A Comparison of Novel Chassis Suspended Machines for Sustainable Forestry.

A comparison of novel chassis suspended machines for sustainable forestry

A Ismoilov, Machine Design, KTH Royal Institute of Technology, Stockholm, Sweden, ismoilov@kth.se

U Sellgren, Machine Design, KTH Royal Institute of Technology, Stockholm, Sweden, ulfse@kth.se

K Andersson, Machine Design, KTH Royal Institute of Technology, Stockholm, Sweden, kan@kth.se

B Löfgren, Swedish Forestry Research Institute Skogforsk, Uppsala, Sweden, bjorn.lofgren@skogforsk.se

Cut-to-length logging (CTL) is a mechanized harvesting process where trees are delimbed and cut to length directly at the stump. CTL lends itself to timber harvesting in plantation forestry where stems are often harvested before they reach large dimensions. CTL is typically a two-man, two-machine operation with a harvester felling, delimbing, and bucking trees and a forwarder transporting the cut logs from the felling area to a landing area close to a road accessible by trucks, or trains. The main challenges for the manufacturers of forestry machines for CTL logging are to address new customer demands and tougher health and environmental legislations by finding means that: (1) further increase the harvesting and log transportation productivity, e.g. by enabling operation on eco-soils, (2) reduce the damage to the soil, e.g. by controlling the ruth depth and preserving the root layer, (3) reduce exhaust emissions, e.g. by reducing the rolling resistance, and (4) reduce the daily vibration dosage for the machine operators, e.g. by active chassis and cabin damping.

This paper presents a number of novel chassis damping concepts that enable hybrid all-wheel steering and all-wheel hybrid traction of forwarders and an analysis of their pros and cons based on results multi-body dynamics simulations on rough hard and soft terrain and some full scale field tests.

The applicable conference tracks where the paper will fit are indicated in the table below.

Track	Description	Highly applicable	Applicable	Not applicable
1	Soil and terrain modeling and characterisation		X
2	Planetary rovers and mobile robotics		X
3	Tires, wheels and tracks modeling		X
4	Agricultural and earth moving equipment	X
5	Operation on snow and ice			X
6	Vehicle dynamics, mobility and safety	X
7	Terramechanics		X