Robotis MX-28AT Manual de usuario

MX-28AR, MX-28AT (Protocol 2.0)

1. Specifications

Item Specifications

MCU ARM CORTEX-M3 (72 [MHz], 32Bit)

Position Sensor Contactless absolute encoder (12Bit, 360 [°])

Maker : ams(www.ams.com), Part No : AS5045

Motor Coreless(Maxon)

Baud Rate 8,000 [bps] ~ 4.5 [Mbps]

Control Algorithm PID control

Resolution 4096 [pulse/rev]

Backlash 20 [arcmin] (0.33 [°])

Operating Mode

Velocity Control Mode

Position Control Mode(0° ~ 360°)

Extended Position Ctrl Mode(Multi-turn)

PWM Control Mode

Weight MX-28AR/AT : 77 [g], MX-28R/T : 72 [g]

Dimensions (W x H x D) 35.6 x 50.6 x 35.5 [mm]

Gear Ratio 193 : 1

Stall Torque

2.3 [Nm] (at 11.1 [V], 1.3 [A])

2.5 [Nm] (at 12 [V], 1.4 [A])

3.1 [Nm] (at 14.8 [V], 1.7 [A])

No Load Speed

50 [rev/min] (at 11.1 [V])

55 [rev/min] (at 12 [V])

67 [rev/min] (at 14.8 [V])

Radial Load 1 30 [N] (10 [mm] away from the horn)

Axial Load 1 15 [N]

Operating Temperature -5 ~ +80 [°C]

Input Voltage 10.0 ~ 14.8 [V] (Recommended : 12.0 [V])

Command Signal Digital Packet

Item Specifications

Protocol Type TTL Half Duplex Asynchronous Serial Communication with 8bit, 1stop, No Parity

RS485 Asynchronous Serial Communication with 8bit, 1stop, No Parity

Physcial Connection RS485 / TTL Multidrop Bus

ID 253 ID (0 ~ 252)

Feedback Position, Velocity, Temperature, Load, Input Voltage, Trajectory, Realtime Tick, etc

Material

Full Metal Gear

Engineering Plastic(Front, Middle, Back)

1 Metal(Front)

Standby Current 100 [mA]

1 Applies to alumium housing products(MX-28AR/AT, MX-64AR/AT, MX-106R/T).

DANGER

(May cause serious injury or death)

Never place items containing water, flammables, and solvents near product.

Never place fingers, arms, toes, and other body parts near product during operation.

Cut power off if product emits strange odors or smoke.

Keep product out of reach of children.

Check the power polarity before wiring.

CAUTION

(May cause injury or damage to product)

Do not operate the product at a temperature exceeding range.

Do not insert sharp blades nor pins during product operation.

ATTENTION

(May cause injury or damage to product)

Do not disassemble or modify product.

Do not drop or apply strong shock to product.

1. 1. Performance Graph

NOTE : The Max Torque and the Stall Torque of Performance Graph are different in measurement

methods. Stall torque is a measured value of the momentary torque that it can reach. This is generally

how RC servos are measured. The Performance graph is also called as N-T curves, which is measured

with the gradually increasing load. The actual motor operation environment is closer to the performance

graph, not stall torque method. For this reason, the performance graph is broadly used in the industrial

field. Generally, Max Torque of the Performance Graph is less than the Stall Torque.

CAUTION : When supplying power

It is recommended using ROBOTIS controller or SMPS2DYNAMIXEL.

Do not connect or disconnect DYNAMIXEL when power is being supplied.

2. Control Table

The Control Table is a structure of data implemented in the device. Users can read a specific Data to

get status of the device with Read Instruction Packets, and modify Data as well to control the device

with WRITE Instruction Packets.

CAUTION

1. MX(2.0) Firmware is different from MX series’ control table and address. Please check the control table

address before usage.

2. MX(2.0) Firmware inherits DYNAMIXEL X’s function. Therefore, it supports Protocol 1.0 and Protocol

2.0, and various Operating Modes, Secondary ID, Drive Mode, Bus Watchdog, etc. Please refer to the

control table for more details.

2. 1. Control Table, Data, Address

The Control Table is a structure that consists of multiple Data fields to store status or to control the

device. Users can check current status of the device by reading a specific Data from the Control

Table with Read Instruction Packets. WRITE Instruction Packets enable users to control the

device by changing specific Data in the Control Table. The Address is a unique value when

accessing a specific Data in the Control Table with Instruction Packets. In order to read or write

data, users must designate a specific Address in the Instruction Packet. Please refer to Protocol

2.0 for more details about Instruction Packets.

