Anthropomorphic Learning Facilitator Robot (Summer 2008)

1. Overview | Download Project PDF

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Based on the considerations of a child focused design philosophy, the project implementation then involves the construction of an anthropomorphic learning facilitator in a shared interaction environment with the child where the focus is on the minimally complex design of the facilitator that provides a creative stimulus to the child to facilitate its learning. This stimulus is based on the theoretical understanding of imitative behavior and symbolic play in their developmental role in learning. Accordingly, the behavior of the AI facilitator then involves the constant provision of this stimulus through a simple movement repertoire that involves action and play directed behavior. In the former, the facilitator uses its robotic arms and mobility base to create meaningful gestures such as clap, dance, rotate, embrace and tries to make simple creative modifications of these movements through manipulating the inverse kinematic variables. In the latter, the facilitator involves itself in object play with the child such that it uses its vision system to pickup blocks of objects and arrange them to create different patterns. The goal of the facilitator is thus to show the child a world of creative possibilities by providing the child with a mix of random, goal-directed and playful stimuli such that they induce forms of learning in the child as opposed to providing it with fixed solutions to problems, while providing a sensorimotor exploration of its environment. The aim of the thesis and project is thus to allow for a critical reflection on the view of AI in the child facilitation problem through formulation of an alternative child-centered design philosophy.

B. Technical Overview

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The structural and component configuration of the robot will build on top of the existent omniwheel base design from The Human Game Machine. Starting with the design consideration of providing the robot with the most flexible movement repertoire for imitation inducing and play movements while keeping practical design consideration in mind, a certain minimal number of degrees of freedom will be incorporated by implementing a combination of high and low torque servos. The aim will be to achieve a very simple structural design that allows the creation of an anthropomorphic form and functionality for of a mobile robot that navigates its environment and interact with the child. The mobility will be provided by the already built omniwheel assembly while interactivity and functionality will be achieved primarily by two robotic arms made out of custom and off-the shelf components such as grippers that are detailed in the next section. The already built custom ATMEGA-168 circuit that is RF enabled and extended for up to 24 servos will be used so that no significant basic electronic design changes occur. The only electronic component that will need interfacing is the vision system of the robot that will use the open source architecture of the CMUcam3 to build on its wireless mote functionality that can be interfaced directly with the XBee radio for wireless vision functionality. Since the ViSP platform provides for both eye-in-hand and eye-to-hand based configurations of a vision system, the camera can be incorporated both in an off the shelf Pan and Tilt Camera Turret or it can be mounted on the wrist. The structural base will either be metal or the light and strong Lexan 9034 polycarbonate material.

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The Robotic Arm is a 5 DOF Arm having shoulder, arm, elbow, wrist and gripper rotations to allow the robot to flexibly grasp an object within its vicinity while keeping in mind the overall design consideration of not increasing the degrees of freedom which would make the custom C++ code written on top of ViSP’s inverse kinematics engine unnecessarily complex. ViSP provides a generic interface for robot manipulators up to 6 DOF, but in this case 5 would suffice. To keep the construction of the arm light and strong, any polycarbonate based material such as Lexan 9034 or PVC Sheet will be used. The choice of servos that provide the necessary torque for needed manipulation has been made after referring to a number of existent and marketed robotic arms. The arm from the base up to the wrist will be custom made while the gripper will be integrated as a separate modular piece that is sold as is by a popular hobbyist store called as Lynxmotion.com Two such robotic arms will be constructed that will be fused into the upper torso of the robot. The arms will be located at an appropriate level above the ground such that when the shoulder servo is pulsed to 180 degrees and the elbow servo is pulsed at 90 degrees the gripper should easily be able to position itself within the reach of a play object. To serve the minimally required objectives of the project, only one of the arms will be equipped with an IEEE 1394 vision camera or CMUcam3 for Eye-in-hand configuration provided by ViSP while the other arm will be used for non-grasping tasks of the robot.

C. Architecture

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