Flexible joint methods for upper limb exoskeleton robot need !!

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I am working on project of building a upper limb exoskeleton robot with 4 dof. In order to get human like motion, it need to catch the axis offset at human anatomy in to my robot. I though that it may can get from some flexible coupling, but still not sure. Any of u have idea of how to get flexible motion into robot in order to get human like motion. do you know any machine components which are available to generate flexible motion in robotic joints? it is better that if u can provide some useful links to search for details. Thanks