Whole-body Coordination Research Articles

2A1-N-060 人間共存ロボットの觝触適応行動 : 第20報:環境との接触を回避しつつ人間追従性と作業性の両立が可能な全身運動制御(人間機械協調3,生活を支援するロボメカ技術のメガインテグレーション)

2A1-N-060 人間共存ロボットの觝触適応行動 : 第20報:環境との接触を回避しつつ人間追従性と作業性の両立が可能な全身運動制御(人間機械協調3,生活を支援するロボメカ技術のメガインテグレーション)

Coordination of a step with a reach

Although natural reaching behavior can easily include forward body movement, most laboratory studies of reaching have constrained the body to be stationary. Recently, however, it has been shown that normal subjects exhibit a different pattern of errors when attempting to pinpoint remembered target locations, depending on whether or not the reach includes a step. In the study of Flanders et al., these errors appeared to be due to the strategy of eye/head/hand coordination which normally comes into play when the body is moving toward the target. Since the spatial positioning of the head was found to partially explain the errors in hand placement, the present study examined the movements of patients with bilateral vestibular deficits in order to further analyze the whole-body coordination. Somewhat surprisingly, the patients exhibited the same pattern of head movement and the same errors in hand placement as did the control subjects. Nevertheless, the patients' movements clearly exhibited evidence for an abnormal decomposition of elbow extension and trunk rotation. Furthermore the patients' (spatial) hand paths were significantly more curved than those of control subjects and, only in the patients, paths to remembered targets were significantly more curved than paths to visible targets. Thus for movements to remembered targets, the patients tended to move the hand to the same incorrect spatial positions as control subjects but spatiotemporal aspects of the arm and body movement differed. The results are consistent with the idea that vestibular patients are overly dependent upon visual cues, and support the hypothesis that this stepping and reaching behavior is largely dependent upon a visual reference signal.

Reaching beyond reach.

The analysis of errors in two-joint reaching movements has provided clues about sensorimotor processing algorithms. The present study extends this focus to situations where the head, trunk, and legs join with the arm to help reach targets placed slightly beyond arm's length. Subjects reached accurately to touch "real targets" or reached to the remembered locations of "virtual targets" (i.e., targets removed at the start of the reach). Subjects made large errors in the virtual-target condition and these errors were analyzed with the aim of revealing the implications for whole-body coordination. Subjects were found to rotate the head less in the virtual-target condition (when compared with accurate movements to real targets). This resulted in a more limited range of head postures, and the final head angles at the end of the movements were geometrically related to the incorrect hand locations, perhaps accounting for some portion of the errors. This suggests that head-eye-hand coordination plays an important role in the organization of these movements and leads to the hypothesis that a representation of current gaze direction may serve as a reference signal for arm motor control.

Applying Bandwidth Feedback Scheduling to a Golf Shot

Bandwidth knowledge of results (KR) involves the presentation of precise error KR only on those trials in which a preset criterion of accuracy is not met. When the criterion is met, only a general statement referring to this success is given. It has been shown that bandwidth KR increases movement consistency relative to 100% relative frequency KR (Lee & Carnahan, 1990). While this and other KR schedules have been successful in promoting motor learning, there has been no attempt to generalize this finding to a motor task requiring whole-body coordination. This study examined whether, by using information feedback suited to a complex task (Kernodle & Carlton, 1992), the findings relating to bandwidth feedback would transfer to such a task. Participants practiced a golf chipping task with either KR or error correcting transitional information, under 0, 5, or 10% bandwidth conditions. Participants in the 10% bandwidth condition who had received transitional information performed more consistently in retention than all other participants. This result provides support for the generalization of bandwidth feedback principles to complex tasks.