Stakeholder-Driven Design Evolution of the Leveraged Freedom Chair Developing World Wheelchair

The Leveraged Freedom Chair (LFC) is a low-cost, all-terrain, variable mechanical advantage, lever-propelled wheelchair designed for use in developing countries. The user effectively changes gear by shifting his hands along the levers; grasping near the ends increases torque delivered to the drive-train, while grasping near the pivots enables a larger angular displacement with every stroke, which increases angular velocity in the drivetrain and makes the chair go faster. This paper chronicles the design evolution of the LFC through three user trials in East Africa, Guatemala, and India. Feedback from test subjects was used to refine the chair between trials, resulting in a device 9.1 kg (20 lbs) lighter, 8.9 cm (3.5 in) narrower, and with a center of gravity 12.7 cm (5 in) lower than the first iteration. Survey data substantiated increases in performance after successive iterations. Quantitative biomechanical performance data were also measured during the Guatemala and India trials, which showed the LFC to be 76 percent faster and 41 percent more efficient during a common daily commute and able to produce 51 percent higher peak propulsion force compared to conventional, pushrim-propelled wheelchairs.

Teaching Classical Control System Course With Portable Student-Owned Mechatronic Kits

Teaching classical controls systems design to mechanical engineering students presents unique challenges. While most mechanical engineering programs prepare students to be well-versed in the application of physical principles and modeling aspects of physical systems, implementation of closed loop control and system-level analysis is lagging. It is not uncommon that students report difficulty in conceptualizing even common controls systems terms such as steady-state error and disturbance rejection. Typically, most courses focus on the theoretical analysis and modeling, but students are left asking the questions…How do I implement a phase-lead compensator? …What is a non-minimum phase system? This paper presents an innovative approach in teaching control systems design course based on the use of a low-cost apparatus that has the ability to directly communicate with MATLAB and its Simulink toolbox, allowing students to drag-and-drop controllers and immediately test their effect on the response of the physical plant. The setup consists of a DC micro-motor driving a propeller attached to a carbon-fiber rod. The angular displacement of the rod is measured with an analog potentiometer, which acts as the pivot point for the carbon fiber rod. The miniature circuit board is powered by the USB port of a laptop and communicates to the host computer using the a virtual COM port. MATLAB/Simulink communicates to the board using its serial port read/write blocks to command the motor and detect the deflection angle. This presentation describes a typical semester-long experimental protocol facilitated by the low-cost kit. The kit allows demonstration of classical PID, phase lead and lag controllers, as well as non-linear feedback linearization techniques. Comparison between student gains before and after the introduction of the mechatronic kits are also provided.

International and Multidisciplinary Experiences in Engineering Courses at UNAM

A team of faculty members from the Universidad Nacional Autónoma de México (UNAM) has coordinated multidisciplinary courses in collaboration with universities from other countries. The team, who is composed by faculty from the School of Engineering and the School of Architecture, coordinates with pairs of Stanford University, the University of California at Berkeley, and the Technical University of Munich; to teach three particular design courses. All three courses are related to product innovation but they have different emphasis depending on the collaborating partner. The focal points of each of the three courses are: (1) innovation, (2) user centered design and sustainability and (3) transport in megacities of the future. Engineering and industrial design students are involved in the courses. They are organized in teams that include participants from the two collaborating universities. During the courses teams carry out projects working mostly at a distance; they use different means of communication and information sharing and also pay reciprocal visits between the universities involved in the collaboration. This paper describes each of the three courses highlighting their particular characteristics. The outcomes and results of the courses and specific projects are commented. In the end of the paper lessons learned are discussed and final remarks are presented.

Design, Installation, and Performance Characterization of a Laboratory-Scale Solar Thermal System for Experiments in Solar Energy Utilization

The purpose of this paper is to describe the implementation of a laboratory-scale solar thermal system for the Renewable Energy Systems Laboratory at the Milwaukee School of Engineering (MSOE). The system development began as a student senior design project where students designed and fabricated a laboratory-scale solar thermal system to complement an existing commercial solar energy system on campus. The solar thermal system is designed specifically for educating engineers. This laboratory equipment, including a solar light simulator, allows for variation of operating parameters to investigate their impact on system performance. The equipment will be utilized in two courses: Applied Thermodynamics, and Renewable Energy Utilization. During the solar thermal laboratories performed in these courses, students conduct experiments based on the American Society of Heating, Refrigeration and Air-Conditioning Engineers (ASHRAE) 93-2010 standard for testing and performance characterization of solar thermal systems. Their measurements are then used to quantify energy output, efficiency and losses of the system and subsystem components.

Comparing Mentor and Mentee Perspectives in a Research-Based Undergraduate Mentoring Program

At the University of Colorado Boulder (CU), a research-based undergraduate mentoring program is now in its second year of implementation. The program, Your Own Undergraduate Research Experience (YOU’RE@CU) has three main goals: improve the retention rate of diverse groups in undergraduate engineering, build undergraduate interest in engineering research, and prepare graduate students to take on leadership roles in either academia or industry-based research careers. In YOU’RE@CU, undergraduate students are paired with a graduate mentor and work in the graduate student’s lab several hours a week. Undergraduate mentees enroll in a one-credit seminar course focusing on research and graduate school opportunities, and are assessed via pre- and post-surveys to gauge their excitement and interest in engineering. The undergraduates also respond to biweekly qualitative reflective questions while participating in the program. Graduate mentors complete several reflective questions about their experiences and are required to complete pre- and post-assessments. Adopting a person-centered, case study approach, this paper focuses on two telling examples of research-based mentoring relationships in the YOU’RE@CU program. Given identical mentor training through YOU’RE@CU, two graduate students start the Spring 2012 semester by meeting with their mentees to launch a research project. By examining application, pre-survey, reflective questions, and post-survey responses from these four participants, the differences in the trajectory of the two paired mentoring relationships can be clearly seen over the course of one semester. This close examination of two disparate mentoring relationships is instructive in understanding the subtle details that create either a positive learning environment or an uncomfortable lab situation for young engineers, and assists program administrators in making improvements in subsequent years.

