Oscillating Lift Axle Control for Stability on Uneven Terrain
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Solution Overview
Problem
Traditional boom lifts face challenges in maintaining stability and traction, especially when the boom is extended, as they struggle to effectively manage oscillation and leveling on uneven terrain, which can lead to reduced wheel ground following and compromised safety standards like EN280 pothole tests.
Innovation Solution
The implementation of a leveling system that includes pivotable axles and actuators, controlled by a controller to modulate or lock the pivot angle based on load, tilt, and operational modes, ensuring improved wheel ground following and traction by actively controlling the axles' movement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If the boom assembly is extended to reach higher work areas, then the work capability is improved, but the stability and oscillation control of the lift machine deteriorates
Solution Approach 1:
The axle is designed to be pivotally coupled to the chassis, allowing it to oscillate dynamically in response to terrain variations. This dynamic adjustment enables the axle to adapt to uneven ground while the boom is extended, maintaining better contact with the ground and improving stability during high-position work operations.
Solution Approach 2:
The control system continuously monitors the oscillation state of the axle and the position of the boom assembly. Based on this feedback, the control system adjusts the axle's oscillation parameters in real-time, ensuring optimal stability and ground following regardless of the boom extension length.
2Ease of operation
If the axle is allowed to oscillate freely to follow uneven terrain, then the wheel ground following capability is improved, but the oscillation control and stability management deteriorates
Solution Approach 1:
The control system receives continuous feedback from sensors monitoring the axle's oscillation state and terrain conditions. Based on this feedback, the control system dynamically adjusts the oscillation parameters to optimize both ground following capability and stability control, preventing excessive oscillation while maintaining terrain adaptability.
Solution Approach 2:
The system changes the oscillation parameters of the axle dynamically based on operating conditions. When the boom is retracted, larger oscillation amplitudes are permitted for better ground following. When the boom is extended, the system reduces oscillation amplitudes to maintain stability, thus adapting the oscillation behavior to the current work phase.
3Stability of the object's composition
If the actuator is locked to prevent oscillation during high-position work, then the stability is improved, but the adaptability to terrain variations deteriorates
Solution Approach 1:
The axle oscillation system operates dynamically with different control strategies based on boom position. During high-position work, the system permits controlled oscillation within specific amplitude limits rather than complete locking, maintaining both stability and limited terrain adaptability through dynamic parameter adjustment.
4Device complexity
If the lift machine uses traditional fixed axle design, then the structural simplicity is maintained, but the leveling capability and traction on uneven terrain deteriorates
Solution Approach 1:
The axle is designed with pivotal coupling to the chassis, transforming it from a fixed structure to a dynamic oscillating component. This dynamic design enables the axle to adapt to terrain variations automatically, significantly improving leveling capability and traction on uneven surfaces while adding only moderate structural complexity.
Data Source
AI summary
A lift machine includes a chassis defining a longitudinal center axis, a boom assembly pivotable relative to the chassis, an axle pivotally coupled to the chassis and configured to pivot about the longitudinal center axis, an actuator positioned on a first lateral side of the longitudinal center axis and to facilitate selectively restricting oscillation of the axle, and a controller configured to operate the actuator in a reset mode in response to a tilt angle of the chassis exceeding a first angle threshold. During the reset mode, the controller is configured to (a) prohibit drive functionality of the lift machine and (b) lock the actuator to prevent oscillation of the axle until an elevation angle of the boom assembly is less than a second angle threshold.