The Aibo Story

The Aibo Story (3)

Sony really broke the mould when it realised the first Aibo back in 1999.

Aibo DHS or Droopy Head Syndrome (alternately known as Dropping Head Syndrome) is a behaviour that is characterised by the head of the Aibo uncontrollably dropping when passing past the midway point of downward travel in the neck joint.  This problem is caused by a design flaw in the servo mechanism that controls the head's neck joint.

The same servo's are used for the tilt axis and the pan axis, similar problems are known to occur in these joints also.

The design flaw is where the manufacturer of the servo (let's say Sony for arguments sake) utilised a very compact method of preventing damage to the gearing system used inside the servo when shocks impact the head or the heads movement is restricted.  To enable such a tiny unit (Aibo is very compact after all) the unit uses a planetary gearing system with multiple drop down stages to amplify the torque that the motor puts out to enable it to move the head joints relatively quickly and smoothly.  The side effect of this is that if the head is jammed or stopped from moving (say perhaps from a child holding onto it) this would cause the motor to have a high chance of causing itself or it's gearbox some irreparable damage.  In practice this never seemed to be the problem as the method used was a plastic insert in-between a bell housing and an internal spinner shaft that was designed to create enough friction to spin both parts at the same time but allow slippage if needed.

Unfortunately it didn't quite work out that way and the insert became worn far too quickly and caused slippage well before the initial warranty period of 1 year had elapsed in most cases.  What was even more unfortunate was that this same part seemed to become brittle with age so even new in box units that had been untouched for many years could come straight out of the box and exhibit symptoms of DHS,PAS or TAS straight away without any prior use.

As time went on the spares supply dwindled to the point where there were almost no spare head assemblies left available and other solutions needed to be found.

One such method utilised a small pin inserted between all three components literally fusing the assemblies together.

I wasn't happy with this method as I felt it caused undue stress on the shaft assembly and a high likelihood of allowing irreparable damage and as such I developed my own method which to date has never failed and doesn't weaken the shaft at all.  It also incorporates a failure point should the head be knocked violently.  Without this failure point a pinned servo slipper clutch gearbox would literally destroy itself as all the gears inside it are plastic.

From time to time I have come across modified servos that have done exactly this as they have stripped the teeth off all 3 planetary gears that act on the outer casing of the gearbox.  This particular problem was very time consuming to fix as I had to try to source replacement gears (which I couldn't) and in the end manufacture my own replacements to bring these poor pups back to life.

Needless to say when it comes to the DHS,PAS,TAS three amigos I know all there is to know about repairing them.


<Press Release>

The press releases on this website are provided for historical reference purposes only. Please note that certain information may have changed since the date of release.

May 11, 1999

Sony Launches Four-Legged Entertainment Robot "AIBO" Creates a New Market for Robot-Based Entertainment Limited Edition for Sale Exclusively over the Internet

(Tokyo, Japan) -- Sony Corporation today announced the launch of a four-legged entertainment robot called "AIBO" [ERS-110] and an "AIBO Performer Kit" [ERF-510] motion editor that makes it possible for users to create original movements for "AIBO," the first robot designed for home entertainment purposes. Sony aims to begin building an entirely new market for robot entertainment by making "AIBO" available to residents of Japan and the United States of America in limited quantities while maintaining close contact with the users. All sales will be handled exclusively over the Internet through the following home page.

Product Description

Orders Accepted

Products Shipped

Retail Price (excluding tax)

Production Limit

"AIBO" Entertainment Robot [ERS-110], Station, AC Adapter, Li-Ion Battery [ERA-110B] (set of 2), Sound Commander remote control unit, 8MB pre-recorded Memory Stick, colored ball, and other accessories.

June 1, 1999 09:00 JST

Early July

250,000 yen in Japan

3,000 Units for Japan

June 1, 1999 09:00 EDT

Early July

USD$2500 in the USA

2,000 Units for the USA

"AIBO Performer Kit" Motion Editor [ERF-510], 8MB Memory Stick, Memory Stick PC Adapter Card

June 1, 1999 09:00 JST

Early July

50,000 yen in Japan


June 1, 1999 09:00 EDT

Early July

USD$450 in the USA


"AIBO" Sales Homepage *this link is no longer active and a revised page does not exist.

"AIBO" [ERS-110] is an autonomous robot that acts both in response to external stimuli and according to its own judgement. "AIBO" can express various emotions, grow through learning, and communicate with human beings to bring an entirely new form of entertainment into the home.

Not only is "AIBO" capable of four-legged locomotion by virtue of the 3 degrees-of-freedom in each of its legs, but it can also perform other complex movements using its mouth, tail, and head, which have 1, 2, and 3 degrees-of freedom, respectively. "AIBO" incorporates various sensors and autonomous programs that enable it to behave like a living creature, reacting to external stimuli and acting on its own judgement. "AIBO's" capacity for learning and growth is based on state-of-the-art artificial intelligence technology that shapes the robot's behavior and response as a result of repeated communication with the user and interaction with the external environment.

The "AIBO Performer Kit" [ERF-510] includes an easy-to-use motion editor tool that allows users to create original motions for "AIBO". A graphical user interface that makes it simple to create motion programs for "AIBO" on a personal computer.

Main Features of "AIBO" [ERS-110]

1. Autonomous Judgement and Response

"AIBO" incorporates emotions such as happiness and anger and instincts such as the need for companionship. It operates autonomously in response to external stimuli and its own temperament and express emotions as well. "AIBO" is equipped with adaptive learning and growth capabilities that allow each unit to develop a unique personality including behavior shaped by the praise and scolding of its owner. Moreover, "AIBO" features 'game' and 'performance' modes that allow the user to give instructions to the robot using a tone-based remote control unit called the "Sound Commander." Users can also create motion data using a PC-based motion editor tool, which is sold separately, for the performance mode.

