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This paper proposes positioning and trajectory tracking for Caterpillar Vehicles (CVs) in unknown environments. To do these tasks, the following are performed. Firstly, a system modeling of the Caterpillar Vehicle is presented. Secondly, solving the complicated tracking control problem in unknown environments is a challenging mission. Therefore, to guarantee the Caterpillar Vehicle system to be strong robustness against external disturbances in the unknown environments, a MIMO robust servo controller for tracking the desired trajectory is designed by using a Linear Shift Invariant Differential (LSID) operator. The CVs are able to accomplish various tasks in dangerous places where workers cannot enter. Thirdly, the positioning of the CV can be obtained using a Simultaneous Localization and Mapping (SLAM) method. This paper develops perfectly the SLAM algorithm for positioning of the CV based on laser sensor Lidar. The main advantage of this method is that it does not need to use more landmarks. Landmarks can be obtained from the unknown environment. Thus, the CV can work even in unknown environments and unsafe places. Finally, to verify the effectiveness of the proposed MIMO robust servo controller and the SLAM positioning algorithm, the experimental results are presented. The experimental results demonstrate the adequate tracking performance of the proposed MIMO robust servo controller in the unknown environment.

This paper presents the design and simulation evaluation of a self-contained submersion robot that mimics the actual flexible locomotion of American knifefish. First, a prototype of the bio-inspired submersion robot with a single undulating fin running along the length of the robot is developed. This undulating fin is a segmental fin comprised of sixteen fin rays that produce sinusoidal waves to propel the robot. Then, a system modeling of the robot is established to investigate the kinematics of undulating propulsion. A feedback linearization controller is employed to achieve the undulating propulsion velocity. The simulation results demonstrate that the developed prototype of the bio-inspired submersion robot can realize the desired thrust and velocity by the means of the undulating fin propulsion.

Magnetic flux leakage (MFL) detection is frequently used for oil and gas pipeline inspection, especially for evaluation of the integrity of pipelines. The success of the MFL technique depends on many parameters. However, a sensitive magnetic sensor is an important requirement. Therefore, magnetic field sensors based on different mechanisms have been developed and applied to the MFL technique. In this paper, we evidence for the first time the capability of an innovative device based on a planar Hall magnetoresistance sensor devoted to MFL detection. This promising prototype combines all the required qualifications such as high sensitivity, low thermal drift, and bipolar and linear responses to the magnetic field. New achievements are carried out on embedded sensors in a testing platform reflecting pipeline environments. The ultrasensitive magnetic mapping concludes to a convincing technical approach with a high potential application toward MFL inspection, especially for the detection of shallow defects appearing at near side, far side, and sub-surface of a pipe wall.

International audience; Quantitatively monitoring the thickness reduction of a pipe by using magnetic flux density method remains a major challenge due to the small and gradual change in magnetic flux density over a long distance along a pipe. This signal change is hindered in the background signal of a detector that has a high temperature dependence and unstable background signal. In this paper, we verify the effectiveness of magnetic flux density method in quantitatively monitoring thickness reduction through simulation and experimental verification. Experimental results show that the proportion of magnetic signal change is 1.4 mT per 10% wall loss. To support this quantitative approach, we optimise an original ultra-high-sensitivity planar Hall sensor with high thermal stability and stable background signal versus time for measurement of the magnetic field over a wide range from 0 to 50 mT. The quantitative measurements were validated on test pipes with varying thickness steps of 0.5 mm.