The Control Strategy for Degrees of Freedom in Remote Prehension with a Tool

Abstract

Constructing movement couplings is essential for decreasing degrees-of-freedom for a compound movement that requires coordination over a multiple segments. Angular movements of joints in the upper limbs are examined, the pattern of movement couplings between prehension performed with the hands (natural prehension) and with a simple grasper held in the hands (remote prehension). In remote prehension, the shoulder and elbow joint are tightly associated with a clear in-phase joint to joint movement; the elbow and wrist display both anti-and in-phase movements due to the change of initial configuration of the upper limb when holding a tool. In contrast, the shoulder-elbow bond is mixed in natural prehension, but the elbow and wrist bond is predominant with an anti-phase pattern. With diversity for joint couplings, the movement consistency of the hinge is preserved with relatively smaller path variability. Results support the end-point control notion, i.e. movement is controlled by extrinsic coordinates close to the end-effectors of the movement system.

The trade-off between flexibility and maneuverability: task performance with articulating laparoscopic instruments

“…For example, articulating instruments would facilitate intracorporeal suturing, especially in difficult positions such as the anterior abdominal wall of the deep pelvis. However, such potential advantages may be offset by the increased complexity of the instrument, which may make it harder to predict the movement outcome and more difficult to build movement coordination between the hand and the tool [6].…”

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