“ … a Tick Collection Robot Christopher Simmons Advisor: Prof. WilliamKeat, PhD Introduction / Background Ticks are small parasitic … ”
Abstract
The overarching goal of this research was to simultaneously design, manufacture, and test different mechanisms for robotic tick collection, along with designing and developing an electronics package and code that would allow the robot to behave in a semi-autonomous fashion. The tick collection mechanisms were designed with the intention of providing an optimal efficiency for physically collecting ticks, minimizing their impact on the overall maneuverability of the robot, being as cost effective as possible, and being as easy to replicate as possible. A total of seven different prototypes were developed and tested under real world conditions. Of these seven, four demonstrated very promising results regarding the functional requirements of the project. The electronics package and accompanying code are being developed with the intention of allowing the robot to autonomously navigate environments which would make manual control difficult, such as dense shrubbery that would impair a direct line of sight.
The goal of this Senior Project was to design and optimize a gearbox for the 2019-2020 Union College Baja SAE Vehicle. Baja SAE is a competition put on by the Society of Automotive Engineers (SAE) in which college students from all around the world design, build, and compete one seat off-road vehicles against each other. I have previously designed a gearbox for the 2018-2019 Union College car but did not have the ability or resources to fully optimize and analyze all aspects. Though the 2018-2019 was the fastest car in Union Baja SAE history, the team felt like it lacked low end torque.To mitigate this problem, a deeper analysis of the gearbox and drivetrain, as well as the car as a whole, was undertaken. The resulting design optimized gear ratio, minimized the weight of the gearbox and employed advanced manufacturing methods to produce the custom low weight gears.
Water contamination increasingly threatens the most vulnerable populations and ecosystems. Small streams, and the Hans Groot Kill (Schenectady, NY) in particular, have been shown to contribute significantly to the pollution of larger bodies of water and present health and safety risks to the communities in which they are situated. This presentation describes the conception, construction, and evaluation of a design for a system to collect pollutants and debris from water flowing through a large pipe and store them for later, proper disposal. An installation site was selected after examining the section of the Hans Groot Kill that is exposed at the surface. The surface velocity and volumetric flow rates were then estimated seasonally at this location. Design requirements and constraints were identified and five alternative solutions were generated. Evaluation of these solutions identified the optimal design to be a passive system that functions by diverting the majority of the flow into a storage bin, where it passes through filtration fabric. The design makes use of several pre-existing stormwater filtration products. Its plywood frame was sized to fit the lower portion of the culvert at the selected site such that all the water passing through the pipe is forced through the system. The solution also employs distance sensors, an Arduino microcontroller, and a small water turbine to alert the user when maintenance is required. This design process and evaluation suggest that a system of this nature is a promising solution to the issue of pollution in small bodies of water carried through culverts.
“ … Origami-inspired Furniture Jiaer Xu Advisor: Professor William Keat Introduction As more and more people are living … Structures 23.9 (2014): 094001. Acknowledgements Professor Keat, Professor Buccinell, Cole Belmont, Professor Dunkin, … ”
Abstract
Origami (from Japanese oru, to fold and kami, paper), is the ancient art of paper folding. Traditional origami usually involves only straight folds on a (square) planar piece of paper without tearing, cutting or gluing. Once folded, the origami constitutes a developable surface that can be unfolded as a flat plane. Though the traditional purpose of origami is rather recreational and artistic, with suitable origami geometry, engineers are able to create self-folding structures. Many origami design principals are applied in space systems, robotics, and small-scale devices that are self-assembling. Because of its ability to compactly store deployable structures, origami has proven to be a good design strategy for transformable furniture. Therefore, the objective of this senior project is to develop a systematic methodology for designing transformable furniture using origami structure. To accomplish this goal, I designed and manufactured a transformable origami structure that can be stored as a flat piece but folds into a chair.
“ … drawings. Last but not least, Professor William Keat helped keep the project on course and provided … ”
Abstract
Constant velocity (CV) joints have a long history of development. They are designed to transmit angular velocity from one axle shaft to another when they are not collinear. The Union College Baja racing team decided to use CV joint axles as outboard drive shafts (half shafts), which deliver the power from the engine to the wheels, in the 2023 car. Due to the geometries of the joints' components, they are difficult to manufacture without specialized equipment. Therefore an axle assembly was ordered. However, it was very difficult to find a CV axle to purchase and without a car it is near impossible to test. Dynamic analysis is a useful tool which could be used to study potential selections and whether they would fail.
A set of portal gearboxes were designed for the Society of Automotive Engineers (S.A.E.)
Baja challenge, an international collegiate competition where students design, build and compete
in a series of off-road racing challenges. The introduction of the new mandatory four-wheel drive
rule has prompted an influx of research and development into different four-wheel-drive designs.
