The Experts below are selected from a list of 303 Experts worldwide ranked by ideXlab platform

Ryosuke Takasu - One of the best experts on this subject based on the ideXlab platform.

  • IROS - Impulse Force Generator based on snap-through buckling of robotic closed elastica: Analysis by quasi-static shape transition simulation
    2013 IEEE RSJ International Conference on Intelligent Robots and Systems, 2013
    Co-Authors: Hiromi Mochiyama, Aya Kinoshita, Ryosuke Takasu
    Abstract:

    In this paper, we investigate the property of an impulse Force Generator based on snap-through buckling of a robotic closed elastic rod which is considered as one of good examples of continuum robots. The impulse Force Generator considered here utilizes a snap through buckling of an elastic rod where its base end is pinned and driven by a rotary actuator forcibly while the tip end is pinned or clamped to the fixed point. One of the most fundamental design problems is to maximize the released elastic energy at each buckling state subject to limited ranges of driving torque and angle of a given actuator. From this design viewpoint, we show two findings obtained from quasi-static planar shape transition simulation of the closed elastica, which will be useful for a design of the robot, that is, the ratio of the elastica length and the endpoint distance decides 1) the buckling angle which relates to the range of an actuator driving angle, and 2) the released elastic energy per the maximum driving torque. We also provide a mathematical description of snap-through buckling based on which we can measure a distance to a buckling point.

  • Impulse Force Generator based on snap-through buckling of robotic closed elastica: Analysis by quasi-static shape transition simulation
    2013 IEEE RSJ International Conference on Intelligent Robots and Systems, 2013
    Co-Authors: Hiromi Mochiyama, Aya Kinoshita, Ryosuke Takasu
    Abstract:

    In this paper, we investigate the property of an impulse Force Generator based on snap-through buckling of a robotic closed elastic rod which is considered as one of good examples of continuum robots. The impulse Force Generator considered here utilizes a snap through buckling of an elastic rod where its base end is pinned and driven by a rotary actuator forcibly while the tip end is pinned or clamped to the fixed point. One of the most fundamental design problems is to maximize the released elastic energy at each buckling state subject to limited ranges of driving torque and angle of a given actuator. From this design viewpoint, we show two findings obtained from quasi-static planar shape transition simulation of the closed elastica, which will be useful for a design of the robot, that is, the ratio of the elastica length and the endpoint distance decides 1) the buckling angle which relates to the range of an actuator driving angle, and 2) the released elastic energy per the maximum driving torque. We also provide a mathematical description of snap-through buckling based on which we can measure a distance to a buckling point.

Hiromi Mochiyama - One of the best experts on this subject based on the ideXlab platform.

  • IROS - Impulse Force Generator based on snap-through buckling of robotic closed elastica: Analysis by quasi-static shape transition simulation
    2013 IEEE RSJ International Conference on Intelligent Robots and Systems, 2013
    Co-Authors: Hiromi Mochiyama, Aya Kinoshita, Ryosuke Takasu
    Abstract:

    In this paper, we investigate the property of an impulse Force Generator based on snap-through buckling of a robotic closed elastic rod which is considered as one of good examples of continuum robots. The impulse Force Generator considered here utilizes a snap through buckling of an elastic rod where its base end is pinned and driven by a rotary actuator forcibly while the tip end is pinned or clamped to the fixed point. One of the most fundamental design problems is to maximize the released elastic energy at each buckling state subject to limited ranges of driving torque and angle of a given actuator. From this design viewpoint, we show two findings obtained from quasi-static planar shape transition simulation of the closed elastica, which will be useful for a design of the robot, that is, the ratio of the elastica length and the endpoint distance decides 1) the buckling angle which relates to the range of an actuator driving angle, and 2) the released elastic energy per the maximum driving torque. We also provide a mathematical description of snap-through buckling based on which we can measure a distance to a buckling point.

