A method for stably controlling the slewing mechanism of a tower crane

Abstract

The invention discloses a method for stably controlling the slewing mechanism of a tower crane. The inverter controls and controls the frequency conversion motor of the tower crane, and the slope conversion module converts the step speed command ω ref Generate a speed command ω that changes according to a preset slope cmd ; The torque motor torque function generation module utilizes the torque motor torque function to generate the first torque command T cmd1 ; The eddy current brake torque function generation module utilizes the eddy current brake torque function to generate the second torque command T cmd2 ; The torque synthesis module receives the first torque command T cmd1 , the second torque command T cmd2 and the input speed direction signal of the speed direction judgment module to generate a torque synthesis command T cmd3 ; Synthesize the torque command T cmd3 As the torque control loop of the frequency converter to drive the variable frequency motor of the tower crane. The invention can make the slewing mechanism of the tower crane start and brake smoothly, the overall acceleration and deceleration time is short, and the work efficiency is high.

Description

technical field [0001] The invention belongs to a control method applied to the slewing mechanism of a crane, in particular to a method for stably controlling the slewing mechanism of a tower crane. Background technique [0002] The characteristics of the overall system of the slewing mechanism of the tower crane are that the boom is long, the weight is large, and the inertia is also large. , the flexibility of the tower body will also bring additional difficulty to the control of the slewing mechanism. [0003] At present, there are several mainstream methods for controlling the slewing mechanism of tower cranes, each of which has advantages and disadvantages in terms of control effect, reliability and cost. The first is that the motor adopts a torque motor with an eddy current brake, and the controller adopts an RCV control mode of the AC voltage regulation type, as disclosed in CN201512374U and CN200910013251. The advantage of this control mode is that the control effect...

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Problems solved by technology

CN201210576592 discloses a method that needs to install an acceleration sensor at the end of the tower arm to measure the acceleration and speed of the end of the tower arm, and then control the motor on the slewing drive side to follow the state of the end of the tower arm at all times to relieve the stress caused by the flexibility of the tower arm. To avoid the phenomenon of tower arm rebound and tower shaking caused by the concentration of stress, this method needs to add additional sensors and introduces unreliable factors

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