Cable-Anchor Robot Implementation using Embedded CD++ [Poster Abstract] ABSTRACT We show the design and implementation of a robot controller with a unique locomotion system. We demonstrate that a discrete-event simulation based design provides a cost-effective, flexible [1] , open workflow for modular robotic development. The robot is designed to translate against a vertical surface using cables fixed at one end that can wind on motor-controlled spools attached to the robot. This architecture was implemented first as a regressively tested simulation within CD++ then ported to Real- time CD++. Using the NXT++ interface library, a hardware implementation of the robot using Lego ® Mindstorms™ was shown to be controllable. Categories and Descriptions B.1.2 [Control Structure Performance Analysis and Design Aids] simulation, I.2.9 [Robotics] Commercial robots and applications General Terms Design, Verification 1. Cable-Anchored Robot In applications where terrain is too difficult to traverse using legs or wheels, other forms of robot locomotion must be found. Examples include disaster areas, such as building collapse, or environmentally sensitive locations where no disturbance can be tolerated. One form of locomotion that could allow 2D and 3D locomotion involves a cable-anchored robot. Rather than wheels, a cable-anchored robot is designed to hang from two or more points fixed above and around the desired area of movement connected by cables. The ends of the cables meet at the robot and are each wrapped around motor-driven spools which the robot can rotate to let out cable or take it in. This effectively allows motion through a space or across a plane. 2. Implementation A subset of this problem using two cables and a planar surface for movement was used as a real-world design specification. The robot would translate against a vertical surface using fixed cables that can wind on motor controlled spools attached to the top of the robot (Figure 3). The attachment points to the surface (in this case instantiated as a Chalk Board) can be arbitrary, and the controller is modeled in such a way that target (x, y) Cartesian coordinates can be translated to desired cable take-up and incremental motor movements. The robot model is implemented so that the path between the current robot position and the desired position is calculated in steps of defined resolution. This allows linear robot movement to the target position regardless of the geometry of the robot and cable attachment points. Figure 1: Robot path between start and target coordinates using a path planner This controller is designed in such a way that it can be implemented using the Lego Mindstorms™ robotics construction toolkit and E-CD++ [3] . Using a bottom-up development and testing process resulted in a complex robot controller system that met desired performance goals. The flexibility of the anchor-cable locomotion system is offset by its geometric complexity; however, this was shown to be successfully addressed with a path planner that could linearize robot motions with controllable fidelity. Gabriel Wainer Carleton University Dept. of Systems and Computer Engineering 1125 Colonel By Drive, Ottawa, Canada, K1S 5B6 gwainer@sce.carleton.ca Mohammad Moallemi Carleton University Dept. of Systems and Computer Engineering 1125 Colonel By Drive, Ottawa, Canada, K1S 5B6 mohammad@sce.carleton.ca Jeremy Kuzub Carleton University Dept. of Systems and Computer Engineering 1125 Colonel By Drive, Ottawa, Canada, K1S 5B6 jkuzub@sce.carleton.ca Keith Holman Carleton University Dept. of Systems and Computer Engineering 1125 Colonel By Drive, Ottawa, Canada, K1S 5B6 keith@sce.carleton.ca Permission to make digital or hard copies of all or part of this work for personal or classroom use is granted without fee provided that copies are not made or distributed for profit or commercial advantage and that copies bear this notice and the full citation on the first page. To copy otherwise, to republish, to post on servers or to redistribute to lists, requires prior specific permission and/or a fee. SIMUTools 2009, Rome, Italy Copyright 2009 ICST, ISBN 978-963-9799-45-5