  • Impulse Force Generator based on snap-through buckling of robotic closed elastica: Analysis by quasi-static shape transition simulation
    2013 IEEE RSJ International Conference on Intelligent Robots and Systems, 2013
    Co-Authors: Hiromi Mochiyama, Aya Kinoshita, Ryosuke Takasu
    Abstract:

    In this paper, we investigate the property of an impulse Force Generator based on snap-through buckling of a robotic closed elastic rod which is considered as one of good examples of continuum robots. The impulse Force Generator considered here utilizes a snap through buckling of an elastic rod where its base end is pinned and driven by a rotary actuator forcibly while the tip end is pinned or clamped to the fixed point. One of the most fundamental design problems is to maximize the released elastic energy at each buckling state subject to limited ranges of driving torque and angle of a given actuator. From this design viewpoint, we show two findings obtained from quasi-static planar shape transition simulation of the closed elastica, which will be useful for a design of the robot, that is, the ratio of the elastica length and the endpoint distance decides 1) the buckling angle which relates to the range of an actuator driving angle, and 2) the released elastic energy per the maximum driving torque. We also provide a mathematical description of snap-through buckling based on which we can measure a distance to a buckling point.

  • Impulse Force Generator Based on a Serial Chain of Torsion Springs for Catapulting an Object
    Journal of the Robotics Society of Japan, 2011
    Co-Authors: Yasuhisa Ichikawa, Hiromi Mochiyama, Hideo Fujimoto
    Abstract:

    In this paper, we propose an impulse Force Generator for catapulting an object. The proposed impulse Force Generator utilizes snap-through buckling of an elastic body. The distinguished feature of the device is to adopt a serial chain of torsion springs with both high elasticity and flexibility as its elastic body. The use of the serial chain of torsion springs enables us to increase the energy density of the elastic body. Experimental results show that the proposed compact and lightweight impulse Force Generator has high capability of catapulting an object. The generated maximum momentum is of 16[Ns] in spite that the maximum driving torque necessary for snap-through buckling is only of 21[Nm].

  • IROS - A compact kick-and-bounce mobile robot powered by unidirectional impulse Force Generators
    2009 IEEE RSJ International Conference on Intelligent Robots and Systems, 2009
    Co-Authors: Takashi Tsuda, Hiromi Mochiyama, Hideo Fujimoto
    Abstract:

    In this paper, we propose a compact kick-and-bounce mobile robot powered by unidirectional impulse Force Generators. The unidirectional impulse Force Generator is a simple mechanical device for generating high-frequency impulse Forces toward a certain direction unilaterally utilizing snap-through bucklings. The proposed kick-and-bounce robot has a pair of the unidirectional impulse Force Generators as the muscles of its biped legs. The robot moves forward rapidly by the repetition of the kicks and bounces to the ground. We show that the developed palm-top mobile robot whose weight is of only 67[g] achieves the velocity of 0.8[m/s] instantaneously.

Jacques Pécréaux - One of the best experts on this subject based on the ideXlab platform.

  • Microtubule Feedback and LET-99-Dependent Control of Pulling Forces Ensure Robust Spindle Position.
    Biophysical journal, 2018
    Co-Authors: Hélène Bouvrais, Laurent Chesneau, Sylvain Pastezeur, Marie Delattre, Danielle Fairbrass, Jacques Pécréaux
    Abstract:

    During asymmetric division of the Caenorhabditis elegans zygote, to properly distribute cell fate determinants, the mitotic spindle is asymmetrically localized by a combination of centering and cortical-pulling microtubule-mediated Forces, the dynamics of the latter being regulated by mitotic progression. Here, we show a, to our knowledge, novel and additional regulation of these Forces by spindle position itself. For that, we observed the onset of transverse spindle oscillations, which reflects the burst of anaphase pulling Forces. After delaying anaphase onset, we found that the position at which the spindle starts to oscillate was unchanged compared to control embryos and uncorrelated to anaphase onset. In mapping the cortical microtubule dynamics, we measured a steep increase in microtubule contact density after the posterior centrosome reached the critical position of 70% of embryo length, strongly suggesting the presence of a positional switch for spindle oscillations. Expanding a previous model based on a Force-Generator temporal control, we implemented this positional switch and observed that the large increase in microtubule density accounted for the pulling Force burst. Thus, we propose that the spindle position influences the cortical availability of microtubules on which the active Force Generators, controlled by cell cycle progression, can pull. Importantly, we found that this positional control relies on the polarity-dependent LET-99 cortical band, the boundary of which could be probed by microtubules. This dual positional and temporal control well accounted for our observation that the oscillation onset position resists changes in cellular geometry and moderate variations in the active Force Generator number. Finally, our model suggests that spindle position at mitosis end is more sensitive to the polarity factor LET-99, which restricts the region of active Force Generators to a posterior-most region, than to microtubule number or Force Generator number/activity. Overall, we show that robustness in spindle positioning originates in cell mechanics rather than biochemical networks.

