Optimal Collision-Free Path Planning for an Autonomous Multi-Wheeled Combat Vehicle

This paper presents an optimal collision-free path planning algorithm of an autonomous multi-wheeled combat vehicle using optimal control theory and artificial potential field function (APF). The optimal path of the autonomous vehicle between a given starting and goal points is generated by an optimal path planning algorithm. The cost function of the path planning is solved together with vehicle dynamics equations to satisfy the vehicle dynamics constraints and the boundary conditions. For this purpose, a simplified four-axle bicycle model of the actual vehicle considering the vehicle body lateral and yaw dynamics while neglecting roll dynamics is used. The obstacle avoidance technique is mathematically modeled based on the proposed sigmoid function as the artificial potential field method. This potential function is assigned to each obstacle as a repulsive potential field. The inclusion of these potential fields results in a new APF which controls the steering angle of the autonomous vehicle to reach the goal point. A full nonlinear multi-wheeled combat vehicle model in TruckSim software is used for validation. This is done by importing the generated optimal path data from the introduced optimal path planning MATLAB algorithm and comparing lateral acceleration, yaw rate and curvature at different speeds (9 km/h, 28 km/h) for both simplified and TruckSim vehicle model. The simulation results show that the obtained optimal path for the autonomous multi-wheeled combat vehicle satisfies all vehicle dynamics constraints and successfully validated with TruckSim vehicle model.

Improvement of Harvesters for Tires by Means of Multi-Physics Simulation

The specific working conditions of piezoelectric harvesters for scooter tires are analyzed. Calculated and experimental results show that the excitation of the harvester can be considered a series of separated impulses. Harvester response to an ideal impulse is analyzed with a single-mode model. An optimal ratio between impulse duration and natural period of the harvester that maximizes harvester excitation is found. A numerical finite element (FE) model of a bimorph cantilever harvester is developed in COMSOL and validated by means of experimental tests. The validated FE model is used for showing that an actual harvester excited by road impulses generates a large voltage only if there is a specific relation between impulse duration and natural period of the harvester. Starting from the validated FE model, small harvesters suited to tires are developed and analyzed. Also these harvesters show the best performance for a specific range of impulse durations, which corresponds to the highest speeds of the speed range of the scooter (50–80 km/h) and to high levels of acceleration.

CAD Platform Independent Software for Automatic Grading of Technical Drawings

Spatial visualization is the ability of an individual to imagine an object mentally and understand its spatial orientation. There have been multiple works proving that spatial visualization skills can be improved with an appropriate training. Such training warrant a critical place in the undergraduate engineering curricula in many engineering schools as spatial skills are considered vital for students’ success in the technical and design fields [1–4]. Enhanced spatial skills help not only professionals in the engineering field but also everyone in the 21st century environment. Drawing sectional views requires mental manipulation and visual thinking. To enhance students spatial reasoning, one of the authors of this study, conducted a class in spatial visualization. The course-learning goal aimed at improving first-year engineering students’ spatial reasoning through instruction on freehand drawings of sectional view. During the semester, two teaching assistants had to grade more than 500 assignments that consisted of sectional views of mechanical objects. This was a tedious and a time consuming task. Motivated by this experience, this paper proposes a software aiming at automating grading of students’ sectional view drawings. The proposed software will also give live feedback to students while they are working on the drawings. This interactive tool aims to 1) improve the learning experience of first year students, with limited CAD knowledge, and 2) introduce a pedagogical tool that can enhance spatial visualization training.

A Case Study of the Effects of Design Project Length on Team Collaboration and Leadership in Senior Mechanical Engineering Projects

This paper describes exploratory research regarding leadership and communication within undergraduate engineering design teams. The case study was performed on student design projects of one and two semester duration to begin to assess the impact of project length on leadership and communication within the design teams. Data was collected using a survey that was given to the participants in three capstone design projects in Clemson University’s senior design course. The survey was administered within one month of course and project completion. While there were differences in the communication and leadership patterns between the teams, there were other possible influences beyond the project length such as team size and organization, organizational and geographic distribution, and the nature of the product. As a result, further research is proposed to study leadership and communication structures within undergraduate teams and multi-team systems (MTS).

