human: Given a hyperedge-centered hypergraph: <hypergraph>, where the center hyperedge is induced by one source paper and its member nodes are the cited papers.

Details of the hypergraph:
Center hyperedge (induced by source paper "a mpc walking framework with external contact forces"):
  Abstract: In this work, we present an extension to a linear Model Predictive Control (MPC) scheme that plans external contact forces for the robot when given multiple contact locations and their corresponding friction cone. To accomplish this we set up a two step optimization problem. In the first optimization, we compute the Center of Mass (CoM) trajectory, foot step locations, and introduce slack variables to account for violating the imposed constraints on the Center of Pressure (CoP). We then use the slack variables to trigger the second optimization, in which we calculate the optimal external force that compensates for the CoP tracking error. This optimization considers multiple contacts with the environment by formulating the problem as a Mixed Integer Quadratic Program (MIQP) that can be solved at the order of 100 Hz. Once contact is created, the MIQP collapses to a single Quadratic Program (QP) that can be solved in real time $<$ 1kHz. Simulations show that the presented control scheme can withstand disturbances 2-5x larger with the additional force provide by a hand contact when considering delays and 3-6x larger when contact is already made.

Includes members:
  Member "when to make a step tackling the timing problem in multi contact locomotion by topp mpc":
    also connected through other hyperedges:
      - Hyperedge HE-1 (induced by source paper "whole body walking generation using contact parametrization a non linear trajectory optimization approach")
  Member "momentum control with hierarchical inverse dynamics on a torque controlled humanoid":
    also connected through other hyperedges:
      - Hyperedge HE-2 (induced by source paper "multi agent manipulation via locomotion using hierarchical sim2real")
  Member "structured contact force optimization for kino dynamic motion generation":
    also connected through other hyperedges:
      - Hyperedge HE-3 (induced by source paper "accelerated admm based trajectory optimization for legged locomotion with coupled rigid body dynamics")
  Member "step timing adjustment a step toward generating robust gaits":
    also connected through other hyperedges:
      - Hyperedge HE-4 (induced by source paper "robust humanoid contact planning with learned zero and one step capturability prediction")
  Member "humanoid momentum estimation using sensed contact wrenches":
    also connected through other hyperedges:
      (none)

Question: Please tell me which class the source paper 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)