Winch Control Apparatus for Crane Torque Compensation
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Solution Overview
Problem
Existing winch control systems for cranes face challenges in preventing suspended load falling during hoisting operations, particularly due to sudden torque application from large loads, leading to reverse rotation phenomena, and existing solutions either increase component count and cost or risk torque estimation errors.
Innovation Solution
A winch control apparatus that includes an electric motor, rotational speed detection, load detection, and compensation torque calculation sections to generate reverse-rotation-preventing and load-bearing torques, preventing falling without additional dedicated devices by calculating compensation torques based on speed and load differences.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a reverse rotation prevention means (mechanical device with ratchet wheel, pawl, cylinder) is added to prevent suspended load falling, then the reliability is improved, but the device complexity increases and cost increases
Solution Approach 1:
The patent replaces the mechanical reverse rotation prevention system (ratchet wheel, pawl, cylinder) with an electric motor control system that calculates compensation torque based on load detection and rotational speed detection, thereby preventing suspended load falling through electronic control rather than mechanical means
Solution Approach 2:
The electric motor control system uses its own detection capabilities (rotational speed detection section and load detection section) to calculate compensation torque and prevent reverse rotation, allowing the system to serve its own protection function without requiring separate dedicated mechanical prevention devices
2Device complexity
If torque estimation control is used without additional devices, then the device complexity is reduced, but estimation errors may occur leading to insufficient torque compensation
Solution Approach 1:
The patent implements feedback control by using rotational speed detection section to detect actual motor speed and load detection section to detect load weight, then calculating compensation torque based on the difference between target speed and actual speed, ensuring accurate torque compensation without estimation errors
Solution Approach 2:
The control system performs preliminary calculation of compensation torque before reverse rotation occurs by detecting load weight and speed deviation in advance, then applying the calculated torque to prevent suspended load falling before the harmful effect manifests
Data Source
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AI summary
Disclosed is a winch control apparatus for a crane, which comprises: a first compensation torque value calculation section (21) which calculates, when a hoisting manipulation being input, based on a difference speed between a detected rotational speed and a target speed according to a manipulation amount of the hoisting manipulation, a first compensation torque value for enabling an electric motor to generate a reverse-rotation-preventing torque which is a torque in a hoisting direction and corresponding to the difference speed; and a second compensation torque value calculation section (22) which calculates, when the hoisting manipulation being input, based on a detected load value, a second compensation torque value for enabling the electric motor to generate a load bearing torque which is a torque in the hoisting direction and necessary for bearing a load of the load value.