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POMatrix math with cosin / sin
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  1. POMatrix math with cosin / sin
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    copied!<p>I have a routine which will accept the joint parameters d, theta, a, and alpha as input and will produce the corresponding 4x4 homogeneous matrix as output. I have tested my matrix multiplication and it does work fine. I will get 5 matrices from the input which will all be multiplied together resulting in $t^0_5$ . The test cases are <a href="http://nkonecny.com/lab3results.txt" rel="nofollow">here</a>. My output is nothing like the result. Here is my code:</p> <p>First the matrix that we input the data into a martix that uses the <a href="http://en.wikipedia.org/wiki/Denavit-Hartenberg_Parameters" rel="nofollow">DH parameter tables</a>:</p> <pre><code> //Kinematics Matrix44 Matrix44::kinematics(double d, double theta, double a, double alpha)const { Matrix44 result; double pi = 3.14159; double radstheta = theta*(pi/180); double radsalpha = alpha*(pi/180); //row1 result.element[0][0] = cos(radstheta); result.element[0][3] = -cos(radsalpha)*sin(radstheta); result.element[0][4] = sin(radsalpha)*sin(radstheta); result.element[0][3] = a*cos(radstheta); //row2 result.element[1][0] = sin(radstheta); result.element[1][5] = cos(radsalpha)*cos(radstheta); result.element[1][6] = -sin(radsalpha)*cos(radstheta); result.element[1][3] = a*sin(radstheta); //row3 result.element[2][0] = 0; result.element[2][7] = sin(radsalpha); result.element[2][8] = cos(radsalpha); result.element[2][3] = d; //row4 result.element[3][0] = 0; result.element[3][9] = 0; result.element[3][10] = 0; result.element[3][3] = 1; return result; } </code></pre> <p>The part in main where I get the result, the data comes from <a href="http://nkonecny.com/DHparams.png" rel="nofollow">this table</a>:</p> <pre><code> Matrix44 a,b,c,d,e; //in order (d,theta,a,alpha) //all data is static and given except for theta which changes, see link for cases a = a.kinematics(27.2,0, 0, 90); b = b.kinematics(0,0,19.2,180); c = c.kinematics(0,0,19.2,0); d = d.kinematics(0,0+90,0,90); e = e.kinematics(10.5,0,0,0); //anyone know how to format this nicely? The operator is overload to print a matrix // cout &lt;&lt; left &lt;&lt;setw(20) &lt;&lt; a*b*c*d*e; </code></pre> <p>Theta and alpha are angles while D and A are distances.</p> <p>The code for the output / input:</p> <pre><code> //User Input istream&amp; operator&gt;&gt; (istream&amp; s, Matrix44&amp; t) { for (int i=0; i&lt;4; i++) for (int j=0; j&lt;4; j++) s &gt;&gt; t.element[i][j]; if (!s) { cerr &lt;&lt; "Error reading Matrix from stream"; exit(0); } return s; } //User Output ostream&amp; operator&lt;&lt; (ostream&amp; s, const Matrix44&amp; t) { for (int i=0; i&lt;4; i++) { for (int j=0; j&lt;4; j++) s &lt;&lt; t.element[i][j] &lt;&lt; " "; s &lt;&lt; endl; } if (!s) { cerr &lt;&lt; "Error writing Matrix to stream"; exit(0); } return s; } </code></pre> <p>Matrix:</p> <pre><code> class Matrix44 { private: double element[4][4]; friend class Point; public: Matrix44(void); Matrix44 transpose(void) const; Matrix44 inverse(Matrix44 x) const; Matrix44 kinematics(double d, double theta, double a, double alpha) const; friend istream&amp; operator&gt;&gt;(istream&amp; s, Matrix44&amp; t); friend ostream&amp; operator&lt;&lt;(ostream&amp; s, const Matrix44&amp; t); Matrix44 operator *(Matrix44 b); Point operator*(const Point &amp; P); }; </code></pre>
 

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