Electrohydrostatic Actuator Layout for Stable Dual-Axis Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Electrohydrostatic actuator systems with multiple consumers face uncontrollable movement and high energy consumption when multiple actuators are operated simultaneously, as the volume flow takes the path of least resistance, leading to inefficiencies and difficulty in controlling pressure.
Innovation Solution
An electrohydrostatic actuator system with a volume and/or speed-variable hydraulic machine driven by an electric motor, featuring two axes with chambers connected to hydraulic lines and valves, and a hydraulic accumulator between the secondary axis and valve, allowing for parallel operation of both axes using a single hydraulic machine, which reduces energy consumption and improves control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If multiple actuators are operated simultaneously with one hydraulic machine, then the number of devices is reduced, but the system becomes uncontrollable as flow takes the path of least resistance
Solution Approach 1:
The hydraulic system is segmented into separate controllable circuits for each actuator. Each actuator has its own hydraulic line with individual control valves, allowing independent flow regulation while sharing a common hydraulic machine. This segmentation enables precise control of each actuator's motion while reducing the overall number of hydraulic machines needed.
Solution Approach 2:
The system incorporates feedback mechanisms through control valves that respond to position or pressure signals, enabling closed-loop control of each actuator. This feedback ensures that each actuator receives the appropriate flow rate regardless of the path of least resistance, maintaining controllability while using a single hydraulic machine.
2Adaptability or versatility
If a constant pressure system with pump train and storage system is used, then multiple actuators can be supplied, but energy consumption increases and control complexity increases
Solution Approach 1:
The hydraulic machine operates dynamically with variable displacement or speed control, adjusting its output to match the actual demands of the actuators. This eliminates the need for constant pressure maintenance and large storage systems, reducing energy consumption while maintaining the ability to supply multiple actuators with varying requirements.
Solution Approach 2:
The system changes operating parameters (pressure, flow rate) dynamically based on actuator needs rather than maintaining constant pressure. Individual control valves regulate flow to each actuator, allowing the hydraulic machine to operate efficiently at varying parameters and reducing overall energy consumption.
3Adaptability or versatility
If a constant pressure system with pump train and storage system is used, then multiple actuators can be supplied, but control complexity increases
Solution Approach 1:
The control system is segmented into individual control valves for each actuator, each managing its own flow independently. This modular control approach simplifies the overall control architecture compared to a centralized constant pressure system, as each valve can be controlled independently based on its specific actuator's requirements.
Solution Approach 2:
A single hydraulic machine performs multiple functions by supplying different actuators with different flow rates and pressures through individual control valves. This multi-functionality eliminates the need for separate pump trains for each actuator, reducing control complexity while maintaining versatility.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration enables efficient and controlled operation of both axes with reduced energy consumption and device count, minimizing potential failures and costs while maintaining pressure stability.
Implementation Method 1
a volume- and/or speed-variable hydraulic machine driven by an electric motor (10), for providing a volume flow of a hydraulic fluid
Implementation Method 2
a main shaft (20) which can be moved by the hydraulic fluid with at least one first chamber (22)
Implementation Method 3
a hydraulic accumulator (40) which is hydraulically connected to the first secondary hydraulic line (62) in the area between the first chamber (32) of the secondary shaft (30) and the first secondary valve (33)
Data Source
Figure 1
Figure 2
Figure 3
AI summary
The electro-hydrostatic actuator system according to the invention comprises a volume-variable and/or rotational-speed-variable hydro machine, which is driven by an electric motor, for providing a volume flow of an hydraulic fluid, and a main shaft which is movable by the hydraulic fluid and which has at least one first chamber, wherein the first chamber, with at least one first main hydraulic line and a first main valve, is hydraulically connected to the hydro machine via a connection line. The actuator system according to the invention further comprises a secondary shaft which is movable by the hydraulic fluid and which has at least one first chamber, wherein the first chamber, with at least one first secondary hydraulic line and a first secondary valve, is hydraulically connected to the hydro machine via a connection line. Furthermore, according to the invention, a hydraulic accumulator is hydraulically connected to the first secondary hydraulic line in the area between the first chamber of the secondary shaft and the first secondary valve.