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Force Limiter

1-D Translational Force Limiter Description The Force Limiter component limits the positive and negative force transmitted between two translational flanges. The force limits can either be set by parameters or controlled via input signals. The parameters $\mathrm{\text{'}df/dv\text{'}}$ and $\mathrm{\text{'}dv/df\text{'}}$ set the slope and inverse slope of the force vs relative velocity curve in the limiting and non-limiting regions, respectively. The parameters $d$ and $m$ add damping and mass to the relative motion between the two flanges. Equations ${s}_{\mathrm{rel}}={s}_{b}-{s}_{a}$ ${v}_{\mathrm{rel}}=\frac{{\mathrm{ds}}_{\mathrm{rel}}}{\mathrm{dt}}=\left\{\begin{array}{cc}s-{f}_{2}+{v}_{2}& \mathrm{minlimited}\\ s-{f}_{1}+{v}_{1}& \mathrm{maxlimited}\\ \frac{{v}_{1.}\left(s-{f}_{2}\right)-{v}_{2.}\left(s-{f}_{1}\right)}{{f}_{1}-{f}_{2}}& \mathrm{otherwise}\end{array}$ $f=-{f}_{a}={f}_{b}=m\cdot \frac{{\mathrm{dv}}_{\mathrm{rel}}}{\mathrm{dt}}+d\cdot {v}_{\mathrm{rel}}+\left\{\begin{array}{cc}{f}_{2}+\left(s-{f}_{2}\right)\cdot \mathrm{\text{'}df/dv\text{'}}& \mathrm{minlimited}\\ {f}_{1}+\left(s-{f}_{1}\right)\cdot \mathrm{\text{'}df/dv\text{'}}& \mathrm{maxlimited}\\ s& \mathrm{otherwise}\end{array}$ $\mathrm{maxlimited}=\left(s<{f}_{1}\right)$ $\mathrm{minlimited}=\left({f}_{2}

Variables

 Name Units Description Modelica ID ${s}_{\mathrm{rel}}$ $m$ Relative distance between flanges s_rel $f$ $N$ Force between flanges f ${v}_{\mathrm{rel}}$ $\frac{m}{s}$ Relative velocity of flanges v_rel

Connections

 Name Description Modelica ID ${\mathrm{flange}}_{a}$ Left flange flange_a ${\mathrm{flange}}_{b}$ Right flange flange_b $\mathrm{fmax}$ Optional real input signal that sets maximum force ($N$) fmax $\mathrm{fmin}$ Optional real input signal that sets minimum force ($N$) fmin

Parameters

 Name Default Units Description Modelica ID Use ${f}_{\mathrm{max}}$ input $\mathrm{false}$ True (checked) means use an input signal to set maximum force useFmaxInput Use ${f}_{\mathrm{min}}$ input $\mathrm{false}$ True (checked) means use an input signal to set minimum force useFminInput ${f}_{\mathrm{max}}$ $+1$ $N$ Maximum force f_max ${f}_{\mathrm{min}}$ $-1$ $N$ Minimum force f_min $m$ $0$ $\mathrm{kg}$ Relative translational inertia m $d$ $0$ $N\cdot \frac{s}{m}$ Relative translational damping constant d df/dv $0$ $N\cdot \frac{s}{m}$ Slope of $f$ vs ${v}_{\mathrm{rel}}$ curve when force limited df/dv dv/df $0$ $\frac{m}{N\cdot s}$ Inverse slope of ${v}_{\mathrm{rel}}$ vs $f$ curve when not force limited dv/df