In this paper we present a motion planning algorithm for a mobile robot, suspended by seven cables. We formulate the motion planning algorithm as a convex optimization problem. We analyze the robots' statics and kinematics in order to implement them into the motion planning. The robot consists of cable mechanisms and a central body. Each cable mechanism includes a thin cable with a simple gripper at the end, and a dispensing and rolling mechanism. The robot dispenses the cables towards possible grasping points in the surroundings, and then pulls the cables simultaneously in a coordinated manner. Depending on the geometry of the grasping points and the coordinated pulling, the robot can perform stable motion over curved surfaces or around and over obstacles. Simulations results are presented as well as experiments which are conducted on a novel underconstrained four cable suspended mobile robot.