Sekundärreglerad hydraulisk transmission i en sexhjulig skotare
Liselott EricsonLinköpings universitet
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Soil damages
• Outdoor activities and recreation values• Biological effects• Damages which lead to reduced timber
production
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Pendulum arms
Purpose• Even soil pressure• Increased comfort for
the operator• Reduced slip
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Forwarder transmission
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Primary controlSecondary units
• The primary unit controls the speed of the load
• The torque is the result of the load
Primary unit
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p
eppref
Secondary control
Cp
Primary unit
Secondary units
• The primary unit controls the system pressure
• The secondary unit controls the torque or speed of the load
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Cp
eppref
p
Speed control strategy
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Speed control strategy
wref
C ,1w
w1
em,1
C ,2w
w2em,2
vref
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Speed control strategy
em,1
C ,2w
w2
C ,1w
w1
wrefKinematicmodel wref,2
wref,1
em,2
vref
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Torque control strategy
vref CT
vcurrent
wref,2wref,1
em,1 em,2
w1
Cs,1
w2
Cs,2
p
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Summary
• Two control strategies is purposed– Speed control – differential lock with adjusted
wheel speed– Torque control – differential with slip counter
measure• Soil damage is supposed to be reduced by less
slip• Next step: Try and compare the strategies in
the forwarder