kobuki_driver: Appendix : Protocol Specification

: Payload is a consist of several sub-payloads.

Payload
Sub-Payload 0	Sub-Payload 1	Sub-Payload 2	...	Sub-Payload N-1

Serialization is the process of converting a data structure into a bytestream. Deserialization is reversal process. Each data types are serialized and deserialized by <a href="http://en.wikipedia.org/wiki/Least_significant_byte">LSB</a>-First Order. It means Least Significant Bytes will comes first on the bytestream. For example, The integer number 2,864,434,397(0xAABBCCDD) can be serialized into:

0xDD

0xCC

0xBB

0xAA

So, 0xDD will arrive first in bytestream.

Here are template functions to handle it on kobuki_deriver, buildVariable() and buildBytes().

$\mbox{1/}(f \cdotp a)$ , where $f$ is frequency of sound in Hz, and $a$ is 0.00000275

Duration

Duration of playing note in milli-seconds

Warning: This command is implemented on the kobuki with firmware, but not implemented yet on driver software(kobuki_driver).

	Name	Size	Value	Value in Hex	Description
Header	Identifier	1	12	0x0C	Fixed
Length	Size of data field	1	2	0x02	Fixed
Data	Digital output flags	2			Set the flags to set high on output pins of expansion port 0x0001 for digital output ch. 0 0x0002 for digital output ch. 1 0x0004 for digital output ch. 2 0x0008 for digital output ch. 3 Set the flags to turn on external powers 0x0010 for external power 3.3V ch. 0x0020 for external power 5V ch. 0x0040 for external power 12V/5A ch. 0x0080 for external power 12V/1.5A ch. Set the flags to turn on LEDs 0x0100 for red colour of LED1 0x0200 for green colour of LED1 0x0400 for red colour of LED2 0x0800 for green colour of LED2

	Name	Size	Value	Value in Hex	Description
Header	Feedback Identifier	1	1	0x01	Fixed
Length	Size of data field	1	15	0x0F	Fixed
Data	Timestamp	2			Timestamp generated internally in milliseconds It circulates from 0 to 65535
	Bumper	1			Flag will be setted when bumper is pressed 0x01 for right bumper 0x02 for central bumper 0x04 for left bumper
	Wheel drop	1			Flag will be setted when wheel is dropped 0x01 for right wheel 0x02 for left wheel
	Cliff	1			Flag will be setted when cliff is detected 0x01 for right cliff sensor 0x02 for central cliff sensor 0x04 for left cliff sensor
	Left encoder	2			Accumulated encoder data of left and right wheels in ticks Increments of this value means forward direction It circulates from 0 to 65535
	Right encoder	2
	Left PWM	1			PWM value that applied to left and right wheel motor This data should be converted signed type to represent correctly Negative sign indicates backward direction
	Right PWM	1
	Button	1			Flag will be setted when button is pressed 0x01 for Button 0 0x02 for Button 1 0x04 for Button 2
	Charger	1			0 for DISCHARGING state 2 for DOCKING_CHARGED state 6 for DOCKING_CHARGING state 18 for ADAPTER_CHARGED state 22 for ADAPTER_CHARGING state
	Battery	1			Voltage of battery in 0.1 V Typically 16.7 V when fully charged
	Overcurrent flags	1			Flag will be setted when overcurrent is detected 0x01 for left wheel 0x02 for right wheel

Note: This sub-payload will be sent by default.

See also: Appendix : Kobuki Parameters - necessary parameters for conversion of encoder ticks to robot pose.

This value is related with distance between sensor and floor surface. See the datasheet for more detailed information.

This data also available in the Cliff field of enBasicSensorData , as a boolean type, processed on the kobuki.

	Name	Size	Value	Value in Hex	Description
Header	Identifier	1	5	0x05	Fixed
Length	Size of data field	1	6	0x06	Fixed
Data	Right cliff sensor	2			ADC output of each PSD Data range: 0 ~ 4095 (0 ~ 3.3V) Distance range: 2 ~ 15 cm Distance is not linear w.r.t. ADC output. See the datasheet for more detail.
	Central cliff sensor	2
	Left cliff sensor	2

Note: This sub-payload will be sent by default.

See also: enBasicSensorData

Raw gyro data 0

x-axis

ADC output of each-axis in 0.00875 deg/s

y-axis

z-axis

:
:

Raw gyro data N-1

x-axis

y-axis

z-axis

Note: This sub-payload will be sent by default.

Warning: Sensing axis of 3d gyro is not match with robot. It is rotated 90 degree counterclockwise about z-axis. So, below conversion will needed.
const double digit_to_dps = 0.00875;

angular_velocity.x = -digit_to_dps * (short)raw_gyro_data.y;

angular_velocity.y = digit_to_dps * (short)raw_gyro_data.x;

angular_velocity.z = digit_to_dps * (short)raw_gyro_data.z;