componentLibrary/1Dmechanics/rotational/clutchesBrakes/TorqueLimiter - Help

Home : Support : Online Help : componentLibrary/1Dmechanics/rotational/clutchesBrakes/TorqueLimiter

Torque Limiter

1-D Rotational Torque Limiter

 Description The Torque Limiter component limits the positive and negative torque transmitted between two rotational flanges. The torque limits can either be set by parameters or controlled via input signals. The parameters $\mathrm{\text{'}dtau/dw\text{'}}$ and $\mathrm{\text{'}dw/dtau\text{'}}$ set the slope and inverse slope of the torque vs relative velocity curve in the limiting and non-limiting regions, respectively. The parameters $d$ and $J$ add damping and inertia to the relative angular motion between the two flanges.
 Equations ${\mathrm{\phi }}_{\mathrm{rel}}={\mathrm{\phi }}_{b}-{\mathrm{\phi }}_{a}$ ${w}_{\mathrm{rel}}=\frac{\mathrm{dφ}}{\mathrm{dt}}=\left\{\begin{array}{cc}s-{\mathrm{\tau }}_{2}+{w}_{2}& \mathrm{minlimited}\\ s-{\mathrm{\tau }}_{1}+{w}_{1}& \mathrm{maxlimited}\\ \frac{{w}_{1.}\left(s-{\mathrm{\tau }}_{2}\right)-{w}_{2.}\left(s-{\mathrm{\tau }}_{1}\right)}{{\mathrm{\tau }}_{1}-{\mathrm{\tau }}_{2}}& \mathrm{otherwise}\end{array}$ $\mathrm{\tau }={\mathrm{\tau }}_{a}=-{\mathrm{\tau }}_{b}=d\cdot {w}_{\mathrm{rel}}+J\cdot \frac{{\mathrm{dw}}_{\mathrm{rel}}}{\mathrm{dt}}+\left\{\begin{array}{cc}{\mathrm{\tau }}_{2}+\left(s-{w}_{2}\right)\cdot \mathrm{\text{'}dtau/dw\text{'}}& \mathrm{minlimited}\\ {\mathrm{\tau }}_{1}+\left(s-{w}_{1}\right)\cdot \mathrm{\text{'}dtau/dw\text{'}}& \mathrm{maxlimited}\\ s& \mathrm{otherwise}\end{array}$ ${\mathrm{\tau }}_{1}=\left\{\begin{array}{cc}-\mathrm{tauxmax}& \mathrm{use taumax input}\\ -{\mathrm{\tau }}_{\mathrm{max}}& \mathrm{otherwise}\end{array}$ ${\mathrm{\tau }}_{2}=\left\{\begin{array}{cc}-\mathrm{tauxmin}& \mathrm{uset aumin input}\\ -{\mathrm{\tau }}_{\mathrm{min}}& \mathrm{otherwise}\end{array}$ ${w}_{1}=\mathrm{\text{'}dw/tau\text{'}}\cdot {\mathrm{\tau }}_{1}$ ${w}_{2}=\mathrm{\text{'}dw/tau\text{'}}\cdot {\mathrm{\tau }}_{2}$ $\mathrm{maxlimited}=\left(s<{\mathrm{\tau }}_{1}\right)$ $\mathrm{minlimited}=\left({\mathrm{\tau }}_{2}

Variables

 Name Units Description Modelica ID ${\mathrm{\phi }}_{\mathrm{rel}}$ $\mathrm{rad}$ Relative rotation angle phi_rel $\mathrm{\tau }$ $N\cdot m$ Torque between flanges tau ${w}_{\mathrm{rel}}$ $\frac{\mathrm{rad}}{s}$ Relative angular velocity of flanges w_rel

Connections

 Name Description Modelica ID ${\mathrm{flange}}_{a}$ Left flange flange_a ${\mathrm{flange}}_{b}$ Right flange flange_b $\mathrm{taumax}$ Optional real input signal that sets maximum torque ($N·m$) taumax $\mathrm{taumin}$ Optional real input signal that sets minimum torque ($N·m$) taumin

Parameters

 Name Default Units Description Modelica ID Use ${\mathrm{\tau }}_{\mathrm{max}}$ input $\mathrm{false}$ True (checked) means use input signal to set maximum torque useTauMaxInput Use ${\mathrm{\tau }}_{\mathrm{min}}$ input $\mathrm{false}$ True (checked) means use input signal to set minimum torque useTauMinInput ${\mathrm{\tau }}_{\mathrm{max}}$ $+1$ $N\cdot m$ Maximum torque tau_max ${\mathrm{\tau }}_{\mathrm{min}}$ $-1$ $N\cdot m$ Minimum torque tau_min $d$ $0$ $\frac{N\cdot m\cdot s}{\mathrm{rad}}$ Rotational damping constant d $J$ $0$ $\mathrm{kg}\cdot {m}^{2}$ Rotational inertia J 'dtau/dw' $0$ $\frac{N\cdot m\cdot s}{\mathrm{rad}}$ Slope of $\mathrm{\tau }$ vs ${w}_{\mathrm{rel}}$ curve when torque limited 'dtau/dw' 'dw/dtau' $0$ $\frac{\mathrm{rad}}{N\cdot m\cdot s}$ Inverse slope of $\mathrm{\tau }$ vs ${w}_{\mathrm{rel}}$ curve when not torque limited 'dw/dtau'