Determining design parameters is often a challenging procedure, especially in human-friendly robot design due to competition between robot safety and performance. Presenting an analytical model of hybrid actuation for humanfriendly robot development, this paper proposes design methodologies to improve performance factors such as range of motion, payload, and acceleration while maintaining the safety factor of effective inertia. The optimized parameters for various design requirements have been provided for 1DOF and 2DOF applications. Comparison between current design parameters and the optimized parameters for a current platform shows the performance improvement. In future work this research will be extended to systems with higher degrees of freedom.