Another Look at Skidder Ride Vibration…

Wegscheid, E. L.

doi:10.1080/08435243.1994.10702657

Cited by 9 publications

(5 citation statements)

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“…The relationship between higher WBV and speed seems likely (Eger andothers 2011, Marin andothers 2016), but a quantitative relationship is needed for skidders. Most operators choose or are directed to drive speeds and shift lengths that subject them to WBV exposure that could have cumulative health effects (Lynch 2017, Neitzel and Yost 2002, Wegscheid 1994).…”

Section: Discussionmentioning

confidence: 99%

“…The advantage of the TM approach is the exploration of feasible combinations of machine speed (empty and loaded) and load size given terrain and machine parameters. Understanding load and speed tradeoffs may be important to managing machine productivity (t pmh -1 ), fuel efficiency (t mJ -1 ), (Manner and others 2016), and operator comfort (Wegscheid 1994). The objective of this analysis is to estimate TM parameters from published skidder production data and compare TM results to a traditional regression approach.…”

Section: Introductionmentioning

confidence: 99%

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Terra-mechanical and statistical analyses of four-wheel grapple skidder performance data

Smidt

Thompson

McDonald

et al. 2023

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Studies of skidder productivity typically involve a range of conditions that support specific study objectives related to harvest system, terrain, forest attribute, or other aspects of the harvest. Skidder production models often fit the data well because cycle time and productivity are strongly related to load size and skid distance. Changes in skidder design over time have increased load capacity, potential machine speed, and operator comfort. Since the harvest system often limits the observed range in speed and load size, the tradeoffs between those factors have not been a primary focus of production studies. We analyzed 33 studies with 77 estimates of skidder productivity using a typical regression approach and an approach based on the Wismer and Luth terra-mechanical (TM) relationships. The regression approach resulted in a good fit of productivity but poorer fits of cycle and element times. Nonlinear models developed with the TM approach also fit but had larger values for mean square error (MSE) than the linear regressions. The use of 14 additional studies with 33 estimates as validation data produced a lower mean square prediction error (MSPE) for nonlinear TM models when compared to the linear regression models. The TM approach allowed for the tradeoff between speed and load size to be modeled explicitly. We developed a spreadsheet production model to demonstrate the effect of choices made by harvest planners, logging managers, and operators on specific production goals.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Terra-mechanical and statistical analyses of four-wheel grapple skidder performance data

Smidt

Thompson

McDonald

et al. 2023

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“…A number of studies conducted on mobile machines have assessed chassis vibration [10,13,[15][16][17]22,[27][28][29]. Vibration exposure measurements were collected in accordance with ISO 2631-1 procedures from 1978 or 1997, and relevant information from these studies can be found in Tables V-IX.…”

Section: Discussionmentioning

confidence: 99%

“…There are few studies which report Crest Factors (CF) (Table VIII), and two are for forestry skidders [10,22,27,35]. As mentioned by Els (2005), CF is a ratio, which will decrease with an increase in terrain roughness (resulting from an increase in rRMS) [10].…”

Section: Quantification Of 6-degree-of-freedom Chassis Whole-body Vibmentioning

confidence: 99%

Quantification of 6-Degree-of-Freedom Chassis Whole-Body Vibration in Mobile Heavy Vehicles Used in the Steel Making Industry

Conrad

Oliver

Jack

et al. 2012

Journal of Low Frequency Noise, Vibration and Active Control

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Whole-body vibration (WBV) of mobile machines used in the steel making industry has not previously been quantified in six-degrees-of-freedom (6DOF). The purpose of this paper was to quantify 6DOF vibrations during the daily operating tasks of 5 commonly used mobile machines types used in the steel making and metal smelting industries. Vibration data were recorded from the chassis of five commonly used mobile machines using a MEMSense MAG3 triaxial accelerometer & gyroscope (MEMSense, SD, USA), and analyzed using custom MatlabTM code. Elevated values were observed at the chassis for crest factors, peak running root mean squared accelerations, and vibration total values, resulting in ISO 2631-1 (1997) comfort predictions ranging from Uncomfortable to Extremely Uncomfortable. Vibration dominant frequencies were generally between 1 and 8Hz. A second peak which occurred at approximately 27 Hz was observed for each vehicle in almost all axes. Occurring at a frequency that has the potential to produce negative health effects, this second peak was probably caused by the engine idling or running at low speeds. Field vibration profiles from this study have been used as inputs to a 6DOF robot for use in a corresponding laboratory study designed to optimize seat selection thus allowing the steel making and other similar industries to select operator seats based on industry specific field vibration characteristics.

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“…The vehicle interactions with rough forest terrains may cause the suspension seat to exceed its free travel and transmit high intensity vibration or shock motions due to end-stop impacts. Furthermore, a few studies have shown that the suspension seats used in skidders do not offer reductions in vertical vibration [3,24], while these may amplify the vibration transmitted to the operators. Alternatively, various concepts in cab suspension have evolved to attenuate vibration along the translational as well as rotational axes [25][26][27][28][29].…”

Section: Introductionmentioning

confidence: 99%

Ride dynamic evaluations and design optimisation of a torsio-elastic off-road vehicle suspension

Pazooki

Cao

Rakheja

et al. 2011

Vehicle System Dynamics

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The ride dynamic characteristics of a novel torsio-elastic suspension for off-road vehicle applications are investigated through field measurements and simulations. A prototype suspension was realized and integrated within the rear axle of a forestry skidder for field evaluations. Field measurements were performed on forestry terrains at a constant forward speed of 5 km/h under the loaded and unloaded conditions, and the ride responses were acquired in terms of accelerations along the vertical, lateral, roll, longitudinal and pitch axes. The measurements were also performed on a conventional skidder to investigate the relative ride performance potentials of the proposed suspension. The results revealed that the proposed suspension could yield significant reductions in magnitudes of transmitted vibration to the operator seat. Compared to the unsuspended vehicle, the prototype suspended vehicle resulted in nearly 35%, 43% and 57% reductions in the frequency-weighted rms accelerations along the x-, y-and z-axis, respectively. A 13-DOF ride dynamic model of the vehicle with rear-axle torsioelastic suspension was subsequently derived and validated in order to study the sensitivity of the ride responses to suspension parameters. Optimal suspension parameters were identified using Pareto technique based on the genetic algorithm to obtain minimal un-weighted and frequencyweighted rms acceleration responses. The optimal solutions resulted in further reduction in the pitch acceleration in the order of 20%, while the reductions in roll and vertical accelerations ranged from 3.5 to 6%.

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Another Look at Skidder Ride Vibration…

Cited by 9 publications

References 0 publications

Terra-mechanical and statistical analyses of four-wheel grapple skidder performance data

Terra-mechanical and statistical analyses of four-wheel grapple skidder performance data

Quantification of 6-Degree-of-Freedom Chassis Whole-Body Vibration in Mobile Heavy Vehicles Used in the Steel Making Industry

Ride dynamic evaluations and design optimisation of a torsio-elastic off-road vehicle suspension

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