NOTE : Two’s complement is applied for the negative value. For more information, please refer to Two’s

complement from Wikipedia.

2. 1. 1. Area (EEPROM, RAM)

The Control Table is divided into 2 Areas. Data in the RAM Area is reset to initial values when

the power is reset(Volatile). On the other hand, data in the EEPROM Area is maintained even

when the device is powered off(Non-Volatile).

Data in the EEPROM Area can only be written to if Torque Enable(64) is cleared to ‘0’(Off).

2. 1. 2. Size

The Size of data varies from 1 ~ 4 bytes depend on their usage. Please check the size of data

when updating the data with an Instruction Packet. For data larger than 2 bytes will be saved

according to Little Endian.

2. 1. 3. Access

The Control Table has two different access properties. ‘RW’ property stands for read and write

access permission while ‘R’ stands for read only access permission. Data with the read only

property cannot be changed by the WRITE Instruction. Read only property(‘R’) is generally

used for measuring and monitoring purpose, and read write property(‘RW’) is used for

controlling device.

2. 1. 4. Initial Value

Each data in the Control Table is restored to initial values when the device is turned on. Default

values in the EEPROM area are initial values of the device (factory default settings). If any

values in the EEPROM area are modified by a user, modified values will be restored as initial

values when the device is turned on. Initial Values in the RAM area are restored when the

device is turned on.

2. 2. Control Table of EEPROM Area

Address Size

(Byte) Data Name Description Access Initial

Value

0 2 Model Number Model Number R 30

2 4 Model Information Model Information R -

Address Size
(Byte) Data Name Description Access Initial
Value
1 Firmware Version Firmware Version R -
1 ID DYNAMIXEL ID RW 1
1 Baud Rate Communication Baud Rate RW 1
1 Return Delay Time Response Delay Time RW 250
1 Drive Mode Drive Mode RW 0
1 Operating Mode Operating Mode RW 3
1 Secondary(Shadow) ID Secondary ID RW 255
1 Protocol Type Protocol Type RW 2
4 Homing Offset Home Position Offset RW 0
4 Moving Threshold Velocity Threshold for Movement Detection RW 10
1 Temperature Limit Maximum Internal Temperature Limit RW 80
2 Max Voltage Limit Maximum Input Voltage Limit RW 160
2 Min Voltage Limit Minimum Input Voltage Limit RW 95
2 PWM Limit Maximum PWM Limit RW 885
4 Acceleration Limit Maximum Acceleration Limit RW 32767
4 Velocity Limit Maximum Velocity Limit RW 230
4 Max Position Limit Maximum Position Limit RW 4,095
4 Min Position Limit Minimum Position Limit RW 0
1 Shutdown Shutdown Error Information RW 52
3. Control Table of RAM Area
Address Size
(Byte) Data Name Description Access Initial
Value
1 Torque Enable Motor Torque On/Off RW 0
1 LED Status LED On/Off RW 0
1 Status Return Level Select Types of Status Return RW 2
1 Registered Instruction REG_WRITE Instruction Flag R 0
1 Hardware Error Status Hardware Error Status R 0
2 Velocity I Gain I Gain of Velocity RW 1920
2 Velocity P Gain P Gain of Velocity RW 100
2 Position D Gain D Gain of Position RW 0
2 Position I Gain I Gain of Position RW 0
2 Position P Gain P Gain of Position RW 850

Address Size
(Byte) Data Name Description Access Initial
Value
2 Feedforward 2nd Gain 2nd Gain of Feed-Forward RW 0
2 Feedforward 1st Gain 1st Gain of Feed-Forward RW 0
1 BUS Watchdog DYNAMIXEL BUS Watchdog RW 0
2 Goal PWM Desired PWM Value RW -
4 Goal Velocity Desired Velocity Value RW -
4 Profile Acceleration Acceleration Value of Profile RW 0
4 Profile Velocity Velocity Value of Profile RW 0
4 Goal Position Desired Position RW -
2 Realtime Tick Count Time in Millisecond R -
1 Moving Movement Flag R 0
1 Moving Status Detailed Information of Movement Status R 0
2 Present PWM Present PWM Value R -
2 Present Load Present Load Value R -
4 Present Velocity Present Velocity Value R -
4 Present Position Present Position Value R -
4 Velocity Trajectory Desired Velocity Trajectory from Profile R -
4 Position Trajectory Desired Position Trajectory from Profile R -
2 Present Input Voltage Present Input Voltage R -
1 Present Temperature Present Internal Temperature R -
2 Indirect Address 1 Indirect Address 1 RW 224
2 Indirect Address 2 Indirect Address 2 RW 225
2 Indirect Address 3 Indirect Address 3 RW 226
… … … … … …
2 Indirect Address 26 Indirect Address 26 RW 249
2 Indirect Address 27 Indirect Address 27 RW 250
2 Indirect Address 28 Indirect Address 28 RW 251
1 Indirect Data 1 Indirect Data 1 RW 0
1 Indirect Data 2 Indirect Data 2 RW 0
1 Indirect Data 3 Indirect Data 3 RW 0
… … … … … …
1 Indirect Data 26 Indirect Data 26 RW 0
1 Indirect Data 27 Indirect Data 27 RW 0

