NEW DEVELOPMENTSIN AGRICULTURAL EQUIPMENT TRACTORS R. T. Schuler National AgrAbility Project University of Wisconsin - Madison November 14, 2006.

NEW DEVELOPMENTSIN AGRICULTURAL EQUIPMENT TRACTORS

R. T. SchulerNational AgrAbility Project

University of Wisconsin - Madison

November 14 , 2006

Tractors

Guidance and Auto-Steer Global Positioning System Guidance Auto-Steer Autonomous

Transmissions Number of gears/speeds CVT - Continuously Variable

Transmission IVT - Infinitely Variable Transmission

Suspension Tractor Chassis Cab Seat

Global Position Systems

Basic GPSSatellite System Only (3 of 24)Low cost – automobilesError – 100 feet

Satellite Constellation



Satellites plus free beaconIntermediate costError – 2 to 3 feet




Satellites plus geostationary satelliteMore costlyError – 3 to 5 inches




Satellites plus geostationary satelliteMore costlyError – 3 to 5 inches

Satellites plus base station nearbyCostly ($18,000 in 2006)One inch or less

Guidance and Automatic Steering Adoption

Most systems use GPS Payback

Improve productivityIncreased forward speedReduced crop inputsReduced operator fatigueAbility to operate longer hours

(darkness) Simple installation – 30 minutes Lower cost in recent years

Line A – B is base line called Track 0Guidance provided between points A and B

Example of a Light BarLocated in front of

operator

All lights on in test mode

Green light – acceptable areaYellow light - caution areaRed light - unacceptable

Light Bar

Middle green light is on-

Driving right on target

Light Bar

Right most green light is on:Driving to right of center but acceptable(error increment can be adjusted)

Light BarFirst yellow light is on:

Caution – corrective steering should be taken

Light Bar

Red light is on:

Operator needs to make steering correction

Another Display SystemGreen rectangle represents front end of tractorand angle of line indicates error (magnitude of error also displayed)

Track Error

No Error

Another Display System

Green rectangle represents front end of tractorand angle of line indicates error (magnitude of error also displayed)

Track Error Track 2 ft.

No Error Small Error

Audio alarm when error occurs

Another Display SystemGreen rectangle represents front end of tractorand angle of line indicates error (magnitude of error also displayed)

Track Error Track 2 ft. Track 5ft

No Error Small Error Large Error

Audio alarm when error occurs

New Special Feature

New Features – automatic headland turn around

New Special FeatureAutomatic turn around on headland

Option with GPS

• Guidance e.g. lightbar

Option with GPS

• Guidance• Autosteer

– Steering wheel control

Option with GPS

• Guidance• Autosteer

– Steering wheel control– Steering control system valve

Machine Vision – Non-GPS

Transmissions for Mobile Equipment Gear

Speed changes in stepsSingle power transmission pathEfficiency at part loads dependent on the number of

gears Hydrodynamic

Automotive transmission Infinitely variableNot adaptable to high torque

Hydrostatic Infinitely variable Inefficient

Infinitely/continuously variablePower split in the transmissionElectronic control of transmission and engine for most

efficient operation

Background-Gear Transmissions

Early Tractors had one or two forward speeds, one reverse

More forward speeds were added Speed change without clutching-torque

amplifier Synchronized transmission Shifting on the go Infinitely/continuously variable transmission

Tractor Engine and Driveline for Two Wheel DriveSingle path for the flow of power through transmission

Engine

Clutch

Transmission

Differential

Axles

Infinitely/Continuously Variable Transmission

Power is directed into two pathsPlanetary gear systems facilitates thisPower from the two paths are merged

Basic CVT/IVT Transmission

Planetary Gear Set(power split)

Carrier

Sun Fixed path

Ring

2 gears

VariablePathInput

Output

Basic CVT/IVT Transmission

Planetary Gear Set(power merge)

CarrierFixed path Sun

2 gears

VariablePathInput

OutputRing

IVT/CVT Characteristics

• Hand control for forward, reverse, speed changes and stopping

• Smooth, seamless shifting• Unlimited speeds from 0.03 to 26 mph (Deere)• Improved fuel economy at reduced load• Reduced load-maintain forward speed with

changing engine speed• Need for feet only to start the tractor engine • Cost – $9780 (right side), $10,490 (left side)

Suspension System Goals

Improve operator comfort and reduce long term health issuesReduce vibration from traveling over rough terrainReduce vibration due engine and drive train

vibration

Improve tractor performanceReduce the potential for power hop on FWD and

FWA Improve contact between wheels and soil surface

Background on seat suspension

First tractor operators had to standSeats rigidly attached to tractor chassisSpring supported seats-passiveSpring plus shock absorbers -passiveAir suspensions seats-passiveActive suspension seats

John Deere Active Seat- $3641Source: Dufner and Shick, Deere

Control Valve Assembly

Auxiliary Air Reservoir

Controller

Position Sensor Accelerometer

Actuator

Figure 2. John Deere Active SeatSource: Dufner and Shick, Deere

0.00

0.50

1.00

1.50

2.00

2.50

3.00

3.50

4.00

4.50

Acceleration, ft/sec-sec

Cab Input Typical AirSuspension

ActiveSuspension

John Deere Active SeatSource: Dufner and Shick, Deere

John Deere Active Seat Source: Dufner and Shick, Deere

Tractor chassis suspensionMore beneficial for the higher speedsFront axle suspension – DeereFront and rear axle suspension - Fastrac

Tractor chasis suspensionMore beneficial for the higher speedsFront axle suspension – DeereFront and rear axle suspension - Fastrac Reduces potential for power hopImproved performance with FWA tractor

Concluding remarks

Guidance and auto-steerIVT/CVT

Fuel savingAutomatic shift up-throttle back

Suspension SystemsSeatCabChassis

QUESTIONS

NEW DEVELOPMENTSIN AGRICULTURAL EQUIPMENT TRACTORS R. T. Schuler National AgrAbility Project University of Wisconsin - Madison November 14, 2006.

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