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Contents 1 HyKim's Features 1.1 Features 1.2 Design 1.3 Processing 1.4 OS_coverage 1.5 Sensors 1.6 Displays 1.7 Motors 1.8 Power_Source

[edit] HyKim's Features

[edit] Features

HyKim Features - image shows HyKim v2

[edit] Design

The main features of HyKim’s design are:

1. HyKim’s ability to move both as a biped and quadruped robot.
2. HyKim’s torso can move laterally about the base of it’s spine, allowing for realistic bipedal and quadrupedal movements.
3. HyKim’s can rotate about the shoulders, unlike other quadrupedal robots (such as Sony Aibo).
4. HyKim’s body is currently made from ABS plastic, and
5. HyKim’s front feet have an ingenious non-motorised design.This allows the front paw to be straight whilst in the bipedal position and bent as a paw would bee whilst in a quadrupedal position Another advantage of this design is that it cushions HyKim’s transition from biped to quadruped.

[edit] Processing

HyKim has a central processing module, known as HyInt, and 2 smaller mcu’s, known as the Body Data Acquisition Module (RM0605) and the Head Data Acquisition Module (RM0604), which provide localised data collection and basic pre-processing of the collected data.

The HyInt processing module is based around Compulab’s CM-iGLX computer module. Detailed information on the system can be found later in this document, but a brief summary of it’s features are listed below:

• AMD Geode 500MHz mcu,
• 256kb cache,
• 256 Mb DDR,
• 512Mb FLASH Disk,
• 802.11g wireless,
• 100Mbps Ethernet,
• 2 COM ports (both used for communications with Data Acquisition modules),
• 3 USB ports (1 used for Dynamixel interface,& 1 used for Webcam)
• 1Mbps interface to Dynamixel modules, and
• Battery monitoring circuitry.

HyInt communicates serially to two Data Acquisition modules in the Body and the Head, i.e. HyInt_COM2 - Body UART1 and HyInt_COM1 - Head UART0. The Data Acquisition modules allow data to be collected locally, pre-processed and then the results can be transferred serially to HyInt. The data acquired by these modules is from:

• 3-axis Accelerometer,
• 1-axis Gyro,
• Infrared Distance Sensor, and
• Tilt compensated Digital Compass (Body module only).

The local acquisition of data, along with 21 mcu’s within the Dynamixel modules, means that there are 23 mcu’s distributed around HyKim’s body (not including HyInt), making HyKim’s design a highly distributed processing architecture.

Both Data Acquisition modules are based around the Atmel ATMega128 mcu. Both of these mcu’s connect serially to HyInt, this serial channel can be used to either:

1. program the ATMega via a bootloader (located within the ATMega), or
2. transfer the information collected from the various sensors.

Detailed information on the Head and Body Data Acquisition modules, can be found in the relevant section of this User Manual.

[edit] OS_coverage

Compulab’s CM-iGLX can run either:

1. Embedded Linux,
2. Windows CE, or
3. Windows XP.

Tribotix have developed an embedded Linux image based around debian etch (Debian 4.0r2), Linux Kernel: 2.6.18 which includes all the required device drivers. This image may be downloaded from our web site, be aware though that this image is approximately 250Mb.

[edit] Sensors

HyKim has various sensors spread across it’s body. A detailed description of each sensor can be found later in the document, but a brief summary of available sensors follows:

• Sensors located in HyKim's head:

1. Logitech Pro5000 Webcam (drivers available for both Linux & Windows),
2. 3-axis Accelerometer,
3. 1-axis Gyro,
4. Infrared Distance Sensor,
5. 3 Capacitive Touch Switches (under HyKim's chin).

• Sensors located within HyKim'sbody:

1. Tilt-Compensated Digital Compass,
2. 3-axis Accelerometer,
3. 1-axis Gyro,
4. Infrared Distance Sensor.

As well as the standard sensors mentioned above, both of HyKim's Data Aquisition modules, have all GPIO, iic bus and the SPI bus from the ATMega128's brought out to IDC Headers allowing the user to add additional sensor if required.

[edit] Displays

HyKim has 2 128x128 OLED’s mounted in its head and are connected via an SDI bus to the Head Data Acquisition module, HySense Lite.

These OLED’s can either be used as ‘eyes’ or to display diagnostic information, which can be extremely useful for debugging the embedded system.

[edit] Motors

HyKim is based around Robotis’s RX Dynamixel range of serially controlled, smart servo motors which are:

• based around quality Swiss Maxon motors,
• contain all metal gears to ensure durability,
• use a bearing at the final axis to ensure that there is no efficiency degradation with high external loads on the output shaft, and
• able to communicate at 1Mbps on a half-duplex RS485 network.

DX-117’s and RX-64’s were used for HyKim – there are 3 RX-64’s used, these are used for the top of the hind legs and also to control the lateral ‘side-to-side’ motion of torso.

A summary of the specifications for the RX module used follows:

Dynamixel Module Specifications

DX-117	RX-64
Reduction Ratio: 1/192 Holding Torque: 28.9kg-cm Speed: 0.172sec/60° (Specs at 12V)	Reduction Ratio: 1/200 Holding Torque: 64.0kg-cm Speed: 0.162sec/60° (Specs at 18V)

[edit] Power_Source

Whilst operating autonomously HyKim is powered by an 11.1V 2480mAh Lithium Polymer rechargeable battery pack. During normal operation, HyKim draws an average of 2.5~3.0A – so a fully charged battery pack should give 45~55 minutes of operation. The time period quoted is based on average power consumption, some operations (such as the transition from quadruped to biped) can draw significant large currents (up to 6A), so obviously the operational time from the battery pack will depend largely on the movements performed by HyKim .

HyKim processing system, HyInt , converts the 11.1V provided by the battery to both 5V and 3.3V. Circuitry within HyInt monitors both the battery voltage and the current drawn from the battery. Two separate voltage thresholds for the battery are set such that when the voltage from the battery starts to decay, power will be removed from the Dynamixel modules - this allows HyInt to shutdown gracefully before it loses power. Please note that Lithium Polymer (LiPo) battery packs have a very ‘sharp’ discharge curve, i.e. as the charge within the battery pack reduces, the voltage seen at the batteries terminals will fall to 0V very quickly.

Also for convenience, when developing software HyKim can be powered by a conventional lab power supply.