This paper presents a novel methodology for positioning an explosive ordnance device (EOD) which consists of a mobile manipulator with 12° of freedom. The approach uses an extension of a homogeneus transformation graph (HTG) which can be used in the kinematic modeling of mobile manipulators and unmanned aerial vehicles. In this approach the complete kinematics is modeled as one unit in contrast to previous approaches where the manipulator and mobile body are decoupled. The system is tested in several escenarios (simulated and real experimentation) like approaching to an explosive device location on the plane as well as in slope ways, climbing stairs, lifting itself and manipulating procedures. All the aforementioned scenarios were developed using the HTG which establishes the appropriate transformations and interaction parameters of the coupled system. Finally, the system is tested (simulated and real experimentation) for positioning its end device in a target with a RMS positioning average error ofr 7.91 mm which is acceptable for this kind of devices.