@ThU 485, @ Carl Love 10485

It is strange. I use Maple 18 to run this code and following error comes up for 2 last lines:

J_O_L1.q_dot;
%;
Error, (in Vector[column]) Matrix index out of range

Dear @vv

Thank you for your answer 

Thank you @vv for your answer. 

I edited the code as you said, but unfortunately the problem 1 still exists. Could you please upload the corrected file that solve 2 problems?

Dear @Mac Dude. Thank you for notable tips. All 9 equations from E_1 to E_9 are easy but nonlinear equations. Many terms in these equations are zero and the size of equation reduces considerably. You are right about E_7 equation, as you can see in @Kitonum code, the L unknown becomes zero always. Therefore, E_7 can be removed.

Dear @Kitonum. Thank you for your answer. It seems that there is no direct method to include constraint equation into system of equations to be solved simultaneously. The only way is to change the input data and solve 9 equations again with solve command and check whether C[1] is satisfied or not. I mean a try and error procedure. Am I right???

@ecterrab 

Thanks for your thorough answer. you mean that Maple cannot solve this system of ODE's??

Dear @ecterrab 

I am waiting for your answer impatiently. That's very kind of you. Thank you.

Thank you @tomleslie for your answer.

@tomleslie 

Can you show me how to use ExportMatrix/ImportMatrix command with an example in order to not regeneration for each session?

Thanks

@Carl Love 

Thanks for your answer.

@Markiyan Hirnyk 

Thanks for your answer.

@Markiyan Hirnyk 

Dear Markiyan Hirnyk. After evaluation of these 139 parameters, how can I solve the system effectively and exactly?

@Markiyan Hirnyk 

Thanks for your answer dear Markiyan Hirnyk.

Dear @tomleslie

Indeed, in these equations, we have 6 unknowns in which 4 of them, i.e. "ud","vd","wd","rd" are assumed to be known. For these 4 unknowns, I assume some certain function. Based on these assumed functions, I want to find what are the value of 2 others, i.e "pd" and "qd". The other parameters such as m[b], I[xx] and so on have values and I have not substituted them yet. I want the answer parametrically. 

@Carl Love 

Thanks dear Carl Love for your guidance