Department of Mechanical Automation Engineering

In order to recover casing gas efficiently and safely, a new scheme is proposed to recover casing gas by using an ejector. The influence of the nozzle diameter and the distance from nozzle to throat on the performance of the ejector under different working conditions is studied. The results show that when the nozzle diameter is constant, the inspiratory capacity increases with the increase of water pressure. Compared three nozzles with different diameters, the inspiratory capacity and water flow were approximately linear. Under different working fluid pressures, as the distance from nozzle to throat increases, the ejection ratio of the ejector first increases and then decreases, and there is an optimal distance. In the field test, the gas flow rate of the recovered casing is about 35.27 m 3 /h.

Ships or vessels at sea for their entire lifespan are in contact with the
conditions that causes rusting. these ships bodies made from metals have
constantly been exposed to such harsh humid environment. Dealing with
the rusting to prevent potential failures and breakdowns can be very
tedious and dangerous as well. The wall climbing robot technology have
been on a surge for such industries due to the numerous capabilities and
benefits to it.
In this paper, a wall climbing robot of 700mm x 540mm x 240mm length,
width and height respectively is proposed. The robot is designed in the
Sketchup 3D software, and various force analysis including Dynamic and
Static forces are performed thus the proposed wall robot will employ the
idea of tracks for locomotion and the use of permanent magnet modules
for adsorption onto the surface of the metallic wall. From the force analysis,
the proposed wall climbing robot incorporates the design of a pair of
electromagnets each 400N force and enhances detaching of the robot by
switching off. The robot is driven by two powerful motors from the drive
force analysis, each producing at least 240Nm torque one on each side of
the tracks, sufficient torque to produce motion and capable of moving at
critical angles. The robot with 300N adsorption force per magnet module
can absorb on the wall at all angles ranging from 0°-90°.
Keywords: Wall climbing robot, electromagnets, permanent magnets

Coverage path planning (CPP) is in great demand with applications in agriculture, mining, manufacturing, etc. Most research in this area focused on 2D CPP problems solving the coverage problem with irregular 2D maps. Comparatively, CPP on uneven terrains is not fully solved. When there are many slopy areas in the working field, it is necessary to adjust the path shape and make it adapt to the 3D terrain surface to save energy consumption. This article proposes a terrain-shape-adaptive CPP method with three significant features. First, the paths grow by themselves according to the local terrain surface shapes. Second, the growth rule utilizes the 3D terrain traversability analysis, which makes them automatically avoid entering hazardous zones. Third, the irregularly distributed paths are connected under an optimal sequence with an improved genetic algorithm. As a result, the method can provide an autonomously growing terrain-adaptive coverage path with high energy efficiency and coverage rate compared to previous research works. It is demonstrated on various maps and is proven to be robust to terrain conditions.