Construction Machine Drive Control via Dynamic Range Shifting
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Solution Overview
Problem
Construction machines, such as wheel loaders, face challenges in managing varying driving dynamics requirements due to their operational modes, leading to inefficiencies and potential overload or wheel slip issues with current drive systems.
Innovation Solution
A method for controlling the drive device of construction machines using a power-split transmission with switchable driving ranges, allowing for dynamic adjustments based on detected driving dynamics requirements, including shifting between different gear ratios and controlling rotational speed to achieve increased or normal driving dynamics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single-range transmission is used with electric drives, then the device complexity is reduced, but the adaptability to different driving dynamics requirements deteriorates
Solution Approach 1:
The patent implements a multi-range transmission system with switchable driving ranges (first driving range with higher gear ratio, second driving range with lower gear ratio) that can be dynamically switched based on driving conditions. This allows the transmission to adapt its characteristics in real-time, resolving the contradiction between structural simplicity and adaptability by making the structure dynamically configurable rather than fixed.
2Power
If the drive range transmission is shifted from second driving range to first driving range, then the driving dynamics are increased, but the energy loss increases
Solution Approach 1:
The control device predicts future driving dynamics requirements based on current driving state and environmental conditions, and proactively shifts the transmission range in advance before the actual need arises. This preliminary action allows the system to be pre-positioned in the optimal driving range, avoiding energy-intensive last-minute shifts and reducing overall energy loss while maintaining ready access to increased driving dynamics when needed.
3Reliability
If the rotational speed of the driving force source is controlled to not fall below a limit speed, then the reliability is improved, but the productivity decreases
Solution Approach 1:
The system dynamically switches between driving ranges to manage rotational speed control. When approaching the limit speed threshold, the transmission shifts from the second driving range (lower gear ratio) to the first driving range (higher gear ratio), which allows the engine to maintain higher rotational speed while the vehicle decelerates. This dynamic range switching enables the system to maintain reliability by keeping the driving force source above minimum operational speed while still achieving the required deceleration performance for productivity.
Data Source
AI summary
A method of controlling a drive device of a construction machine with a split transmission, which is at least coupled, at an input side, to a drive force source and, on the output side, with a drive range change transmission so as to set at least two shiftable drive ranges. The method includes a detection step (S1) for detecting drive dynamic requests for operation of the construction machine and a determination step (S2) for determining whether a drive dynamic request with an increased drive dynamic is present. If a drive dynamic request with increased drive dynamics is determined, then a shifting step (S4) is executed for shifting the drive range change transmission from a second, of the at least two drive ranges, to a first of the at least two drive ranges, to achieve increased driving dynamics of the construction machine.