Human haptic perception can be influenced by interaction with other senses, like vision [1]. The mismatch between visually perceived object size including existing knowledge (top-down) and incoming data via the somatosensory system (bottom-up) can cause illusions at the human operator called size-weight illusion (SWI) [2]. Especially in novel human-robot collaboration systems like cobots [3], where a machine amplifies human strength, this phenomenon may lead to usability and performance issues [4]. The presented study should help to understand human behavior in horizontal manipulation tasks (HMT) such as bimanual imprecise pushing and pulling of heavy loads. Results show that a significant difference in expected strain between a small and a large object does not result in a strong subjective SWI with imprecise HMT operations. However, objective data reveals that, in lower mass conditions, significantly higher forces and force rates were applied while the larger object was present. A possible shared control approach incorporating a Bayesian framework is presented.
['Jonas Schmidtler', 'Klaus Bengler']
Size-weight illusion in human-robot collaboration