Metsämaan kantavuuden mittaus CAN-väylästä taltioidun tiedon avulla

1. © Natural Resources Institute Finland© Natural Resources Institute Finland
Jari Ala-Ilomäki, Harri Lindeman, Aura
Salmivaara, Samuli Launiainen, Matti Siren,
Kalle Kiilo and Jori Uusitalo
EFFORTE-retkeily Hyytiälä/Kuru
11.11.2017
Metsämaan kantavuuden mittaus
CAN-väylästä taltioidun tiedon avulla

2. © Natural Resources Institute Finland
Harvester CAN-bus data: mapping principles
• Harvester motion resistance can be measured using the data
in harvester CAN-bus aiming at site trafficability map for the
forwarder, which follows the harvester and is heavier:
– At steady speed on level ground engine power via
transmission is expended on overcoming motion
resistance
– Motion resistance is mainly dependent on wheel sinkage
– Wheel sinkage is dependent on soil strength vs. loading

3. © Natural Resources Institute Finland
• Expended power monitored from CAN-bus
– Pressure and flow of transmission hydraulics or
transmission power deduced from engine power
– Power losses in mechanical transmission components
must be estimated
– True ground speed needed for power to force calculus
– Further corrections:
• Acceleration
• Inclination

4. © Natural Resources Institute Finland
– Dimensionless output:
coefficient of motion resistance =
𝑚𝑜𝑡𝑖𝑜𝑛 𝑟𝑒𝑠𝑖𝑠𝑡𝑎𝑛𝑐𝑒
𝑣𝑒ℎ𝑖𝑐𝑙𝑒 𝑤𝑒𝑖𝑔𝑡ℎ
• CAN-bus mapping benefits:
– Assessing trafficability by measuring
– Comprehensive and continuous assessing
– Low-cost of assessment

5. © Natural Resources Institute Finland
• Production application likely to be based on mere engine power
– No need for additional sensors
– Hydraulic transmission efficiency to be determined
– In our study:
• Transmission efficiency determined based on test drives,
where both transmission and engine power (from ECU)
were measured
• Ground speed from harvester GPS
• Acceleration omitted, near constant speed in tests
0,6<v<1m/s
• Inclination: GPS coordinates and DEM elevations in 10 m
sections

6. © Natural Resources Institute Finland
Summer 2016
Field trials in Vihti
• Test trail laid on
soil with varying
bearing capacity
• Nine 20 m long test
sites selected
• Manual
measurement of rut
depth at 1 m
intervals after each
machine pass

7. © Natural Resources Institute Finland
• Test trail first driven by a
Ponsse Scorpion King –
harvester, mass 22,5 t
• After harvester 2 to 4 passes
with loaded Ponsse Elk
forwarder, mass 30,0 t

8. © Natural Resources Institute Finland
Engine power, kW
Transmissionpower,kW
• Transmission power vs. engine power in test drives
Results
y=-23.9838+0.5561048x

9. © Natural Resources Institute Finland
• Power losses in the meachanical part of the transmission
– Ten gear meshes in the drop box – final drive – bogie casing –
hub reduction transmission chain with a coefficient of efficiency
of 0,97 results in a total efficiency of 0,74
• Efficiency coefficients do not change the relative order of the test
tracks

10. © Natural Resources Institute Finland
• Rolling resistance coeff on forest road a reasonable 0,085
• Engine power results in acceptacle accuracy in measuring
rolling resistance

11. © Natural Resources Institute Finland
• Harvester rolling resistance coefficient in site trafficability mapping

12. © Natural Resources Institute Finland
• Harvester rolling resistance coefficient in site trafficability mapping
Soft sites

13. © Natural Resources Institute Finland
• Harvester rolling resistance coefficient in site trafficability mapping
Soft sites

14. © Natural Resources Institute Finland
• Harvester rolling resistance coefficient in site trafficability mapping
Soft sites

15. © Natural Resources Institute Finland
• Harvester rolling resistance coefficient in site trafficability mapping
Soft sites

16. © Natural Resources Institute Finland
• Harvester rolling resistance coefficient in site trafficability mapping
Medium bearing capasity

17. © Natural Resources Institute Finland
• Harvester rolling resistance coefficient in site trafficability mapping
w/o w logging residue, shallow soil on bedrock

18. © Natural Resources Institute Finland
• Harvester rolling resistance coefficient in site trafficability mapping
w/o w logging residue, shallow soil on bedrock

19. © Natural Resources Institute Finland
• Harvester rolling resistance coefficient in site trafficability mapping
Rock outcrop, obstacle resistance

20. © Natural Resources Institute Finland
• Harvester rolling resistance coefficient in site trafficability mapping
Dry clay: permanent soil deformation, slope

21. © Natural Resources Institute Finland
• Test arrangements: two parallel test tracks ranging from peatland to mineral soil,
five 20 m long test sections per track, four 5 m long study plots per section
• Aim #1 at the effect of bogie tracks on CAN bus measurement
CAN bus (and 2-d laser scanner) field tests in Kuru 5-6/2017
First harvester with and without tracks on two parallel test tracks
GPS/Glonass -
positioning
2-d laserscanner
Harvester followed by a
loaded fwd up to six passes
Harvester courtesy of Ponsse
Plc

22. © Natural Resources Institute Finland
Peatland
Wet fine-grained
mineral soil with
organic top layer
Stony mineral soil
• Aim #2 at wide variety of soil conditions

23. © Natural Resources Institute Finland
• Aim #3 at the effect of logging residue on the measurement
devices: peatland with and without logging residue

24. © Natural Resources Institute Finland
• The results are promising, especially in detecting soft sites
• The technology is readily available and improvements are
more than likely in the future
• There is a good chance CAN-mapping will see production
• Research needed on the effect of soil type, cutting debris,
steep downhill slopes and steel tracks
Conclusions

25. © Natural Resources Institute Finland
Thank you!

26. © Natural Resources Institute Finland