1. A system, comprising: multiple input/output systems coupled together to provide a view of a common scene from perspectives of each of the systems, each system comprising: a display/sensor assembly presenting the view to a viewer and sensing a user position and user viewpoint; a robotic arm coupled to the assembly and providing display position and orientation information; a computer determining the view responsive to the user position and viewpoint, producing a display responsive to the position and viewpoint, comparing the user position to position range limits and producing robot motion control information to keep the user position within the range limits, the robotic arm moving and orienting the assembly responsive to the motion control information.