Stroke is a chronic, lifelong illness, and full recovery requires continuous physical and cognitive rehabilitation. Such long-term rehabilitation is cost-prohibitive; however an approach to providing long-term therapy that has recently gained traction is the use of socially assistive agent (SAA) systems. These systems make use of non-contact communication devices and can be used to guide people through a variety of rehabilitative tasks. They have the potential supplement current rehabilitation practices by providing motivation during intense exercises, and can extend the reach of the therapist into remote and home settings. Though SAA systems have been used in a variety of rehabilitative and assistive contexts, there remain questions regarding the best design for such systems. Currently there is a lack of detail on what type of feedback optimizes user performance, and the role that the delivery medium (e.g., a human coach, a tablet, or a robot) plays in user performance. The purpose of this thesis is the design of a system to investigate the interaction between feedback and medium type when implemented for a novel motor task. The selected task is modeled on the shuffleboard game, with the delivery medium including a human coach and tablet and two types of augmented feedback. The designed system incorporates various hardware and software components. A vision system communicates with a laptop to record and analyze motor task data, with a program that also interfaces with a control circuit. The control circuit may transmit data through Bluetooth to a custom-built app on the tablet, which then provides augmented feedback with audio dialogue. Otherwise, the human coach is provided designed feedback from the laptop. An initial system evaluation was performed with this constructed system using pilot participants to validate the design. The initial system evaluation demonstrated the ability to improve participant performance; however, it also demonstrated a high level of task difficulty. Several changes may need to be incorporated to the system to ensure better learning for participants. This includes changes to the physical setup, as well as changes to the frequency of the augmented feedback. This thesis may be used as the foundation for future experimentation with different delivery media or types of augmented feedback to discover how to best optimize user performance for a novel motor task.

This thesis focuses on the comprehensive study of controlling a customized Active Magnetic Bearing (AMB) installed on Bently Nevada’s RK4 rotor kit in Cal Poly’s Vibrations and Rotordynamics Lab. The AMB was uniquely designed and manufactured by a Cal Poly senior project team to fit Bently’s rotor kit and the results of this research are distinctive to the custom system. To achieve practical functionality of the AMB system, we designed a controller a Virtual Instrument (VI) using the National Instrument software, LabVIEW. From the experimental study, we calibrated the programming to find unknown parameters of the AMB system and validated the design using a well-established industrial rotordyanmics software, Bentley Nevada System 1. The development of the control programming consists of theoretical analysis (MATLAB/ Simulink) and simulation validation (MSC ADAMS View). Both linear and non-linear models were implemented in MATLAB and Simulink to effectively tune a Proportional-Integral-Derivative (PID) control developed for various AMB models. To validate the theoretical results, we compared them to results from a co-simulation using MSC Adams VIEW, a multi-body dynamics simulation, and Simulink. From experimental trial and error at a shaft rotational speed of 2800 rpm, a 16% decrease in shaft orbit was achieved. These results demonstrate the practicality of the control program and custom AMB rotor kit that can be used for further research.

Concrete is a widely used product and is an important application throughout industry due to its inexpensive cost and wide range of applications. This work focuses on understanding the behavior of high strength concrete in high strain rate ballistic impact loading scenarios. A finite element analysis was created with the implementation of the Concrete Damage and Plasticity Model 2 (CDPM2) to represent the material behavior. The model’s parameters were calibrated to existing literature and the results were analyzed by a comparison of the impact velocity to residual velocity and a qualitative assessment of the impact crater. The model captured the impact dynamics of the contact between the projectile and the concrete target with defined fracture patterns. Impact velocity and target thickness indicated a relatively linear relationship with the final projectile velocity.

Brainstorming is a critical part of the engineering design process and can have a significant impact on the outcomes of the overall project. While research has studied the outcomes of brainstorming and the ideas that teams generate, the role that language and conversation play in these activities is still relatively underexplored. Observing the different ways people use specific types of discourse can reveal how conversations can affect brainstorming itself. To that end, this research aims to answer the following questions: 1) What are the different kinds of discursive moves that students make during engineering brainstorming activities? 2) What patterns or themes emerge among these discursive moves? We collected data by recording conversations that took place during team brainstorming activities with engineering students. These conversations were transcribed, and we used discourse analysis to code our data according to the speaker's intent. We combined quantitative and qualitative analysis to identify and explore correlation patterns within these conversations. Three prominent themes emerged from our analyses: Active Engagement, Group Rapport, and Exploring the Problem. These themes highlight the range of different conversational elements that work together to support effective brainstorming discussions. Engineers and engineering educators can be mindful of the way that they frame their brainstorming activities so that the team’s discourse encourages more active engagement, stronger group rapport, and deeper exploration of the problem at hand.

