Embedded Real-Time Linux for Cable Robot Control

Linux is a version of the Unix operating system distributed according to the open source model. Programmers are free to adapt the source code for their purposes, but are required to make their modifications or enhancements available as open source software as well. This model has fostered the widespread adoption of Linux for typical Unix server and workstation roles, and also in more arcane applications such as embedded or real-time computing. Embedded applications typically run in small physical and computing footprints, usually without fragile peripherals like hard disk drives. Special configurations are required to support these limited environments. Real-time applications require guarantees that tasks will execute within their deadlines, something not possible in general with the normal Linux scheduler. Real-time extensions to Linux enable deterministic scheduling, at task periods at tens of microseconds. This paper describes embedded and real-time Linux, and an application for distributed control of a Stewart Platform cable robot. Special Linux configuration requirements are detailed, and the architecture for teleoperated control of the cable robot is presented, with emphasis on the resolved-rate control of the suspended platform.

Design and Manufacturing of Customized Braces for Scoliosis Treatment

A new method to design and manufacture customized braces is introduced in this research for scoliosis treatment. In this method, a geometric model of a scoliosis patient’s torso is achieved using a laser optical scanning device. The brace geometry is obtained by generating the offset geometry of the torso’s surface, selecting vertical boundaries, removing holes and noise data, creating symmetrical geometry, and modifying the geometry near the pelvis curves. Manufacturing of the brace is conducted by producing a male die with a sculptured surface using a custom-designed 5-axis CNC milling machine and creating the plastic brace using a thermoforming process.

An Intelligent Manufacturing Advisor for Casting and Injection-Moulding Based on a Mid-Surface Approach

Products that are manufactured using near net-shape manufacturing processes must be designed with regard to the constraints of the manufacturing process. The purpose of this research project is to develop a knowledge based manufacturing advisor to assist designers of products for casting and injection moulding. The manufacturing advisor is tightly integrated with a CAD solid modeller, and uses a novel feature recognition approach to identify the manufacturing features of the part. A mid-surface abstraction from the part’s solid geometry is used as the basis for feature recognition, and it is argued that this is a better approach to feature recognition for this class of parts than a CAD solid model. Initial testing indicates that the feature recognition process is able to effectively recognise a range of features but that the quality of the feature recognition is dependent on the mid-surface representation that is generated.

Experimental Investigation of Heat Transfer in Two-Pass Coolant Passages With Ribs and Film Cooling Hole Ejection

A study of flow in two stationary models of two-pass internal coolant passages is presented, which focuses on the heat transfer characteristics in the two-pass coolant channel. Heat transfer measurements were made with a transient technique using thermochromic liquid crystal technique to measure a surface temperature. The technique allows full surface heat transfer coefficient measurements on all the walls. The coolant passage model consisted of two square passages, each having a 20 hydraulic diameter length, separated by a rounded-tip web of 0.2 passage widths, and connected by a sharp 180 deg bend with a rectangular outer wall. Ribs were mounted on the bottom and top walls of both legs, with a staggered arrangement, and at 45 deg to the flow. The rib height and spacing were 0.1 and 1.0 passage heights, respectively. The measurements were obtained for Reynolds numbers of 25000, 50000 and 70000. One geometry is equipped with extraction holes to simulate holes for film cooling. Two series of holes are placed solely in the bottom wall, 4 holes are located in the bend, and 12 in the downstream leg. The global extraction through the holes was set to 30%, 40% and 50% of the inlet massflow. This paper presents new measurements of the heat transfer in the straight legs, and in the bend of the passage. It shows the influence of Reynolds number and extraction on full surface measurements and area averaged results.

Architecture and Implementation of a Design Repository System

This paper describes the design and development of a design repository software system. This system is a prototype implementation intended to demonstrate the role of design repositories as part of a vision for the next generation of product development software systems. This research involves not only the creation of a prototype software system, but is part of a broader effort that also includes the development of a core product knowledge representation, and that seeks to address terminological and semantic issues associated with computer-aided product development. This paper focuses on the interfaces that have been developed to support authoring and navigation of the product models stored in design repositories, as well as the software architecture and associated rationale that provide the framework on which the system is built.

