Adaptive Milling Drum Control Prevents Lurch Events
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Solution Overview
Problem
Construction machines with milling drums often experience undesirable lurch forward or backward events due to excessive reaction forces from the ground surface, which existing systems can only address after the event occurs by shutting down the machine.
Innovation Solution
A control system that senses reaction forces using strain gages or load cells to adjust the rate of the milling drum's lowering and apply braking forces, preventing lurch events by maintaining the reaction force within a defined operating range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the milling drum is lowered quickly into the ground surface, then productivity is improved, but the reaction force causes uncontrolled lurch forward or backward events
Solution Approach 1:
The control system performs preliminary action by detecting changes in reaction force parameters and preemptively adjusting the lowering rate before uncontrolled lurch events occur. The system monitors strain gage or load cell outputs and modifies hydraulic ram operation in advance to prevent instability, rather than reacting after the lurch event begins.
Solution Approach 2:
The system implements feedback control by continuously monitoring the reaction force parameter through strain gages or load cells, comparing it against desired operating ranges, and automatically adjusting the lowering rate via hydraulic ram control. This closed-loop feedback ensures productivity is maintained while preventing lurch events through real-time parameter adjustment.
2Productivity
If the reaction force is allowed to exceed control forces, then cutting efficiency is improved, but the machine experiences uncontrolled lurch movements
Solution Approach 1:
The system applies dynamics by making the lowering rate adjustable and adaptive rather than fixed. The control system dynamically modifies the lowering speed based on real-time reaction force measurements, allowing the machine to operate at high efficiency when conditions permit while automatically reducing speed when reaction forces approach dangerous levels, thus maintaining controllability.
Solution Approach 2:
The invention changes the parameter of lowering rate based on detected reaction force parameters. When strain gage or load cell readings indicate increasing reaction force, the system adjusts the lowering rate parameter to prevent lurch events. This parameter adaptation allows the machine to optimize cutting efficiency while maintaining ease of operation through automatic control adjustments.
3Reliability
If prior art systems shut down the machine upon detecting lurch events, then safety is improved, but productivity is reduced due to operational interruptions
Solution Approach 1:
The system applies partial action by making selective adjustments to the lowering rate rather than complete shutdowns. When reaction force changes are detected, the control system applies only the necessary degree of braking or speed reduction to prevent lurch events while maintaining continuous operation. This partial action approach preserves safety through controlled parameter modification without the excessive action of full operational shutdowns.
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
Effectively prevents lurch events by rapidly responding to changes in reaction forces, maintaining machine control and efficiency while reducing the likelihood of uncontrolled movements.
Implementation Method 1
A parameter corresponding to a reaction force acting on the milling drum is sensed... the sensed parameter comprises an output from at least one strain gage located on either the frame or the milling drum housing
Implementation Method 2
a pressure in a hydraulic ram connecting one of the ground engaging supports to the frame may be sensed... applying a braking force to at least one of the ground engaging supports
Data Source
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AI summary
An adaptive advance system for a construction machine (10) senses the reaction forces applied by the ground surface (14) to a milling drum (12), and in response to the sensed changes in those reaction forces controls the motive power applied to an advance drive (40,42) of the machine (10) or the slowing of a rate of lowering the rotating milling drum (12). Early and rapid detection of such changes in reaction forces allow the control system to aid in preventing lurch forward events or the lurch forward or backward events respectively of the construction machine (10).