An innovative robotic training system imitating the cervical spine behaviors during rotation–traction manipulation

The present study demonstrated an innovative humanoid robot applied during Rotation–Traction (RT) manipulation practice and evaluation process. A mass–damper–spring mechanical system with an electromagnetic clutch was designed to emulate the cervical spine and a 3-DOF non-planar model was built to replace the neck part. With the help of an excellent electromechanical system and appropriate control strategy, the robot could imitate the entire dynamic responses of the human cervical spine during the RT manipulation process. Moreover, a novel adaptive force tracking impedance control was adopted to ensure a variable contact force in the unknown environment to imitate the real biomechanics of the human neck. In comparison to existing impedance control methods, the proposed control scheme is not only utility but also robust against external disturbances such as varying stiffness or uncertainties of the robot. The stability of the proposed impedance control was theoretically examined. Test results revealed that the cervical spine robot could faithfully replicate the biomechanical properties of the human cervical spine during RT manipulation and it is helpful in training and evaluating interns.