Address Size
(Byte) Data Name Description Access Initial
Value
251 1 Indirect Data 28 Indirect Data 28 RW 0
578 2 Indirect Address 29 Indirect Address 29 RW 634
580 2 Indirect Address 30 Indirect Address 30 RW 635
582 2 Indirect Address 31 Indirect Address 31 RW 636
… … … … … …
628 2 Indirect Address 54 Indirect Address 54 RW 659
630 2 Indirect Address 55 Indirect Address 55 RW 660
632 2 Indirect Address 56 Indirect Address 56 RW 661
634 1 Indirect Data 29 Indirect Data 29 RW 0
635 1 Indirect Data 30 Indirect Data 30 RW 0
636 1 Indirect Data 31 Indirect Data 31 RW 0
… … … … … …
659 1 Indirect Data 54 Indirect Data 54 RW 0
660 1 Indirect Data 55 Indirect Data 55 RW 0
661 1 Indirect Data 56 Indirect Data 56 RW 0
CAUTION : Protocol 1.0 does not support addresses greater than 256. Therefore, Indirect Address 29 ~
56 and Indirect Data 29 ~ 56 can only be accessed with Protocol 2.0.
2. 4. Control Table Description
CAUTION : Data in the EEPROM Area can only be written when the value of Torque Enable(64) is
cleared to ‘0’.
2. 4. 1. Model Number(0)
This address stores model number of DYNAMIXEL.
2. 4. 2. Firmware Version(6)
This address stores firmware version of DYNAMIXEL.
2. 4. 3. ID(7)
The ID is a unique value in the network to identify each DYNAMIXEL with an Instruction
Packet. 0~252 (0xFC) values can be used as an ID, and 254(0xFE) is occupied as a broadcast
ID. The Broadcast ID(254, 0xFE) can send an Instruction Packet to all connected DYNAMIXEL
simultaneously.

NOTE : Please avoid using an identical ID for multiple DYNAMIXEL. You may face communication

failure or may not be able to detect DYNAMIXEL with an identical ID.

2. 4. 4. Baud Rate(8)

Baud Rate determines serial communication speed between a controller and DYNAMIXEL.

Value Baud Rate Margin of Error

7 4.5M 0.000%

6 4M 0.000%

5 3M 0.000%

4 2M 0.000%

3 1M 0.000%

2 115,200 0.000%

1(Default) 57,600 0.000%

0 9,600 0.000%

NOTE : Less than 3% of the baud rate error margin will not affect to UART communication.

NOTE : For the stable communication with higher Baudrate, configure USB Latency value to the lower.

USB Latency Setting

2. 4. 5. Return Delay Time(9)

After the DYNAMIXEL receives an Instruction Packet, it delays transmitting the Status Packet

for Return Delay Time(9). For instance, if the Return Delay Time(9) is set to ‘10’, the Status

Packet will be returned after 20[μsec] when the Instruction Packet is received.

Unit Value Range Description

2[μsec] 0 ~ 254 Default value ‘250’(500[μsec]), Maximum 508[μsec]

2. 4. 6. Drive Mode(10)

This address configures Drive Mode of DYNAMIXEL.

Bit Item Description

Bit 7(0x80) - Unused, always ‘0’

Bit 6(0x40) - Unused, always ‘0’

Bit 5(0x20) - Unused, always ‘0’

Bit 4(0x10) - Unused, always ‘0’

Bit 3(0x08) - Unused, always ‘0’

Bit 2(0x04) - Unused, always ‘0’

Bit Item Description

Bit 1(0x02) - Unused, always ‘0’

Bit 0(0x01) Normal/Reverse Mode [0] Normal Mode: CCW(Positive), CW(Negative)

[1] Reverse Mode: CCW(Negative), CW(Positive)

NOTE : Time-based Profile is available from firmware V42.

