Hydraulic systems use pressurised fluid to transmit force. The use of hydraulics in robotics is ideal for fine control applications requiring power density in limited spaces. Central to hydraulic effectiveness are servo valves, which enable precise control of fluid flow and pressure, optimising the performance of hydraulic actuators. Domin Valves, high-quality servo valves, are optimally designed to meet the demands of applications that require high precision in a compact package, such as the robotics industry. These features include the ability to generate and control substantial amounts of power within a compact package. They also allow for precise regulation of hydraulic fluid flow and pressure, enabling fine control of actuator movement. Additionally, hydraulic systems support compact robotic designs that can exert significant force or perform complex, nuanced movements, all without the need for large electric motors.
This article will further discuss the role of hydraulics in robotics, electric vs. hydraulic actuators, future trends in robotics hydraulics, and Domin’s role in the industry.
The Role of Hydraulics in Robotics
Robotics can utilise hydraulic principles for force multiplication, converting fluid power into mechanical power to perform essential tasks. The useful work tasks can be observed in precision robotic welding or fine surgical procedures.
Actuators driven by hydraulic servo valves deliver high-precision power in a small footprint, making them ideal for tasks that demand strength and precision from industrial handling robots to humanoid robots. Servo valves effectively control fluid flow, enabling controlled movement despite the high forces involved. This combination of power and precision in a compact form allows hydraulic systems to excel in robotics where space is limited but force and control are critical.
Hydraulic vs. Electric Actuation: Making the Right Choice
When choosing between hydraulic and electric actuators for robotics, the decision largely depends on the application’s power, precision, size, and complexity requirements.
Hydraulic actuators excel in high-force, high-torque, high-definition applications. This refers to the precise and highly accurate positioning or movement of components, often using advanced technologies. It involves using high-resolution or high-accuracy systems to control the movement or rotation of parts within a system. In robotics, hydraulic systems are ideal for applications with limited space, as they can deliver large forces in compact units, enabling powerful movements without requiring large, bulky components. They are ideal for heavy lifting, gripping, or rapid, high-stress movements. Hydraulic actuators are commonly found in industrial robots, humanoid robots, and animatronics. They are superior for continuous, high-force applications due to their ability to generate substantial power in power-dense units making them ideal for tasks requiring sustained force. When utilising the precise control of hydraulic servo valves, hydraulics can provide the strength and reliability required in performance-critical, high-stress environments. However, hydraulic systems can consist of various components, including pumps, reservoirs, hoses, valves, and actuators, all of which can introduce maintenance concerns, such as leakage, wear, and fluid contamination.
Electric actuators offer compact, integrated, and low-maintenance designs. They are well-suited for applications where speed and efficiency are key, such as in stepper motors or brushless motors. Electric actuators offer high efficiency, especially in lower power applications, and do not rely on the additional components often associated with hydraulic systems. Electric actuators are generally quieter and simpler, making them ideal for minimised noise and complexity. They offer efficiency and control. However, electric actuators are limited in power, meaning they struggle to deliver the same force-to-size ratio as hydraulic actuators. They struggle with generating the high forces needed in high-load applications. In such cases, larger motors may increase system size and weight, but the actuator itself is complicated and has a higher cost-to-strength ratio.
Domin’s Commitment to Make Efficiency a Reality
Domin Valves introduce the world’s smallest direct-drive servo valve with an improved design to lower downtime and servicing costs. Advanced algorithms in Domin’s servo valves offer increased precision and repeatability. By using Domin valves, you can save up to one tonne of CO2 emissions per year, per valve.
Read the full report on the next generation of servo valves.
Quadruped robots are increasingly used for tasks such as package delivery, inspection, and search and rescue thanks to their ability to navigate rough terrain. Hydraulic systems enable high performance by offering greater power density and shock tolerance than electric systems, allowing the robots to carry heavy loads and absorb impacts. Precise control of these actuators is essential for stable movement, with Domin S4 Pro electro hydraulic servo valves providing the accuracy and speed required for agile robot gaits.