An Investigation Into the Driving Factors of Creativity in Design for Additive Manufacturing

Additive manufacturing (AM) provides engineers with nearly unlimited design freedom, but how much do they take advantage of that freedom? The objective is to understand what factors influence a designer’s creativity and performance in Design for Additive Manufacturing (DFAM). Inspired by the popular Marshmallow Challenge, this exploratory study proposes a framework in which participants apply their DFAM skills in sketching, CAD modeling, 3D-Printing, and a part testing task. Risk attitudes are assessed through the Engineering Domain-Specific Risk-Taking (E-DOSPERT) scale, and prior experiences are captured by a self-report skills survey. Multiple regression analysis found that the average novelty of the participant’s ideas, engineering degree program, and risk seeking preference were statistically significant when predicting the performance of their ideas in AM. This study provides a common framework for AM educators to assess students’ understanding and creativity in DFAM, while also identifying student risk attitudes when conducting an engineering design task.

The Design Focused Engineering Outreach to a Middle School Using Arduino Projects

Most engineering outreach programs are a part of STEM outreach efforts and they often fail to bring engineering-specific interests. We present a unique engineering outreach effort with the focus on “engineering design” with the use of Arduino UNO board. Arduino UNO board was used to achieve the design oriented learning and bring creativity through various projects targeting 7–8th graders. In order to achieve the design oriented outreach goal, several strategies were employed. The program was called “Science Art’ to provide familiar concept of design and challenge them with technology. College engineering students directly mentored 7–8th graders in a small group setting to teach technical details. In addition, the efforts were sustained for an entire quarter. It successfully drew the participants in all diverse ethnic and gender groups. The use of Arduino board project allowed development of design concepts and promoted creativity to the middle school students. Student mentees’ feedback was very positive, showing almost perfect approval. At the same time, college mentors equally benefited from the experiences by increasing interpersonal skills and gaining technical confidence. In conclusion, the close mentorship and sustained effort provided a great way to implement the Arduino based program to a middle school and thus achieve the design oriented outreach goal. This approach can be widely used for other design oriented outreach program.

Optimization of Novel Corner Module for Urban Electric Vehicle

With urban populations on the rise, sustainable design of cities will be necessary to maintain reasonable quality of life for its inhabitants. Space to accommodate citizens in these densely populated cities will be in short supply and high demand. Strategic shifts in the transportation industry can alleviate the lack of space for residential and commercial facilities in densely populated areas. One opportunity to mitigate this growing problem is to reduce the size of personally owned, commuter vehicles. Smaller vehicles will reduce the storage space and increase the density of vehicles on roads. Another solution gaining traction in the automotive industry today are autonomous vehicles. Autonomous technology can allow cars to travels closer to one another without increasing the likelihood of a crash. Lastly, changing the market from personally owned vehicles to fleets owned by the company to be used as public transportation would reduce the traffic density. These changes to the automotive industry will facilitate a change in the layout and packaging of commercial vehicles to meet new objectives. This paper proposes a novel corner module design that meets the market’s needs for mass production of X-by-wire systems integrated into a compact space while maintaining current levels of vehicle stability, handling and ride comfort. The proposed corner module features an in-wheel motor with electronic steering and braking. To increase the handling of the vehicle, the corner module has active camber control and can be modified for active ride height adjustment. Furthermore, the simplicity and minimal quantity of the components makes the corner module design ready for mass production. The geometry of the purposed corner module was optimized using a genetic algorithm. The objectives were to target a wheel lateral displacement of 10 cm at the −15° of camber angle and to minimize the longitudinal displacement of the wheel in a steer range of −20° to 20° at 0° of camber angle. The optimization had three types of constraints: packaging space limits, component interference and cylinder size. The optimization successfully found a solution that met both objectives while remaining within the constraints. The workspace of the wheel was limited by the rear cylinder size and the fixed length of the linkage.