  • astral microtubule dynamics regulate anaphase oscillation onset and set a robust final position for the caenorhabditis elegans zygote spindle
    bioRxiv, 2017
    Co-Authors: Hélène Bouvrais, Laurent Chesneau, Sylvain Pastezeur, Marie Delattre, Jacques Pécréaux
    Abstract:

    Background: During asymmetric division of the Caenorhabditis elegans nematode zygote, the polarity cues distribution and daughter cell fates depend on the correct positioning of the mitotic spindle which results from both centering and cortical pulling Forces. Revealed by spindle rocking, these pulling Forces are regulated by the Force Generator dynamics, which are related to mitosis progression. This may be combined with a second regulation, this one by the posterior spindle pole position, which can be seen when comparing related species. Results: After delaying anaphase onset, we identified a positional pulling Force regulation in C. elegans, which we ascribed to microtubule dynamics at the cortex. Indeed, in mapping the contacts we found a correlation between the centrosome-cortex distance and the microtubule contact density. This density in turn modulates pulling Force Generator activity. We expanded our model of spindle rocking and predicted then experimentally validated that the oscillation onset position resists changes in cellular geometry and number of Force Generators. Consistent with final spindle position measurements, this new model accounts for a lower dependence on Force Generator dynamics and quantities than predicted by the previous model. Conclusion: The spindle position regulates the rapid increase in Forces needed for anaphase oscillation and positioning through the spatial modulation of microtubule-cortex contacts. This regulation superimposes that of Force Generator processivity, putatively linked to the cell cycle. This novel control confers resistance to variations in zygote geometry and dynamics of cortical Force Generators. Interestingly, this robustness originates in cell mechanics rather than biochemical networks.

  • astral microtubule dynamics regulate anaphase oscillation onset and set a robust final position of the c elegans zygote spindle
    arXiv: Subcellular Processes, 2017
    Co-Authors: Hélène Bouvrais, Laurent Chesneau, Sylvain Pastezeur, Marie Delattre, Jacques Pécréaux
    Abstract:

    Background: The correct positioning of the mitotic spindle during the asymmetric division of the nematode C. elegans zygote relies on the combination of centering and corticalpulling Forces. These Forces, revealed by centrosome anaphase oscillations, are regulated through the dynamics of Force Generators, related to mitosis progression. Recently, we reported the control of oscillation onset by the posterior spindle pole position in related species C. briggsae, necessitating a re-evaluation of the role of astral microtubules dynamics. Results: After exhibiting such a positional switch in C. elegans, we mapped the microtubule ends at the cortex and observed a correlation between the proximity of the centrosomes and the density of microtubule contacts. To explore the functional consequences, we extended the tug-of-war model and successfully accounted for the positional switch. We predicted and experimentally validated that the control of oscillation onset was robust to changes in cell geometry or maximum number of attached Force Generators. We also predicted that the final position of the posterior centrosome and thus the spindle has a reduced dependence upon the Force Generator dynamics or number. Conclusion: The outburst of Forces responsible of spindle anaphase oscillations and positioning is regulated by the spindle position through the spatial modulation of microtubule contacts at the cortex. This regulation superimposes that of Force Generator processivity putatively linked to the cell cycle. This novel control provides robustness to variations in zygote geometry or detailed properties of cortical Force Generators.

  • LET-99-dependent spatial restriction of active Force Generators makes spindle’s position robust
    2017
    Co-Authors: Hélène Bouvrais, Laurent Chesneau, Sylvain Pastezeur, Marie Delattre, Jacques Pécréaux
    Abstract:

    During the asymmetric division of the Caenorhabditis elegans nematode zygote, the polarity cues distribution and daughter cell fates depend on the correct positioning of the mitotic spindle, which results from both centering and cortical pulling Forces. Revealed by anaphase spindle rocking, these pulling Forces are regulated by the Force Generator dynamics, which are in turn consequent of mitotic progression. We found a novel, additional, regulation of these Forces by the spindle position. It controls astral microtubule availability at the cortex, on which the active Force Generators can pull. Importantly, this positional control relies on the polarity dependent LET-99 cortical band, which restricts or concentrates Generators to a posterior crescent. We ascribed this control to the microtubule dynamics at the cortex. Indeed, in mapping the cortical contacts, we found a correlation between the centrosome-cortex distance and the microtubule contact density. In turn, it modulates pulling Force Generator activity. We modelled this control, predicting and experimentally validating that the posterior crescent extent controlled where the anaphase oscillations started, in addition to mitotic progression. Finally, we propose that spatially restricting Force Generator to a posterior crescent sets the spindle's final position, reflecting polarity through the LET-99 dependent restriction of Force Generators to a posterior crescent. This regulation superimposes that of Force Generator processivity. This novel control confers a low dependence on microtubule and active Force Generator exact numbers or dynamics, provided that they exceed the threshold needed for posterior displacement. Interestingly, this robustness originates in cell mechanics rather than biochemical networks.

