Road Milling Machine Vibration Control via Hydraulic Counter-Drive
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Solution Overview
Problem
Self-propelled construction machines, such as road milling machines, experience rocking due to vibrations that occur when the working device runs unevenly, leading to reduced operational efficiency as operators must slow down to prevent machine oscillation, limiting the machine's utilization.
Innovation Solution
A control unit continuously adjusts the hydraulic drive system's speed to compensate for detected fluctuations in the construction machine's longitudinal speed, generating a counter-vibration that reduces or eliminates rocking, allowing the machine to maintain its desired speed without reducing the set speed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the machine speed is reduced to prevent oscillation, then machine stability is improved, but productivity deteriorates
Solution Approach 1:
The patent applies mechanical vibration by generating counter-vibrations through the hydraulic drive system that oscillate at the same frequency as detected machine vibrations but with opposite phase. This actively counteracts the harmful vibrations causing oscillation, allowing the machine to maintain higher speeds without sacrificing stability.
Solution Approach 2:
The patent implements feedback by using detection devices to continuously monitor machine vibrations and feeding this information back to the control unit. The control unit then adjusts the hydraulic drive system in real-time based on the detected vibration characteristics, creating a closed-loop control system that maintains stability while optimizing speed.
2Stability of the object's composition
If the set speed is reduced to avoid rocking, then machine stability is improved, but operational efficiency deteriorates
Solution Approach 1:
The patent uses mechanical vibration principles to generate counter-oscillations that actively cancel out the harmful vibrations causing rocking. By matching the frequency and phase of the counter-vibration to the detected oscillation, the system eliminates rocking without requiring speed reduction, thereby maintaining operational efficiency.
Solution Approach 2:
The control unit continuously receives feedback from detection devices about machine oscillations and dynamically adjusts the hydraulic drive system's output. This real-time feedback control enables the machine to maintain the desired set speed while actively compensating for vibrations, thus preserving both stability and operational efficiency.
3Productivity
If the machine operates at desired speed, then productivity is improved, but machine oscillation worsens
Solution Approach 1:
The patent employs mechanical vibration by using the hydraulic drive system to generate counter-vibrations that oscillate at the same frequency as the harmful vibrations but with opposite phase. This active vibration cancellation allows the machine to operate at desired high speeds without experiencing harmful oscillations, thus maintaining both productivity and stability.
Solution Approach 2:
The system uses detection devices to monitor machine vibrations and feeds this information back to the control unit, which continuously adjusts the hydraulic drive system. This closed-loop feedback control enables the machine to maintain desired operating speeds while actively compensating for vibrations, thereby achieving both high productivity and machine stability.
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 solution effectively prevents rocking, enabling the construction machine to operate at its desired speed without compromising efficiency, as the control unit adapts the drive speed to match and counteract the frequency and amplitude of the detected vibrations, ensuring stable operation.
Implementation Method 1
a detection device (44) is provided which detects fluctuations in the longitudinal speed of the construction machine (1) when the machine is moving
Implementation Method 2
the drive speed specified by means of the hydraulic drive system (50) for driving the transport devices (2) is periodically changed in such a way that a counter-oscillation is generated which reduces or compensates for the detected fluctuations
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
In a self-propelled construction machine (1), in particular a road milling machine, recycler, stabilizer or surface miner, comprising a machine frame (4), at least two drive units (2), at least one hydraulic drive system (50) for driving at least two drive units (2), and at least one working unit, in particular a milling drum (6), for processing the ground surface (3), a detection device (44, 60, 62) is provided which detects fluctuations in the longitudinal speed (vist) of the construction machine (1) when the machine is moving, wherein, depending on the detected fluctuations, a control unit (38) controls the hydraulic drive system (50) in such a way that the drive speed (vAntrieb) specified by means of the hydraulic drive system (50) for driving the drive units (2) is continuously adjusted so that the detected fluctuations are reduced or compensated.