][\[Theta]2]
   }, 
   {t, 0, 490}, 
   MaxSteps -> 100000
  ]; 
    
\[Theta]1n[t_] := Evaluate[\[Theta]1[t] /. sols[[1,1]]]
\[Theta]2n[t_] := Evaluate[\[Theta]2[t] /. sols[[1,4]]]
\[Theta]d1n[t_] := Evaluate[Derivative[1][\[Theta]1][t] /. sols[[1,1]]]
\[Theta]d2n[t_] := Evaluate[Derivative[1][\[Theta]2][t] /. sols[[1,4]]]

x1n[t_] := R1*Sin[\[Theta]1n[t]]
y1n[t_] := (-R1)*Cos[\[Theta]1n[t]]
x2n[t_] := R1*Sin[\[Theta]1n[t]] + R2*Sin[\[Theta]2n[t]]
y2n[t_] := (-R1)*Cos[\[Theta]1n[t]] - R2*Cos[\[Theta]2n[t]]

Manipulate[
  Show[
    ParametricPlot[
      {{x1n[t], y1n[t]}, {x2n[t], y2n[t]}}, 
      {t, 0, tf}, 
      PlotStyle -> {{Red}, {Blue}}, 
      AspectRatio -> Automatic, 
      PlotRange -> {{-R1 - R2, R1 + R2}, {-R1 - R2, (R1 + R2)/3.5}}, 
      Axes -> True, 
      GridLines -> Automatic, GridLinesStyle -> Directive[LightGray]
    ], 
    Graphics[
      {
        {AbsoluteThickness[2], Red, Line[{{0, 0}, {x1n[tf], y1n[tf]}}]}, 
        {AbsoluteThickness[2], Blue, Line[{{x1n[tf], y1n[tf]}, {x2n[tf], y2n[tf]}}]}, 
        {PointSize[Large], Red, Point[{x1n[tf], y1n[tf]}]}, 
        {PointSize[Large], Blue, Point[{x2n[tf], y2n[tf]}]}
      }
    ]
  ], 
  {tf, 0.01, 14, 0.1}
]