  • astral microtubule dynamics regulate anaphase oscillation onset and set a robust final position of the c elegans zygote spindle
    bioRxiv, 2017
    Co-Authors: Hélène Bouvrais, Laurent Chesneau, Sylvain Pastezeur, Marie Delattre, Jacques Pécréaux
    Abstract:

    Background: The correct positioning of the mitotic spindle during the asymmetric division of the nematode C. elegans zygote relies on the combination of centering and cortical-pulling Forces. These Forces, revealed by centrosome anaphase oscillations, are regulated through the dynamics of Force Generators, related to mitosis progression. Recently, we have presented the control of oscillation onset by the posterior spindle pole position in related species C. briggsae, necessitating a re-evaluation of the role of astral microtubules dynamics. Results: After exhibiting such a positional switch in C. elegans, we mapped the microtubule ends at the cortex and observed a correlation between the proximity of the centrosomes and the density of microtubule contacts. To explore the functional consequences, we extended the "tug-of-war" model and successfully accounted for the positional switch. We predicted and experimentally validated that the control of oscillation onset was robust to changes in cell geometry or maximum number of attached Force Generators. We also predicted that the final position of the posterior centrosome and thus the spindle has a reduced dependence upon the Force Generator dynamics or number. Conclusion: The outburst of Forces responsible of spindle anaphase oscillations and positioning is regulated by the spindle position through the spatial modulation of microtubule contacts at the cortex. This regulation superimposes that of Force Generator processivity putatively linked to the cell cycle. This novel control provides robustness to variations in zygote geometry or detailed properties of cortical Force Generators.

Aya Kinoshita - One of the best experts on this subject based on the ideXlab platform.

  • IROS - Impulse Force Generator based on snap-through buckling of robotic closed elastica: Analysis by quasi-static shape transition simulation
    2013 IEEE RSJ International Conference on Intelligent Robots and Systems, 2013
    Co-Authors: Hiromi Mochiyama, Aya Kinoshita, Ryosuke Takasu
    Abstract:

    In this paper, we investigate the property of an impulse Force Generator based on snap-through buckling of a robotic closed elastic rod which is considered as one of good examples of continuum robots. The impulse Force Generator considered here utilizes a snap through buckling of an elastic rod where its base end is pinned and driven by a rotary actuator forcibly while the tip end is pinned or clamped to the fixed point. One of the most fundamental design problems is to maximize the released elastic energy at each buckling state subject to limited ranges of driving torque and angle of a given actuator. From this design viewpoint, we show two findings obtained from quasi-static planar shape transition simulation of the closed elastica, which will be useful for a design of the robot, that is, the ratio of the elastica length and the endpoint distance decides 1) the buckling angle which relates to the range of an actuator driving angle, and 2) the released elastic energy per the maximum driving torque. We also provide a mathematical description of snap-through buckling based on which we can measure a distance to a buckling point.

  • Impulse Force Generator based on snap-through buckling of robotic closed elastica: Analysis by quasi-static shape transition simulation
    2013 IEEE RSJ International Conference on Intelligent Robots and Systems, 2013
    Co-Authors: Hiromi Mochiyama, Aya Kinoshita, Ryosuke Takasu
    Abstract:

    In this paper, we investigate the property of an impulse Force Generator based on snap-through buckling of a robotic closed elastic rod which is considered as one of good examples of continuum robots. The impulse Force Generator considered here utilizes a snap through buckling of an elastic rod where its base end is pinned and driven by a rotary actuator forcibly while the tip end is pinned or clamped to the fixed point. One of the most fundamental design problems is to maximize the released elastic energy at each buckling state subject to limited ranges of driving torque and angle of a given actuator. From this design viewpoint, we show two findings obtained from quasi-static planar shape transition simulation of the closed elastica, which will be useful for a design of the robot, that is, the ratio of the elastica length and the endpoint distance decides 1) the buckling angle which relates to the range of an actuator driving angle, and 2) the released elastic energy per the maximum driving torque. We also provide a mathematical description of snap-through buckling based on which we can measure a distance to a buckling point.