Digital Interfaces: The Key to Effective Decision-Making in Distributed Collaborative Design and Manufacturing

In product development, the interfaces between distinct phases of a design process are not well defined and largely misunderstood. The same ambiguity holds true for interactions among distributed stakeholders engaged in shared, concurrent design tasks. Such vagueness fosters poor communication, problematic changeovers, and hard-to-manufacture designs. Resulting design processes tend to be iterative and not only increase product development costs and extend time-to-market, but also ultimately impede collaboration. What is needed is the ability to propagate decision-critical, up-to-date information alongside design knowledge for both sequential and concurrent design tasks. This is particularly important for dependent and interdependent decisions that cannot be made in isolation. To address this need, digital interfaces are being developed as key components to successful collaboration in distributed design and manufacture applications. Such digital interfaces will constitute a means of communicating critical information and will address the need for allocating responsibility for decisions. The potential implementation of a digital interface is illustrated in an example focusing on the production of a functional prototype of a disposable camera spool.

An Integrated Computer-Aided Data Acquisition and Control System

PC-based data acquisition systems are used in a wide variety of applications. In laboratories, in field services and in manufacturing facilities, these systems act as general-purpose measurement and control tools well suited for measuring voltage signals. Teaching and learning experiences may be enhanced by integrating new-technologies in the engineering curriculum, particularly in experimental-type courses. By installing plug-in data acquisition boards and signal-conditioning hardware, and appropriate software, the general-purpose computers become enormously flexible virtual-instruments with data acquisition and analysis capability. This paper describes a Computer-Aided Testing System which uses a commercially available A/D board to offer users a wide array of measurement and control capabilities. It can be used for making repeated high speed measurement, controlling motors or teaching data acquisition.

Automatic Generation of Product Family Member CAD Models Supported by a Platform Using a Template Approach

Current global markets are volatile, where companies are striving to deliver greater quality, more customization, faster response, more innovative designs and lower prices. New models need to be introduced in the market more frequently, which has given momentum for designing family of products. Development of family of Products using a platform approach requires making decisions regarding platform selection and trade-off studies, which require analysis and evaluation of performance for the entire family instead of an individual products. One of the first steps in performing these activities require development of solid models for the entire family quickly and automatically as platform and family member configurations and size are changed. This paper presents an approach to automatically generate CAD models for a family of products. In the approach, a product family template that integrates configuration and parametric design information is presented. The template is implemented in the developed Product Family CAD (PF-CAD) module for Pro/E. A coffeemaker product family is used as a case study to automatically generate solid models of product family members from customer input.

Development of a Computer Controlled Valve System for an Internal Combustion Engine

A newly emerging method of improving gas mileage and emissions from spark ignition engines is by computer control of the operation of the engine intake and exhaust valves. By controlling valve timing and duration the elimination of the throttle, a source of pumping loses can be minimized. One system is now in production by BMW, which uses a mechanism that varies the rocker arm ratio to vary the intake valve’s lift. As part of two Senior Design Projects a spark ignition internal combustion engine was modified at Minnesota State University, Mankato, to allow computer control of the engine’s valves. These projects worked at replacing the mechanically operated intake and exhaust valves with pneumatically operated valves controlled by computer in the form of a Programmable Logic Controller. The valves controlled by the solenoids switched compressed air to pneumatic cylinders that operate the existing poppet intake and exhaust valves on the engine. This paper will present the background, operational issues, and the initial results of the project.

Towards a Hybrid Solver: Integration of a Genetic Algorithm Within “DSIDES”

In contributing to the body of knowledge for decision-based design, the work reported in this paper has involved steps towards building a hybrid genetic algorithm to address systems design. Highlighted is a work in progress at the Australian Defence Force Academy (ADFA). A genetic algorithm (GA) is proposed to deal with discrete aspects of a design model (e.g., allocation of space to function) and a sequential linear programming (SLP) method for the continuous aspects (e.g., sizing). Our historical Decision Based Design (DBD) tool has been the code DSIDES (Decision Support In the Design of Engineering Systems). The original functionality of DSIDES was to solve linear and non-linear goal programming styled problems using linear programming (LP) and sequential (adaptive) linear programming (SLP/ALP). We seek to enhance DSIDES’s solver capability by the addition of genetic algorithms. We will also develop the appropriate tools to deal with the decomposition and synthesis implied. The foundational paradigm for DSIDES, which remains unchanged, is the Decision Support Problem Technique (DSPT). Through introducing genetic algorithms as solvers in DSIDES, the intention is to improve the likelihood of finding the global minimum (for the formulated model) as well as the ability of dealing more effectively with nonlinear problems which have discrete variables, undifferentiable objective functions or undifferentiable constraints. Using some numerical examples and a practical ship design case study, the proposed GA based method is demonstrated to be better in maintaining diversity of populations, preventing premature convergence, compared with other similar GAs. It also has similar effectiveness in finding the solutions as the original ALP DSIDES solver.