Loki

Loki

“Loki” is named after the Norse god of Mischief.  Since with Robotics, “anything that can go wrong, will go wrong… and usually break something important”, Loki seemed like an appropriate name.  Loki is just under 80lbs, and 4 feet tall.

Loki builds upon the software of Seeker and Mr. Roboto, including remote control and diagnostics over WiFi, but adds more capable vision processing, speech recognition, indoor pathfinding (Using A*), basic Artificial Intelligence, and general refinement of the architecture.

Loki Design

The “body” of Loki is built completely from scratch, using mostly aluminum.  The unique design allows a laptop computer to double as the robot brains, and also as a display screen in Loki’s “chest”.

The Cameras are two Logitech Notebook Pro webcams, to allow me to experiment with stereo vision. (I have basic stereo vision working with OpenCV, but not happy with the depth perception yet.)

The laptop software is programmed in C++ and C#.  The PC gets sensor data and controls power and lights via a processor board connected through USB.  Most of my robots use a PIC processor (Mark III board), which is programmed using the CCS “C” compiler, but in early 2013 I replaced the PIC on Loki with an Arduino..The I/O is expanded with several I2C chips; one in the head, and one in each arm.  Sensor inputs include 2 PIR motion detectors, 10 IR range detectors, 2 Ultrasonic rangers, 4 bumpers, an electronic compass, and motor speed and direction monitors for each wheel.  Head motion and arms are handled by Dynamixel servos.  The shoulder joints are custom chain-drive driven by precisely controlled motors, using a Kerr motor controller.

Click on a link below for hardware design info, or the source code.  See the Seeker documentation for an overview of the source code to get the “big picture”.  Also, the source code .zip has latest hardware schematic info, etc:

Electronics

Software

Mechanical