Author: knrrnd

Hydraulic component of KNR Systems Inc. (Series #2 Servo valve)

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2. Servo valve

The servo valve is a key component in the hydraulic robot configuration that is paired with the actuator to control the flow of hydraulic pressure.
The construction excavator is designed to perform relatively easy tasks, so it consists of a simple valve that can be operated on and off control.
However, hydraulic robots require more precise control, requiring a high-performance servo valve that can control the flow rate quickly and accurately. In addition to performance, the size must be small to attach to the robot, and the price is also important because it requires as many valves as the number of actuators. The size of the servo valve used in robots is about the size of a thumb, but the price is very high and requires high manufacturing technology, so there are only a few suppliers.

hydraulic servo valve - KSV

<Servo valve : KSV-NF07>

Hydraulic servo valve technology needs to be very difficult to implement, especially small servo valves with excellent performance are limited to defense industries such as missiles and rockets, and only five or fewer companies worldwide produce most servo valves. KNR’s servo valve has more than 90% of Moog’s performance, which is a top-notch global company, and has equivalent or higher performance compared to STAR’s servo valve in the UK. It also has price competitiveness compared to its competitors by realizing low manufacturing costs with the latest special manufacturing method.

Hydraulic component of KNR Systems Inc. (Series #1 Actuator)

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The hydraulic components for the robot can be divided into five basic components (modules), including (1) hydraulic actuator, (2) servo valves, (3) various sensors, (4) controllers, and (5) hydraulic power units (HPU) depending on their function and role. These components can be combined to develop hydraulic robot arms or mobile platforms. Explain each configuration module to the hydraulic robot arm of KNR Systems as follows.

hydraulic components

<Hydraulic components>

1. Hydraulic actuator - Rotary actuator or Linear actuator

The actuator generates displacement and force to construct the hydraulic robot. Compared to motor-based robots, the driving cause is not a motor.
This can be said to be used, the motor driven robot must be used with a moderator attached to the motor, but the hydraulic robot consists of a hydraulic actuator.
The hydraulic actuators for the robot can generate about 9 to 10 times as much power per volume as motors, and have the advantage of being useful in extreme environments such as high temperatures, water and radioactivity.
The hydraulic actuators can be classified into linear actuators and rotary actuators depending on their behavior and can be selected and used appropriately for their intended use.

hydraulic linear actuator - KLH

<Linear Actuator : KLH>

The linear actuator is similar to the piston structure of the excavator, allowing straight motion and relatively large force relative to its size, but it has the disadvantage of having to re-create the straight motion into rotary motion for use with the robot.
 
KNR Systems’ linear actuators feature low friction actuators with polymer coating technology, creating excellent control features. KNR Systems’ ‘Polymer Coat Technology’, which is applied to the actuators, has an operational performance that guarantees flexibility and durability that is incomparable to the Sealing type, and it also shows the efficiency of an extractor far superior to that of global competitors.
hydraulic rotary actuator - KRH

<Rotary Actuator : KRH>

Rotary actuators can be attached directly to the robot joints without the conversion of linear motion, which generally results in more expensive and internal friction due to the nature of the structure.

KNR Systems’ rotary actuator incorporates a suitable bearing for the robot joint construction, and the sensor and controller are also developed to be built into the form of smart actuators. In particular, the internal friction, which is small and has a significant impact on control performance, has been extremely low, especially with sufficient light to construct the robot (approximately 10% compared to the same gear motor and 50% compared to conventional hydraulic rotary actuators).

Boston Dynamics has recently conducted a performance evaluation using KNR Systems’ rotary actuator, and indirectly proves its technical skills by requesting the sharing of the lower friction test results of the new product. (The world’s leading hydraulic robot company Boston Dynamics in the U.S. and the European IIT are building robots that use the our actuators for mass production and multi-year applications.) In 2020, we have developed manufacturing methods that can be produced within KNR Systems, and we estimate that we will be able to reduce product costs by at least 50% compared to last year by building processing equipment.

Product classification composition of KNR Systems Inc. Robot division

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KNR Systems Hydraulic Robot Business can be classified as a target product, divided into “hydraulic component group” for robots, “robot arm“, “high-weight mobile platform“, and so on. Hydraulic robots can operate heavier heavy loads than conventional motor-based robots and work in dangerous environments.

<Hydraulic components>

“Hydraulic component for robots” means the key components for use in hydraulic robots, such as small/precise hydraulic actuator, servo valve, hydraulic controller, hydraulic power source, etc., developed as a robot.
The robot arm, which is constructed using these hydraulic components and can operate high-weight materials in multiple induction, is referred to as the “hydraulic robot arm“, and the standard mobile device for free movement of flat land carrying high-weight logistics or robot arms is referred to as the “high-weight moving platform“.

Until now, motor-based robots have played a role in improving productivity by supporting people faster and more precise than humans, but hydraulic robots have the characteristics to improve their applicability to new business areas such as innovative process improvement and new businesses by working in the operation of heavy materials and hazardous environments that humans cannot perform. Hydraulic robots can be a representative application of the plant industry, which requires frequent handling of work in hazardous environments and heavy loads. Despite the high need for robots in these areas, there are few existing robots that can actually be used due to problems such as high temperature, high dust, and high weight control, and hydraulic robots can be the solution. The defense industry also requires heavy material manipulation and extreme durability, increasing the demand for hydraulic robots in the field of defense wearable robots and ground-based drones.

<example of an applications>