Warrior's Woman by Johanna Lindsey

Warrior's Woman (Avon) - Tedra De Arr is the top security officer on her planet, Kystran.  While she is attending to a situation outside the capital, the government is taken over by the tyrant, Crad Ce Moerr.  With aid from her friends, she sets out across the galaxy to get help to rescue her planet.  Her personal computer, Martha, guides the ship to the mother planet, Sha-Ka'an, of the Sha-Ka'ar warriors who are employed by Crad Ce Moerr.  There she finds the warrior Challen Ly-San-Ter.  Before she can employ the warriors, she must accoustom herself to the Sha-Ka'ani ways that have the women completely subservient to men.