US Patent 7331436 Communications spooler for a mobile robot

A cable handling system mounted to a mobile robot to dispense and retrieve cable at zero tension includes a cable reel drive and a downstream tension roller drive that includes an idler. As a cable passes through the tension roller drive, position along the length of the cable and/or the cable speed is monitored accurately by a sensor attached to the idler. A system controller in communication with the sensor controls the cable reel drive and the tension roller drive for dispensing and retrieving cable downstream of the tension roller drive.