Axis Communications AX-12 User Manual

Dynamixel

Closer to Real,

User’s Manual 2006-06-14

X-12

DYNAMIXEL

Contents

AX-12

1. Summary

1-1. Overview and Characteristics of AX-12 Page 2 1-2. Main Specifications Page 3

2. Dynamixel Operation

2-1. Mechanical Assembly Page 4 2-2. Connector Assembly Page 5 2-3. Dynamixel Wiring Page 6

3. Communication Protocol

3-1. Communication Overview Page 9 3-2. Instruction Packet Page 10 3-3. Status Packet Page 10 3-4. Control Table Page 12

4. Instruction Set and Examples

4-1. WRITE_DATA Page 19 4-2. READ_DATA Page 20 4-3. REG WRITE and ACTION Page 2 0 4-4. PING Page 21 4-5. RESET Page 22 4-6. SYNCWRITE Page 23

5. Example

Appendix

Page 30

Page 24

DYNAMIXEL

AX-12

1. Dynamixel AX-12

1-1. Overview and Characteristics of AX-12

Dynamixel AX-12 The Dynamixel series robot actuator is a smart, modular actuator that incorporates a

gear reducer, a precision DC motor and a control circuitry with networking functionality, all in a single package. Despite its compact size, it can produce high torque and is made with high quality materials to provide the necessary strength and structural resilience to withstand large external forces. It also has the ability to detect and act upon internal conditions such as changes in internal temperature or supply voltage. The Dynamixel series robot actuator has many advantages over similar products.

Precision Control Position and speed can be controlled with a resolution of 1024 steps.

Compliance Driving The degree of compliance can be adjusted and specified in controlling position.

Feedback Feedback for angular position, angular velocity, and load torque are available.

Alarm System The Dynamixel series robot actuator can alert the user when parameters deviate from

user defined ranges (e.g. internal temperature, torque, voltage, etc) and can also handle the problem automatically (e.g. torque off)

Communication Wiring is easy with daisy chain connecti on, and it support communication speeds u p to

1M BPS.

Distributed Control Position, velocity, compliance, and torque can be set with a single command packet,

thus enabling the main processor to control many Dynamixel units even with very few resources.

Engineering Plastic The main body of the unit is made with high quality engineering plastic which enables it

to handle high torque loads.

Axis Bearing A bearing is used at the final axis to ensure no efficiency degradation with high external

loads.

Status LED The LED can indicate the error status to the user.

Frames A hinge frame and a side mount frame are included.

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AX-12

1-2. Main Specifications

AX-12 Weight (g) 55 Gear Reduction Ratio 1/254 Input Voltage (V) at 7V at 10V Final Max Holding Torque(kgf.cm) 12 16.5 Sec/60degree 0.269 0.196

Resolution 0.35° Operating Angle 300°, Endless Turn Voltage 7V~10V (Recommended voltage: 9.6V) Max. Current 900mA Operate Temperature -5 ~ +85℃℃ Command Signal Digital Packet Protocol Type Half duplex Asynchronous Serial Communication (8bit,1stop,No Parity) Link (Physical) TTL Level Multi Drop (daisy chain type Connector) ID 254 ID (0~253) Communication Speed 7343bps ~ 1 Mbps Feedback Position, Temperature, Load, Input Voltage, etc. Material Engineering Plastic

DYNAMIXEL

AX-12

2. Dynamixel Operation

2-1. Mechanical Assembly

Frames Provided The two frames provided with AX-12 are shown below.

OF-12SH Installation The OF-12SH (hinge frame) can be installed on the AX-12 as the following.

OF-12S Installation The OF-12S (side mount frame) can be installed on the AX-12 as the following. The OF-

12S can be mounted on any of the three faces (left, right, or under side) of the AX-12 body as needed.

Horn2Body

Body2Body

OF-12SH OF-12S

Exploded view

Exploded view Assembled

Assembled

DYNAMIXEL

AX-12

2-2 . Connector Assembly

Assemble the connectors as shown below. Attach the wires to the terminals using the

correct crimping tool. If you do not have access to a crimping tool, solder the terminals to the wires to ensure that they do not become loose during operation.

DYNAMIXEL

AX-12

2-3. Dynamixel Wiring

Pin Assignment The connector pin assignments are as the following. The two connectors on the

Dynamixel are connected pin to pin, thus the AX-12 can be operated with only one connector attached.

Wiring Connect the AX-2 actuators pin to pin as shown below. Many AX-12 actuators can be

controlled with a single bus in this manner.

Control Box “CM-5”

Main Controller To operate the Dynamixel actuators, the main controller must support TTL level half duplex

UART. A proprietary controller can be used, but the use of the Dynamixe l controller CM-5 is recommended.

PC LINK A PC can be used to control the Dynamixel via the CM-5 controller.

RS232

Level

TTL

Level

PC Dynamixels

CM-5

PIN1: GND PIN2: VDD PIN3: Data

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bioloid A robot can be built using only the CM-5 controller and a number of AX-12 actuators. An

Connection to UART To control the Dynamixel actuators, the main controller needs to convert its UART

AX-12

edutainment robotic kit named “Bioloid” is available which is based on the CM-5 controller and the AX-12 actuators.

An example of a robot built with Bioloid

For details, please refer to the Bioloid manual.

signals to the half duplex type. The recommended circuit diagram for this is shown below.

