Assembly of parts with a gap of 0.1 mm in approximately 3 seconds
No need for expensive force-torque sensors, making it affordable


Today, industrial collaborative robots are widely used for 'peg-in-hole' operations, where one part is inserted into another. This is an assembly method in which a robotic arm moves along a pre-set path, grasps the part, and fits it in a single step.

However, if the assembly position differs from the set value or errors occur between parts, it disrupts the production process. Accordingly, robotic hand manipulation technology capable of responding with the precision and flexibility of a human hand is attracting attention.

The Korea Institute of Industrial Technology (KITECH) announced on the 24th that it has developed the world's first assembly technology capable of performing fast and precise pack-in-hole operations by grasping objects with only three robot fingers, mimicking human hand movements.

In conventional robot arms used in industrial settings, a pincer-shaped gripper acts as a substitute for the hand. However, this has the disadvantage that the size and shape of the gripper must vary depending on the component's configuration, and error correction is difficult because the gripper becomes fixed once it grasps an object.

Academics are primarily researching technology that assembles objects using 'force-torque sensors' attached to robot hands. Although it can handle errors in component positioning, it has the disadvantage of being expensive, with the sensor costing about 10 million won per unit, making commercialization difficult.

A research team led by Dr. Bae Ji-hoon of the Robot Application Research Division at the Korea Institute of Industrial Technology (KITECH) developed a new collaborative robot by advancing the dual-arm robot technology they had independently developed in 2016 to create a robot hand with three fingers, each having three to four joints, and attaching it to a commercial robot arm.

This robot uses two fingers to grasp an object and the remaining fingers to slightly tilt it, then drag it to the assembly position and shake it. It utilizes the principle that a resultant force is generated in the direction of the hole where the part will go, causing it to be pulled in.

In addition, the robot is equipped with an 'AI Map' that can independently determine the work location and situation, allowing it to self-correct even if errors occur. It performs assembly primarily by moving its finger joints while minimizing unnecessary arm movements.

The developed collaborative robot can perform pack-in-hole operations with a gap of only 0.1 mm in about 3 seconds, making it as fast and precise as a human hand.

It features a proprietary drive mechanism that does not require expensive force-torque sensors, and uses commercially available robot arm components, making manufacturing costs low. By minimizing the number of fingers to three compared to the research team's dual-arm robot, which used four fingers, it lowered specifications and increased usability in small and medium-sized manufacturing sites.

Dr. Bae Ji-hoon of the Korea Institute of Science and Technology stated, “The ultimate goal is to match the speed and accuracy of a human hand so that it can move freely and error-free, just like a real hand,” adding, “We plan to continue follow-up research to lower production costs to a practical level by applying this technology to existing dual-arm robot hands.”

Meanwhile, the dual-arm robot developed by Dr. Bae Ji-hoon was featured in the electronics and electrical engineering publication 'IEEE Spectrum' in 2016.