A Low-cost Kinematic Simulator Of Continuum-rigid Hybrid Manipulators

Continuum robots have shown some advantageous characteristics in recent researches on mini-mal invasive surgery over traditional robots. It is foreseeable that more efforts would be devoted into this area and continuum surgical robots could also bring commercialization opportunities in the near future. A kinematic simulator provides a convenient tool for a first-time user to operate continuum robots, especially before operate actual continuum surgical robots.No simulator for continuum robots has been reported in the existing literatures. In order to close this gap, this thesis presents a general kinematic simulator for continuum-rigid hybrid manipulators. This simulator mimics a tele-operation paradigm and could visualize the motions of hybrid manipulators that possess different structural parameters. Motion control commands would be generated by a low-cost vision-based tracker.To implement this simulator, a general kinematics model is firstly derived for single-segment and multi-segment hybrid structures by expanding previous works on continuum robots. The simulator is then based on this general modelling frame for both continuum manipulators and continuum-rigid hybrid manipulators. The simulator could visualize the motion capabilities of various manipulators with different structures, using its user interface for parameter setting.Continuum-rigid hybrid manipulators in the simulators would be driven using a resolved rate method involving inverse kinematics. The inverse kinematics are based on various forms of pseudo inverses of the manipulator’s Jacobian matrix. Motions of the manipulators are visualized using the anaglyph method in the simulator.Tele-operation is considered as the most typical paradigm in a surgical robotic system. Existing master consoles are mostly too expensive for preliminary experimental usage. The motion commands in the simulator are generated by a low-cost vision-based tracker that consists of two webcams. All the algorithms required to implement an optical tracker, such as lens distortion correction, edge detection, image correspondence matching, etc., are discussed in this study.With the tracker integrated, the simulator can simultaneously visualize the motions of two hybrid manipulators in3D via the anaglyph, when the guiding tools move in the field of view of the tracker. A complete test bench, consisting of the optical tracker (master console), the hybrid manipulator (slave), and the control system is built to validate the kinematics model derived and demonstrate this simulator can serve as a low-cost and reliable tool to perform pre-operation trainings of continuum surgical robots.