Construction Machine Drive Control Device for Area Limiting
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Solution Overview
Problem
Existing drive control devices for construction machines, such as hydraulic excavators, fail to reliably stop the machine by setting the operating lever to a neutral position and prevent the working mechanism from deviating from a predetermined spacious area, especially when controller malfunctions occur.
Innovation Solution
A drive control device that includes a drive permission determination section and a drive signal selecting section, which selects the drive signal to prevent the control valve from driving hydraulic actuators not permitted by the determination section, allowing the operator to set the operating lever to neutral and stop the machine, while controlling the working mechanism to stay within the predetermined area, even with abnormal drive signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the controller drives the proportional solenoid valve based on lever operating information, then the machine can operate according to operator intent, but when controller malfunction occurs or noises are mixed in, the controller may drive the proportional solenoid valve in error and the machine cannot stop even when the operating lever is returned to neutral position
Solution Approach 1:
A drive permission determination section is introduced as an intermediary between the controller and proportional solenoid valve. This intermediary determines whether drive permission is granted based on lever operating information before allowing the controller to drive the solenoid valve, thus preventing erroneous operation when controller malfunction occurs while maintaining normal operation control.
2Manufacturing precision
If the controller controls pilot pressure to prevent working mechanism from deviating from predetermined spacious area, then the working mechanism stays within the area, but when controller malfunction occurs, the controller may drive the proportional solenoid valve in error causing the working mechanism to deviate from the area
Solution Approach 1:
The drive permission determination section performs preliminary determination of drive permission based on lever operating information before the controller drives the proportional solenoid valve. This preliminary action ensures that even if the controller malfunctions, the working mechanism cannot deviate from the predetermined spacious area because the drive permission is already restricted.
3Reliability
If a blockade device is provided to block drive signal when operating lever is in neutral position, then the machine can stop when lever is neutral, but the drive signal is blocked even when the operating lever is operated, preventing the working mechanism from staying within predetermined area
Solution Approach 1:
The drive permission determination dynamically adjusts drive permission based on lever operating information. When the operating lever is in neutral position, drive permission is determined as not permitted, allowing the machine to stop. When the operating lever is operated, drive permission is determined as permitted, allowing the working mechanism to stay within the predetermined area. This dynamic adjustment resolves the contradiction between stopping capability and working mechanism control.
Data Source
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AI summary
An area limit control part (40) as a control section outputs a requested boost pilot pressure (43) for driving a control valve (14A), based upon a pilot pressure (37) in accordance with an operating amount of an operating lever (15A) and a posture signal of a posture sensor (31). A drive permission determination part (48) determines whether or not a drive of a hydraulic actuator (22) is permitted based upon the pilot pressure (37) in accordance with the operating amount of the operating lever (15A). A pilot pressure selecting part (50) selects the requested boost pilot pressure (43) from the area limit control part (40) in such a manner as to drive the control valve (14A) with the requested boost pilot pressure (43) to the hydraulic actuator (22) the drive of which is permitted, and not to drive the control valve (14A) to the hydraulic actuator (22) the drive of which is not permitted.