Hélène Bouvrais - One of the best experts on this subject based on the ideXlab platform.

  • Microtubule Feedback and LET-99-Dependent Control of Pulling Forces Ensure Robust Spindle Position.
    Biophysical journal, 2018
    Co-Authors: Hélène Bouvrais, Laurent Chesneau, Sylvain Pastezeur, Marie Delattre, Danielle Fairbrass, Jacques Pécréaux
    Abstract:

    During asymmetric division of the Caenorhabditis elegans zygote, to properly distribute cell fate determinants, the mitotic spindle is asymmetrically localized by a combination of centering and cortical-pulling microtubule-mediated Forces, the dynamics of the latter being regulated by mitotic progression. Here, we show a, to our knowledge, novel and additional regulation of these Forces by spindle position itself. For that, we observed the onset of transverse spindle oscillations, which reflects the burst of anaphase pulling Forces. After delaying anaphase onset, we found that the position at which the spindle starts to oscillate was unchanged compared to control embryos and uncorrelated to anaphase onset. In mapping the cortical microtubule dynamics, we measured a steep increase in microtubule contact density after the posterior centrosome reached the critical position of 70% of embryo length, strongly suggesting the presence of a positional switch for spindle oscillations. Expanding a previous model based on a Force-Generator temporal control, we implemented this positional switch and observed that the large increase in microtubule density accounted for the pulling Force burst. Thus, we propose that the spindle position influences the cortical availability of microtubules on which the active Force Generators, controlled by cell cycle progression, can pull. Importantly, we found that this positional control relies on the polarity-dependent LET-99 cortical band, the boundary of which could be probed by microtubules. This dual positional and temporal control well accounted for our observation that the oscillation onset position resists changes in cellular geometry and moderate variations in the active Force Generator number. Finally, our model suggests that spindle position at mitosis end is more sensitive to the polarity factor LET-99, which restricts the region of active Force Generators to a posterior-most region, than to microtubule number or Force Generator number/activity. Overall, we show that robustness in spindle positioning originates in cell mechanics rather than biochemical networks.

  • astral microtubule dynamics regulate anaphase oscillation onset and set a robust final position for the caenorhabditis elegans zygote spindle
    bioRxiv, 2017
    Co-Authors: Hélène Bouvrais, Laurent Chesneau, Sylvain Pastezeur, Marie Delattre, Jacques Pécréaux
    Abstract:

    Background: During asymmetric division of the Caenorhabditis elegans nematode zygote, the polarity cues distribution and daughter cell fates depend on the correct positioning of the mitotic spindle which results from both centering and cortical pulling Forces. Revealed by spindle rocking, these pulling Forces are regulated by the Force Generator dynamics, which are related to mitosis progression. This may be combined with a second regulation, this one by the posterior spindle pole position, which can be seen when comparing related species. Results: After delaying anaphase onset, we identified a positional pulling Force regulation in C. elegans, which we ascribed to microtubule dynamics at the cortex. Indeed, in mapping the contacts we found a correlation between the centrosome-cortex distance and the microtubule contact density. This density in turn modulates pulling Force Generator activity. We expanded our model of spindle rocking and predicted then experimentally validated that the oscillation onset position resists changes in cellular geometry and number of Force Generators. Consistent with final spindle position measurements, this new model accounts for a lower dependence on Force Generator dynamics and quantities than predicted by the previous model. Conclusion: The spindle position regulates the rapid increase in Forces needed for anaphase oscillation and positioning through the spatial modulation of microtubule-cortex contacts. This regulation superimposes that of Force Generator processivity, putatively linked to the cell cycle. This novel control confers resistance to variations in zygote geometry and dynamics of cortical Force Generators. Interestingly, this robustness originates in cell mechanics rather than biochemical networks.

