Although industrial robot mechanisms are relatively mature, few manipulator arms are available for use outside of the factory. This paper presents several techniques of improving the performance of robot manipulators designed for use in unstructured or hazardous environments. These methods include a means of passive, mechanical, and energy-conservative gravity compensation, a remote actuation technique, and the use of tension-element transmission and speed reduction. In comparison with a conventional arm, an arm incorporating these techniques moves faster, handles a larger payload, and responds better to external forces. In addition, simulation results show that it consumes less than one-tenth the energy.