Analysis of human-operated motions and trajectory replanning for kinematically redundant manipulators

Mettin, Uwe; Westerberg, Simon; Shiriaev, Anton S.; Hera, Pedro X. La

doi:10.1109/iros.2009.5354362

Cited by 8 publications

(11 citation statements)

References 9 publications

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“…Despite today's lack of operationally reliable sensors, automated crane movement (e.g. AutoMove) might be feasible in the near-future (Mettin et al 2009) but probably not automated mounding (AutoMound). According to planting device manufacturers, creating correctly sized, good quality mounds on variable terrain is a much more complex task than general crane movement.…”

Section: Discussionmentioning

confidence: 99%

Simulated productivity of one- and two-armed tree planting machines

Ersson¹,

Jundén²,

Bergsten³

et al. 2013

Silva Fenn.

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Simulated productivity of one-and two-armed tree planting machinesErsson B. T., Jundén L., Bergsten U., Servin M. (2013). Simulated productivity of one-and two-armed tree planting machines. Silva Fennica vol. 47 no. 2 article id 958. 23 p. Highlights• Using discrete-event simulation and detailed terrain and machine models, the productivities of excavator-based one-and two-armed tree planting machines were simulated.• The machines' arms were equipped with one-and two-headed planting devices.• Two planting heads per arm rather than two arms per base machine is better for increasing the productivity of intermittently advancing planting machines on Nordic clearcuts. AbstractTo increase mechanized planting, planting machine productivity must increase in order to improve cost-efficiency. To determine if excavators with two crane arms could potentially help to increase planting machine productivity under Nordic clearcut conditions, we modelled one-armed and semiautomated two-armed excavators with one-and two-headed planting devices. Using a recently developed tool for discrete-event simulation, these machine models then mounded and planted seedlings on terrain models with moraine soil having various frequencies of obstacles (stumps, roots and stones). Compared to if the two heads were mounted pairwise on only one arm, the results showed that productivity did not increase if two planting heads were attached individually to two separate crane arms. But productivity did increase if the planting machine had four planting heads mounted pairwise on two separate arms. However, despite assuming automated mounding and crane motion between planting spots, the two-armed, four-headed model never achieved high enough productivity levels to make it more cost-efficient than one-armed machines. The simulations illustrate that our terrain models generate realistic root architecture and boulder content distributions in moraine soil, while our machine models functionally describe mechanized planting work. Based on our assumptions, we conclude that further development work on two-armed excavator-based planting machines for Nordic clearcut conditions is not warranted. Our simulations reveal that increasing the number of planting heads per crane arm rather than number of crane arms per base machine offers the greatest potential to raise the productivity of intermittently advancing planting machines.

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Section: Discussionmentioning

confidence: 99%

Simulated productivity of one- and two-armed tree planting machines

Ersson¹,

Jundén²,

Bergsten³

et al. 2013

Silva Fenn.

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“…In the literature, Mettin et al [12], Löfgren [13] and Ortiz Morales et al [1] addressed the joint-limited minimum-time redundancy resolution of hydraulic manipulators, and Löfgren [13] has also studied redundancy resolution which maximises load capacity. Furthermore, Beiner and Mattila [10] have derived a pseudo-inverse method for redundancy resolution in the hydraulic manipulator's actuator space to minimise the cylinder velocity norm or the weighted kinetic energy instantaneously.…”

Section: Literature Reviewmentioning

confidence: 99%

“…[1] and Mettin et al [12], and it is practical as such. Extensive measurements by Ortiz Morales et al…”

Section: Paper Contribution and Organizationmentioning

confidence: 99%

“…[1], Mettin et al [12] and Westerberg [2] have shown that the typical workspace activity for 4-DOF manipulator is concentrated on specific areas, which consequently means that there are in practice a limited number of significant point-to-point movements to optimise with respect to energy consumption. However, at the implementation stage, it might be feasible to pre-compute the energy-optimal trajectories over a few time horizons for all of these significant point-to-point movements so that it would be possible to choose between slower and faster energy-optimal trajectories in real-time.…”

Section: Paper Contribution and Organizationmentioning

confidence: 99%

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Global Energy-Optimal Redundancy Resolution of Hydraulic Manipulators: Experimental Results for a Forestry Manipulator

Nurmi

Mattila

2017

Energies

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This paper addresses the energy-inefficiency problem of four-degrees-of-freedom (4-DOF) hydraulic manipulators through redundancy resolution in robotic closed-loop controlled applications. Because conventional methods typically are local and have poor performance for resolving redundancy with respect to minimum hydraulic energy consumption, global energy-optimal redundancy resolution is proposed at the valve-controlled actuator and hydraulic power system interaction level. The energy consumption of the widely popular valve-controlled load-sensing (LS) and constant-pressure (CP) systems is effectively minimised through cost functions formulated in a discrete-time dynamic programming (DP) approach with minimum state representation. A prescribed end-effector path and important actuator constraints at the position, velocity and acceleration levels are also satisfied in the solution. Extensive field experiments performed on a forestry hydraulic manipulator demonstrate the performance of the proposed solution. Approximately 15-30% greater hydraulic energy consumption was observed with the conventional methods in the LS and CP systems. These results encourage energy-optimal redundancy resolution in future robotic applications of hydraulic manipulators.

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“…The resulting maps may be used for autonomous navigation, including path planning [7], documentation, and also for various semi-autonomous functions. The machine may for example automatically position the harvester head and grip a tree that the operator selects by pointing on a screen [12]. To achieve high precision in the SLAM algorithms, the center of the tree must be accurately determined [13].…”

Section: Introductionmentioning

confidence: 99%

Enhanced Algorithms for Estimating Tree Trunk Diameter Using 2D Laser Scanner

et al. 2013

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Accurate vehicle localization in forest environments is still an unresolved problem. Global navigation satellite systems (GNSS) have well known limitations in dense forest, and have to be combined with for instance laser based SLAM algorithms to provide satisfying accuracy. Such algorithms typically require accurate detection of trees, and estimation of tree center locations in laser data. Both these operations depend on accurate estimations of tree trunk diameter. Diameter estimations are important also for several other forestry automation and remote sensing applications. This paper evaluates several existing algorithms for diameter estimation using 2D laser scanner data. Enhanced algorithms, compensating for beam width and using multiple scans, were also developed and evaluated. The best existing algorithms overestimated tree trunk diameter by ca. 40%. Our enhanced algorithms, compensating for laser beam width, reduced this error to less than 12%.

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Analysis of human-operated motions and trajectory replanning for kinematically redundant manipulators

Cited by 8 publications

References 9 publications

Simulated productivity of one- and two-armed tree planting machines

Simulated productivity of one- and two-armed tree planting machines

Global Energy-Optimal Redundancy Resolution of Hydraulic Manipulators: Experimental Results for a Forestry Manipulator

Enhanced Algorithms for Estimating Tree Trunk Diameter Using 2D Laser Scanner

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