Abstract:The lack of an efficient and reliable power supply is currently one of the bottlenecks restricting the practical application of unmanned ocean detectors. Wave energy is the most widely distributed ocean energy, with the obvious advantages of high energy density and predictability. In this paper, a novel wave energy converter (WEC) for power supply of low-power unmanned ocean detectors is proposed, which is a small-scale counter-rotating self-adaptive point absorber-type WEC. The double-layer counter-rotating absorbers can achieve the torque balance of the whole device. Besides, the self-adaptation of the blade to the water flow can maintain a unidirectional continuous rotation of the single-layer absorber. The WEC has several advantages, including small occupied space, simple exchange process and convenient modular integration. It is expected to meet the power demand of low-power ocean detectors. Through modeling and CFD analysis, it was found that the power and efficiency characteristics of WEC are greatly influenced by the relative flow velocity, the blade angle of the absorber and the interaction between the upper and lower absorbers. A physical prototype of the WEC was made and some related experiments were conducted to verify the feasibility of WEC working principle and the reliability of CFD analysis.

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In-pipe robots are usually used to carry many kinds of equipment to operate in the pipeline. In this article, a novel selflocking mechanism for continuous propulsion inchworm in-pipe robot is proposed. The constant power and continuous locomotion principle is obtained by upgrading the traditional pipeline robot. The structure of the inchworm in-pipe robot is designed including self-locking mechanism and telescopic mechanism. The operating principle of self-locking mechanism is analyzed for parameter design and performance evaluation. A new type of hydraulic cylinder series circuit is introduced, which realizes synchronous motion in the related mechanisms of pipe robot. And the dynamic characteristics of the hydraulic cylinders are analyzed and simulated to verify feasibility of the circuit. The prototype is developed to prove that the novel inchworm in-pipe robot can adapt to diameter of 140-180 mm pipe and has 550 N traction ability with the average speed of 0.11 m/s.

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