2. Smooth Movement with 18 Degrees-of-Freedom
A total of 18 degrees-of-freedom (1 for mouth, 2 for tail, 3 for head, and 3 for each leg) allow "AIBO" to walk smoothly on four legs as well as perform other complex motions.

3. Memory Stick for Easy Replacement of Programs
A pre-recorded 8MB "Memory Stick" comes as an accessory to "AIBO". It is used to store the software modules that control "AIBO's" movements and data that is generated during the learning process. "Memory Stick" makes it easy for users to insert new software modules into "AIBO," including original motion programs created by the user using the motion editor (sold separately).

4. Modular Software Based on the OPEN-R Architecture
"AIBO" employs modular software based on the OPEN-R architecture to facilitate the quick and easy addition and/or replacement of individual software modules.

5. Advanced Sensors Provide Increased Autonomy

The use of sensors, microphones, and speakers that roughly correspond to the sensory organs of a living creature make it possible for "AIBO" to communicate and react to external stimuli with a high degree of autonomy.

Touch Sensor Color CCD Camera

Range Finder
LED Lamps
Mini Stereo Microphone

Miniature Speaker Acceleration Sensor

Angular Velocity Sensor

6. Other Features

: For recognizing tactile stimulation like being pet or hit

: For detecting the shapes and colors of objects when approaching or avoiding them

: For detecting the distance to objects

: For expressing happiness (green) and anger (red)

: For detecting the direction of a sound source and hearing sound from the Sound Commander remote control

: Allows "AIBO" to make sounds

: For use in maintaining balance and regaining balance when recovering from a fall

: For detecting rotary motion

- Powerful 64-bit RISC processor
- Equipped with 16MB of Main Memory
- Employs Sony's "Aperios" Real-time Operating System - Comes with two special Li-Ion Batteries

Main Features of [ERF-510]

1. Simple Creation of Original Motions for "AIBO"
Even users with no prior robotics or programming experience will find it easy to create original motions for "AIBO." Through the use of a graphical user interface, users can manipulate a 3-Dimensional model of "AIBO" to edit the robot's movements in a manner that resembles the editing of video footage. In addition, sound editor software already on the market makes it possible to create sounds in the MIDI and WAVE file formats and use them to replace "AIBO's" original sounds.

2. Incorporates Timeline Editing, Simulation Features
All of the robot's motions can be displayed on a computer screen along with a timeline feature, which allows users to confirm each of the motions, edit them very efficiently, change their order, and add new motions. Moreover, the software can conduct a simulation to confirm that none of the motions exceed the mechanical limitations of the robot's limbs and that none of the moving parts will collide with one another. The simulation also allows the user to check other factors, such as the speed of the robot's movement.

3. Supports "Memory Stick" IC Recording Media
User can store newly created motion data on a "Memory Stick" for easy transfer into "AIBO" or exchange with friends. Furthermore, "Memory Stick" includes features that ensure that data is stored correctly.

[ERS-110] Technical Specifications


64-bit RISC Processor

Main Memory


Program Memory

8MB Memory Stick (Accessory)

Moving Parts

Mouth: 1 degree-of-freedom
Head: 3 degrees-of-freedom
Legs: 3 degrees-of-freedom (x 4)
Tail: 2 degrees-of-freedomspacesTotal: 18

Video Input

180,000 pixel color CCD camera (x 1)


Internal Sensors

Audio Input

Stereo microphone (one on each side)


Audio Output

Speaker (x 1)


Heat Detector

Heat Sensor (x 2)


Range Finder

Infra-red range finding sensor (x 1)


Acceleration Detector

Spatial acceleration sensor (x 1)


Rotation Detector

Angular velocity sensor (x 1)


Contact Detectors

Touch sensor (x 1), Switch (x 4)

Head, Legs

Power Source

DC7.2V (Lithium Ion Battery [ERA-110B])

Energy Consumption

12.6W (autonomous mode)

Operating Time

Approx. 1.5 hours (using fully charged battery)

Dimensions (l x w x h)

Approx. 274 x 156 x 266mm (not including tail)


About 1.4kg (Body Only)
About 1.6kg (Including Memory Stick and Battery)

[ERF-510] Main Features

[ERF-510] System Requirements

* "AIBO," the "AIBO" logo, "Memory Stick" and "OPEN-R" are trademarks of Sony Corporation. * Pentium® is a registered trademark of Intel Corporation.
* Windows95® and Windows98® are registered trademarks of Microsoft Corporation.
Other product and company names herein may be trademarks of their respective owners.

Motion Editing Functions (3 Types)

1) Exchange and replacement of motion data 2) Editing of motion data
3) Creation of original motion data

Simulation Functions

1) Ensures that limbs do not exceed mechanical limitations 2) Confirms of that limbs will not collide
3) Checks the speed of each limb


Timeline editing function, Memory Stick data check, etc.

Computing Platform

IBM PC/AT compatible


Pentium®200Mhz equivalent or faster


Windows®95 or Windows®98


32MB or greater

PC Card Slot

Type II PC Card

Display Mode

800 x 600 resolution or greater

Display Color Capability

16-bit High Color or greater


CD-ROM Drive (For Installation)


Just in case anyone wants to know, My own ERS-110 is called Freddie (I also have a sprocker spaniel called Freddie which gets at least one of them confused quite often).