Description
The Ball & Beam module consists of a steel rod in parallel with a nickel-chromium wirewound resistor forming the track on which the metal ball is free to roll. The position of the ball is obtained by measuring the voltage at the steel rod. When the ball rolls along the track, it acts as a wiper similar to a potentiometer resulting in the position of the ball. When coupled to the SRV02 plant, the DC motor will drive the beam such that the motor angle controls the tilt angle of the beam. The ball then travels along the length of the beam.


Nonlinear equation \[\begin{array}{*{20}{c}} \begin{array}{l} {F_{ball}}(t) = {F_{x,t}}(t) - {F_{x,r}}(t)\\ \\ {F_{x,t}}(t) = {m_b}g\sin \alpha (t)\\ {F_{x,r}}(t) = \frac{{{J_b}}}{{{r_b}^2}}(\frac{{{\partial ^2}}}{{\partial {t^2}}}x(t)) & & \leftarrow \end{array}&{\left( \begin{array}{l} {F_{x,r}}(t) = \frac{{{\tau _b}}}{{{r_b}}}\\ {\tau _b}(t) = {J_b}(\frac{{{\partial ^2}}}{{\partial {t^2}}}{\gamma _b}(t))\\ x(t) = {r_b} \times {\gamma _b}(t) \end{array} \right)} \end{array}\\ \frac{{{\partial ^2}}}{{\partial {t^2}}}x(t) = \frac{{{m_b}g\sin \theta (t){r_{arm}} \times {r_b}^2}}{{{L_{beam}}({m_b}{r_b}^2 + {J_b})}} = {K_{bb}}\sin \theta (t)\] Linearization \[\mathop {\lim }\limits_{\theta \to 0} \,\,{K_{bb}}\sin \theta (t) \approx {K_{bb}}\theta (t)\] Plant model \[{P_s}(s) = \frac{K}{{s\left( {\tau s + 1} \right)}}\] State-space model \[{X^T} = \left[ {\begin{array}{*{20}{c}} {{x^T}}&{{\dot x}^T}&{\theta ^T}&{\dot \theta^T } \end{array}} \right]\\ \dot X(t) = \left[ {\begin{array}{*{20}{c}} 0&1&0&0\\0&0&{{K_{bb}}}&0\\0&0&0&1\\0&0&0&{ - \frac{K}{\tau }}\end{array}} \right]X(t) + \left[ \begin{array}{l}0\\0\\0\\\frac{1}{\tau }\end{array} \right]u(t)\]


Control Engineering Lab., School of Elec. Eng., CBNU
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