Abstract: Provided is an off-road robot, including a front side portion, a rear side portion and a middle portion. The front side portion includes a front vehicle frame, a front wheel and a first driving system; the front wheels and the first driving system are disposed at the front vehicle frame; and the first driving system drives the front wheels. The rear side portion includes a rear vehicle frame, a rear wheel and a second driving system; the rear wheel and the second driving system are disposed at the rear vehicle frame; and the second driving system drives the rear wheels. The middle portion includes a first frame and a second frame; the first frame and the second frame are detachably connected; the front vehicle frame is connected with the first frame; and the rear vehicle frame is connected with the second frame.

Abstract: The present invention provides a multilevel read-only optical disk and the method for producing the same. The multilevel read-only optical disk comprises a plurality of the recording pits, each of the longitudinal sections of the recording pits has a multilevel arbitrary shape; the areas of the longitudinal sections of the recording pits are not identical each other; the area of each of the longitudinal sections of the recording pits is defined by the following formula: S=?h(x)dx, where S represents the area of each of the longitudinal sections of the recording pits, x represents the coordinate value along the width direction of the recording pits, h(x) represents the pit-depth distribution function of the longitudinal sections of the recording pits and the region of the integration covers the whole longitudinal sections of the recording pits. Furthermore, the run length of the multilevel read-only optical disk is limited.

Abstract: The present invention provides a multilevel read-only optical disk and the method for producing the same. The multilevel read-only optical disk comprises a plurality of the recording pits, each of the longitudinal sections of the recording pits has a multilevel arbitrary shape; the areas of the longitudinal sections of the recording pits are not identical each other; the area of each of the longitudinal sections of the recording pits is defined by the following formula: S=?h(x)dx, where S represents the area of each of the longitudinal sections of the recording pits, x represents the coordinate value along the width direction of the recording pits, h(x) represents the pit-depth distribution function of the longitudinal sections of the recording pits and the region of the integration covers the whole longitudinal sections of the recording pits. Furthermore, the run length of the multilevel read-only optical disk is limited.