Guochen Niu

Collision free path planning based on region clipping for aircraft fuel tank inspection robot

Continuum robot has potential to run freely through a cluttered environment as aircraft fuel tank. To improve manual maintenance, we designed an aircraft fuel tank inspection robot which was composed of cable-driven sections. A suitable path is essential for the robot to reach the target zone while avoiding obstacles, but path planning for continuum robot is a challenge due to their complex kinematics models. To depict the collision free planning problem, a nonlinear, constrained optimization formulation was adopted. Projection strategy was presented and an imaginary straight line between the origin and the target was made up as a reference line to simplify the planning problem. We focused on the decrease of computing time complexity, and based on region clipping, a novel forward search method was proposed to solve this optimization-based planning problem. With the reference straight line, the minimum distance summation (MDS) was calculated to decide the optimal path relatively. Experiments on MATLAB were reasonably designed. Simulations and results analysis demonstrated excellent performance of region clipping search method and feasibility of the avoidance algorithm.

Set-point stabilization of nonholonomic mobile robot based on optimizing Bezier curve

The optimization algorithm of nonlinear controller based on cubic Bezier curve is presented. The nonholonomic mobile robot is stabilized to a desired pose, and the real-time planning and motion control is realized at the same time curvaturepsilas changing minimization is introduced to evaluate the Bezier curve. Using the penalty function method the problem of nonlinear constrained optimization is converted into unconstrained. Furthermore, the parameters of controller is optimized based on the improved Powell method. Simulation results is implemented on the VC++6.0 platform, and it was shown that the proposed approach is effective.

Attitude control based on fuzzy logic for continuum aircraft fuel tank inspection robot

With a compliant structure and excellent bending properties, continuum robot has hyper-redundant degrees of freedom, and can be used in space-constrained environments as the aircraft fuel tank. Therefore, a continuum robot is designed to help crews inspect aircraft fuel tanks, which can improve maintenance efficiency and reduce the intensity of crews. According to the requirements of aircraft fuel tank inspection, the compliant and extensible drive mechanisms of the continuum robot are designed. The kinematic models of single joint segment and multi-joint segments of continuum robot are analyzed, and homogeneous transformation matrices are obtained. To improve control performance, a closed-loop fuzzy controller based on attitude feedback is proposed. The attitude sensor is installed on the top of each joint segment of a snake-like arm to form a closed-loop control system, and a fuzzy controller is designed to achieve fast and accurate control of the robot. The prototype platform of the continuum robot is built, and practical experiments are implemented on the platform. The effectiveness and stability of the fuzzy controller based on attitude feedback are verified.

Design Bionic Structure and Analysis of Kinematics for Aircraft Fuel Tank Inspection Robot

Aircraft fuel tank leakage is a very common maintenance problem. A snake-like robotic detector was designed for troubleshooting leaks of fuel tank which has strong constraint and is also explosive. The robot has several flexible sections based on bionics, and it can achieve actuation redundancy by independently pulling its four driven cables to carry out a bending motion of two-degrees of freedom. A solution framework was established among the cables length, angle and tip coordinate of single section by projection curvature and coordinates transformation. The decoupled kinematics equation between the multi-sections was deduced based on the analysis of single-section kinematics. Finally the correctness of the kinematics method was demonstrated by prototype testing.

Global Localization of Terminal Service Robot Based on PTZ Vision

According to environment characteristic of airport terminal, a simple and feasible global localization method of terminal service robot based on PTZ vision is presented. Terminal signs are searched intermittently along “S” trajectory and zoomed by PTZ camera. To sight them accurately, the PTZ vision behavior based on fuzzy logic controller is designed. Then the signs will be identified based on SIFT features, and the global location of the robot can be finally gotten according to their location information and geometric pattern. The validity and practicability of this method are confirmed by actual robot experiments.

Model analysis for a continuum aircraft fuel tank inspection robot based on the Rzeppa universal joint

A continuum robot was designed to assist aircraft crew in inspecting fuel tanks, thereby decreasing the workload of fuel tank inspection and improving the efficiency of maintenance. The Rzeppa universal joint and cylindrical helical spring were taken as the joint section of the main body, and the load capacity of continuum robot had been improved greatly. Based on the isokinetic feature of the Rzeppa universal joint, the single-section kinematic analysis of the continuum robot was conducted according to the unit load method of cylindrical helical spring. Next, the influence of variable curvature bending properties of the plant was reduced, and the mapping relationship among the end position, joint variables, and the length of driving cables was obtained. Finally, the simulation and prototype experiments were performed, and the results proved the strong loading capacity of the continuum robot and the effectiveness of the kinematic model.

Mechanism Design of the Inspection Robot for Aircraft Fuel Tank

To improve reliability and security of the aircraft fuel tank inspection and decrease labor intensity of maintenance personnel, an inspection robot is developed. Maintenance workers’ work, which include entering the fuel tank and inspecting defects and so on, can be performed by the robot. Approach of switching motion mode is presented based on wheel-tracked mobile mechanism in order to adapt to the particular structure of aircraft fuel tank. Wheeled mechanism and tracked mechanism can be switched to each other at some time. By means of remote control and wireless video transmission, the worker can operate the robot and observe the scenario of fuel tank conveniently. Experimental result shows that the work of the robot is stable and reliable, and the design is reasonable and feasible.