Velocity source

Forces the flange to follow the input velocity.

  • signal
  • translational
  • Modelica Standard Library
  • 2 ports
  • 1 parameter
BlockVelocity sourceKindtransSpeedSourceLibraryTranslational

Description

Forces the flange to follow a reference velocity, supplying whatever force that takes. The reference passes through a first-order filter with critical frequency f_crit.

Example

End stops and motion sources A sliding mass that hits its stops, a mass pushed into an elastic stop, and masses driven by speed and position sources.

20 sin(πt) NForce sourceMass with stopsPosition (stops)Push 10 NMass 1 kgElastic stopStop at 0.1 mPosition (elastic stop)0.2 m/sSpeed sourceMass 1 kg (speed)Velocity (speed source)0.1 sin(πt) mPosition sourceMass 1 kg (position)Position (position source)
In Gradara, select a Velocity source block and press F1, then choose Open example. It opens as a new model in My models, ready to run.

Also in this example:ConstantSine waveFixed (translational)MassHard stopMass with stopsForce sourceConstant forcePosition sourcePosition sensorVelocity sensor

Ports

Inputs 1

  • vv_refsignal · m/s

    Reference velocity, in m/s.

Conserving terminals 1

  • shaftflangetranslational

    Driven flange.

Parameters

  • Filter frequencyf_crit50 Hz

    ≥ 0

    Corner frequency of the reference filter, in Hz. Must be positive; at 0 the velocity never changes.

Equations

Modelica
v = d(flange.s)/dt
dv/dt = 2π · f_crit · (v_ref − v)
Initial: flange.s = 0, v = v_ref

Implementation

Modelica Standard Library 4.1.0Modelica.Mechanics.Translational.Sources.Speed
MSL documentation

Assumptions and limitations

  • The initial position is fixed at 0 and the initial velocity at v_ref. Force is unlimited.

See also

Select a block in Gradara and press F1 to open its page offline.