| Metro track laying cranes are widely used in subway construction.Due to the arc shape of the subway tunnel surface,traditional hoisting methods require holes to be drilled on the tunnel surface to set up temporary rails for the crane to walk,which has the problems of low construction efficiency,large amount of engineering,and affecting the tunnel life.Based on a new type of eight-leg-wheeled metro track laying crane which does not need temporary rails,this paper designed and developed a special control system for it to improve the construction efficiency.The main contents are as follows:According to the movement requirements of the new track laying crane,special functions such as combination action,differential cornering,fuselage self-balancing,and two-machine synchronization are analyzed and solutions are proposed.Simulation analysis and verification are performed based on ADAMS.In order to improve the synchronization control accuracy of the wheels of the new type of track laying crane,the electro hydraulic proportional amplifier is researched and improved from the aspects of the drive circuit and the dither superposition.Based on the theory and modeling simulation,the shortcomings of the inverse discharging drive circuit were analyzed,and the bilateral drive circuit were proposed.The experiments show that the circuit has the advantages of both single tube drive circuit and inverse discharging drive circuit,which can realize the rapid reversing of the proportional directional valve and ensure the positioning accuracy of the valve.A dither superposition method of digital proportional amplifier was presented,and the effects of the types and parameters of dither on the sensitivity and hysteresis of the spool were compared through modeling simulation and experiments.The results show that the square wave dither is superior to the triangular wave and sine wave,which can effectively improve the sensitivity of the spool,reduce the spool hysteresis and improve its positioning accuracy.In order to ensure the synchronous control performance of the wheels of the crane under load disturbance and the rapid reversal of the hoist,based on theoretical analysis and modeling simulation,a “PID + dead zone compensation + feedforward” closed-loop control scheme for the proportional valve-controlled motor system was determined.And its effectiveness is verified by experiments.The multi-microprocessor modular architecture of the control system was determined,and the hardware circuits of the control system were planned,designed,and developed.Based on theoretical analysis,virtual prototype simulation,and finite state machine control,the fuselage self-balancing and combined actions were given.Software implementation methods for special functions such as twomachine synchronization,complete the design and development of the system software and manual controller interface. |
