Construction Machinery Joystick Control Valve Interference Prevention
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Solution Overview
Problem
Conventional methods for controlling main control valves in construction machinery often result in unintentional operation of undesired actuators due to erroneous joystick manipulations, leading to interference between control valves and reduced fuel efficiency.
Innovation Solution
A control method and device that differentiate between true and unintentional joystick displacement signals by applying a weighted threshold to determine the validity of joystick inputs, preventing interference and ensuring precise operation of intended actuators.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a single joystick controls multiple control valve devices, then the ease of operation is improved, but the reliability deteriorates due to unintentional operation of undesired actuators
Solution Approach 1:
The control device continuously monitors the operation state of each control valve device and compares it with the current joystick input signal. When a joystick signal is detected while another valve is already operating, the system provides feedback by raising the threshold for the currently operating valve, thereby preventing unintentional operations while maintaining the single-joystick control structure
Solution Approach 2:
The threshold for valve operation initiation is made dynamic rather than fixed. The threshold automatically adjusts based on the real-time operation state of the control valves - it increases when another valve is operating and decreases when no valve is operating, allowing the system to adapt its sensitivity to prevent interference while enabling normal operation
2Measurement precision
If the threshold for valve operation initiation is lowered to detect small joystick movements, then the measurement precision is improved, but the reliability deteriorates due to increased false triggering
Solution Approach 1:
The threshold is transformed from a static value to a dynamic parameter that changes based on system state. When the control device detects that a control valve is already operating, it dynamically raises the threshold for that valve, preventing false triggering from small joystick movements while maintaining the ability to detect genuine operational signals when the valve is at rest
3Reliability
If the threshold for valve operation initiation is raised to prevent false triggering, then the reliability is improved, but the measurement precision deteriorates due to inability to detect small joystick movements
Solution Approach 1:
The system employs a dynamic threshold that adapts to the operational context. When no valve is operating, the threshold remains low to detect small joystick movements with high precision. When a valve is already operating, the threshold automatically increases to prevent false triggering, thus achieving both high measurement precision and high reliability through state-dependent threshold adjustment
4Device complexity
If multiple control valve devices share one joystick, then the device complexity is reduced, but the reliability deteriorates due to interference between control valves
Solution Approach 1:
The control device implements a feedback mechanism that monitors the operation state of all control valve devices controlled by the single joystick. When interference is detected (joystick signal received while another valve is operating), the system responds by raising the threshold for the currently operating valve, thereby preventing interference while maintaining the simplified single-joystick control architecture
Solution Approach 2:
The threshold parameter is made dynamic and state-dependent, automatically adjusting based on the operational status of the control valves. This dynamic adjustment prevents interference between valves sharing the same joystick without requiring additional physical control devices, thus maintaining low device complexity while improving reliability
Data Source
AI summary
In a method of controlling a main control valve in construction machinery, a first joystick signal for controlling a first control valve device and/or a second joystick signal for controlling a second control valve device are received from one joystick. While one of the first and second control valve devices operates, whether or not a joystick signal for controlling another of the first and second control valve devices is inputted is determined. A weighted value is applied to a threshold of valve operation initiation with respect to a joystick displacement to determine a raised threshold of valve operation initiation. If the inputted joystick displacement satisfies the raised threshold of valve operation initiation, a valve stoke corresponding to the inputted joystick displacement is calculated and outputted.