Loading of one fluid control device with respect to other fluid control devices in a fluid system is evaluated by a Dynamic Relative Load Rate DRLR variable that is common to each devices. The device comprises a body, a motor driven wheel coupled to the body, and a hitch coupled to the body and adapted for engaging the hospital bed. There is at least one attachment means provided on the upper surface or the perimeter for securing a cleaning sheet over the lower surface of the cleaning head.