Milling Drum Speed Adaptation to Prevent Critical Vibration States
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Solution Overview
Problem
Self-propelled construction machines, such as road-milling machines, face challenges in operating efficiently across varying conditions due to the need to balance milling drum rotational speed with travel speed to prevent critical operating states, leading to increased wear, fuel consumption, and suboptimal performance.
Innovation Solution
The implementation of an adaptive open-loop control system that adjusts the milling drum's rotational speed based on characteristic measurement variables, allowing the machine to operate within a non-critical state by increasing or decreasing speed as needed to match changing operating conditions, independent of travel speed control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the rotational speed of the milling drum is reduced to lower wear and fuel consumption, then the kinetic energy becomes insufficient and the milling drum enters a critical operating state with vibrations and rocking
Solution Approach 1:
The patent implements dynamic adjustment of the milling drum's rotational speed based on real-time monitoring of operating parameters. The control unit continuously adapts the rotational speed to maintain optimal kinetic energy levels, preventing the drum from entering a critical operating state while minimizing energy consumption. This dynamic control allows the system to respond to changing conditions rather than operating at a fixed speed.
Solution Approach 2:
The patent employs a feedback mechanism where sensors monitor operating parameters such as vibrations, power consumption, and milling depth. This information is fed back to the control unit, which adjusts the rotational speed accordingly. The feedback loop ensures that the milling drum operates in a non-critical state by detecting early signs of instability and increasing speed before a critical state is reached, thereby preventing vibrations and rocking while optimizing fuel consumption.
2Reliability
If the travel speed is reduced to prevent critical operating state of the milling drum, then the performance of the construction machine is unnecessarily reduced
Solution Approach 1:
The patent decouples the control of travel speed from milling drum rotational speed, allowing independent optimization of both parameters. The rotational speed of the milling drum is dynamically adjusted based on monitoring of operating parameters, while the travel speed can be maintained at optimal productivity levels. This independent dynamic control eliminates the need to reduce travel speed to prevent critical operating states, thereby maintaining both reliability and productivity.
Solution Approach 2:
The feedback mechanism specifically monitors parameters related to milling drum operation (such as power consumption, vibrations, and milling depth) and adjusts only the rotational speed of the milling drum accordingly. This targeted feedback control allows the travel speed to remain unchanged and maintain high productivity, while the rotational speed is optimized to prevent critical operating states. The feedback loop ensures that productivity is not compromised by enabling precise control of the milling parameters.
3Ease of operation
If a fixed rotational speed is preset for the milling drum, then the control is simplified, but the machine cannot adapt to changing operating conditions such as material hardness and temperature
Solution Approach 1:
The patent implements a self-adjusting control system where the milling drum's rotational speed is automatically regulated based on real-time monitoring of operating parameters. The control unit independently adjusts the rotational speed without requiring manual intervention from the operator, even though the operator can still preset a reference speed. This self-service capability allows the system to adapt to changing conditions such as material hardness and temperature while maintaining ease of operation through automated control.
Solution Approach 2:
The patent dynamically changes the rotational speed parameter of the milling drum based on monitored operating conditions. The control unit adjusts the rotational speed parameter in response to variations in material properties, milling depth, and environmental conditions such as temperature. This parameter adaptation allows the machine to optimize its performance for different operating scenarios while the operator retains the ability to preset reference values, combining adaptability with operational simplicity.
Data Source
AI summary
The self-propelled construction machine, in particular road-milling machine, recycler, stabiliser or surface miner, comprises a machine frame 2, which is supported by a chassis 1, which has wheels or tracks 1A, 1B. A milling drum 4 is arranged on the machine frame. The wheels or tracks 1A, 1B and the milling drum 4 are driven by a drive unit 8. Furthermore, the construction machine comprises a control unit 19 for controlling the drive unit 8 and a signal-receiving unit 18 for detecting at least one measurement variable M(t) which is characteristic of an operating state of the milling drum 4. The construction machine is characterised in that the rotational speed of the milling drum 4 is adapted, on the basis of at least one measurement variable M(t) which is characteristic of a critical operating state of the milling drum, to the operating conditions of the construction machine in such a way that the milling drum is operated in a non-critical operating state. The adaptive open-loop control of the milling drum rotational speed allows the construction machine to be operated at an optimum operating point with respect to the milling drum rotational speed.