Difference between revisions of "CAN Bus"

Revision as of 15:33, 4 August 2010 (view source) Donald (Talk | contribs) (→‎CANID_SELECTJUMPER) ← Older edit		Revision as of 15:36, 4 August 2010 (view source) Donald (Talk | contribs) (→‎CANID_DISTANCE) Newer edit →
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	|-valign="top"		|-valign="top"
	|'''Interval'''		|'''Interval'''
−	|50ms	+	|10ms - 70ms, depends on distance (round trip time of sonic pulse). The farther the target, the longer it takes.
	|-valign="top"		|-valign="top"
	|'''Producer'''		|'''Producer'''
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	|-valign="top"		|-valign="top"
	|'''Semantics'''		|'''Semantics'''
−	|Todo	+	|An integer value, holding the distance to the next obstacle detected ahead in centimeters. Detector unit is the supersonic sensor SRF02.
		+	*0, if no obstacle has been detected (>6m or obstacle too small)
		+	*15-600, if obstacle in measurement range
		+	*do not consider other values
	|}		|}

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Revision as of 15:36, 4 August 2010

CAN Bus Configuration

The communication in the Concept Car is implemented via a high-speed (1Mbit/s) CAN-Bus (Controller-area network), featuring a message based protocol. Each message has a message identifier to distinguish between different message types. CAN standard 2.0A is applied, so the message identifiers are 11 bits wide, allowing 2048 distinct messages. Further details about the CAN-Bus can be found in [ZS08].

In the ConceptCar, only messages with the length of 4 Bytes, which are interpreted as an unsigned integer number, are used. How the message data has to be interpreted depends only on the message identifier, further details are given in the next section.

CAN Bus Messages

The following table gives an overview over all messages present on the CAN bus. Further detailed descriptions can be found below.

Messages present on the CAN Bus

ID (hex)	ID	Symbolic constant	Short Description	Source
0x008	8	CANID_WHEELSPEED_FL	Rotation Speed Front Left Wheel	Sensorboard Throttle
0x009	9	CANID_WHEELSPEED_FR	Rotation Speed Front Right Wheel	Sensorboard Steering
0x00a	10	CANID_WHEELSPEED_RL	Rotation Speed Rear Left Wheel	Sensorboard Steering
0x00b	11	CANID_WHEELSPEED_RR	Rotation Speed Rear Right Wheel	Sensorboard Throttle
0x00d	13	CANID_VOLTAGE	Voltage of the electrical System	Sensorboard Inertial
0x00e	14	CANID_RESETCOUNTER	Number of Resets since last ECU flashing	Sensorboard Inertial
0x010	16	CANID_INERTIAL_AX	Longitudinal Acceleration	Sensorboard Inertial
0x011	17	CANID_INERTIAL_AY	Lateral Acceleration	Sensorboard Inertial
0x012	18	CANID_ROTATION	Rotation Speed Car	Sensorboard Inertial
0x020	32	CANID_SELECTJUMPER	Actorboard Source Selection	Actorboard
0x022	34	CANID_THROTTLE	Throttle from SensorBoard	Sensorboard Throttle
0x122	290	CANID_THROTTLE_ARM7	Throttle from ARM7 Board	ARM7 Board
0x023	35	CANID_BRAKEFL	Front Left Brake Signal from SensorBoard	Sensorboard Throttle
0x123	291	CANID_BRAKEFL_ARM7	Front Left Brake Signal from ARM7 Board	ARM7 Board
0x024	36	CANID_BRAKEFR	Front Right Brake Signal from SensorBoard	Sensorboard Throttle
0x124	292	CANID_BRAKEFR_ARM7	Front Right Brake Signal from ARM7 Board	ARM7 Board
0x025	37	CANID_STEERING	Steering from SensorBoard	Sensorboard Steering
0x125	293	CANID_STEERING_ARM7	Steering from ARM7 Board	ARM7 Board
0x030	48	CANID_DISTANCE	Front Distance (Ultrasonic Sensor)	Sensorboard Distance
0x400	1024	CANID_ERROR	Error Message	ALL

CANID_WHEELSPEED

CAN ID	0x8 (FL), 0x9 (FR), 0xa (RL) and 0xb (RR)
Interval	50ms
Producer	Sensorboard Steering (0x9 and 0xa) and Sensorboard Throttle (0x8 and 0xb)
Consumer	Not yet specified
Semantics	Todo

CANID_VOLTAGE

CAN ID	0xd
Interval	200ms
Producer	Sensorboard Inertial
Consumer	Not yet specified
Semantics	The voltage of the battery driving the electrical system.

CANID_RESETCOUNTER

CAN ID	0xe
Interval	Once at boot time of the Sensorboard Inertial
Producer	Sensorboard Inertial
Consumer	Not yet specified
Semantics	An integer with the number of times the Sensorboard Inertial has been booted.

CANID_INERTIAL

CAN ID	0x10 (longitudinal) and 0x11 (lateral)
Interval	20ms
Producer	Sensorboard Inertial
Consumer	Not yet specified
Semantics	The longitudinal and lateral acceleration of the car, measured with the ADIS16006 accelerometer.

CANID_ROTATION

CAN ID	0x12
Interval	20ms
Producer	Sensorboard Inertial
Consumer	Not yet specified
Semantics	The rotation speed of the car around its axis, measured with the ADIS16100 gyroscope.

CANID_SELECTJUMPER

CAN ID	0x20
Interval	1s, and sent when switch on Actorboard has been toggled.
Producer	Actorboard
Consumer	Not yet specified
Semantics	Binary value, announces which source the Actorboard is configured to use. 0 if the source is from the Sensorboards Steering and Throttle (thus CAN ids 0x22 to 0x25) 1 if the the source is the Controlboard (thus CAN ids 0x122 to 0x125). See #CANID_THROTTLE, #CANID_STEERING and #CANID_BRAKE.

CANID_THROTTLE

CAN ID	0x22 and 0x122
Interval	~20ms, depends on remote transceiver (currently 17ms)
Producer	Sensorboard Throttle (0x22) and ARM7 Board (0x122)
Consumer	Not yet specified
Semantics	Todo

CANID_BRAKE

CAN ID	0x23 and 0x123 (left), 0x24 and 0x124 (right)
Interval	~20ms, depends on remote transceiver (currently 17ms)
Producer	Sensorboard Throttle (0x23 and 0x24) and ARM7 Board (0x123 and 0x124)
Consumer	Not yet specified
Semantics	Todo

CANID_STEERING

CAN ID	0x25 and 0x125
Interval	~20ms, depends on remote transceiver (currently 17ms)
Producer	Sensorboard Steering (0x25) and ARM7 Board (0x125)
Consumer	Not yet specified
Semantics	Todo

CANID_DISTANCE

CAN ID	0x30
Interval	10ms - 70ms, depends on distance (round trip time of sonic pulse). The farther the target, the longer it takes.
Producer	Sensorboard Distance
Consumer	Not yet specified
Semantics	An integer value, holding the distance to the next obstacle detected ahead in centimeters. Detector unit is the supersonic sensor SRF02. 0, if no obstacle has been detected (>6m or obstacle too small) 15-600, if obstacle in measurement range do not consider other values

CANID_ERROR

CAN ID	0x400
Interval	50ms
Producer	all
Consumer	Not yet specified
Semantics	Todo