Dynamics Study Of Inspection Robot For High-voltage Transmission Lines

Inspection robot for high-voltage transmission lines, a frontier in robotics, has great application prospects. Nowadays, there are few domestic and overseas reported results in this area, especially in dynamics research. This dissertation presents a self-developed robot with the transmission lines as the working medium, capable of inspecting the entire transmission line system with inspection and communication devices. In-depth and systematical works of theoretical modeling, numerical simulation and experimental studies, have been done to analyze its Multi-Rigid-Body Dynamics, coupling dynamics (when we take the flexible environment into account), and structural vibration. The main efforts and innovation of this dissertation are as following. First, a six-joint & two-arm dissymmetric hanging structure is presented to assure the robot performance on the transmission line system. After movement planning of barrier crossing along the straight line, we make out its four typical working states and the relevant postures of the robot in its whole inspection work. Second, study the rigid dynamics of the inspection robot systematically: establish the coordinates of each link and find out the relevant parameters; model its Multi-Rigid-Body System Dynamics with Lagrange equations, derive the inertia items, coupling inertia items, centripetal force items, Coriolis acceleration items and gravity items, and establish all the dynamic equations of the robot; plan the dynamic simulation programs, and simulate the forward dynamics of three typical states (including rolling along the non-barrier section of the transmission line, crossing different barriers, and transferring between jumper and phase line). Simulation results indicate that this structure with the joint driven torque, could fulfill the movement control plans. Third, study the coupling features between the rigid-body movement of the inspection robot and its flexible working environment by modeling and simulating the coupling dynamics of the robot and the transmission lines. The works include: establish the coupling dynamics model of the robot and one span transmission line with big sag; simulate the forward dynamics of the typical states in three flexible working environment and study the effects of the flexible environment on the robot performance. Simulation results indicate, in the flexible working environment: robot has larger fluctuate in joint acceleration, joint velocity and relevant driven torque; the fluctuate of response results grows with the flexibility of the working environment; the fluctuate of joint velocity and joint acceleration damps with time. Forth, run the dynamic response experiments on the inspection robot III on the 1:1 scale 220KV simulation overhanging transmission line in the laboratory. Comparison of the numerical simulation and the testing results proofs validity of the theoretical model and the numerical simulation. Last, study the vibration features of the inspection robot in the rigid environment condition, with FEA (finite element analysis) method and mode experiments. Make out the dynamic parameters through mode experiments of the inspection robot III in the typical postures. Then, utilize FEA method to establish the 3D solid finite element model of the robot at several typical working states, revising this theoretical model with experimental mode parameters, and work out the natural frequencies and vibration modes. Later, analyze the effects of topological structure of the robot to its dynamic performance, and find out the great effects of the joint stiffness between arm and slide on the robot performance. In the areas of further dynamics and control, the above works paves the way to the future development of the inspection robot for the high-voltage transmission lines.