Diaphragm Wall Gripper Control for Variable Residual Tensile Force
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Solution Overview
Problem
Existing grab solutions for diaphragm wall construction do not account for varying soil or bulk material properties, leading to inefficient and user-unfriendly digging processes due to inconsistent residual tensile forces.
Innovation Solution
A working device with a control unit that adjusts the residual tensile force on grab buckets based on real-time closing force measurements, using sensors to optimize the closing process by varying the setpoint force to maintain an optimal pulling force.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a static residual tensile force is set during active free fall, then the grab does not rest completely on the ground during the digging process, but is held by the winch for the holding cable, but this solution does not take into account different soil or bulk material properties, so that the grab is sometimes held with a residual tensile force that is too high or too low
Solution Approach 1:
The patent applies dynamics by transitioning from a static residual tensile force setting to a dynamic adjustment mechanism. The control unit continuously monitors the closing force via sensors and automatically adjusts the residual tensile force through the cable winch in real-time, allowing the system to adapt to varying soil conditions and material properties during the digging process.
Solution Approach 2:
The patent implements feedback by using sensors to detect the closing force exerted by the grab buckets on the material. This detected closing force is fed back to the control unit, which then adjusts the residual tensile force accordingly. This closed-loop feedback system ensures optimal performance across different soil types by continuously monitoring and responding to actual operating conditions.
2Productivity
If the grab is held with a predetermined residual tensile force, then the digging process can proceed without the grab resting completely on the ground, but the efficiency and user-friendliness are reduced due to inconsistent performance across different soil conditions
Solution Approach 1:
The patent applies self-service by enabling the system to automatically adjust its own operating parameters. The control unit autonomously monitors the closing force and adjusts the residual tensile force without requiring manual intervention from the operator. This self-adjusting capability maintains high digging efficiency across different soil conditions while simplifying operation, as the system adapts itself rather than requiring user knowledge of varying soil properties.
3Reliability
If a high residual tensile force is applied to prevent the grab from resting on the ground, then the grab remains suspended during the digging process, but excessive stress is placed on the winch and cable system
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting the residual tensile force parameter based on the detected closing force. Rather than maintaining a constantly high residual tensile force, the control unit modulates this parameter in real-time according to actual digging conditions. This ensures the grab remains properly suspended for reliability while reducing unnecessary stress on the winch and cable system when high suspension force is not required.
Data Source
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AI summary
The invention relates to a work device, in particular a cable excavator or a special foundation engineering machine, comprising a grab, in particular a diaphragm wall grab, which is suspended from the work device by a cable, a winch on which the cable is mounted for winding and unwinding the grab, a first measuring device with which a closing value, representing a closing force acting during an excavation operation when the grab buckets close, can be detected, and a control unit connected to the first measuring device by means of which the winch can be actuated. According to the invention, the control unit is configured to control or regulate the winch during an excavation operation based on a setpoint value such that the grab is held with a predetermined residual tensile force, and to change the setpoint value depending on the detected closing value.The invention further relates to a method for carrying out a digging operation using the work device according to the invention and a corresponding computer program product.