Abstract: The present invention discloses a positioning and navigation method for automatic inspection of an unmanned aerial vehicle in a water diversion pipeline of a hydropower station, comprising: using a laser radar carried by an unmanned aerial vehicle (UAV) to scan the inside of a water diversion pipeline to obtain point cloud data; determining the central axis of the cylinder model; determining the foot point of the current position coordinate of the UAV in the central axis in a body coordinate system; calculating the actual speed of the UAV in a central axis coordinate system according to the distance change of central axes of two frames; and adjusting the attitude of the UAV according to the actual speed and the desired speed of the UAV. The present invention can adapt to pipeline environments with different bending degrees.

Abstract: The present disclosure provides a method and a system for modelling a poor texture tunnel based on a vision-lidar coupling. The method includes: obtaining point cloud information collected by a depth camera, laser information collected by a lidar, and motion information of an unmanned aerial vehicle (UAV); generating a raster map based on the laser information, and obtaining pose information of the UAV based on the motion information; obtaining a map model through fusing the point cloud information, the raster map, and the pose information by a Bayesian fusion method; and correcting a latest map model by feature matching based on a previous map model.

Abstract: Tunnel defect detecting method and system using unmanned aerial vehicle (UAV) are provided, and the UAV is equipped with a light-emitting diode (LED) module, a camera, a laser radar, an ultrasonic distance meter and an inertial measurement unit (IMU). The method includes: collecting images in a tunnel based on the LED module and the camera to obtain a training image set; training by using the training image set to obtain a defect detecting model, collecting real-time tunnel images, detecting suspected defects to the real-time tunnel images by the defect detecting model, obtaining pose information of the UAV based on the camera, the laser radar, the ultrasonic distance meter and the IMU to control the UAV to hover. The method can realize accurate pose estimation and defect detection in the tunnel with no GPS signals and highly symmetrical inside.

Abstract: Disclosed is an unmanned aerial vehicle (UAV) positioning method based on a millimeter-wave radar, including a calibration stage and a positioning stage. The calibration stage includes: acquiring ground coordinates of the unmanned aerial vehicle; and extracting feature points from radar point cloud data and get the ground coordinates of the feature points. The positioning stage includes: acquiring radar point cloud data of a current frame and pre-processing; acquiring UAV motion data and fuse the data with radar point cloud data; extracting characteristic line segment from radar point cloud data; registering the characteristic line segment of the current frame with the characteristic line segment of the previous frame, and finding matching feature points and newly added feature points; and obtaining the ground coordinates of UAV and the ground coordinates of newly added feature points based on the ground coordinates of matched feature points on the map.

Abstract: The embodiment of this present disclosure provides a control method of unmanned aerial vehicle (UAV) hovering in tunnel, which comprises the following steps: acquiring hovering information of hovering position of UAV; acquiring the position information of the current position of the UAV; determining flight parameters based on hovering information and position information. The flight parameters are used to control the UAV to move from the current position to the hovering position.

Abstract: The vibration exciter system with a feedback control unit based on an optical linear encoder includes a vibration exciter, a signal generator and a power amplifier. The exciter system further comprises an optical linear encoder converting the displacement of moving component of the exciter into A/B pulse with a phase difference of 90° , a filtering, shaping and level translator unit converting the A/B pulse into standard pulse with standard shape and level, a subdivider and orientation recognizer unit refining standard pulse and recognizing the moving orientation, an analog converter unit converting refined standard pulse into analogue signal that reflects the displacement of the moving component. The standard signal outputted by the signal generator and the converted analogue signal are inputted into a subtracter as the minuend and subtrahend respectively. The output of the subtracter is inputted into the power amplifier and then into the vibration exciter as a driving signal.

Abstract: The electromagnetic vibration exciter system with an adjustable electro-viscoelastic suspension device comprises an electromagnetic vibration exciter, a power amplifier and an adjustable electro-viscoelastic suspension device, which acts as the suspension device of the electromagnetic vibration exciter. The adjustable electro-viscoelastic suspension device contains a displacement sensor detecting the displacement of the moving component, a first adjustable amplifier and a second adjustable amplifier, a differentiator, an adjustable phase shifter, an adder and a proportioner. The linearity of the stiffness and damping of the exciter system is excellent, which can be adjusted as need through the adjustment of gain of the adjustable amplifier, the proportioner, the adjustable phase shifter. This invention has adjustable and linear parameters and it is also easy to be realized.

Abstract: The electromagnetic vibration exciter system with an adjustable electro-viscoelastic suspension device comprises an electromagnetic vibration exciter, a power amplifier and an adjustable electro-viscoelastic suspension device, which acts as the suspension device of the electromagnetic vibration exciter. The adjustable electro-viscoelastic suspension device contains a displacement sensor detecting the displacement of the moving component, a first adjustable amplifier and a second adjustable amplifier, a differentiator, an adjustable phase shifter, an adder and a proportioner. The linearity of the stiffness and damping of the exciter system is excellent, which can be adjusted as need through the adjustment of gain of the adjustable amplifier, the proportioner, the adjustable phase shifter. This invention has adjustable and linear parameters and it is also easy to be realized.

Abstract: The vibration exciter system with a feedback control unit based on an optical linear encoder comprises a vibration exciter, a signal generator and a power amplifier. The exciter system further comprises an optical linear encoder converting the displacement of the moving component of the exciter into A/B pulse with a phase difference of 90°, a filtering, shaping and level translator unit converting the A/B pulse into standard pulse with standard shape and level, a subdivider and orientation recognizer unit refining the standard pulse and recognizing the moving orientation, an analog converter unit converting the refined standard pulse into analogue signal that reflects the displacement of the moving component. The standard signal outputted by the signal generator and the converted analogue signal are inputted into a subtracter as the minuend and subtrahend respectively. The output of the subtracter is inputted into the power amplifier and then into the vibration exciter as a driving signal.