NOTE : If the value of Bit 0(Normal/Reverse Mode) of the Drive Mode(10) is set to 1 , rotational

direction is inverted.

Thus, Position, Velocity, Current, PWM will have a inverted direction.

This feature can be very useful when configuring symmetrical joint or wheel system.

2. 4. 7. Operating Mode(11)

Value Operating

Mode Description

Velocity Control

Mode

(0° ~ 360°)

This mode controls velocity and ideal for wheel operation.

This mode is identical to the Wheel Mode(endless) from existing DYNAMIXEL.

3(Default) Position Control

Mode

This mode controls position and identical to the Joint Mode.

Operating position range is limited by Max Position Limit(48) and Min Position

Limit(52).

This mode is ideal for articulated robots that each joint rotates less than 360°.

Extended

Position Control

Mode

(Multi-turn)

This mode controls position and identical to Multi-turn Mode.

512 turns are supported(-256[rev] ~ 256[rev]) and ideal for multi-turn wrists or

conveyer systems or a system that requires an additional reduction gear.

PWM Control

Mode

(Voltage Control

Mode)

This mode directly controls PWM output (Voltage Control Mode)

NOTE : Switching Operating Mode will reset gains(PID, Feedfoward) properly to the selected

Operating Mode. The profile generator and limits will also be reset.

1. Profile Velocity(112), Profile Acceleration(108) : Reset to ‘0’

2. Goal PWM(100) : Reset to PWM Limit(36)

NOTE : PWM is the abbreviation for Pulse Width Modulation that modulates PWM Duty to control

motors.

It changes pulse width to control average supply voltage to the motor and this technique is widely

used in the motor control field.

1. PWM Control Mode is similar to the Wheel Mode of DYNAMIXEL AX and RX series.

2. Use Goal PWM(100) on PWM Control Mode in order to control supply voltage for DYNAMIXEL.

NOTE : Present Position(132) represents 4 byte continuous range from -2,147,483,648 to
2,147,483,647 when Torque is turned off regardless of Operating Mode(11).
However, Present Position(132) will be reset to an absolute position value of one full rotation in those
cases:
1. When Operating Mode(11) is changed to Position Control Mode, Present Position(132) will be
reset to an absolute position value of a full rotation.
2. When torque is turned on in Position Control Mode, Present Position(132) will be reset to an
absolute position value of one full rotation.
3. When turning off the power supply on Extended Position Control Mode, Present Position(132) will
be reset to an absolute position value of one full rotation.
Present Position(132) value can be affected by Homing Offset(20) .
2. 4. 8. Secondary(Shadow) ID(12)
Set the DYNAMIXEL’s Secondary ID. Secondary ID(12) is a value to identify each
DYNAMIXEL, just like the ID(7). However, unlike ID(7), Secondary ID(12) is not a unique value.
Therefore, DYNAMIXEL with the same Secondary ID value form a group. The differences
between Secondary ID(12) and ID(7) are as follows :
1. Secondary ID(12) is not a unique value. i.e., a lot of DYNAMIXEL may have the same
Secondary ID value.
2. ID(7) has a higher priority than Secondary ID(12). i.e., if Secondary ID(12) and ID(7) are the
same, ID(7) will be applied first.
3. The EEPROM area of the Control Table cannot be modified with Secondary ID(12). Only
the RAM area can be modified.
4. If Instruction Packet ID is the same as Secondary ID(12), the Status Packet will not be
returned.
5. If the value of Secondary ID(12) is 253 or higher, the Secondary ID function is deactivated.
Values Description
0 ~ 252 Activate Secondary ID function
253 ~ 255 Deactivate Secondary ID function, Default value ‘255’
The following are examples of operation when there are five DYNAMIXEL with ID (7) set from 1
to 5.
1. Set all five DYNAMIXEL’ Secondary ID(12) to ‘5’.
2. Send Write Instruction Packet(ID = 1, LED(65) = 1).
3. Turn on LED of DYNAMIXEL with ID ‘1’ and return the Status Packet.
4. Send Write Instruction Packet(ID = 5, LED(65) = 1).
5. Turn on LED on five DYNAMIXEL. However, Status Packet of DYNAMIXEL with ID ‘5’ will
be returned.
6. Set the Secondary ID(12) of all five DYNAMIXEL to ‘100’.
7. Send Write Instruction Packet(ID = 100, LED(65) = 0).
8. Turn off LED on five DYNAMIXEL. However, as there is no DYNAMIXEL with ID ‘100’,
Status Packet is not returned.