Hydraulic Valve Control for Speed-Adaptive Joystick Response
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Solution Overview
Problem
The responsiveness and aggressiveness of hydraulic circuits in work vehicles, such as telehandlers, are influenced by vehicle speed, leading to inefficient operation as the engine speed increases, making small joystick movements necessary for corrections, which worsens handling, especially on steep terrain, and requires manual adjustment of control signal parameters.
Innovation Solution
An electronic control method that continuously monitors and adjusts the hydraulic pump's operational characteristics by processing input parameters like output shaft speed, input shaft speed, gear selection, and joystick position to automatically optimize the maximum and minimum current values and control signal shape, allowing the vehicle to adapt its responsiveness without operator intervention.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the vehicle speed increases, then the engine speed increases and the hydraulic power increases, but the responsiveness of the hydraulic power circuit becomes excessive making small joystick movements necessary for corrections
Solution Approach 1:
The control unit dynamically adjusts the control parameters (dead band, maximum control signal value, shape, dynamic parameter) based on the detected vehicle speed. As speed increases, the system automatically reduces responsiveness by increasing the dead band and adjusting the control signal characteristics, allowing the operator to maintain comfortable joystick handling across all operating conditions without manual intervention.
Solution Approach 2:
The system changes the control parameters of the hydraulic circuit based on vehicle speed detection. The control unit modifies the dead band width, maximum control signal value, signal shape curve, and dynamic filtering characteristics according to the current speed, thereby adapting the hydraulic system's responsiveness to match the operator's needs at each speed level.
2Power
If the vehicle speed decreases, then the hydraulic power decreases, but the responsiveness of the hydraulic power circuit becomes insufficient for efficient task execution
Solution Approach 1:
The control unit dynamically increases the responsiveness of the hydraulic circuit when vehicle speed decreases. By automatically adjusting the control parameters (reducing dead band, optimizing control signal value and shape), the system ensures that the hydraulic actuated elements respond quickly and efficiently to joystick movements, maintaining high productivity during low-speed heavy lifting operations.
Solution Approach 2:
The system modifies the control parameters to enhance responsiveness at low speeds. The control unit increases the maximum control signal value, adjusts the shape parameter for more aggressive response characteristics, and optimizes the dynamic parameter to reduce filtering, thereby compensating for lower hydraulic power and maintaining efficient task execution capability.
3Ease of operation
If the control parameters are manually adjusted for different speed conditions, then the responsiveness can be optimized, but the operator intervention and time required for adjustment increases
Solution Approach 1:
The control unit automatically detects the vehicle speed and independently adjusts all control parameters (dead band, maximum control signal value, shape, dynamic parameter) without operator intervention. The system serves itself by continuously monitoring speed and adapting the hydraulic responsiveness in real-time, eliminating the need for manual parameter adjustment and saving the operator's time.
Solution Approach 2:
The system implements a feedback loop where the control unit continuously detects vehicle speed and uses this information to automatically adjust the control parameters. The detected speed feeds back to the control unit, which then modifies the hydraulic circuit responsiveness accordingly, creating a closed-loop system that adapts automatically to changing operating conditions.
Data Source
Figure 1
Figure 2
AI summary
Method (100) for controlling valve means (5) of a hydraulic power circuit of a work vehicle, comprising an engine (1) carrying a hydraulic pump for providing fluid in pressure to the power circuit and a torque converter (2) coupled, via clutch means (7) to a transmission (8) of the work vehicle, a driveline controller (9) configured to control the clutch means (7) and/or the transmission (8), and a joystick (10) configured to generate an electric signal configured to control said valve means (5) as a function of its displacement (10) and an electronic unit (6) electrically connected to the driveline controller (9) and to the joystick (10), and comprising elaboration means configured to acquire data from said work vehicle, elaborate this latter according to such method in order to modify the signal taken by the joystick to control the valve means (5).