Master of Engineering (ME)

The goal of this thesis is to enable a robot to actively collaborate with a person to move an object in an efficient, smooth and robust manner. For a robot to actively assist a person it is key that the robot recognizes the actions or phases of a collaborative tasks. This requires the robot to have the ability to estimate a person’s movement intent. A hurdle in collaboratively moving an object is determining whether the partner is trying to rotate or translate the object (the rotation versus translation problem). In this thesis, Hidden Markov Models (HMM) are used to recognize human intent of rotation or translation in real-time. Based on this recognition, an appropriate impedance control mode is selected to assist the person. The approach is tested on a seven degree-of-freedom industrial robot, KUKA LBR iiwa 14 R820, working with a human partner during manipulation tasks. Results show the HMMs can estimate human intent with accuracy of 87.5% by using only haptic data recorded from the robot. Integrated with impedance control, the robot is able to collaborate smoothly and efficiently with a person during the manipulation tasks. The HMMs are compared with a switching function based approach that uses interaction force magnitudes to recognize rotation versus translation. The results show that HMMs can predict correctly when fast rotation or slow translation is desired, whereas the switching function based on force magnitudes performs poorly.

This research utilizes CFD to analyze blood flow through pathways representative of central shunts, commonly used as part of the Fontan procedure to treat cyanotic heart disease. In the first part of this research, a parametric study of steady, Newtonian blood flow through parabolic pathways was performed to demonstrate the effect that flow pathway curvature has on wall shear stress distribution and flow energy losses. In the second part, blood flow through two shunts obtained via biplane angiograms is simulated. Pressure boundary conditions were obtained via catheterization. Results showed that wall shear stresses were of sufficient magnitude to initiate platelet activation, a precursor for thrombus formation. Steady results utilizing time-averaged boundary conditions showed excellent agreement with the time-averaged results obtained from pulsatile simulations. For the points of interest in this research, namely wall shear stress distribution and flow energy loss, the Newtonian viscosity model was found to yield acceptable results.

This thesis is an investigation of the fabrication and assembly methodologies employed in the development of a proof-of-principle prototype electric guitar composed of laminated copolyester. The objective of the project was to develop the processes and procedures to create an optimized physical and visual bond between layers to minimize vibratory dissipation, thus maximizing sustain. A high speed CNC router, abrasive waterjet, laser engraver-cutter, as well as various manual fabrication and assembly methods were investigated in the construction of the guitar prototypes. The lamination processes explored include low-temperature, heat-assisted pressure bonding, solvent and chemical welding, and contact adhesives. The project concluded with the completion of a working guitar comprised of a laminated copolyester body and a traditional bolton wooden neck.

The application of Computer Simulation and Animation (CSA) in the instruction of engineering dynamics has shown a significant growth in the recent years. The two foremost methods to evaluate the effectiveness of CSA tools, including student feedback and surveys and measuring student change in performance, suggest that CSA modules improve student learning in engineering dynamics. However, neither method fully demonstrates the quality of students’ cognitive changes. This study examined the quality of effects of application of CSA modules on student learning and problem solving in particle dynamics. It also compared CSA modules with textbook-style problem-solving regarding the changes they cause in students’ cognitive process. A qualitative methodology was adopted to design and implement a study to explore the changes in participants’ learning and problem-solving behavior caused by using a CSA module. Collected data were coded and analyzed using the categories of cognitive process based on the Revised Bloom’s Taxonomy. An analysis of the results revealed that the most significant effects were observed in understanding, analyzing, and evaluating. The high frequency of “inference” behavior after working with modules indicated a significant increase in participants’ understanding activity after working with computer modules. Comparing behavior changes of computer-simulation group students with those who worked with a textbook-style example demonstrated that the CSA modules ignited more analytical behavior among students than did textbook-style examples. This study illustrated that improvement in learning due to the application of CSA is not limited to conceptual understanding; CSA modules enhance students’ skills in applying, organizing, and evaluating as well. The interactive characteristics of CSA play a major role in stimulating students’ analytical reasoning and critical thinking in engineering dynamics.

Myocardial infarction (i.e., a heart attack) is the most common heart disease in the United States. Mitral valve regurgitation, or the backflow of blood into the atrium from the left ventricle, is one of the complications associated with myocardial infarction. In this dissertation, a validated model of a sheep heart that has suffered myocardial infarction has been employed to study mitral valve regurgitation. The model was rebuilt with the knowledge of geometrical changes captured with MRI technique and is assigned with anisotropic, inhomogeneous, nearly incompressible and highly non-linear material properties. Patch augmentation was performed on its anterior leaflet, using a simplified approach, and its posterior leaflet, using a more realistic approach. In this finite element simulation, we virtually installed an elliptical patch within the central portion of the posterior leaflet. To the best of the author’s knowledge, this type of simulation has not been performed previously. In another simulation, the effect of patch within the anterior leaflet was simulated. The results from the two different surgical simulations show that patch implantation helps the free edges of the leaflets come close to one another, which leads to improved coaptation. Additionally, the changes in chordal force distributions are also reported. Finally, this study answers a few questions regarding mitral valve patch augmentation surgeries and emphasizes the importance of further investigations on the influence of patch positioning and material properties on key outcomes. The ultimate goal is to use the proposed techniques to assess human models that are patient-specific.