Navigation is necessary for autonomous mobile robots that need to track the roads in outdoor environments. These functions could be achieved by fusing data from costly sensors, such as GPS/IMU, lasers and cameras. In this paper, we propose a novel method for road detection and road following without prior knowledge, which is more suitable with small single lane roads. The proposed system consists of a road detection system and road tracking system. A color-based road detector and a texture line detector are designed separately and fused to track the target in the road detection system. The top middle area of the road detection result is regarded as the road-following target and is delivered to the road tracking system for the robot. The road tracking system maps the tracking position in camera coordinates to position in world coordinates, which is used to calculate the control commands by the traditional tracking controllers. The robustness of the system is enhanced with the development of an Unscented Kalman Filter (UKF). The UKF estimates the best road borders from the measurement and presents a smooth road transition between frame to frame, especially in situations such as occlusion or discontinuous roads. The system is tested to achieve a recognition rate of about 98.7% under regular illumination conditions and with minimal road-following error within a variety of environments under various lighting conditions.
Variable frequency speed regulation system in electric actuator is researched. In order to improve the run-time performance of the actuator motor, the technology of vector control is introduced. In vector control, the AC motor is equivalent to the DC motor by coordinate transformation. The decoupling control of the electromagnetic torque can be completely realized by using vector control. The strategy of the vector control is also discussed in detail. For the voltage source inverter, the method of rotor flux orientation and waveform generation of current-traced SPWM are adopted. The simulation model of the system is established under MATLAB according to the vector control model. The simulation of given step speed, simulation of slow start and slow shut-off are made. The simulation results show that the vector control model for the electric actuator has good dynamic performance.
While the hardware of the domestic hotel has reached the international first-class, there is still much room left in software and benefit level at present. According to the outlook on scientific development and the requirement of sustainable development, we have to face up to the problem of the lack of environmental protection in the course of hotel construction in the tide of global competition. The author puts forward some problems in the transition process from the traditional hotel to green hotel. The author also gives corresponding countermeasures to solve the problems in the hotel industry through the explanation of the green hotels.
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