Crane inching control method and system

Abstract

The invention discloses a crane inching control method and system. The method includes that when a hydraulic motor starts, a pressure sensor, arranged on a pressure measuring port of the hydraulic motor, periodically sends a hydraulic motor pressure value measured in real time to a pressure comparer at a first time interval; the pressure comparer calculates difference between an instantaneous pressure value before last stop of the hydraulic motor and the currently received hydraulic motor pressure value; a PID (proportion integration differentiation) controller calculates a current increase slope value according to the received difference; a current control unit generates gradually-increasing control current by the aid of the current increase slope value and a preset control current value, and provides the generated control current to the hydraulic pump. Inching control is performed from the perspective of compensating leakage of a whole hydraulic control circuit, and the hydraulic motor is prevented from impact, shaking or gliding and the like.

Description

technical field [0001] The invention relates to the field of crane control, in particular to a crane inching control method and system. Background technique [0002] At present, more and more cranes adopt electronic control methods in motion control, that is, use electric control handles, electromagnetic proportional valves, controllers, etc. to control the execution of hydraulic mechanisms such as hydraulic pumps and hydraulic motors, and the opening of the handle corresponds to the control current. upper and lower limits. While simplifying the system, it also brings some control problems, and micro-control is one of them. The inching control in this article refers to the control of the hydraulic system when the control handle is in the micro opening, that is, just leaving the dead zone. In addition, since the hydraulic motor in the crane generally drives the winch, the focus is on the winch as an example. [0003] The most common problems of inching control are winch sh...

AI Technical Summary

Problems solved by technology

There are various mechanical losses and power losses in the hydraulic system itself, and it is affected by different working pressures, speeds, temperatures, and even the slope of the crane's working ground. Therefore, even if the calculation formula takes these influencing factors into account, it is still difficult to fully reflect the actual situation. It will cause the given theoretical pressure value to be inaccurate, resulting in deviation

Moreover, the control structure of the compensation pressure setting value does not form a closed loop, so it cannot be corrected, and there is a possibility of further expanding the compensation pressure deviation

[0010] 3. The scheme does not take into account the influence of the engine speed on the hydraulic control circuit

Therefore, it is necessary to redesign the hydraulic components and give them the required installation space, which increases the cost and installation requirements accordingly

At the same time, due to the addition of a control link, there is an additional point of failure

And when the compensation device is working, it will always output pressure, and it also has leakage and loss, which will also cause energy waste

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