Search

With the rapid development of the economy, the scale of transmission networks has been expanding, bring higher demands and challenges on transmission line operation and maintenance. In this paper, the multi-rotor unmanned aerial vehicles (UAVs) safety inspection rules and automatic detailed inspection methods for transmission towers are studied. The theoretical model of multi-rotor UAVs of transmission lines inspection is established. The imaging calculation range of multi-rotor UAV-equipped cameras is determined. According to the inspection theory model, the flight safety judgment standard is designed, and the key parts of the transmission lines that need to be inspected are determined according to the accurate model of the transmission tower. Then the inspection waypoints are manually operated, and the photographing position and angle of each waypoint from the flight control are recorded through the waypoint planning function. Finally, the waypoints are connected in order, and the inspection route is automatically generated to achieve automatic detailed inspection. The inspection efficiency, error analysis and position accuracy comparing the proposed method with some state-of-the-art methods have been evaluated. The results show that the position error of UAVs automatic detailed inspection is less than 10 cm. The error of height is between 1.26 and 1.76 meter. Compared with the traditional manual inspection, the efficiency of multi-rotor UAVs automatic detailed inspection can be increased by 57.98%~62.88% and can be applied to large-scale inspection of transmission lines.

In order to explore the mechanical situation of special component about an electromagnetic rotating ball valve with double direction metal sealing in the closing condition, the stress and deformation of valve stem and valve plate had been analyzed, when the pipe forward and backward flow velocity was 5 m/s, by fluid-stricture interaction with fluid simulation software Star-ccm+ and finite element analysis software ABAQUS. Results show that the maximum stress is focused on the places where the valve stem and valve rod contact, the maximum deformation area of the stem is near the plate center, the size is about 3.6cm. The valve plate maximum stress is mainly concentrated in the support beams which are behind the valve plate, as well as the contact area of valve plate and stem. In addition, the maximum deformation area of plate is at the top, the size is about 9.3cm. Therefore, in order to ensure that the stem and the plate are not compromised and the sealing of the valve, the surface oxidation treatment could be used for improving the fatigue strength of the stem and a material by high-temperature forged steel or high-alloy steel could be used for madding plate to improve its mechanical strength.

In order to study the vibration characteristics of new type two-way zero leakage valve, multi-degrees of freedom dynamic mathematical model was established and solved based on the principle of the valve. The virtual prototype model of the valve was built with the Adams. With the help of the vbration module the forced vibration analysis was established, and the frequency response of the system was analyzed with the forced incentive between 1Hz-500Hz. The simulation result shows that the first-order modal vibration mode was torsional vibration, the natural frequency was 5.09Hz, the damping ratio was 0.3755, and the paper lists the former 6 order modal parameter values, and the results provide the theory support to the design and manufacture of the new two-way zero leakage valve.

In order to study the dynamic characterization of a new type zero leakage valve with double direction, in this paper, we simplify the model of the new type zero leakage valve with double direction and establish a mathematical dynamic model of single degree of freedom torsion system. Based on the theory, the software of Adams was adopted to establish the dynamic model of virtual prototype, and the dynamic characterization was considered in the case of a positive flow when the valve being closed and opened. The simulation results show that due to the design of the valve shaft, the torque of the valve being opened is significantly larger than the valve being closed, but the change of driving force is gentle without obvious mutation phenomenon. The changes of the angle and the angular velocity of the valve plate are relatively gentle, and the vibration phenomena will not occur. The result shows a good dynamic performance.

Chassis is one of the key components of tracked test vehicle. The strength and rigidity of chassis must be considered and structure resonance should be avoided during the process of structure design. The stress nephogram and strain nephogram of chassis are obtained, after static analysis in the finite element analysis software ANSYS. The maximum stress is 65.13MPa and the maximum strain is 0.00032mm. They both occur in the place where stiffener of bottom plate and side plate of speed reducer box are welded together. A kind of improved scheme is put forward, considering that the welding allowable stress is smaller than the allowable stress of parent material, and also the stress concentration and residual welding stress exist, though the maximum stress is in the allowed range. Static analysis is made to the improved chassis. The maximum stress becomes 45. 573MPa with 30% reduced, and the maximum strain becomes 0.00022786mm with 28.8% reduced. And the position of maximum stress and maximum strain transfer to the internal corner of crossbeam. And the first six extended natural frequencies of the improved chassis are obtained via modal analysis.

A motion simulator of deep-sea mining ship is designed for the 6000m deep-sea poly-metallic mining system, the control methods and the performance of the simulator are researched and tested. PID control is chosen. To determine PID control parameters, mathematical model of valve controlled cylinder system is established and validated by simulation tests. Based on the mathematical model, PID control parameters are adjusted in Simulink and further readjusted during the tests to ensure better control effect. The motion tests are performed and the results show that the deep-sea mining ship motion simulator can move in the light of given periods and amplitudes under the predetermined attitudes, and is able to simulate the random motion of mining ship.

The tracked nodule collector for sea floor mining is one of the key technologies for a deep-sea polymetallic nodule mining system, this paper builds a simulation model of walking hydraulic system for a tracked nodule collector on the basis of AMESim platform, a closed loop control system is constituted in the paper according to the negative feedback of the hydraulic motor angular velocity, a stimulation analysis is also made on the response characteristics of pedrail speed and motor pressure. Through the comparative study between the results of experiment and simulation, this paper verifies the validity of modeling a walking hydraulic system for tracked nodule collector for sea floor mining, manifesting that the created walking hydraulic system meets the demand of China’s polymetallic nodule mining system on benthal tracked nodule collector.

The impact between track and wheels of an amphibious armored vehicle in operation is the important reason of fatigue failure, and it will be the most complex in the steering condition. A dynamic model of an amphibious armored vehicle was established based on the ATV module of the ADAMS software. Simulations in the steering condition were carried out according to several typical arrangements of the support rolls. The simulation results show that reasonable arrangement of the support rolls would make the vertical beating of the upper side of the track and the impact between the track and the sprocket smaller, and improve the dynamic performance of the amphibious armored vehicle.