Approach distance is constrained by social norms
Aliases: proxemic distance · robot personal space · social distance
What it is
Human–robot proxemics concerns how people apply personal-space and social-distance conventions to robots. Acceptable separation is not a fixed radius; it changes with task, orientation, speed, robot scale, escape space, culture, and experience. Handover may require proximity, whereas passing on patrol rarely requires close stationary contact.
Why it happens
Distance jointly regulates collision margin, sensory intensity, and social meaning. Proximity magnifies motion, noise, and gaze cues while reducing time to interpret and evade. Frontal space often carries stronger interaction intent. People balance task value against defensive space, and tolerance forced by a narrow corridor should not be mistaken for comfort.
Studying it
Stop-distance tasks, comfort adjustment, controlled approaches, and natural trajectory observation can measure preferred distance, retreat onset, body orientation, performance, and discomfort. Starting pose, direction, speed, robot scale, room geometry, and access to a stop control must be reported. Otherwise numerical distances are not comparable, and a single laboratory choice cannot represent long-term cohabitation.
Where it stops holding
No universal personal-space value applies. Wheelchair users, children, sensory-impaired people, and those unable to evade quickly may require different margins. Rescue and cooperative carrying can justify temporary proximity. Failure to step back may reflect constrained passage, politeness, or lack of control rather than acceptance.
Applying it
- Define separate distance policies for meeting, following, handover, and joint work; when a person retreats, enlarge rather than chase the gap.
- Include robot scale, stopping distance, and human escape direction in separation logic, slowing or waiting in narrow spaces.
- Validate with trajectories and video of closest approach, retreat, and torso rotation, then ask why people did not object. Analyse by role and mobility.