Sekundärreglerad hydraulisk transmission i en sexhjulig skotare Liselott Ericson Linköpings universitet.

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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The forwarder

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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