Hydraulic Bleed Valve Control for Actuator Stability
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Solution Overview
Problem
Rapid acceleration operations in hydraulic systems lead to unstable actuator behavior due to instantaneous changes in bleed valve opening area, causing wasteful energy consumption as hydraulic oil is continuously released to the tank during slow acceleration operations.
Innovation Solution
A hydraulic system with a controller that adjusts the bleed valve's opening area based on the operation signal, maintaining a minimum value during rapid acceleration and zero during slow acceleration to stabilize the actuator and prevent energy wastage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the opening area of the bleed valve is set to a minimum value greater than zero during rapid acceleration operation, then the behavior of the hydraulic actuator is stabilized, but energy is consumed wastefully due to continuous release of hydraulic oil to the tank
Solution Approach 1:
The patent applies dynamics by making the bleed valve opening area adjustable and time-dependent. During rapid acceleration operation, the opening area is dynamically set to a minimum value greater than zero to stabilize actuator behavior. During slow acceleration operation, the opening area is dynamically reduced to zero to eliminate wasteful energy consumption. This dynamic adjustment resolves the contradiction between stability and energy efficiency.
Solution Approach 2:
The patent changes the parameter of bleed valve opening area based on operation conditions. By detecting whether rapid acceleration is occurring and adjusting the opening area parameter accordingly (greater than zero during rapid acceleration, zero during slow acceleration), the system achieves both stable actuator behavior when needed and energy efficiency when possible.
2Speed
If the opening area of the bleed valve changes instantaneously during rapid acceleration operation, then the response speed of the hydraulic system is improved, but hunting occurs in the behavior of the hydraulic actuator due to inertia and compressibility
Solution Approach 1:
The patent applies beforehand cushioning by setting the bleed valve opening area to a minimum value greater than zero before and during rapid acceleration operation. This pre-established minimum opening acts as a cushion that prevents instantaneous changes in opening area, thereby suppressing hunting caused by the inertia of the hydraulic actuator and compressibility of the hydraulic oil while still maintaining rapid response capability.
Data Source
AI summary
A hydraulic system includes: an operation device that outputs an operation signal corresponding to an operating amount of an operating unit; a pump that supplies hydraulic oil to a hydraulic actuator via a control valve; a bleed valve that defines a bleed flow rate, at which the hydraulic oil is released to a tank; and a controller that controls the bleed valve, so an opening area of the valve decreases in accordance with increase in the operation signal. The controller: when a rapid acceleration operation is not performed on the device, changes the opening area of the valve between a maximum value and zero along a normal opening line; and when the rapid acceleration operation is performed, changes the opening area of the valve between the maximum value and minimum value greater than zero along a special opening line from when the operation is started until a predetermined time elapses.