To steer a needle around delicate or bony structures during needle insertion for targeting tumor in minimally invasive surgery, we proposed a novel continuum robot mechanism named “Active Sheath” and applied the mechanism to a novel steerable needle with a bevel tip. The mechanism contains only two units, that is, a guide tube and a loop-shaped inner arm inserted into the tube. When the base of each arm is pulled or pushed, the arm could be deflected in the guide and therefore the guide tube could also be deflected following the arm deformation. The control system of the steerable needle insertion was derived as a nonholonomic affine model to calculate the needle paths numerically. The prototype of the needle with 2.1[mm] outer diameter was developed and evaluated for the steering performance to measure the tip location and orientation by inserting it into an agar phantom. The path steered by using inner arm could be deflected maximum 24 times larger than that of the non-driving needle deformed by reaction force only. From the results we concluded that the proposed mechanism has the potential to target tumors safely by avoiding delicate or bony structures during needle insertion.
This paper presents a walking control system for biped robots on loose soil. The proposed method realizes long time continuous walking and stable stopping on sand. Characteristics of the proposed system is landing position (modification) control. In this control, as a balance index, amount of CoM position modification is utilized. Considering past modification history, amount of current landing position modification is decided. In oder to evaluate the proposed control system, the small humanoid robot performed walking, stepping and turning on sand.
Recently, low back pain of laborer is social issue in Japan. This problem is caused by excessive load on waist joint or uncomfortable posture of heavy labor, such as lifting up heavy objects. To resolve the problem, we have developed endoskeleton-type power assist suit. In previous study, the design and operation method of the assist suit was designed using simple static model. However, this method is insufficient for designing the assist suit because structure of human body is more complex than the model practically. Therefore, we use the musculoskeletal model to design the assist suit and its operation method in this paper. Firstly, motion of worker is analyzed using 3D motion capturing and this results are applied to musculoskeletal model “Anybody”. Secondly, with these simulation results, the assist suit and its operation method are designed. Finally, effectiveness of the assist suits confirmed by measurement of electromyography and assistive force.