Skip to main content

Underwater Walking Robot - Crabster CR200

The underwater walking robot named Crabster CR200 is developed by researchers at the Korean Institute of Ocean Science and Technology (KIOST). The task of the Crabster CR200 is to inspect the seabed structure and shipwrecks off the coast of Korea Peninsula. This summer the robot will explore wrecks despite the powerful surge of tidal current.

The CR200 has 6 legs for mechanical contact with seabed and like its biological cousins, the forward 2 legs also work as robotic arms for underwater manipulation. It can pick up objects and store them inside a frontal compartment. The Crabster is equipped with 10 optical cameras and a long-range scanning sonar which scans up to 200 m (650 ft) away, so the robot is able to perform the precise inspection and manipulation in a low visibility environment.

The CR200 endures the tidal current by controlling the posture of its body and legs. Researches used computer simulations to streamline the robot's main shell, that improves the stability:

The numerical simulations were performed for the evaluation of current loads acting on the CR200 with a variety of incident angles using ANSYS-CFX package. The Reynolds-averaged Navier-Stokes equations were solved to simulate the fluid flow around the CR200 to calculate forces and moments induced by incoming current with angles.

The robot is powered through an external power cable and it can operate under water for more than 24 hours

Let us see, how its first major underwater test looked. Test took place at KIOST's South Sea Research Institute, located in Geoje City, South Korea. The robot's weight is 600 kg (1322 lb) and in total it is 2.42 m long, 2.45 m wide, and 2 m high (7.9 ft x 8 ft x 6.5 ft). The robot and its remote control station were designed to be easily transported in a pair of shipping containers.

Four people remotely control the Crabster CR200 from the control station inside the shipping container. The pilot controls the robot's walking and posture. Manipulators, cameras, and lights are controled by a co-pilot. A sonar engineer monitors the scanning sonar and other sensors, while a navigator plans its movement and keeps track of its position.
Robot's equipment is shown in the figure below. It's equipped with i.a. an acoustic camera, acoustic doppler current profiler, high resolution scanning sonar, and several contact force sensor.

The Crabster performed well during its first dive. Bong-Huan Jun, a principal research scientist at KIOST, said:

I was very excited, but on the other hand I was nervous during the test. There are many mechanical and electrical parts inside the legs, such as the electrical motors, reduction gears, amplifiers, and interface boards. If even one sealing is faulty, seawater will enter the container which could cause shorts and corrosion. Any single minor problem would require a long time to fix.

Here is the video of the first major underwater test at KIOST's South Sea Research Institute:

The Crabster CR200 team includes researchers from five universities:

  • Seoul National University of Science and Technology developed the gait algorithm, using Little Crabster as a test-bed;
  • Mokpo National University performed hydrodynamic analysis and estimation of current load on the robot;
  • Chungnam National University helped with optimal joint path planning for swimming motion;
  • Pukyong National University studied how to implement fault tolerance gait;
  • Kookmin University contributed with numerical modeling and simulation of the robot.

The video below shows the robot's standing-up posture. The Crabster CR200 is a really big robot.


Anonymous said…
Nice mechatronics project. Very complex from technical point of view.

You might also like

    Popular posts

    What is Mechatronics?

    Mechatronics definition Mechatronics is a synergistic combination of precision engineering, electronic control and mechanic systems. It is the science, that exists at the interface among the other five disciplines: mechanics, electronics, informatics, automation, robotics. It is one of the most dynamically developing fields of technology and science. The word 'mechatronics' appeared for the first time in Japan in 1969. mechatronics = mecha nics + elec tronics + computing

    Intro to Mechatronics [e-book pdf]

    Intro to Mechatronics - lecture by Professor Vikram Kapila, New York University Mechatronics Defined Mechatronics: Working Definition for us Product Realization Paradigm Disciplinary Foundations of Mechatronics Multi-/Cross-/Inter-Disciplinary Sequential/Concurrent Product Realization Mechatronics-based Product Realization Mechatronic Design Process

    Ascento - The Two-Wheeled Jumping Robot

    All-terrain capabilities are required to extend beyond flat surfaces the application range of wheeled robots. First think is four or six-legged robots which have been well known for years. Nowadays, thanks to more and more perfect gait algorithms, the two-legged (bipedal) robots appears more and more often. ETH Zürich students combine the advantages of wheeled robot and two-legged robot.

    How 6-Axis Industrial Robots Work

    6-axis industrial robots are commonly used in the manufacturing industry due to their flexibility, powerful programming software, payload capacities ranging from 5kg up to 1000kg and accuracy to 0.1mm or better. Here is a basic breakdown of how a standard 6-axis robot works. The way it rotates, how it is programmed, and the different types of tooling and grippers.

    DIY Low Cost 6-Axis Desktop Robot

    Learning how to build a robot is a long way. It is the way by mechanics, electronics and programming. Such a mechatronics project is associated with problems such as stiffness (mechanics), overvoltage (electronics) or bug (software). Of course, if something is wrong, we always say 'it's not a bug, it's a feature', but finally a robot has to start working properly.

    Smart Home Makes Your Life Easier

    Smart homes are also called intelligent, automated or autonomous houses. Nowadays, you can also automate the flats. Dynamic development of automation technology gives you opportunities that were only seen in sci-fi movies in the past. Soon, probably only your imagination will be the limit. What gives us the smart home system?

    Mechatronic Systems Applications [e-book pdf]

    Mechatronics is the synergistic blend of mechanics, electronics, and computer science. This book is concerned with applications of mechatronic systems in various fields, like robotics, medical and assistive technology, human-machine interaction, unmanned vehicles, manufacturing, and education.

    How Automated Parking System Works

    An automated car parking system is a mechatronic system designed to transport and park cars automatically. The first semi-automated parking system was used in Paris, France in 1905 at the Garage Rue de Ponthieu (the car was transported to selected level using an internal elevator and the vehicle was parked by attendants). An automated storage and retrieval system for cars is a solution to cities' parking problems, such as the space wasting in a multi-story parking.

    Automatic Sorting of Skittles or M&Ms by Colour

    Do you sort M&Ms or Skittles by colour before eating them?  For example, eat all the yellow ones first, then the red ones, then the blue and so on. Brian Egenriether, an electrical engineer, decided to make a small machine that looked like an appliance, which could perform these tasks automatically. This mechatronics project took him about 5 weekends to make. The use of the machine is very simple: pour Skittles or M&Ms into it, push a button and have candies sorted. Let us look at the construction.