The Influence of Haptic Feedback and Visual Information on Multi-Limb Coordination

Multi-limb coordination is necessary for many daily activities. It also has particular relevance for a growing area of human-system applications such as teleoperated robot operation and supernumerary robot operation where an additional robotic limb may complement natural limb functions. Introducing sup-plemental sensory information, specifically haptic feedback, has shown the potential to improve assistive robotics control, human-machine interactions, and even human motor learning. However, there has been little research on how sensory information, including haptic feedback and visual information, contributes to the execution of multi-limb coordinated tasks. In this paper, we designed a tri-limb coordinated task where participants move a cursor to a randomly positioned target on a screen guided by variations of both haptic feedback and visual information. Our results indicated that while haptic feedback could partially sub-stitute for visual information, it could not completely replace nor surpass the task performance achieved with visual information as feedback. Importantly, haptic feedback does not negatively impact performance metrics such as how often the participant coordinates multiple limbs simultaneously (coordination score), controls their limbs without redundant movement (normalized sub-optimal path), completes the task (success rate), and the mental workload perceived during the task (cognitive load). This study provides insight into the contribution of sensory feedback in facilitating multi-limb coordination, providing relevant guidance for numerous applications of human interactions with assistive technologies.