A Continuum Robotic Arm for Intra-Cavity Inspection and Manipulation
December 2014 to September 2016
This work was supported in part by the National Natural Science Foundation of China (Grant No. 51375295 and Grant No. 51435010), in part by the State Key Laboratory of Mechanical Systems and Vibration (Grant No. MSVZD201406 and Grant No. MSVZD201504), and in part by the Joint Research Center of Advanced Aerospace Technology (Grant No. USCAST2013-17).
Slim and dexterous manipulators with long reaches and exchangeable end effectors can perform various intra-cavity tasks in confined spaces, such as inspection, foreign objects removal, laser cutting, welding, manipulation, assembling, etc. These appealing potential applications have led to a variety of research activities.
Inspired by the continuum robots with multiple backbones and push-pull actuation, a slim and dexterous continuum manipulator is designed as shown in the figure. The manipulator consists of two continuum segments. Each continuum segment possesses three DoFs. A camera unit with integrated LEDs for illumination is installed at the distal tip with a lumen in the manipulator body for passing different tools for various tasks.
The continuum segments of the manipulator are actuated by pushing and pulling their backbones, utilizing the benefits of a newly proposed dual continuum mechanism concept. The backbones are made from super-elastic nitinol rods which could undertake both compressive and stretching loads. All the actuators are located at the proximal end of the manipulator and they work collectively to drive the segments. And the segments are bent due to compatible deformations of all the structural members, when the backbones are pulled and pushed. Tensions on the backbones needn’t be deliberately maintained. The Young’s modulus of the nitinol is considerably higher than that of the non-metal elastic materials such as rubber and silicone. Using nitinol to construct the continuum segments could lead to better payload capabilities and higher positioning accuracy, with proper motion calibrations implemented. With the structure synthesized using the kinematics model, the continuum manipulator can navigate through a mockup environment to perform inspections or manipulations at remote locations in a deep cavity.
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