Solving nonlinear system of equations for variables











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I would like to solve the following system of equations for $α_1$ and $α_2$:



$$
begin{bmatrix}
frac{alpha_1 sin(alpha_1 +alpha_2)-sin(alpha_1) alpha_1 +sin(alpha_1) alpha_2}{alpha_1 alpha_2}\
frac{-alpha_1 cos(alpha_1+alpha_2)+cos(alpha_1)alpha_1+alpha_2-alpha_2 cos(alpha_1)}{alpha_1 alpha_2}
end{bmatrix}
=
begin{bmatrix}
x\
y
end{bmatrix}
$$



Obviously, this is not straight forward. The equations describe a Cartesian robotic end-effector position depending on the two angles $α_1$ and $α_2$. I would like to get your feedback how to proceed.



1.) Is there an analytic solution to compute $α_1$ and $α_2$ for a given $x$ and $y$?



2.) If not, would you try to fit an approximation around the working point?



3.) Is there any other approach I don't have in mind?



Every feedback is appreciated. Thank you very much!










share|cite|improve this question






















  • I doubt there is a closed form solution. Did you consider Newton's Method? The danger is that there may be periodic roots and you might have to deal with that once roots are found.
    – Moo
    Nov 22 at 16:39










  • Usually, when you have both angle and a trigonometric function of the angle, the only way to solve it is numerically.
    – Andrei
    Nov 22 at 16:40










  • @Moo - Yes, I thought of Newton's Method and yes there are periodic roots. I hoped for any more elegant solution. Thanks, for your feedback.
    – Markus
    Nov 22 at 16:59










  • @Andrei - that's what I guessed - I just hoped someone might know a better solution. Thanks though!!
    – Markus
    Nov 22 at 17:00















up vote
0
down vote

favorite












I would like to solve the following system of equations for $α_1$ and $α_2$:



$$
begin{bmatrix}
frac{alpha_1 sin(alpha_1 +alpha_2)-sin(alpha_1) alpha_1 +sin(alpha_1) alpha_2}{alpha_1 alpha_2}\
frac{-alpha_1 cos(alpha_1+alpha_2)+cos(alpha_1)alpha_1+alpha_2-alpha_2 cos(alpha_1)}{alpha_1 alpha_2}
end{bmatrix}
=
begin{bmatrix}
x\
y
end{bmatrix}
$$



Obviously, this is not straight forward. The equations describe a Cartesian robotic end-effector position depending on the two angles $α_1$ and $α_2$. I would like to get your feedback how to proceed.



1.) Is there an analytic solution to compute $α_1$ and $α_2$ for a given $x$ and $y$?



2.) If not, would you try to fit an approximation around the working point?



3.) Is there any other approach I don't have in mind?



Every feedback is appreciated. Thank you very much!










share|cite|improve this question






















  • I doubt there is a closed form solution. Did you consider Newton's Method? The danger is that there may be periodic roots and you might have to deal with that once roots are found.
    – Moo
    Nov 22 at 16:39










  • Usually, when you have both angle and a trigonometric function of the angle, the only way to solve it is numerically.
    – Andrei
    Nov 22 at 16:40










  • @Moo - Yes, I thought of Newton's Method and yes there are periodic roots. I hoped for any more elegant solution. Thanks, for your feedback.
    – Markus
    Nov 22 at 16:59










  • @Andrei - that's what I guessed - I just hoped someone might know a better solution. Thanks though!!
    – Markus
    Nov 22 at 17:00













up vote
0
down vote

favorite









up vote
0
down vote

favorite











I would like to solve the following system of equations for $α_1$ and $α_2$:



$$
begin{bmatrix}
frac{alpha_1 sin(alpha_1 +alpha_2)-sin(alpha_1) alpha_1 +sin(alpha_1) alpha_2}{alpha_1 alpha_2}\
frac{-alpha_1 cos(alpha_1+alpha_2)+cos(alpha_1)alpha_1+alpha_2-alpha_2 cos(alpha_1)}{alpha_1 alpha_2}
end{bmatrix}
=
begin{bmatrix}
x\
y
end{bmatrix}
$$



Obviously, this is not straight forward. The equations describe a Cartesian robotic end-effector position depending on the two angles $α_1$ and $α_2$. I would like to get your feedback how to proceed.



