Tests and error analysis of a self-positioning shearer operating at a manless working face

Self-positioning of a shearer is the key technology for mining with a man-less working face. In an underground coal mine all radio navigation; satellite positioning or celestial navigation methods have their limitations. We analyzed an inertial navi-gation system intended to guide the movement a shearer and designed a self-positioning device for the shearer. Simulation tests were also performed on the system. We analyzed the errors observed in these tests to show that the main reason for the low preci-sion of the self-positioning system is accumulated error in the inertial sensor. A Kalman filtering algorithm used in combination with the shearer motion model effectively reduces the measurement errors of the self-positioning system by compensating for gyroscopic drift. Finally, we built an error compensation model to reduce accumulated errors using continuous correction to provide self-positioning of the shearer within a certain range of accuracy.

The radial self-positioning algorithm of intelligent ultrasonic probe array in oil/gas pipeline

The working principle of the pipeline intelligent pig and the structure of ultrasonic probe array used to detect defects in oil/gas pipeline are introduced. The effects of the array＇ s radial position in pipe on defect resolution are analyzed. The causes leading to radial positioning error are investigated. An algo- rithm for the radial self-positioning is presented. The experimental results show that the radial self-positioning algorithm can eliminate the array＇ s space position error effectively and improve the defect resolution.

A Self-Position Estimation Algorithm for Multiple Mobile Robots Using Two Omnidirectional Cameras and an Accelerometer

This paper proposes a self-position estimate algorithm for the multiple mobile robots; each robot uses two omnidirectional cameras and an accelerometer. In recent years, the Great East Japan Earthquake and large-scale disasters have occurred frequently in Japan. From this, development of the searching robot which supports the rescue team to perform a relief activity at a large-scale disaster is indispensable. Then, this research has developed the searching robot group system with two or more mobile robots. In this research, the searching robot equips with two omnidirectional cameras and an accelerometer. In order to perform distance measurement using two omnidirectional cameras, each parameter of an omnidirectional camera and the position and posture between two omnidirectional cameras have to be calibrated in advance. If there are few mobile robots, the calibration time of each omnidirectional camera does not pose a problem. However, if the calibration is separately performed when using two or more robots in a disaster site, etc., it will take huge calibration time. Then, this paper proposed the algorithm which estimates a mobile robot＇s position and the parameter of the position and posture between two omnidirectional cameras simultaneously. The algorithm proposed in this paper extended Nonlinear Transformation （NLT） Method. This paper conducted the simulation experiment to check the validity of the proposed algorithm. In some simulation experiments, one mobile robot moves and observes the circumference of another mobile robot which has stopped at a certain place. This paper verified whether the mobile robot can estimate position using the measurement value when the number of observation times becomes 10 times in n/18 of observation intervals. The result of the simulation shows the effectiveness of the algorithm.

A Study on Hovering Control of Small Aerial Robot by Sensing Existing Floor Features

Since precise self-position estimation is required for autonomous flight of aerial robots, there has been some studies on self-position estimation of indoor aerial robots. In this study, we tackle the self-position estimation problem by mounting a small downward-facing camera on the chassis of an aerial robot. We obtain robot position by sensing the features on the indoor floor.In this work, we used the vertex points(tile corners) where four tiles on a typical tiled floor connected, as an existing feature of the floor. Furthermore, a small lightweight microcontroller is mounted on the robot to perform image processing for the onboard camera. A lightweight image processing algorithm is developed. So, the real-time image processing could be performed by the microcontroller alone which leads to conduct on-board real time tile corner detection. Furthermore, same microcontroller performs control value calculation for flight commanding. The flight commands are implemented based on the detected tile corner information. The above mentioned all devices are mounted on an actual machine, and the effectiveness of the system was investigated.

The Sandwich Man:A Representative Rhetoric of Ressentiment toward the Empire in Taiwan Residents New Wave Cinema

The Sandwich Man(1983),the groundbreaking work of Taiwan Residents New Wave Cinema,had a significant impact.The movie are made up of three short films The Sandwich Man(Hou Hsiao-hsien),Xiaoqi’s Hat(Tseng Ch’ang-hsiang),and The Taste of Apples(Wan-ren),are typically seen as tales of modernity from the countryside to the city,but also contains native Taiwan Residents imperial ressentiment,particularly the ressentiment toward the American Empire in The Taste of Apples and the social sentiment of being wounded by Japan that haunts Xiaoqi’s hat,while The Sandwich Man attempts to seek to position themselves in their role.