A Pressure Modulating Sensorized Soft Actuator Array for Pressure Ulcer Prevention

Pressure ulcers are a serious reoccurring complication among wheelchair users with impaired mobility and sensation. It is postulated that external mechanical loading, specifically on bony prominences, is a major contributing factor in pressure ulcer formation. Prevention strategies mainly center on reducing the magnitude and duration of external forces acting upon the body. Seat cushion technologies for reducing pressure ulcer prevalence often employ soft materials and customized cushion geometries. Air cell arrays used in time-based pressure modulation techniques are seen as a promising alternative; however, this approach could be further enhanced by adding real-time pressure profile mapping to enable automated pressure modulation customizable for each user’s condition. The work presented here describes the development of a prototype support surface and pressure modulation algorithm which can monitor interface pressure as well as automatically offload and redistribute concentrated pressure. This prototype is comprised of arrays of sensorized polymeric soft air cell actuators which are modulated by a pneumatic controller. Each actuator’s pressure can be changed independently which results in a change to the interface pressure allowing us to offload targeted regions and provide local adjustment for redistribution. The pressure mapping, redistribution, and offloading capabilities of the prototype are demonstrated using pressure modulation algorithms described here.

Temperature Rise Real-Time Measurement of Metro Tread Based on the Multi-Sensor Fusion and Online Compensation Method

To study the temperature rise of the metro wheel tread, the simulation is conducted, finding that the highest temperature emerges in the tread area during the braking process, up to 350 °C. The range of temperature measurement should include 0∼350 °C. The temperature rise of the tread surface and the temperature near the side of the wheel tread tend to be consistent after the braking. The temperature measurement on the side of the wheel can provide a reference for the tread temperature measurement. Then several kinds of temperature sensors used for testing the tread temp are introduced, the accuracy and influencing factors of the measurement of the tread surface temperature sensor was analyzed. For the temperature measurement of wheel tread, featuring bright surface emission, low and unstable emissivity, a real-time temperature test method with multi-sensor compensation and data fusion is proposed and a more realistic curve of the tread temperature is obtained. Taking the actual line pure-air brake condition as an example, the above method is used to measure the temperature of tread surface. The results show that the measurement accuracy of multi-sensor data compensation and fusion is better than that of using the single infrared thermometer method, up by 15%; The law of temperature rise is consistent with that of transient simulation. reflecting that this testing method can offer important references to the real-time measurement of tread temperature.

Influence of Altitude on the Performance of a Bicycle-Cyclist Set

There is a tradeoff between power delivery and aerodynamic drag force when cyclists ride at different altitudes. The result is particular to the characteristics of the bicycle as well as the aerobic fitness of the cyclist. This work proposes a methodology based on an integrated approach to the study of the influence of altitude on power output and aerodynamic drag over a particular bicycle-cyclist set. The methodology consists of an independent analysis for each of the effects, to conclude with an integration of results that allows estimating the overall effect of altitude on cycling performance. A case study for the application of the methodology was developed, and the obtained results apply for the specific bicycle-cyclist set under analysis. First, the relationship between power and time was analyzed for a male recreational cyclist based on all-out effort tests at two different altitudes: 237 meters and 2652 meters above sea level (m.a.s.l). Second, the effects of environmental conditions on air density and drag area coefficient due to altitude changes were analyzed based on Computational Fluid Dynamics (CFD) simulations. It was found that for the bicycle-cyclist set under study, the sustainable power output for 1-hour cycling was reduced 45W for the high-altitude condition as a consequence of the reduction in the maximum oxygen uptake capacity. In addition, the aerodynamic drag force is reduced in greater proportion due to the change in air density than due to the change in drag coefficient. Finally, the results of both effects were integrated to analyze the overall influence of altitude on cycling performance. It was found that for the analyzed case study, the aerodynamic advantage at higher altitude dominates over the disadvantage of reduction in power output: despite delivering 45W less, the subject can travel an additional distance of 900 meters during a one hour ride for the high-altitude condition compared to that in low altitude.