Electro Hydraulic Fine Metering Control Method
Publication Date: 2015-Nov-11
The IP.com Prior Art Database
Page 01 of 4
Title: Electro‐Hydraulic Fine Metering Control Method
Brief Description of the Drawings:
Figure 1 is a diagram demonstrating the traditional arrangement of determining current command based on deadband and reported joystick position for implementing a joystick deadband.
Figure 2 is a diagram demonstrating the disclosed arrangement of determining current command based on deadband and reported joystick position for implementing a joystick deadband.
Figure 3 is a diagram representing the logic that is used for determining travel percent as a function of joystick sensor voltages and calibration points for the joystick of Figures 1 and 2, and the relationship between calibrated joystick sensor inputs and calculated travel position.
As shown in the attached illustrations(s) and described below, a method for electro‐hydraulic (EH) valve controllability by utilizing a region of the input lever travel to ramp into the effective valve control range, is disclosed.
In an Electro‐Hydraulic (EH) implement system, some form of a lever or handle, such as a joystick, is often used for the operator to interface with for control of the EH valves. This lever or handle can embody many different forms, but it is often electronic. In the case of an electronic lever, techniques can be employed to modify the "feel" of the system control, including the use of a "deadband".
"Deadband" refers to an area of travel that is intentionally unused for the purpose of improving system controllability. In the most common implementation, a "deadband" is intentionally programmed around the neutral position of the lever. This creates a scenario by which the operator must overcome a certain amount of travel before getting any flow output from the valve. Typically, this "deadband" is designed in such a way that the operator needs to overcome it before any control current is sent to the EH valve.
The control current that is engaged upon overcoming the "deadband" is commonly referred to as the "threshold" current, and is often calibrated for each valve on a piece of equipment. This "threshold" current is typically calibrated on each valve due to part variance, and helps ensure that when the lever overcomes it's "deadband", the valve is stepping to a true start‐of‐flow point.
However, the calibration threshold can vary slightly based on system operating conditions (ambient temperatures, oil temperatures, etc). As such, conditions can arise whereby the valve may feel like it's stepping on too much when the lever "deadband" is ove...