Draft Version 1.0, Outlined by Gavin Tersteeg
The [CO]mbination [G]ui and [NAV]iation system (COGNAV) interfaces with the CyBOT playform using the ARAP protocol. It serves to extend CyBOT functionality in a number of facets. These include:
- Improved graphical feedback to the user
- Simplified robot state switching
- Teleop robot control through keyboard or gamepad
- Enhanced navigation using map creation and pathfinding
Communication will be done through the ARAP protocol, with COGNAV acting as the server, and the CyBOT acting as the client. The CyBOT will poll the COGNAV registers for instructions to execute, and will update these registers with relevant information about the robot. The contents and functionality of these registers are as follows:
Data Format: ?
ARAP special function register, outlined in ARAP.txt
Read: Resend last packet
Write: Send ping packet
Data Format: Unsigned Byte (8 bits)
Command register; Used to send opcode commands to the client, or for the client to confirm that an opcode has finished execution. The definitions for each opcode can be found in the OPCODES section
Read: Will send at maximum one arg back, this being the current opcode to execute. This opcode will continue to be send until the client confirms that this opcode command has finshed execution. If there is no operation to execute, no arguments will be sent.
Write: Writing anything (even with no arguments) will tell COGNAV that the current opcode has finished executing. COGNAV will place the next opcode in the buffer to be read
Data Format: Float (32 bits)
Rotational Position register; Used to obtain the requested rotational position, or to indicate that the rotational position has changed.
Read: Will send exactly one argument back. If a ROT instruction has been sent, then this register will return the desired angle. Otherwise it will return the angle that COGNAV thinks the robot is at the moment.
Write: Used to update COGNAV with an exact rotational position after a rotational event has occured.
Data Format: Float (32 bits)
Linear Displacement register; Used to obtain the requested linear displacement, or to indicate that the linear position has changed.
Read: Will send exactly one argument back. If a MOVE instruction has been sent, then this register will return the desired displacement. Otherwise it will return "0".
Write: Used to update COGNAV with an exact displacement after a linear displacemnt event has occured.
Data Format: Float (32 bits)
Object Angle Offset register; Used to define the offset angle that an object is at when transferring object data to COGNAV.
Write: Any value written will be used to set the object's angluar offset. This angle starts at the front of the robot, and wraps clockwise around it.
Data Format: Float (32 bits)
Object Distance register; Used to define how far away that an object is when transferring object data to COGNAV.
Write: Any value written will be used to set the object distance. This is measured in centimeters, and begins at the center of the robot.
Data Format: Float (32 bits)
Object Width register; Used to define how wide an object is when transferring object data to COGNAV.
Write: Any value written will be used to set the object width. This is measured in centimeters.
Data Format: Unsigned Byte (8 bit)
Object Type register; Used to give addition metadata about an object being sent to COGNAV. When this register is written to, it will cause COGNAV to register a new object using data found in registers 4 through 6.
Write: Only accepts on argument at time, any more will be ignored. The written value is used to define the object type
0x00 - Temporary Unidentified Visual Object
0x01 - Unidentified Visual Object
0x02 - Confirmed Wide Visual Object
0x03 - Confirmed Thin Visual Object
0x04 - Bumper Collision Object
0x05 - White Tape Object
0x06 - Hole
Data Format: Float (32 bit)
Left Analog Stick register; Returns the current position of the left analog stick current attached to the COGNAV software. Used for direct robot control in manual mode.
Read: A value ranging from -1.0 to 1.0
Data Format: Float (32 bit)
Right Analog Stick register; Returns the current position of the right analog stick current attached to the COGNAV software. Used for direct robot control in manual mode.
Read: A value ranging from -1.0 to 1.0
-- work in progress --