A real-time path generation method for a mobile robot is newly proposed based on the virtual tangential vector (VTV). The VTV is for imposing a feature to drive a robot along with the tangential direction to a circular obstacle virtually generated in real-time. Subjected to multiple obstacles, a weighted resultant vector of all the VTVs, so-called weighted VTV (WVTV), is defined. Together with the conventional objectives such as the goal attractive vector and the obstacle repulsive vector, the WVTV is included in a multi-objective optimisation framework. Significant performance enhancements are demonstrated by simulations for complicated unknown environments.