FindGrashofInstance

FindGrashofInstance[type, n]
searches n pair four-bar mechanism instances of the specified grashof type type. The function returns pairs of four-bar mechanisms each of them in different solution branches.
  • FindGrashofInstance function searches four-bar mechanism belonging to the specified grashof class. The classification is based on the range of movement of the input and output links.
LinkLengthConditionsAutomaticAdditional length constraints on the link's length
  • Given the 3 Grashof constant T1, T2, T3 if the product of the three constant is positive then the fou-bar linkage is called Grashof linkage otherwise it is a non-Grashof linkage T1=l0-l1+l2-l3 T2=l0-l1-l2+l3 T3=-l0-l1+l2+l3
  • The fourbar1 and fourbar2 linkages have one additional linkage record called "$GrashofConstants". This record contains the definition of the Grashof constraints in a list.
  • 4 Grashof linkage classes are defined as follows:
    NameT1T2T3
    $CrankRocker+++
    $RockerCrank+--
    $DoubleCrank--+
    $GrashofDoubleRocker-+-
    4 Non-Grashof linkage classes are defined as follows:
    NameT1T2T3
    $00DoubleRocker---
    $0PiDoubleRocker++-
    $Pi0DoubleRocker+-+
    $PiPiDoubleRocker-++
    4 foldable linkage classes are defined as follows:
    NameCondition
    $FoldabeCrankT1*T2=0T3>0
    $Foldabe0RockerT1*T2 ==0 T3<0
    $FoldabePiRockerT1*T2 <0 T3==0
    $FoldabeRhombusT1*T2 ==0 T3==0
Load the LinkageDesigner package
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Find two pairs of crank-rocker linkages
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Display the four-bar linkage instances
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Change the width of the links to 3 unit and animate the resulted linkage
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