Biped robot research at MEL

Since 1985, we have been working on biped robots. Our approach is characterized by following points.
First, we don't stick to human type legs but mechanically optimal leg system.
Second, patterns of leg motion are not prepared before walking but are generated in real-time.
So far, we have developed biped robots: Meltran I, II and III. Especially, Meltran II realized dynamic walk on flat floor, stairs walk with prior knowledge, sensor based stair walk without prior information. If you are interested in a biped robot which has wheels at the ends of its legs, please take a look here.


Biped robots developed in MEL
Meltran I
This robot was developed at the very beginning of our project. Although it was designed for 3D dynamic walk, it had many mechanical problems and could not perform reliable walk.
Meltran II
Our second biped robot was built after learning a lot from a trouble of Meltran I. In this page, I will introduce experiments of this robot.
Meltran III
This is a robot to study lateral stability. It can perform side walk, but that's all Meltran III can do :-) A rate gyro is equipped on its body.

Highlights of walking experiment

Walking experiments with Meltran II. Click a caption or a picture at the left side to start movie.
[Walk on a flat floor: m2mov.mov(835KB)]
Walk of Meltran II. One step is 12cm and average walking speed is about 0.5km/h. The strategy of control is to keep body height constant at every moment of walking. This makes walking control simpler than former walking control algorithms.
[Walk over a stair: us_step.mpg(337KB)]
Meltran II is equipped with ultrasonic sensor so that the robot can detect the height of engaging floor. Without giving any prior information about stairs (location, height, steps etc.), the robot walk over stairs.
[Walk over a obstacle us_obs.mpg(464KB)]
Walk over a small square pipe. The robot decides walking pattern by itself. Please observe the robot adjust its steps in the front of the object.

Structure of Meltran II

Meltran II is a small robot for scientific experiment. The power source and computer is placed on the floor and connected to robot via umbilical cable. The robot has wide feet to obtain lateral stability. The robot can walk only forward and backward. It cannot do side walk, nor change its walking direction.

You can see a finer drawing here.

NameMeltran II
Built 1989
Degree of freedom6 in sagittal plane
DimensionsHeight 45.0cm, Weight 4.7kg
MaterialsAluminum, Dulalumin
SensorsSix potentiometers
Four pulse encoders (attached to servomotors)
ActuatorsDC servomotors
To drive legs 11Wx4(Sanyo R301-011E7)
To drive ankles 6.4Wx2 ( -- SM26/106-3001)
ControllerNEC PC9801RA(Intel i386+387 16MHz)
and DSP(NEC uPC77230 6.7MHz)
LanguagesBorland Turbo Pascal 3.0,DSP Assembly language

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