1.) Is there an analytic solution to compute $α_1$ and $α_2$ for a given $x$ and $y$?



2.) If not, would you try to fit an approximation around the working point?



3.) Is there any other approach I don't have in mind?



Every feedback is appreciated. Thank you very much!










share|cite|improve this question













I would like to solve the following system of equations for $α_1$ and $α_2$:



$$
begin{bmatrix}
frac{alpha_1 sin(alpha_1 +alpha_2)-sin(alpha_1) alpha_1 +sin(alpha_1) alpha_2}{alpha_1 alpha_2}\
frac{-alpha_1 cos(alpha_1+alpha_2)+cos(alpha_1)alpha_1+alpha_2-alpha_2 cos(alpha_1)}{alpha_1 alpha_2}
end{bmatrix}
=
begin{bmatrix}
x\
y
end{bmatrix}
$$



Obviously, this is not straight forward. The equations describe a Cartesian robotic end-effector position depending on the two angles $α_1$ and $α_2$. I would like to get your feedback how to proceed.



1.) Is there an analytic solution to compute $α_1$ and $α_2$ for a given $x$ and $y$?



2.) If not, would you try to fit an approximation around the working point?



3.) Is there any other approach I don't have in mind?



Every feedback is appreciated. Thank you very much!







trigonometry systems-of-equations nonlinear-system






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share|cite|improve this question











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asked Nov 22 at 16:33









Markus

1




1












  • I doubt there is a closed form solution. Did you consider Newton's Method? The danger is that there may be periodic roots and you might have to deal with that once roots are found.
    – Moo
    Nov 22 at 16:39










  • Usually, when you have both angle and a trigonometric function of the angle, the only way to solve it is numerically.
    – Andrei
    Nov 22 at 16:40










  • @Moo - Yes, I thought of Newton's Method and yes there are periodic roots. I hoped for any more elegant solution. Thanks, for your feedback.
    – Markus
    Nov 22 at 16:59










  • @Andrei - that's what I guessed - I just hoped someone might know a better solution. Thanks though!!
    – Markus
    Nov 22 at 17:00


















  • I doubt there is a closed form solution. Did you consider Newton's Method? The danger is that there may be periodic roots and you might have to deal with that once roots are found.
    – Moo
    Nov 22 at 16:39










  • Usually, when you have both angle and a trigonometric function of the angle, the only way to solve it is numerically.
    – Andrei
    Nov 22 at 16:40










  • @Moo - Yes, I thought of Newton's Method and yes there are periodic roots. I hoped for any more elegant solution. Thanks, for your feedback.
    – Markus
    Nov 22 at 16:59










  • @Andrei - that's what I guessed - I just hoped someone might know a better solution. Thanks though!!
    – Markus
    Nov 22 at 17:00
















I doubt there is a closed form solution. Did you consider Newton's Method? The danger is that there may be periodic roots and you might have to deal with that once roots are found.
– Moo
Nov 22 at 16:39




I doubt there is a closed form solution. Did you consider Newton's Method? The danger is that there may be periodic roots and you might have to deal with that once roots are found.
– Moo
Nov 22 at 16:39












Usually, when you have both angle and a trigonometric function of the angle, the only way to solve it is numerically.
– Andrei
Nov 22 at 16:40




Usually, when you have both angle and a trigonometric function of the angle, the only way to solve it is numerically.
– Andrei
Nov 22 at 16:40












@Moo - Yes, I thought of Newton's Method and yes there are periodic roots. I hoped for any more elegant solution. Thanks, for your feedback.
– Markus
Nov 22 at 16:59




@Moo - Yes, I thought of Newton's Method and yes there are periodic roots. I hoped for any more elegant solution. Thanks, for your feedback.
– Markus
Nov 22 at 16:59












@Andrei - that's what I guessed - I just hoped someone might know a better solution. Thanks though!!
– Markus
Nov 22 at 17:00




@Andrei - that's what I guessed - I just hoped someone might know a better solution. Thanks though!!
– Markus
Nov 22 at 17:00















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