  • astral microtubule dynamics regulate anaphase oscillation onset and set a robust final position of the c elegans zygote spindle
    arXiv: Subcellular Processes, 2017
    Co-Authors: Hélène Bouvrais, Laurent Chesneau, Sylvain Pastezeur, Marie Delattre, Jacques Pécréaux
    Abstract:

    Background: The correct positioning of the mitotic spindle during the asymmetric division of the nematode C. elegans zygote relies on the combination of centering and corticalpulling Forces. These Forces, revealed by centrosome anaphase oscillations, are regulated through the dynamics of Force Generators, related to mitosis progression. Recently, we reported the control of oscillation onset by the posterior spindle pole position in related species C. briggsae, necessitating a re-evaluation of the role of astral microtubules dynamics. Results: After exhibiting such a positional switch in C. elegans, we mapped the microtubule ends at the cortex and observed a correlation between the proximity of the centrosomes and the density of microtubule contacts. To explore the functional consequences, we extended the tug-of-war model and successfully accounted for the positional switch. We predicted and experimentally validated that the control of oscillation onset was robust to changes in cell geometry or maximum number of attached Force Generators. We also predicted that the final position of the posterior centrosome and thus the spindle has a reduced dependence upon the Force Generator dynamics or number. Conclusion: The outburst of Forces responsible of spindle anaphase oscillations and positioning is regulated by the spindle position through the spatial modulation of microtubule contacts at the cortex. This regulation superimposes that of Force Generator processivity putatively linked to the cell cycle. This novel control provides robustness to variations in zygote geometry or detailed properties of cortical Force Generators.

  • LET-99-dependent spatial restriction of active Force Generators makes spindle’s position robust
    2017
    Co-Authors: Hélène Bouvrais, Laurent Chesneau, Sylvain Pastezeur, Marie Delattre, Jacques Pécréaux
    Abstract:

    During the asymmetric division of the Caenorhabditis elegans nematode zygote, the polarity cues distribution and daughter cell fates depend on the correct positioning of the mitotic spindle, which results from both centering and cortical pulling Forces. Revealed by anaphase spindle rocking, these pulling Forces are regulated by the Force Generator dynamics, which are in turn consequent of mitotic progression. We found a novel, additional, regulation of these Forces by the spindle position. It controls astral microtubule availability at the cortex, on which the active Force Generators can pull. Importantly, this positional control relies on the polarity dependent LET-99 cortical band, which restricts or concentrates Generators to a posterior crescent. We ascribed this control to the microtubule dynamics at the cortex. Indeed, in mapping the cortical contacts, we found a correlation between the centrosome-cortex distance and the microtubule contact density. In turn, it modulates pulling Force Generator activity. We modelled this control, predicting and experimentally validating that the posterior crescent extent controlled where the anaphase oscillations started, in addition to mitotic progression. Finally, we propose that spatially restricting Force Generator to a posterior crescent sets the spindle's final position, reflecting polarity through the LET-99 dependent restriction of Force Generators to a posterior crescent. This regulation superimposes that of Force Generator processivity. This novel control confers a low dependence on microtubule and active Force Generator exact numbers or dynamics, provided that they exceed the threshold needed for posterior displacement. Interestingly, this robustness originates in cell mechanics rather than biochemical networks.

  • astral microtubule dynamics regulate anaphase oscillation onset and set a robust final position of the c elegans zygote spindle
    bioRxiv, 2017
    Co-Authors: Hélène Bouvrais, Laurent Chesneau, Sylvain Pastezeur, Marie Delattre, Jacques Pécréaux
    Abstract:

    Background: The correct positioning of the mitotic spindle during the asymmetric division of the nematode C. elegans zygote relies on the combination of centering and cortical-pulling Forces. These Forces, revealed by centrosome anaphase oscillations, are regulated through the dynamics of Force Generators, related to mitosis progression. Recently, we have presented the control of oscillation onset by the posterior spindle pole position in related species C. briggsae, necessitating a re-evaluation of the role of astral microtubules dynamics. Results: After exhibiting such a positional switch in C. elegans, we mapped the microtubule ends at the cortex and observed a correlation between the proximity of the centrosomes and the density of microtubule contacts. To explore the functional consequences, we extended the "tug-of-war" model and successfully accounted for the positional switch. We predicted and experimentally validated that the control of oscillation onset was robust to changes in cell geometry or maximum number of attached Force Generators. We also predicted that the final position of the posterior centrosome and thus the spindle has a reduced dependence upon the Force Generator dynamics or number. Conclusion: The outburst of Forces responsible of spindle anaphase oscillations and positioning is regulated by the spindle position through the spatial modulation of microtubule contacts at the cortex. This regulation superimposes that of Force Generator processivity putatively linked to the cell cycle. This novel control provides robustness to variations in zygote geometry or detailed properties of cortical Force Generators.