<<CheminPackLocaux`

r=3;d=0.2 r;t0=0; t1=2 π;t2=t1+r+2 d;
Unprotect[C];o={0,0};c=t2;C={c,0};
n=24;   (* de préférence pair  *)
ω=2; φ=(π/2);
α[t_]:=ω t+φ;
x[t_]:=r Cos[α[t]];
y[t_]:=r Sin[α[t]];
p[t_]:={x[t],y[t]};
g[j_]:=Plot[y[τ],{τ,t0,j((2 π)/n)},Prolog->
{Circle[C,r],{PointSize[0.01],Point[C],Point[p[j((2 π)/n)]+C],Point[{j((2 π)/n),y[j((2 π)/n)]}]},{Dashing[{0.02}],Line[{C,p[j((2 π)/n)]+C,{j((2 π)/n),y[j((2 π)/n)]}}]},Text["H(t)",1.15p[j((2 π)/n)]+C]},AspectRatio->Automatic,PlotRange->{{-2d,t2+r+d},{-r-d,r+d}},Ticks->{{{0,"0"},{j((2 π)/n),"t"}},{{y[j((2 π)/n)],"y(t)"}}},ImageSize->{500,300},AspectRatio->(3/5)];
Animate[g[j],{j,1,n}]