Research And Development Of The Comprehensive Monitoring System For The Construction Hoist

The construction hoist is widely used in the field of architecture,the problem of its safety monitoring methods lack and automatic control function lag is becoming more and more prominent,which not only endangers the safety of production,but also hinders the improvement of production efficiency.The domestic and foreign enterprises,research institutes and universities have carried out a series of related research,but their products have the defeat of single function,high cost and low intelligence universally.In this paper,a kind of comprehensive monitoring system for the construction hoist was designed,it is based on the combination architechture of field monitoring terminals and the remote monitoring platform,and integrates several functions such as drivers' identification and management function,overcrowding and overweight monitoring and alarm function,closed-loop maintenance supervision function,multiple-master and two-way floor call function and intelligent dispatching and automatic leveling function.The system provides an integrated solution for the construction hoist's safety monitoring and automatic control.The main research contents and innovation achievements are as follows:The drivers' identification and management mechanism was improved.The traditional identification methods based on password and IC cards were obsoleted because of their fraudulent characteristic.The fingerprint technology was introduced to strengthen the identification and management of drivers.The phenomenon of driving without a license was prevented by verifying drivers' fingerprint at the moment of the construction hoist booting and during its operation time.The overcrowding and overweight monitoring and alarm scheme was perfected.A kind of infrared sensors' array and its matching algorithm for the crew number detection was designed.Under the cooperation of the weighing sensor,the infrared sensors' array could detect the load condition of the cage.If the cage's load overruns,the system would alarm in the form of diagrams and sounds.In this way,the illegal driving phenomenon was prevented.The closed-loop maintenance supervision mode was innovated.The field monitoring terminal was responsible for acquiring the construction hoist's running data,diagnosing and reporting its faults and locking it at the right time.The remote monitoring platform was responsible for giving repair instructions according to the faults report and sending periodic maintenance instructions based on the plan.The field monitoring terminal released tasks to maintainers in the form of short messages.The maintainers gave feedback information through the touchscreen of the field monitoring terminal.So the whole process of faults diagnosis and repairing,maintenance plan and implementation was supervised in a compulsive way.A kind of multiple-master and two-way floor call device was designed.The multiple-master communication among different floor call nodes was realized through the CAN bus,the two-way contact between the floor call device and the cage's control device was realized through the 2.4G module.The principle of light load priority,the same direction priority and the nearest priority was adopted.In this way,the efficiency of floor call and the cage's responding action was greatly increased.The intelligent dispatching and automatic leveling strategy was proposed.The cage's position and running direction were detected using the photoelectric encoder.The cage's gravity was detected using the weighing sensor.So the cage's "braking distance" could be pre-calculated based on the Lagrange interpolation algorithm.An appropriate braking opportunity could be obtained according to the "braking distance"which would realize an accurate leveling of the cage.Finally,the above scheme was verified to be feasible through the comprehensive test in the laboratory and the construction site.Every function module can workproperly,and the overall performance of the system is sable and reliable,so the system can meet the application requirements of safety monitoring and automatic control for the construction hoist.