Performance indicators for stability of slackline balancing

In this study we analyze slackline balancing, a task where the subject has to maintain balance on a narrow elastic ribbon that is mounted between two anchor points. We investigate a list of potential performance indicators for stability and their relationship to successful and unsuccessful slackline balancing. We captured the motions of 11 subjects of three different skill levels (beginners, sportive beginners and experts) and recorded a total of 205 standing and 180 walking motions on the slackline. We analyzed all trials fitting subject specific, dynamic rigid body models to the measured kinematic motions. The results show that experts are able to precisely control their angular momentum. They mainly balance in the transverse plane and reduce motion in the sagittal plane and around the vertical axis. We also found their walking style being adapted to these criteria. Further, experts are able to move their contact foot in the transverse plane while keeping their center of mass steady. They adjust their ankle and knee compliance in the stance leg. Sufficient center of mass acceleration control in the vertical direction was found to be a necessary skill to walk on a slackline. Additionally, we found consistent hand coordination patterns in all experts and already in sportive beginners.

[1]  Lara A. Thompson,et al.  Balance Performance as Observed by Center-of-Pressure Parameter Characteristics in Male Soccer Athletes and Non-Athletes , 2017, Sports.

[2]  Kentaro Kodama,et al.  Whole-Body Coordination Skill for Dynamic Balancing on a Slackline , 2015, JSAI-isAI Workshops.

[3]  L Mahadevan,et al.  Balancing on tightropes and slacklines , 2012, Journal of The Royal Society Interface.

[4]  P. Fransson.  Analysis of Adaptation in Human Postural Control , 2005 .

[5]  Masayuki Inaba,et al.  Extended Three-Dimensional Walking and Skating Motion Generation for Multiple Noncoplanar Contacts With Anisotropic Friction: Application to Walk and Skateboard and Roller Skate , 2019, IEEE Robotics and Automation Letters.

[6]  Susanne W. Lipfert,et al.  Upright human gait did not provide a major mechanical challenge for our ancestors. , 2010, Nature communications.

[7]  M. Vukobratovic,et al.  On the stability of anthropomorphic systems , 1972 .

[8]  Claudio Belvedere,et al.  Multi-segment trunk kinematics during locomotion and elementary exercises. , 2011, Clinical biomechanics.

[9]  R Roth,et al.  Effects of Slackline Training on Balance, Jump Performance & Muscle Activity in Young Children , 2013, International Journal of Sports Medicine.

[10]  Gabriele Nava,et al.  Modeling and control of humanoid robots in dynamic environments: ICub balancing on a seesaw , 2017, 2017 IEEE-RAS 17th International Conference on Humanoid Robotics (Humanoids).

[11]  D. Roetenberg,et al.  Xsens MVN: Full 6DOF Human Motion Tracking Using Miniature Inertial Sensors , 2009 .

[12]  Martin L. Felis,et al.  Modeling Emotional Aspects in Human Locomotion , 2015 .

[13]  W. Taube,et al.  Improved postural control after slackline training is accompanied by reduced H‐reflexes , 2012, Scandinavian journal of medicine & science in sports.

[14]  Martin L. Felis.  RBDL: an efficient rigid-body dynamics library using recursive algorithms , 2017, Auton. Robots.

[15]  P. Leva.  Adjustments to Zatsiorsky-Seluyanov's segment inertia parameters. , 1996 .

[16]  Melanie Keller,et al.  Balancing on a Slackline: 8-Year-Olds vs. Adults , 2013, Front. Psychol..

[17]  B. Mishra,et al.  Some discussion of static gripping and its stability , 1989, IEEE Trans. Syst. Man Cybern..

[18]  Sergey V. Drakunov,et al.  Capture Point: A Step toward Humanoid Push Recovery , 2006, 2006 6th IEEE-RAS International Conference on Humanoid Robots.