Roadheader which is a kind of special equipment for large tunnel excavation has been widely used in Coal Mine. It is one of the main mechanical-electrical equipment for mine production and also has been regarded as the core equipment for underground tunnel driving construction. With the deep application of the rapid driving system, underground tunnel driving methods with higher automation level are required. In this respect, the real-time position and orientation measurement technique for roadheader is one of the most important research contents. For solving the problem of position and orientation measurement automatically in real time for roadheaders, this paper analyses and compares the features of several existing measuring methods. Then a new method based on the combination of monocular vision and strap down inertial navigation system (SINS) would be proposed. By realizing five degree-of-freedom (DOF) measurement of real-time position and orientation of roadheader, this method has been verified by the rapid excavation equipment in Daliuta coal mine. Experiment results show that the accuracy of orientation measurement is better than 0.1°, the standard deviation of static drift is better than 0.25° and the accuracy of position measurement is better than 1cm. It is proved that this method can be used in real-time position and orientation measurement application for roadheader which has a broad prospect in coal mine engineering.
Automatic guided vehicle (AGV) as a kind of mobile robot has been widely used in many applications. For better adapting to the complex working environment, more and more AGVs are designed to be omnidirectional by being equipped with Mecanum wheels for increasing their flexibility and maneuverability. However, as the AGV with this kind of wheels suffers from the position errors mainly because of the frequent slipping property, how to measure its position accurately in real time is an extremely important issue. Among the ways of achieving it, the photoelectric scanning methodology based on angle measurement is efficient. Hence, we propose a feasible method to ameliorate the positioning process, which mainly integrates four photoelectric receivers and one laser transmitter. To verify the practicality and accuracy, actual experiments and computer simulations have been conducted. In the simulation, the theoretical positioning error is less than 0.28 mm in a 10 m×10 m space. In the actual experiment, the performances about the stability, accuracy, and dynamic capability of this method were inspected. It demonstrates that the system works well and the performance of the position measurement is high enough to fulfill the mainstream tasks.
The workshop Measuring Position System (wMPS) based on intersection of optical planes is widely applied in large-scale metrology. However, in guidance areas concerning more about horizontal directions such as in the area of transporting with AGVs, the coordinate of z axis which represents the height of the vehicle is of no particular importance. Also, the installation and parameters calibration of wMPS is complex and time-consuming. In this paper, a new method with single transmitter measuring two dimensional coordinate to guide the moving object (except the vertical direction) is proposed and demonstrated. The three dimensional coordinate of receiver was calculated if its horizontal angle, vertical angle and the coordinate of vertical direction are given. In order to get the receiver’s horizontal and vertical angle, a serious of mathematical formulas was derived from a model of single transmitter with two rotating laser planes. The coordinate of vertical direction was obtained by the laser tracker and mapped from laser tracker coordinates to transmitter coordinates. Concerning that the coordinate of the vertical direction remains almost the same if the object moves in the level ground, a series of vertical-direction coordinates of moving object was measured beforehand and the average value of coordinates was the approximate vertical-direction coordinates of every point. To verify this method, the points acquired by the transmitter were remeasured by the laser tracker. Finally, the coordinates were compared and the results were analyzed. The experiment results show that the method’s measuring accuracy has reached 5mm.