A six degree of freedom force transducer is provided on a manipulator's hand and includes a plurality of I-beam modules having strain gauges on the flat surfaces of the thin legs of each I-beam for measuring the bending moments of each leg. According to one embodiment, a pair of strain gauges are located on each side of the leg, providing a total of four gauges in each leg. The end bells of each I-beam are adapted to be rigidly interconnected with either other I-beams, structural members of the manipulator fingers, the drive member for the manipulator, or to intermediate coupling blocks designed to rigidly interconnect I-beams. A plurality of I-beams and interconnecting blocks can be connected in various configurations to provide a determination by the strain gauges of the six components of forces and moments which are applied by forces and moments on the fingers of the manipulator system. The I-beams and interconnecting blocks are arranged in x-y-z orthogonal directions such that the structural stiffness is in the same order in different directions. The moment at each basic module can be measured by the voltage output of a bridge associated with the strain gauges. In this fashion, a determination of the position and orientation of an object in the manipulator's hand can be readily provided by a computer which solves the force and moment equilibrium equations associated with the I-beam strain gauges.