Reddy Update

Schedule

Week 31, July 27 - August 1	Ordered new coupling for shoulder Fab. + installation of head mechanism for gravity assist (previous one had interference problems with other head parts) Assembly and installation of 1 motor PCB for neck Assembly and installation of the speaker PCB + support Final tuning of motor controllers Documentation (protocol)
Week 32, August 3 - August 9	Final tests & tuning
Week 33, August 10 - August 15	Schedule a meeting for robot exchange

Arm Improvements

To have better control of the arm (and neck) motors, we did the following :

• Change the Motor PCB to support
  • Temperature detector. A signal will be sent to the motor controller if the motor temperature is higher than 60 degrees celcius. Analog temperature value is also available.
  • Potentiometer feedback.
  • Motor power connection.
• Design a new PCB with support to 4 motors
• Communicate with the CAN bus already available on Reddy
• Allow position feedback from the RS-232 interface
• Create a tuning GUI for easier setup of the robot controllers

Motor Controllers

• A new motor drive that can connect up to 4 motors have been designed.
• A new adjustable bracket for fixing the drive to the side of the robot have been designed.
• We installed two motor controllers (one on each side) to allow the modification of 8 motors. Motors modified are :
  • Arm-elbow (x2)
  • Arm-shoulder (x2)
  • Arm-updown (x2)
  • Neck-YES (x1)
  • Neck-NO (x1)

Cabling Improvements

• Cables are now better organized
• Added connectors inside the arm to disconnect motors easily for repairs
• Signals are color coded as follow (TODO ADD DOCUMENTATION)
  • Red
  • Green
  • Black
  • Yellow
  • Purple
  • Gray
  • White
  • Blue

Head Improvements

Motor controllers for head movement (YES-NO)

• Same motor controllers were used for the neck to add overheating protection and better feedback / control
• Internal servo potentiometers were used for position control.

Tuning the motor controller

A GUI was created to facilitate motor tuning.

RS-232 protocol enhancements

• We added a CAN command to the RS-232 robot interface to allow direct communication with the motor controllers. The RS-232 robot interface now acts as a RS-232 to CAN bridge and bidirectional communication is now possible. This will allow feedback from the motor controllers (current, position, speed, etc.)

(RS-232 CAN COMMAND) <------------------------> (MOTOR DRIVE CAN INTERFACE)

CAN command format for RS-232 communication

HEADER	CAN_PRIORITY	CAN_MSG_TYPE	CAN_MSG_BOOT_RTR_LENGTH	CAN_MSG_CMD	CAN_MSG_DEST	CAN_MSG_DATA
(3 bytes)	(1 byte)	(1 byte)	(1 byte)	(1 byte)	(1 byte)	(8 bytes)

Future Improvements

• Single 12V power supply could be useful for direct connection to Pioneer robots. A 12V-->8.5V DC-DC (100W) converter is required for this operation. This item can be ordered at Vicor. 8.5V batteries would then be useless.