Load level forwarding work element analysis based on automatic follow-up data

Manner, Jussi; Palmroth, Lauri; Nordfjell, Tomas; Lindroos, Ola

doi:10.14214/sf.1546

Cited by 35 publications

(53 citation statements)

References 18 publications

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“…In this scenario, the understanding of the forwarding operation is decisive for good planning of the thinning operation in different sites. Forwarding is a complex activity, consisting of several work elements, each of them affected by several factors (Nieminstö et al 2012, Manner et al 2016a, Berg et al 2017. The theoretical analysis and operation planning are intrinsically dependent on the existence of precise time and productivity models (Nurminen et al 2006, Lindroos andWästerlund 2014).…”

Section: Introductionmentioning

confidence: 99%

“…The productivity of forest extraction with forwarders depends on timber volume by load and the cycle time consumption (Nurminen et al 2006). For the purpose of the analysis, the forwarding cycle can be divided into five work elements: driving empty, loading, driving while loading, driving loaded and unloading (Manner et al 2016a). Other activities can be considered, including driving empty on the road and driving loaded on the road.…”

Section: Introductionmentioning

confidence: 99%

“…Based on their loading capacity, forwarders have been classified as light (<10 t), medium (10-14 t) and heavy (>14 t) equipment (Stankić et al 2012). Around seventy-five per cent of the time is spent on loading, driving while loading and unloading (Manner et al 2013, Manner et al 2016a). Therefore, the forwarding distance is not the main productivity explicative factor, requiring an analysis of the factors that affect load formation and unloading (Stankić et al 2012, Eriksson and Lindroos 2014, Manner et al 2016a.…”

Section: Introductionmentioning

confidence: 99%

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Time Consumption Analysis of Forwarder Activities in Thinning

Hildt

Leszczuk

Donagh

et al. 2019

Croat. j. for. eng. (Online)

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Forwarding can be divided into separate work elements. These are affected by several factors: forwarding distance, load volume, and types of assortments harvested. For a detailed planning of thinning, productivity models should include these factors. This study analysed the time consumption of forwarder thinning operations in five pine plantations in the north-east of Argentina, determining how the log size and log concentration affect each work element. Time-and-motion studies were carried out, recording the activities with digital video cameras, and tracking the forwarder movements with global navigation satellite system (GNSS) receivers. Different linear mixed models were fitted to estimate the time consumption of each work element in relation to different predictive factors. When driving on the road, the forwarders had an average speed of 71.6 m min-1 empty and 75.7 m min-1 loaded. When driving in the stand, the average speed was 56.9 m min-1 empty and 52.2 m min-1 loaded. These speeds did not correlate with the forwarder size or load volume. For the loading and unloading elements, the linear mixed model explained 56% and 49% of the variability considering only the fixed effect of the logs size and the load volume. For driving while loading, the total volume loaded, and the log concentration of the assortment loaded explained 50% of the time consumption variability, with 17% being explained by random effects. The general time and productivity model developed can be applied to support accurate decisions in the process of thinning planning.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Time Consumption Analysis of Forwarder Activities in Thinning

Hildt

Leszczuk

Donagh

et al. 2019

Croat. j. for. eng. (Online)

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“…The steering principles of CBC and IBC are described in Section 2.1. Manner et al (2017) found that using IBC, instead of CBC, improves the crane-work productivity of beginner-level operators (i.e. students at vocational school) because of the improved crane manoeuvrability provided by IBC.…”

Section: Introductionmentioning

confidence: 99%

Comparing forwarder boom-control systems based on an automatically recorded follow-up dataset

Manner¹,

Mörk²,

Englund³

2019

Silva Fenn.

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Highlights• Boom-tip control saves time compared to the conventional system. • This study introduced a field-study design enabling establishment of causal relationships during ordinary forwarding operations. • Although the study design requires some extra arrangements, it efficiently combines the representativeness of conventional follow-up datasets with establishment of causal relationships that traditionally have been possible only through observational time studies or standardized experiments. AbstractCrane work is the most time-consuming work element in forwarding. Hence, assist systems like boom-tip control are of interest. The first commercially available boom-tip control for forwarders was introduced in 2013. In this study we analysed whether replacing conventional boom control (CBC) with John Deere's version of boom-tip control (named Intelligent Boom Control, IBC), increases crane-work productivity. We used data automatically gathered from 10 final-felling stands, covering typical logging conditions for southern, central and northern Sweden. Two John Deere 1510E and two John Deere 1910G forwarders were operated by seven experienced operators during the follow-up study, covering 1238 loads in total. A split-plot design was applied to isolate effects of the boom-control system being used (CBC, IBC). We found that using IBC for loading work (crane work and driving included) saved 5.2% of productive machine time compared to using CBC (p ≤ 0.05). The corresponding saving when using IBC for unloading work was 7.9% (p ≤ 0.05). Depending on geophysical factors, this corresponds to approximately 4% savings in productive machine time for forwarding as a whole, including pure transport (with and without load). Moreover, the study introduced in cut-to-length context a novel field-study design to collect a large follow-up dataset in the course of ordinary forwarding operations. We found the study design to be a cost-efficient way to combine the representativeness of conventional follow-up datasets with the ability to establish causal relationships. Establishment of causal relationships has traditionally been possible only through observational time studies or standardized experiments. Silva Fennica vol. 53 no. 2 article id 10161 · Manner et al. · Comparing forwarder boom-control systems based …

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“…Generally, the crane work is the most time-consuming work element (Kellogg and Bettinger 1994;Nurminen et al 2006;Manner et al 2016b). Though, relative time consumption distribution between the work elements depends on extraction distance, assortment-specific log concentrations (expressed e.g.…”

Section: Introductionmentioning

confidence: 99%

Forwarder crane’s boom tip control system and beginner-level operators

Manner¹,

Gelin²,

Mörk³

et al. 2017

Silva Fenn.

Self Cite

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Highlights• Boom tip control (BTC) allows the operator to control boom tip movements directly, instead of controlling each movement separately to achieve the desired boom tip movement.• BTC eased boom control, so beginner-level operators using BTC achieved higher productivity than beginner-level operators using a conventional (reference) system. • There were no significant differences in the slopes of learning curves between the systems. AbstractThe forwarder loads processed wood and transports it to a landing. Productivity of forwarding could be improved by increasing driving speed, but difficult forest terrain limits this. According to current literature, crane work is the most time-consuming work element of forwarding, so improving crane work productivity is essential for improving forwarding productivity. One way to do this is through automation of recurrent boom movement patterns, or alternatively automation can be used to ease crane work. When using conventional boom control (CBC), the operator manually controls each of the independent boom joint movements and combines them to achieve a desired boom tip movement, but boom tip control (BTC) allows the operator to control boom tip movements directly. The objective of the present study was to examine whether BTC facilitates crane work and affects the slopes of learning curves for beginner-level forwarder operators. The study was carried out using a standardised test routine to evaluate effects of two fixed factors, system (levels: CBC, BTC) and point of time (four levels), on five dependent variables. Four of the five dependent variables measured ease of boom control and the fifth measured crane work productivity. The results showed that there were no significant differences in the slopes of learning curves between the systems but the BTC did increase crane work productivity and made boom control easier.

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Load level forwarding work element analysis based on automatic follow-up data

Cited by 35 publications

References 18 publications

Time Consumption Analysis of Forwarder Activities in Thinning

Time Consumption Analysis of Forwarder Activities in Thinning

Comparing forwarder boom-control systems based on an automatically recorded follow-up dataset

Forwarder crane’s boom tip control system and beginner-level operators

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