human: Given a node-centered hypergraph: <hypergraph>, where nodes represent papers and hyperedges represent sets of papers co-cited by a source paper.

Details of the hypergraph:
Center node: "omnidirectional bipedal walking with direct fused angle feedback mechanisms"
  Abstract: An omnidirectional closed-loop gait based on the direct feedback of orientation deviation estimates is presented in this paper. At the core of the gait is an open-loop central pattern generator. The orientation feedback is derived from a 3D nonlinear attitude estimator, and split into the relevant angular deviations in the sagittal and lateral planes using the concept of fused angles. These angular deviations from expected are used by a number of independent feedback mechanisms, including one that controls timing, to perform stabilising corrective actions. The tuning of the feedback mechanisms is discussed, including an LQR-based approach for tuning the transient sagittal response. The actuator control scheme and robot pose representations in use are also addressed. Experimental results on an igus Humanoid Open Platform demonstrate the core concept of this paper, that if the sensor management and feedback chains are carefully constructed, comparatively simple model-free and robot-agnostic feedback mechanisms can successfully stabilise a generic bipedal gait.

Connected through hyperedge HE-1 (induced by source paper "nimbro robots winning robocup 2018 humanoid adultsize soccer competitions"):
  with members:
    - "grown up nimbro robots winning robocup 2017 humanoid adultsize soccer competitions"
    - "hierarchical and state based architectures for robot behavior planning and control"
    - "fused angles a representation of body orientation for balance"
    - "robocup 2016 humanoid teensize winner nimbro robust visual perception and soccer behaviors"
    - "a monocular vision system for playing soccer in low color information environments"
    - "nimbro op2x adult sized open source 3d printed humanoid robot"
    - "combining simulations and real robot experiments for bayesian optimization of bipedal gait stabilization"
    - "online visual robot tracking and identification using deep lstm networks"

Connected through hyperedge HE-2 (induced by source paper "robocup 2019 adultsize winner nimbro deep learning perception in walk kick push recovery and team play capabilities"):
  with members:
    - "nimbro robots winning robocup 2018 humanoid adultsize soccer competitions"
    - "grown up nimbro robots winning robocup 2017 humanoid adultsize soccer competitions"
    - "location dependency in video prediction"
    - "a monocular vision system for playing soccer in low color information environments"
    - "online balanced motion generation for humanoid robots"
    - "real time visual tracking and identification for a team of homogeneous humanoid robots"
    - "nimbro op2x adult sized open source 3d printed humanoid robot"
    - "online visual robot tracking and identification using deep lstm networks"

Connected through hyperedge HE-3 (induced by source paper "nimbro op2x adult sized open source 3d printed humanoid robot"):
  with members:
    - "on the convergence of adam and beyond"
    - "grown up nimbro robots winning robocup 2017 humanoid adultsize soccer competitions"
    - "fused angles a representation of body orientation for balance"
    - "a ros based software framework for the nimbro op humanoid open platform"
    - "a monocular vision system for playing soccer in low color information environments"
    - "child sized 3d printed igus humanoid open platform"
    - "combining simulations and real robot experiments for bayesian optimization of bipedal gait stabilization"
    - "nimbro op2 grown up 3d printed open humanoid platform for research"

Connected through hyperedge HE-4 (induced by source paper "combining simulations and real robot experiments for bayesian optimization of bipedal gait stabilization"):
  with members:
    - "fused angles a representation of body orientation for balance"
    - "child sized 3d printed igus humanoid open platform"
    - "bayesian optimization using domain knowledge on the atrias biped"
    - "virtual vs real trading off simulations and physical experiments in reinforcement learning with bayesian optimization"
    - "automatic lqr tuning based on gaussian process global optimization"
    - "safe controller optimization for quadrotors with gaussian processes"

Connected through hyperedge HE-5 (induced by source paper "grown up nimbro robots winning robocup 2017 humanoid adultsize soccer competitions"):
  with members:
    - "learning to improve capture steps for disturbance rejection in humanoid soccer"
    - "robocup 2016 humanoid teensize winner nimbro robust visual perception and soccer behaviors"
    - "a monocular vision system for playing soccer in low color information environments"
    - "child sized 3d printed igus humanoid open platform"
    - "nimbro op2 grown up 3d printed open humanoid platform for research"

Connected through hyperedge HE-6 (induced by source paper "bipedal walking with corrective actions in the tilt phase space"):
  with members:
    - "tilt rotations and the tilt phase space"
    - "fused angles a representation of body orientation for balance"
    - "fused angles and the deficiencies of euler angles"

Connected through hyperedge HE-7 (induced by source paper "robocup 2016 humanoid teensize winner nimbro robust visual perception and soccer behaviors"):
  with members:
    - "fused angles a representation of body orientation for balance"
    - "child sized 3d printed igus humanoid open platform"

Connected through hyperedge HE-8 (induced by source paper "first international harting open source prize winner the igus humanoid open platform"):
  with members:
    - "fused angles a representation of body orientation for balance"
    - "robust sensor fusion for robot attitude estimation"

Question: Please tell me which class the center node belongs to. The 40 classes are: cs.NA(Numerical Analysis), cs.MM(Multimedia), cs.LO(Logic in Computer Science), cs.CY(Computers and Society), cs.CR(Cryptography and Security), cs.DC(Distributed, Parallel, and Cluster Computing), cs.HC(Human-Computer Interaction), cs.CE(Computational Engineering, Finance, and Science), cs.NI(Networking and Internet Architecture), cs.CC(Computational Complexity), cs.AI(Artificial Intelligence), cs.MA(Multiagent Systems), cs.GL(General Literature), cs.NE(Neural and Evolutionary Computing), cs.SC(Symbolic Computation), cs.AR(Hardware Architecture), cs.CV(Computer Vision and Pattern Recognition), cs.GR(Graphics), cs.ET(Emerging Technologies), cs.SY(Systems and Control), cs.CG(Computational Geometry), cs.OH(Other Computer Science), cs.PL(Programming Languages), cs.SE(Software Engineering), cs.LG(Machine Learning), cs.SD(Sound), cs.SI(Social and Information Networks), cs.RO(Robotics), cs.IT(Information Theory), cs.PF(Performance), cs.CL(Computation and Language), cs.IR(Information Retrieval), cs.MS(Mathematical Software), cs.FL(Formal Languages and Automata Theory), cs.DS(Data Structures and Algorithms), cs.OS(Operating Systems), cs.GT(Computer Science and Game Theory), cs.DB(Databases), cs.DL(Digital Libraries), cs.DM(Discrete Mathematics). Directly output the class name.

gpt: cs.RO(Robotics)