Vibratory Roller Phase Angle Control for Temperature Adaptation
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Solution Overview
Problem
Existing methods for controlling vibratory rollers do not effectively account for temperature-induced changes in material properties, leading to inefficient compaction and increased energy consumption, especially with asphalt mix, which becomes stiffer at lower temperatures, requiring higher compaction effort and potentially increasing noise and wear.
Innovation Solution
A method that determines the temperature of the surface to be compacted and adjusts the vibration frequency to maintain a desired phase angle between the eccentric force and drum displacement, optimizing energy transfer and compaction efficiency by working at or near the natural frequency of the drum-material system, reducing the number of passes needed and minimizing noise and wear.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the vibration frequency is continuously adjusted to drive the oscillary system towards natural frequency, then compaction efficiency is improved, but the ability to adapt to temperature-induced material property changes is insufficient
Solution Approach 1:
The patent implements a feedback control system where the actual phase angle is continuously determined by comparing the position of the eccentric mass assembly with the position of the roller drum, and this feedback is used to adjust the vibration frequency to maintain the desired phase angle, thereby adapting to temperature-induced material property changes
Solution Approach 2:
The patent changes the vibration frequency parameter dynamically based on temperature conditions. By determining a desired phase angle based on the temperature of the surface to be compacted and adjusting the vibration frequency accordingly, the system adapts to temperature-induced changes in material stiffness and natural frequency
2Manufacturing precision
If higher compaction effort is applied to compact asphalt mix at lower temperatures, then compaction density is improved, but energy consumption and wear increase
Solution Approach 1:
The patent utilizes mechanical vibration at optimized frequencies to achieve effective compaction. By working at or near the natural frequency of the drum-material system, the vibration amplifies the contact force between the drum and ground, maximizing compaction efficiency while reducing energy consumption
Solution Approach 2:
The patent dynamically adjusts the vibration frequency parameter based on temperature conditions. At lower temperatures where asphalt mix becomes stiffer, the system increases the vibration frequency to match the increased natural frequency of the drum-material system, maintaining compaction effectiveness without requiring excessive compaction effort
3Productivity
If the vibration frequency is increased to compensate for stiffer material at lower temperatures, then compaction effectiveness is improved, but noise and wear increase
Solution Approach 1:
The patent precisely adjusts the vibration frequency parameter to match the natural frequency of the drum-material system at different temperatures. By maintaining operation at or near resonance, the system achieves maximum compaction effectiveness at the lowest possible vibration frequencies, minimizing noise and wear
Solution Approach 2:
The patent exploits resonance phenomena where working at the natural frequency of the combined drum-material system significantly enhances drum amplitude and contact force. This resonant vibration achieves powerful compaction effects at lower frequencies, reducing noise and wear compared to non-resonant high-frequency operation
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
This approach enhances compaction efficiency, reduces energy consumption, and improves operator comfort by allowing lower vibration frequencies, while maintaining cost-effectiveness and robustness without requiring complex mechanical mechanisms.
Implementation Method 1
a vibratory roller comprises eccentric weights mounted on a rotating shaft to cause a roller drum to vibrate at a certain vibration frequency
Implementation Method 2
the drum of a vibratory roller and the material to be compacted work together as a single oscillary system... drive the single oscillary system towards the natural frequency thereof
Implementation Method 3
The forces from the roller drum cause pressure waves in the material, which in turn set the particles in motion to rearrange into a more dense state
Data Source
AI summary
The present invention relates to a method of controlling operation of a vibratory roller comprising a roller drum and a vibratory mechanism. The method comprises determining a temperature of a surface to be compacted by the vibratory roller, determining a desired phase angle based on said determined temperature and maintaining the phase angle at, or close to, said desired phase angle by controlling the vibration frequency of the vibratory mechanism.