DIRECTION_PORT

74HC126

TXD

74HC126

RXD

74HC04

CM-5 internal circuit (HALF DUPLEX UART)

The power is supplied to the Dynamixel actuator from the main controller through Pi n 1 and Pin 2 of the Molex3P connector. (The circuit shown above is presented only to explain the use of half duplex UART. The CM-5 controller already has the above circuitry built in, thus the Dynamixel actuators can be directly connected to it)

The direction of data signals on the TTL level TxD and RxD depends on the DIRECTION_PORT level as the following.

10K

DATA

9.6V GND

DATA(PIN3)

VDD(PIN2) GND(PIN1)

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Half Duplex UART A multi-drop method of connecting multiple Dynamixel actuators to a single node is

Caution Please ensure that the pin assignments are correct when connecting the Dynamixel

Connection Status Verification

Inspection If the above operation was not successful, then check the co nnector pin assi gn ment and

AX-12

• When the DIRECTION_PORT level is High: the signal TxD is output as Data

• When the DIRECTION_PORT level is Low: the signal Data is input as RxD

possible by using the half duplex UART. Thus a protocol that does not allow multiple transmissions at the same time should be maintained when controlling the Dynamixel actuators.

Main

Controlle

[Multi Drop Link]

actuators. Check the current consumption when powering on. T he current consumption of a single Dynamixel actuator unit in standby mode should be no larger than 50mA

When power is applied to the Dynamixel actuator, the LED blinks twice to confirm its connection.

the voltage/current limit of the power supply.

DYNAMIXEL

AX-12

3. Communication Protocol

3-1. Communication Overview

Packet The main controller communicates with the Dynamixel units by sending and receiving

data packets. There are two types of packets; the “Instruction Packet” (sent from the main controller to the Dynamixel actuators) and the “Status Packet” (sent from the Dynamixel actuators to the main controller.)

Communication For the system connectio n below, if the main controller sends an instruction packet with

the ID set to N, only the Dynamixel unit with this ID value will return its respective status packet and perform the required instruction.

Unique ID If multiple Dynamixel units have the same ID value, multiple packets sent

Protocol The Dynamixel actuators communicate through asynchronous serial communication

Instruction Packet(ID=N)

Main

Controlle

simultaneously collide, resulting in communication problems. Thus, it is imperative that no Dynamixel units share the same ID in a network node.

with 8 bit, 1 stop bit and no parity.

Main

Controlle

Instruction Packet

Status Packet

ID=0 ID=1 ID=N

Status Packet(ID=N)

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3-2. Instruction Packet

The Instruction Packet is the packet sent by the main controller to the Dynamixel units to send commands. The structure of the Instruction Packet is as the following.

Instruction Packet

0XFF 0XFF The two 0XFF bytes indicate the start of an incoming packet.

ID The unique ID of a Dynamixel unit. There are 254 available ID values, ranging from

Broadcasting ID ID 0XFE is the Broadcasting ID which indicates all of the conn ected Dynamixel units.

LENGTH The length of the packet where its value is “Number of parameters (N) + 2”

INSTRUCTION The instruction for the Dynamixel actuator to perform.

PARAMETER0…N Used if there is additional information needed to be sent other than the instruction itself.

CHECK SUM The computation method for the ‘Check Sum’ is as the following.

OXFF 0XFF ID LENGTH INSTRUCTION PARAMETER1 …PARAMETER N CHECK SUM

The meanings of each packet byte definition are as the following.

0X00 to 0XFD.

Packets sent with this ID apply to all Dynamixel units on the network. Thus packets sent with a broadcasting ID will not return any status packets.

Check Sum = ~ (ID + Length + Instruction + Parameter1 + ... Parameter N) If the calculated value is larger than 255, the lower byte is defined as the checksum value. ~ represents the NOT logic operation.

3-3. Status Packet(Return Packet)

The Status Packet is the response packet from the Dynamixel units to the Main

Controller after receiving an instruction packet. The structure of the status packet is as the following.

OXFF 0XFF ID LENGTH ERROR PARAMETER1 PARAMETER2… PARAMETER N CHECK SUM

DYNAMIXEL

0XFF 0XFF The two 0XFF bytes indicate the start of the packet.

ID The unique ID of the Dynamixel unit returning the packet. The initial value is set to 1.

LENGTH The length of the packet where its value is “Number of parameters (N) + 2”

ERROR The byte repres enting errors sent from the Dynamixel unit. The meaning of each bit is

AX-12

The meanings of each packet byte definition are as the following.

as the following.

Bit Name Details

Bit 7 0 -

Set to 1 if an undefined instruction is sent or an action

Bit 6 Instruction Error

instruction is sent without a Reg_Write instruction. Set to 1 if the specified maximum torque can't control the

Bit 5 Overload Error

applied load.

Bit 4 Checksum Error Set to 1 if the checksum of the instruction packet is incorrect.

Bit 3 Range Error Set to 1 if the instruction sent is out of the defined range.

Bit 2

Overheating

Error

Angle Limit

Bit 1

Error

Input Voltage

Bit 0

Error

PARAMETER0…N Used if additional information is needed.

CHECK SUM The computation method for the ‘Check Sum’ is as the following.

Set to 1 if the internal temperature of the Dynamixel unit is above the operating temperature range as defined in the control table. Set as 1 if the Goal Position is set outside of the range between CW Angle Limit and CCW Angle Limit. Set to 1 if the voltage is out of the operating voltage range as defined in the control table.

+ 26 hidden pages

Axis Communications AX-12 User Manual

Specifications and Main Features

Frequently Asked Questions

User Manual

1-1. Overview and Characteristics of AX-12

1-2. Main Specifications

2-1. Mechanical Assembly

2-2 . Connector Assembly