XT-28 prototype designed in 2016 by Olle Gelin of Skogforsk, Forestry Research Institute, Bosch Rexroth, University of Linköping in Sweden, and KTH, Royal Institute of Technology in Stockholm was also involved. The Company AB eXtractor of Bollnäs conceived built the machine itself.
The vehicle has 2 yaw joints and 6 pendulum arms hydraulically controlled and driven by computers and sensors. The sensors also serve to limit wheel slip. A gyroscope keeps the machine horizontal. The horizontality allows, with this suspension, a higher speed, and avoids the turning on high obstacles with a load itself high enough. The off-road capacities are therefore increased, for example on a transverse slope. The tire pressure is equal in each wheel and the vibrations greatly reduced at the level of the driver. The 6 wheels are powered by hydraulic motors. The pendulum arms are lighter than conventional bogies and the reduction of vibrations contributes to the longevity of parts, hydraulic among others. It seems that the extra cost to purchase is not too high despite the complexity of hydraulic system.
Engine: 275 horsepower Sisu diesel.
Traction: 280 kilo Newton-meters.
Loading capacity: 14 tons.
Weight: 16,900 kilos.
Driving speed: 0-24 kilometers per hour.
Turning radius outside: 5.4 meters on wheels.
Ground clearance: 31-130 centimeters.
https://www.atl.nu/teknik/ny-konceptmaskin-med-pendelarmar/, https://www.youtube.com/watch?v=omsL0DgC-DU, http://www.mynewsdesk.com/se / skogforsk / videos / skotare-med-pendelarmar-kan-foerbaettra-arbetsmiljoen-och-minska-risken-foer-markskador-26329, https://www.skogforsk.se/kunskap/kunskapsbanken/2017/skonsam-terrangtransport-med -pendelarmar /, https://skogsforum.se/viewtopic.php?f=11&t=21493&start=15, https://www.skogforsk.se/contentassets/d120dff37a2c4e5197d211a873dc1ab8/tsg-xt28_2016.pdf https: // www. atl.nu/skog/xt28-klarar-alla-hinder/