We propose a robotic finger with an exoskeleton-type structure that bends and extends by the deformation force of flat tubes. Our objective is to realize a disposable robot hand for gripping unsanitary objects. To reduce the cost of disposing of the robotic finger, a commercially available cable carrier chain was used for the exoskeleton component, and the flat tubes used in the pneumatic actuator were prepared by thermal processing of a commercially available tube. The driving joint of the robotic finger consists of a hollow link mechanism and two flat tubes, which are respectively arranged inside the hollow link mechanism and at the joint boundary. The proposed joint structure achieves both smooth drivability and good load-bearing capacity. The developed robotic finger weighs approximately 85 g and generates a fingertip force of approximately 4 N when a pressure of 0.25 MPa is applied. Because the developed robotic finger is pneumatically driven, it conforms to the object shape and is compliant to external force. Verification of the mechanism demonstrated that the developed robotic finger is useful because it was able to grasp six types of assumed objects.

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