Adaptive Milling Drum Speed Control for Stable Road Milling
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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 instability
Solution Approach 1:
The patent implements dynamic adjustment of the milling drum rotational speed based on real-time monitoring of operating parameters. The control unit continuously adapts the rotational speed to maintain optimal kinetic energy levels while minimizing fuel consumption, transitioning from static preset speeds to dynamic adaptive control that responds to changing operating conditions.
Solution Approach 2:
The patent employs a feedback mechanism where the control unit monitors operating parameters and adjusts the rotational speed of the milling drum accordingly. This closed-loop control ensures that the drum operates within stable parameters by detecting deviations and correcting them through speed adjustment, preventing entry into critical operating states.
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 dynamically adjusts the rotational speed of the milling drum independently of the travel speed. This allows the machine to maintain high travel speeds for productivity while the control system adapts the drum speed to prevent critical operating states, decoupling the two previously linked control parameters.
Solution Approach 2:
The patent changes the control parameter from travel speed to rotational speed of the milling drum for preventing critical operating states. By monitoring and adjusting the drum's rotational speed specifically, the system can maintain stability without sacrificing overall machine performance and travel speed.
3Reliability
If the rotational speed of the milling drum is increased to prevent critical operating state, then the wear of milling tools and fuel consumption increase
Solution Approach 1:
The system dynamically adjusts the rotational speed to the minimum necessary level to prevent critical operating states, rather than maintaining a constantly high speed. This adaptive approach reduces tool wear and fuel consumption by operating at optimal speeds specific to each moment's conditions.
Solution Approach 2:
The patent optimizes the rotational speed parameter to balance stability and wear. By continuously adjusting this parameter based on monitored conditions, the system maintains the lowest effective speed that prevents critical states, minimizing tool wear and energy consumption simultaneously.
4Ease of operation
If a fixed rotational speed is preset for the milling drum, then the machine cannot adapt to changing operating conditions, leading to suboptimal performance
Solution Approach 1:
The system performs self-adjustment of the milling drum rotational speed based on monitored operating parameters. The control unit automatically adapts the speed without requiring manual intervention, enabling the machine to respond to changing conditions while maintaining simple operation for the user.
Solution Approach 2:
The patent implements automatic feedback control where the system monitors operating conditions and adjusts the rotational speed accordingly. This eliminates the need for manual presetting while maintaining operational simplicity, as the automation handles adaptation to changing conditions.
Data Source
AI summary
The self-propelled construction machine according to the invention, 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.