The overhead crane is an under-actuated system because its degree of freedom is larger than that of actuators. The three state variables of trolley motion, cargo lifting motion and cargo swing are controlled by two input signals composed of trolley driving and cargo lifting forces. In the present study, a novel non-linear control scheme for an overhead crane is proposed based on the combination of two control design techniques. The cargo swing vanishing mechanism is constructed using partial feedback linearization. Control of trolley and cargo tracking is designed based on the sliding mode technique. An anti-swing structure is then merged with the tracking scheme of the trolley and cargo hoisting motions to enable indirect control of the cargo swing angle. Both simulation and experimental results show that the combined controller not only stabilizes all trajectories of system states but also guarantees the robustness in which the shapes of system responses are consistently retained despite the wide variation in crane parameters.
: This paper proposes a method utilizing Differential Global Position System (DGPS) with Real-Time Kinematic (RTK) and pre-built Geo-graphic Information System (GIS) to detect lane departure of a vehicle. The position of a vehicle measured by DGPS with RTK has 18 cm-level accuracy. The preconditioned GIS data giving accurate position information of the traffic lanes is used to set up coordinate system and to enable fast calculation of the relative position of the vehicle within the traffic lanes. This relative position can be used for safe driving by preventing the vehicle from departing lane carelessly. The proposed system can be a key component in functions such as vehicle guidance, driver alert and assistance, and the smart highway that eventually enables autonomous driving supporting system. Experimental results show the ability of the system to meet the accuracy and robustness to detect lane departure of a vehicle at high speed.
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