Research On Tower Crane Anti-Collision System Based On Risk Prediction

In order to increase construction efficiency and reduce operating costs, the construction unit often installs as many tower cranes as possible in a relatively small region, which makes the working ranges of these tower cranes inevitably overlap. In addition, tower cranes must avoid a variety of fixed obstacles due to the complex construction plant environment. Because of great inertia of the high speed rotary tower carne with a full load as well as the tunnel vision of tower crane operator and artificial visual error, the potential risk of collision is hard to find out by tower crane operator. On the basis of modified risk prediction, my thesis studies collision check algorithms which can timely predict the collision between tower cranes or tower crane and fixed obstacle. Hardware and software systems had also been designed to achieve full functionality.Based on the improvement of tower cranes risk prediction method, this article studies collision check algorithms about collision between higher tower crane sling and lower tower crane davit arm, as well as collision between tower crane sling and restricted areas with a certain shape (such as sector areas, circular areas and convex polygon areas). Iterative methods used to accelerate the calculation process, reduce the amount of computation so that the algorithms can be running in low cost embedded systems.For the timeliness of systems, ZigBee devices are used as short-range wireless communication between tower cranes and MCUs with ARM Cortex-M3kernel are used as the controller core of hardware systems. Program design based on embedded real-time multitasking operating system μC/OS-Ⅱ greatly improves the reliability and timeliness of the running system. Tower crane in construction site is likely to collide with more than one tower crane or restricted area, so pre-evaluation of collision risk has been done before collision check between tower cranes or tower crane and restricted areas to ensure system gives preference to the collision check with high risk of collision between tower cranes or tower crane and restricted areas.VB-based application about tower cranes monitoring and preferences is designed to facilitate administrators amending the relevant parameters and monitoring working position of tower cranes.