Electrohydrostatic actuators, or EHAs, are a popular way of controlling motion. These systems use electrical signals to control hydraulic actuators, providing motion control for a variety of industries and applications. While these systems provide accurate, efficient, and powerful motion control, they suffer from a few drawbacks such as their complexity and size.
In this article, we’ll take a look at what EHAs are, and how Domin has innovated on the concept of EHAs to address some of their common pitfalls and open up the door for new possibilities in decentralised hydraulics.
What Is an Electrohydrostatic Actuator?
Electrohydrostatic actuation is the conversion of electrical power to motion. This process converts the flow and pressure of the hydraulic fluid into mechanical power. Electrohydrostatic actuators are popular motion control systems used in a number of industries, such as aerospace and industrial robotics.
Electrohydrostatic actuators are usually self-contained units that consist of a pump, valves, and actuators. The pump is the energy-generation device, which provides hydraulic flow and pressure to the system. By controlling the flow rate and pressure of the hydraulic fluid, the pump can directly control the speed and position of the actuator.
Actuators are devices that simply convert hydraulic power into mechanical motion. The flow characteristics of the hydraulic fluid flowing through the actuator are what ultimately determines its motion characteristics.
Electrohydrostatic actuators are typically compared to electromechanical actuators. Both of these are alternatives to traditional central hydraulic systems, but achieve motion control in different ways. Electromechanical actuators convert electrical energy directly into mechanical power through the use of motors, while electrohydrostatic actuators use electrical signals to control the flow of hydraulic fluid, leading to mechanical motion, as described above.
What Are the Benefits and Pitfalls of EHAs?
Electrohydrostatic actuators are incredibly power-dense and capable of providing highly accurate motion control, while being robust to dirt and shock and having the option to fail-safe for cases such as power loss. They also tend to have a low power consumption over extended periods of use. This is because they only require energy when changing the position of the actuator, and not continuously like with traditional hydraulics.
However, EHAs are usually complex to install and maintain compared to electromechanical actuation, with their many components. By utilising a closed-loop design, this complexity can be mitigated. A closed-loop design simply means that the pump recycles hydraulic fluid directly from the actuator, instead of a reservoir, as is done in traditional central hydraulic systems.
Electrohydrostatic actuators also tend to be large and heavy. This makes them cumbersome to integrate, especially in applications where space is limited, or where weight affects performance, such as in aerospace and automotive applications.
Domin’s Micro-Electrohydrostatic Actuators
At Domin, we have created micro-electrohydrostatic actuators. These micro-EHAs have the benefits of traditional EHAs – power-density, accuracy, and efficiency – with the added advantage of being lightweight and compact. This opens up new possibilities for localised hydraulic systems that provide precision motion control with significant weight reduction compared to traditional EHAs.
Our micro-EHAs are built on top of two of our innovative technologies: our groundbreaking radial piston pumps, and our high-speed hydraulic servo valves.
High-Speed Control Valves
Our best-in-class electrohydraulic servo valve was invented from the ground up by completely reconsidering what a servo valve can be. Thanks to modern technologies and manufacturing techniques, we have been able to create an efficient, lightweight servo valve that produces world-class performance. Our modern onboard electronics allows for real-time monitoring, data collection, and fault detection.
Radial Piston Pumps
Our radial piston pump features a design that unlocks performance that has been unattainable until now. This is only made possible by our use of additive manufacturing, allowing us to create geometries that are impossible with traditional manufacturing techniques. These compact pumps have ultra-high power density, high controllability, and low inertia, making them ideal for space- and weight-sensitive applications, such as in the aerospace and automotive industries.
At Domin, we are focused on redefining hydraulic systems through the use of cutting-edge technologies and innovative design in order to create a future of efficient and sustainable power transmission and control. Our micro-EHAs are just one example of how we are at the forefront of performant, efficient motion control.
