We consider parallel robots, that will be called cams-coupled parallel robots, whose mobile platform has surfaces that are constrained to be in contact at a point with surfaces located on the base. Articulated passive xed length legs connect also the base to the platform while active legs allow to control the motion of the platform. We investigate the mobility of such robot and shows how the inverse and direct kinematics can be solved for arbitrary contact surfaces. We present then preliminary results regarding the synthesis of such robot.