Effective NEMS Education and Training in an Undergraduate Course

Increasing demand on workforce for nanotechnology implementation has resulted in an exponential increase of demand on educational material and methods to qualify this workforce. However, nanotechnology is a field that integrates many areas of science and engineering requiring a significant amount of background knowledge in both theory and application to build upon. This challenge is significantly magnified when trying to teach nanotechnology concepts and applications at the undergraduate engineering level. A considerable amount of time is needed for an undergraduate engineering student to be able to design and build a useful device applying nanotechnology concepts, within one course time. This paper presents an actual experience in teaching hands-on applications in nanotechnology to undergraduate engineering students through an optimized model, within a normal course time. The model significantly reduces the time needed by undergraduate students to learn the necessary manufacturing techniques and apply them to produce useful products at the micro and nano levels, by ensuring that infrastructure and legwork related to the educational process are partially completed and verified, before the course starts. The model also provides improved outcomes as all its pre-course work is also tested with students working under different arrangements of professors’ supervision. The result is an optimized infrastructure setup for micro and nanotechnology design and manufacturing education, built with students in mind, to be completed within the frame of one semester course. The model was implemented at GVSU-SOE as the core hands-on part of a senior undergraduate course titled (EGR 457 nano/micro systems engineering). Students in the course were able to go through the design and build steps of different MEMS and NEMS products, while learning and utilizing cleanroom equipment and procedures. This was based on infrastructural arrangements by students preceding this class by a semester and working closely with the professors. Assessment was conducted on both sides of the model and results were collected for evaluation and improvement of the model.

The Decline of Undergraduate Engineering Education in the United States

Examples of the decline in the mastery of engineering fundamentals and the ability to apply these fundamentals to real world problems are presented. There are enhanced abilities in today’s graduates and these are discussed. No attempt is made to assign blame for the decline in capabilities since there are many contributors to this change. Some of the factors contributing to the decline include student evaluations of instruction, misuse of homework, diminished reading comprehension, pressure on faculty to be productive in research, and the decrease in mastery required in the accreditation process. Each of the factors is discussed in some depth and rational actions are proposed to reverse this disturbing trend.

Micro-Scale Thermal Sensor Manufacturing for Semiconductor Furnace Chamber

As the demand of complex and small scale semiconductor devices has been increased, the measurement technologies were developed to meet the accurate requirement in semiconductor manufacturing process. The uniform temperature requirement on the wafer is the major factor related to the semiconductor device yield. It is normally acquired from the thermocouples following the inner wall of the chamber. However, since the temperature difference between the wall of equipment and the surface of wafer is existed, the actual wafer temperature is commonly measured by a thermocouple wafer to calibrate the temperature measurement accuracy of the equipment. However, as the diameter of the commercial thermocouple wires is larger than the recently demanded pattern size, the TC wafer has not been able to measure the micro scale temperature differences on the micro patterned wafer. We, therefore, designed a micro-scale thermal sensor. The developed sensor has 37 sets of the measurement points on a 4-inch silicon wafer. The size of the measurement point is approximate to 16 um2. Two alloys, chromel and alumel which are as same as the materials of the K-type thermocouple are used to generate the thermoelectric voltage. The sensor has the temperature range of −200°C to 1300°C. The commercial K-type thermocouple extension wires are connected to the pads of the sensor array and they transfer the analog voltage data to a data acquisition device (DAQ). The sensor was calibrated by comparing the EMF voltage at different temperatures to the standard thermocouple EMF voltage. With the developed micro-scale thermal sensor system, the temperature distribution of the wafer in the furnace chamber is obtained.

Design of Experiments: An Integral Part of a Thermal/Fluids Laboratory Course

Laboratory courses can be, and are often used to provide practical demonstrations of physical phenomena studied in various lecture courses. At Manhattan College, a senior-level Thermal-Fluids Laboratory incorporates a Design of Experiments (DoE) component into the syllabus, in which students learn about development of a text matrix, construction of an experiment to fulfill that matrix, and statistical analyses to confirm hypotheses. This paper describes the entire course syllabus, the portions of the course relevant to DoE, and some of the experiments conducted in recent years.

Creativity in Multi Objective Problem Solving

Problem solving is one of the main activities in achieving design and research goal. While problem solving in general is an activity aiming at transforming unacceptable state of reality to acceptable state of reality, problem solving in engineering is usually a means for tackling other activities such as design and research. By breaking down design and research into a set of engineering problem solving activities, the goals of complicated design and research projects can be achieved. For this reason, the transitions from design or research to problem solving in some cases are unidentifiable. The identification of the problem solving activity goals and the transition between the three activities, however, are essentials for creativity and achieving the desired objectives especially when dealing with conflicting objectives and constraints. In this paper, design, research, and problem solving are distinguished as realization activities performed in different reality domains with different beginning and ending states. These three activities use modeling and simulation as basic elements of mapping between realities to perform analysis and integration. While analysis and simulation are mainly the analytical actions, modeling and integration are mainly the creative actions. With these distinctions, the identification of problem solving activity goals, and transitions between activities, can be easily realized. Also, creativity and dealing with conflicting objectives can be greatly facilitated. To demonstrate these concepts and their implications some illustrative examples are discussed.