Researchers at Zhejiang and Nanchang Universities have developed a hydraulic robot leg test bed with three degrees of freedom to evaluate quadruped control algorithms. To actuate the hip and knee joints, they selected Domin S4 Pro servo valves due to their speed, precision, and compactness. The valves, controlled by a custom board using feedback from sensors, achieved target joint trajectories within five degrees of accuracy, enabling stable, programmable gaits for navigating uneven terrain.
Benefits of the Domin S4 Pro Servo Valve are:
- Ultra-Lightweight: Weighing 290g, the S4 Pro minimises mass on moving legs. This allows increased response time and improved dynamic, lifelike movement.
- High Bandwidth: S4 Pro valves offer incredibly responsive control, with bandwidth over 200 Hz. Improved hysteresis for quicker reaction and maintained stability.
- Power Density: A compact but powerful valve, the S4 Pro provides 18 L/min flow in the smallest package. This means that more force can be generated in the legs with decreased weight.
- Fast Response: The 3ms response time allows for precise movements, enabling the legs to make fine adjustments for uneven terrain.
- Precision Control: The superior servo performance of S4 Pro valves enables robotics/animatronics to achieve complex, stable gaits with precise trajectory control.
Future Trends of Hydraulics in Robotics
As robotics continues to change, the role of hydraulics is becoming increasingly pivotal, especially in industries demanding high power, precision, and compact designs. The future of hydraulic robotics is being shaped by a number of trends, with a growing emphasis on:
1. Shift Toward Automation
Industries such as manufacturing, construction, and logistics are adopting robotic systems for tasks traditionally performed by humans. Hydraulics’ ability to deliver substantial force in compact, efficient units makes them ideal for automation tasks like lifting, gripping, or heavy-duty manipulation. The trend toward autonomous and AI-driven systems requires robotics that can perform complex tasks with minimal human oversight. Hydraulic reliability and strength support these evolving robotic capabilities, enabling automated systems that handle everything from routine assembly to complex interactions with the environment.
2. Energy Efficiency and Sustainability
Advances in hydraulic control technologies are significantly improving the efficiency of hydraulic systems in robotics. These innovations, key to Domin’s technology, help reduce energy consumption by optimising fluid flow and pressure regulation, ensuring reduced energy loss. Moreover, innovations in fluid technologies such as biodegradable hydraulic fluids, are enhancing the sustainability of hydraulic robotics.
3. Miniaturisation and Compact Designs
Hydraulic actuators driven by hydraulic servo valves are well-regarded for their power density. However, many current systems remain large and inefficient, highlighting the need for innovations that reduce the size and weight of hydraulic components without compromising power. This miniaturisation will not only improve efficiency but also unlock new possibilities for compact, space-constrained applications where high power and precision are critical.
4. Integration with Hybrid Systems
Advancements in robotics hydraulics may lead to hybrid systems combining hydraulic actuators with integrated electric motors. This fusion combines the high force and precision of hydraulics with the fine control and efficiency of electric motors. By leveraging both technologies, hybrid systems can be precisely tailored to optimise performance, energy efficiency, and cost-effectiveness across a wide range of applications, unlocking new possibilities in robotics with enhanced power, control, and sustainability.
5. Smart and Adaptive Control Systems
In the coming years, the integration of smart, adaptive control systems will further enhance the capabilities of robotics hydraulics. These systems will leverage machine learning algorithms and real-time data to dynamically adjust hydraulic power and fluid flow based on load requirements. This will allow robotic systems to be adaptable, improve performance, and optimise energy requirements.
Looking to the Future
The future of robotics hydraulics is poised for innovation, driven by automation, energy efficiency, miniaturisation, and hybrid systems. Hydraulic actuators, with their high power density and precision, will continue to play a crucial role in enabling robotics to handle demanding, high-force tasks. As automation and efficiency remain at the forefront of the continued evolution of hydraulic systems, Domin will support the next generation of intelligent, capable, and sustainable robotics across various industries.