Crane Swing Brake Control Using Backpressure Feedback in Wind
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Solution Overview
Problem
In neutral-free mode cranes, it is challenging for operators to determine the direction of external forces acting on the revolving upperstructure during strong winds, making it difficult to perform appropriate swing manipulation.
Innovation Solution
A crane equipped with a hydraulic circuit and a controller that estimates the direction and magnitude of external forces using backpressure sensors and displays this information to the operator, allowing for precise manipulation of the swing lever to counteract external forces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the swing brake device is released during strong winds to allow swing motion, then the crane can perform swing operations, but the operator cannot determine the direction of external forces making manipulation difficult
Solution Approach 1:
The patent applies feedback by using backpressure sensors to detect the actual swing motor response and providing this information back to the operator through the display unit. The controller monitors the backpressure values and displays the estimated external force direction, creating a closed-loop information system that helps the operator understand the wind conditions and adjust manipulation accordingly.
Solution Approach 2:
The patent introduces an intermediary information system consisting of the controller and display unit that mediates between the physical swing motion and the operator's perception. Instead of directly sensing wind force, the system uses the backpressure intermediary to infer and display external force direction, bridging the gap between physical conditions and operator awareness.
2Loss of information
If backpressure sensors and display system are added to detect external force direction, then the operator can manipulate the swing lever appropriately, but the device complexity increases
Solution Approach 1:
The patent applies multi-functionality by making the existing swing motor serve multiple purposes: it not only drives the swing motion but also acts as a sensing element through its backpressure characteristics. The backpressure sensors, while adding components, leverage the existing hydraulic system's natural response to external forces, making the detection system integrated with rather than separate from the drive system.
Solution Approach 2:
The system applies self-service by using the swing motor's own backpressure characteristics to provide detection information. Rather than requiring completely separate sensing mechanisms, the system exploits the motor's inherent hydraulic response to external forces, allowing the drive system to contribute to its own control information.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables the operator to effectively manipulate the crane by knowing the direction and magnitude of external forces, ensuring smooth and controlled swinging operations even under strong wind conditions.
Implementation Method 1
When the drive pressure is lower than a higher one of two motor backpressures, a hydraulic brake control valve restricts a flow passage of the hydraulic motor, thereby generating a hydraulic braking force.
Implementation Method 2
A crane equipped with a hydraulic circuit and a controller that estimates the direction and magnitude of external forces using backpressure sensors
Data Source
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AI summary
The crane includes a swing brake device (20) installed between a hydraulic motor (2) and a control valve (6) and having a flow restrictor; a first backpressure detector detecting a motor backpressure between the flow restrictor and one of ports of the hydraulic motor (2); a second backpressure detector detecting a motor backpressure between the flow restrictor and the other port of the hydraulic motor (2); and a control device (13). The control device (13) has an external-force direction estimation unit (13b) that estimates a swing direction of an upperstructure (103) under an external force acting on the upperstructure (103) on the basis of a motor backpressure detected by the first backpuressure detector and a motor backpressure detected by the second backpressure during an operating state of the swing brake device (20). The control device (13) has a notification control unit (13h) that causes the notification device (19) to provide notification of the estimated swing direction of the upperstructure (103).