Electric Construction Machine Drive Control for Low Battery Idle Stop
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Solution Overview
Problem
Existing drive systems for electrically driven construction machines fail to effectively suppress power consumption when operation is absent, leading to a decrease in the stored power level of the power storage device, which limits the machine's operational time.
Innovation Solution
A drive system that includes a controller to execute automatic stop control, setting a shorter predetermined time for stopping the electrically driven motor when the stored power level is low, thereby reducing power consumption and maintaining the power level for a longer duration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If automatic idle control is executed with a constant predetermined time, then the control system is simple to operate, but power consumption cannot be effectively suppressed when lever operation is absent, causing the stored power level to decrease
Solution Approach 1:
The predetermined time for automatic idle control is made variable rather than constant. The controller dynamically adjusts the predetermined time based on the stored power level: when the stored power level is high, a longer predetermined time is used; when the stored power level is low, a shorter predetermined time is used. This dynamic adjustment allows the system to effectively suppress power consumption while maintaining ease of operation.
Solution Approach 2:
The system changes the parameter of predetermined time based on the stored power level condition. By monitoring the stored power level and adjusting the predetermined time parameter accordingly, the system optimizes power consumption without complicating the operation. This parameter change approach resolves the contradiction between ease of operation and power consumption suppression.
2Duration of action of moving object
If the predetermined time for automatic stop control is shortened to suppress power consumption, then the stored power level lasts longer, but the response time for resuming operation may be delayed
Solution Approach 1:
The predetermined time parameter is adjusted based on the stored power level rather than being fixed. When the stored power level is high, a longer predetermined time is allowed, which does not significantly impact response time. When the stored power level is low, the predetermined time is shortened to suppress power consumption, and the system prioritizes rapid response by immediately resuming operation upon detecting lever operation, thus minimizing the loss of time.
Solution Approach 2:
The controller continuously monitors the stored power level and provides feedback to adjust the predetermined time for automatic stop control. This feedback mechanism allows the system to optimize the balance between duration of action and response time based on real-time power conditions, ensuring that power consumption is suppressed when necessary while maintaining acceptable response performance.
3Device complexity
If automatic stop control is implemented with a fixed predetermined time, then the control logic is simple, but it cannot adapt to varying power storage conditions, leading to inefficient power management
Solution Approach 1:
The predetermined time parameter is changed based on the stored power level condition. The controller includes a power level detection function that monitors the stored power level and automatically adjusts the predetermined time parameter accordingly. This approach increases power management efficiency without significantly increasing control logic complexity, as the adjustment follows a clear conditional rule.
Solution Approach 2:
The system implements feedback by continuously monitoring the stored power level and using this information to adjust the predetermined time for automatic stop control. This feedback-based adaptation improves power management efficiency while maintaining relatively simple control logic, as the controller only needs to compare the current power level with threshold values and select the appropriate predetermined time.
Data Source
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AI summary
An object of the present invention is to provide a drive system of an electrically driven construction machine that can suppress decrease in the stored power level of a power storage device in transition to automatic stop control when the stored power level is low and allow the stored power level of the power storage device to last for a long time. A controller of the drive system controls an electrically driven motor 1 to stop revolution of the electrically driven motor when a predetermined time has elapsed as the duration time of a state in which none of a plurality of operation devices is operated. Further, when the stored power level of the power storage device is equal to or lower than a first threshold, the controller sets the predetermined time shorter than that when the stored power level is higher than the first threshold.