Pioneer 3™ Operations Manual

Advanced Robot Control & Operations Software
Table 4. ARCOS standard SIP contents
NAME VALUE DESCRIPTION
HEADER 2 bytes Exactly in order 0xFA (250), 0xFB (251)
BYTE COUNT byte Number of data bytes + 2 (checksum), not including header or
byte-count bytes
TYPE 0x3s Motors status; s = 2 when motors stopped or 3 when robot
moving.
XPOS int Wheel-encoder integrated coordinates in millimeters
(DistConvFactor ‡ = 1.0).
YPOS int
THPOS int Orientation in degrees (AngleConvFactor ‡ = 1.0).
L VEL int Wheel velocities in millimeters per second (VelConvFactor ‡ = 1.0)
R VEL int
BATTERY byte Battery charge in tenths of volts (101 = 10.1 volts, for example)
STALL AND
BUMPERS
uint ╪ Motor stall and bumper indicators. Bit 0 is the left wheel stall
indicator, set to 1 if stalled. Bits 1-7 correspond to the first bumper
I/O digital input states (accessory dependent). Bit 8 is the right
wheel stall, and bits 9-15 correspond the second bumper I/O
states, also accessory and application dependent.
CONTROL int Setpoint of the server’s angular position servo in degrees
FLAGS uint Bit 0 motors status; bits 1-4 sonar array status; bits 5,6 STOP; bits
7,8 ledge-sense IRs; bit 9 joystick fire button; bit 10 auto—
charger power-good.
COMPASS byte Electronic compass accessory heading in 2-degree units
SONAR COUNT byte Number of new sonar readings included in SIP
NUMBER byte If Sonar Count>0, is sonar disc number 0-31; readings follow
RANGE uint Corrected sonar range value in millimeters (RangeConvFactor ‡ =
1.0)
…REST OF THE SONAR READINGS…
GRIP_STATE byte Gripper state byte.
ANPORT byte Selected analog port number 1-5
ANALOG byte User Analog input (0-255=0-5 VDC) reading on selected port
DIGIN byte Byte-encoded User I/O digital input
DIGOUT byte Byte-encoded User I/O digital output
BATTERYX10 int Actual battery voltage in 0.1 V (especially useful for battery
voltages > 25.5)
CHARGESTATE byte Version 1.5 and later. Autocharging state byte; -1 = unknown;
0=not charging; 1=bulk mode; 2=overcharge mode; 3=float.
CHECKSUM int Packet-integrity checksum
‡
Client-side data-conversion factor. Consult the ARIA parameter file your robot.
╪
Explicitly, an unsigned integer; all others sign-extended
The number of client commands you may send per second depends on the HOST serial
baud rate, average number of data bytes per command, synchronicity of the
communication link, and so on. ARCOS’ command processor runs on a one millisecond
interrupt cycle, but the server response speed depends on the command. Typically, limit
client commands to a maximum of one every 3-5 milliseconds or be prepared to recover
from lost commands.
MOTION COMMANDS
The ARCOS motor-control servers accept several different motion commands of two
types: either independent-wheel (VEL2) or translation/rotation movements (VEL, ROT,
etc). Actually, VEL2 commands are composed at the server into their translation and
rotation components and the corresponding limits and (de)accelerations get applied.
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