In hard disk drive (HDD) system, disturbances like rotary vibrations and shocks usually contain frequency components with timevarying phases and magnitudes. The effect of these disturbances has to be attenuated for better servo performance, and the dominant frequencies of these disturbances need to be estimated. In this paper, a new adaptive identification method for frequency estimation is introduced, and adaptive estimation of multiple unknown frequencies has been studied. The proposed adaptive method has been applied to an actual HDD drive, and the experimental results confirm its effectiveness.Index Terms-Adaptive identification, hard disk drive (HDD), frequency estimation.

Based on the fifth generation of mobile communication (5G), 5G open grid computing environment (5G OGCE), in order to realize the exploitation and utilization of marine resources and energy, this paper presents an air and sea robot, which can fly and dive in the sea and air at the same time, and it is called an air and sea (airsea) Manta Ray robot. Its purpose is to carry out resources and energy exploitation and development under the support of 5G OGCE, and perform the tasks of different air and sea operation areas: (1) quickly implement underwater operations, operate in the underwater operation area during long voyage, monitor deep-sea oil exploitation, exploitation and utilization of seabed resources and energy, seabed rare earth and combustible ice mining and ocean current power generation; (2) fly over the ocean during long voyage to track the migration of Marine organisms and Marine migratory birds; (3) build manned air-sea vehicle that can act as the personnel and material transfer machine for the undersea space station. When undersea mining is carried out, it can complete adaptive control, and monitor the work of undersea underwater equipment. (4) Perform work and assignments in a large area of underwater and above water, as well as over the sea, in a swarm working mode and distributed working mode. By using the control-cloud architecture in 5G OGCE, the exploitation of seabed resources and the production of submarine intelligent factories centered on the submarine space station can be realized. CCS Concepts • Computer systems organization ➝ Embedded and cyberphysical systems ➝ Robotics • Computing methodologies ➝ Artificial intelligence ➝Distributed artificial intelligence.

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