Brave Command Dagwon

Floating in space many light years from Earth is a penal colony that holds some of the worse criminals in this part of the galaxy. These criminals were captured by the Dagwon Interstellar Police Force (a Green Lantern style agency) and jailed. However, the inmates took over the jail and began to strike back at their captors by attacking the nearest planet: Earth. After the first attack, 5 high school students are given the power to use their wrist morphers and summon powerful battle armor. In time of crisis they can mentally and physically become one with their respective vehicles and assume a more powerful robot mode. When necessary several of the human/robot hybrids can gattai (or combine) into larger robots with powerful attacks. These 'Brave high school warriors' now attempt to juggle school, love, and saving the planet on a daily basis.

Synopsis from Anime News Network