Sum and Derivate

Questions
,
1

I want to programm a N-Pendulum(the Idea comes from the Doublependulum). And i have the following Problem:

v[q_]:=Sum[Subscript[l, n]Sin[Subscript[\[Phi], n][t]],{n,1,q,1}]

w[q_]:=Sum[-Subscript[l, n]Cos[Subscript[\[Phi], n][t]],{n,1,q,1}]

vko=Subscript[l, 1]Sin[Subscript[\[Phi], 1][t]]

wko=-Subscript[l, 1]Cos[Subscript[\[Phi], 1][t]]

These are the Koordinates of for the mass of the first pendulum. But what happens now is more a technical problem of mathematica, i think.
I put the first point (v,w) in to the kinetic energy:

Tkin = Sum[

  Subscript[m, q]/2 (D[v[q], t]^2 + D[w[q], t]^2), {q, 1, 1, 1}]

Out:

1/2 Subscript[m, 1] (Cos[Subscript[\[Phi], 1][t]]^2 

\!\(\*SubsuperscriptBox[\(l\), \(1\), \(2\)]\) Derivative[1][

     Subscript[\[Phi], 1]][t]^2 + Sin[Subscript[\[Phi], 1][t]]^2 

\!\(\*SubsuperscriptBox[\(l\), \(1\), \(2\)]\) TextCell[

    ""]^2 Derivative[1][Subscript[\[Phi], 1]][t]^2)

The Second Point (vko,wko)

Tkin = Sum[

  Subscript[m, q]/2 (D[vko, t]^2 + D[wko, t]^2), {q, 1, 1, 1}]

Out:

1/2 Subscript[m, 1] (Cos[Subscript[\[Phi], 1][t]]^2 

\!\(\*SubsuperscriptBox[\(l\), \(1\), \(2\)]\) Derivative[1][

     Subscript[\[Phi], 1]][t]^2 + Sin[Subscript[\[Phi], 1][t]]^2 

\!\(\*SubsuperscriptBox[\(l\), \(1\), \(2\)]\) Derivative[1][

     Subscript[\[Phi], 1]][t]^2)

In the first Out u see: mathematica put " ^2" in the solution. But when i give mathematica the koord without the sum, it gives the correct solution without the Textcell[“”]^2.
How can i bring mathematica to stop generating this Textcell?

2

Compare the formulation of a triple pendulum in the demonstrations project http://demonstrations.wolfram.com/TriplePendulum/ occasionally I faced problems with sub- and/or superscripted variable and function names; in such cases instead of

Subscript[f, i]

the

f[i]

does a better job.