The EU Directive on machinery requires the emission of whole-body and hand-arm vibration from mobile machinery to be declared. One of the major problems in development of standards for verification of the declared values that has been experienced by the responsible CEN Technical Committee (TC231) is to define the test conditions, especially the surface over which the machines shall be travelling.
The objective of this project is to develop and evaluate test methods using natural test tracks (roads, natural terrain). Preliminary test methods have been drafted and pre-tests on a limited number of machines have been performed. The machines used include: wheel loader, articulated hauler, small dumper, road milling machine, agricultural transporter and aircraft towing equipment. Measurements of the vibration at a number of accelerometer positions have been made travelling over various test tracks at various speeds.
The reproducibility of the vibration values when travelling over a certain natural test track at a certain speed has been found to be high, with the difference in vibration values between different tests being less than 10% in all cases. The degree of linearity between vibration values measured close to the wheel hubs and on the operator's seat is generally reasonably linear in the vertical direction, although the picture is more scattered for other directions. The lack of linearity will necessitate rather stringent requirements to be set on the level to be achieved at a control point close to the wheel hubs for tests for the measurement of declared vibration levels. A more extensive experimental programme using the proposed testing methodology is now being undertaken.
Funding SchemeCSC - Cost-sharing contracts
53757 Sankt Augustin