Portal gearboxes were designed to serve as the main final drive reduction for the 2022-2023 car.
A portal gearbox is a gear set located within the profile of each wheel that increases the height of
the driveshaft input location. This portal gearbox design increases the effective ground clearance
by 3.2 in, improves steering geometry, and houses a set of sprag clutch bearings. Sprag clutch
bearings allow for free rotation in one direction and can transmit torque in the other. The sprag
bearings were utilized in the design to create a mechanically biased all-wheel-drive (AWD)
system. They also greatly decrease the rolling resistance of the drivetrain system when coasting.
The portal gearboxes feature a 3:1 reduction to supply a peak torque of 433 ft-lbs to the wheel.
The gearboxes were designed to fit within a standard 10 in x 5 in aluminum wheel, allowing for
no compromise in tire selection or off-road performance. The main challenges of the design were
the rigorous loadings seen at the wheel, the slim profile required, the manufacturability, and the
integration with multiple other components like braking and suspension. The portal gearboxes
were implemented on the 2022-2023 Union College Baja car and competed in SAE Oshkosh Baja
event in Wisconsin on May 4th
-7
th
“ … the solenoid valves to the Arduino relay board, Professor William Keat and his student Frank Chu for designing and … between each stick should be different. We asked Professor William Keat and his student Frank Chu to design and … ”
Abstract
Completely soft robots are emerging as attractive systems in the field of soft robotics. Unlike conventional robots, soft robots are far more flexible and can easily adapt to their environments. Because they have these properties, their behaviors are difficult to study and control. We first design and build robots made out of silicone rubber. We then actuate them in order to observe how their morphologies affect their behaviors, tracking their movements with Qualisys Motion Capture cameras. This process allows<br />us to gather their tracking data. We then run the data against a Quality Diversity Algorithm that can autonomously generate a behavioral repertoire of diverse and efficient behaviors so that our robots can be efficient and autonomous.
“ … work as well: Professor Bradford Bruno, Ph.D., Professor WilliamKeat, Ph.D., and Professor Ashok Ramasubramanian, Ph … ”
Abstract
A highly efficient airframe was designed in preparation for the 2014 SAE Aero East Design Challenge. The competition is scheduled to take place in Marietta, GA from the 11th to the 13th of April. The aerodynamic outline of the airplane was generated through extensive fluid mechanics analysis and review of established winning strategies. To construct the aerodynamic forms, load analyses were performed on the wing, fuselage, tail boom, and tail. Using the results of these studies, the best combination of wooden and aluminum components was established. All parts of the airplane were refined numerous times to arrive at the most efficient airframe, in terms of strength, weight, machinability, and cost. This year’s Union College Aero team was the first one to build and test a fully functional prototype between the first and second academic terms of the year. The final design will attempt to outperform all other 75 teams that are going to enter the competition.
“ … and Production of the RowBoard George Kershaw Advisor: William Keat … ”
Abstract
The ergometer is a stationary rowing machine that is used to simulate the motions of watercraft rowing. It can be used for the technical improvement of one's strokes, or simply for exercise. This can be a great convenience because it allows the user to row indoors—making it a useful substitute for practice when the weather is not row-permitting. The disadvantage of ergometers is that their prolonged use can lead to great boredom, much like the long term effects of using treadmills and stationary bicycles. In recent years there have been various attempts at redesigning ergometers with the goal of making them more fun to use. The leading solution has been to give the erg wheels and implement a drivetrain, so that the erg works similar to a bicycle, while still being powered by the original rowing motion of the rider. This design has sprung up in 6 or 7 places worldwide, while two designs have moved to the mass production stage. These products are very different from each other, but neither really grasps the rowing motion to its fullest. They also cost upwards of $1,000. The purpose of my project is to design and build a “rowing vehicle” to be used on land that is easily operated, yet still mimics the correct rowing motions found in the use of a racing shell.
“ … Submitted March 19, 2009 Patrick J. Lingane Senior Thesis William D. Keat, Advisor Department of Mechanical Engineering Union … ”
Abstract
The goal this project was to create a scaled model of a flapping wing aerial vehicle.
The design was initially based on a remote controlled model available at many toy stores.
This model was in the form of a dragonfly but about four times the size in each
dimension. My project was to scale this down, ideally to the size of a real dragonfly. This
however was difficult, and a half scaled prototype (twice life size) was constructed
instead. Scaling was done using dimensionless fluid parameters such as the Reynolds and
Strouhal numbers which effectively related the various properties of each model. Testing
and modification of the prototype were carried out, and in the process an analytical model
was made to model the dynamics. Although still not flying, the prototype will hopefully
soon be ready for testing against the theory. In the future, more testing will be completed,
and minor modifications made to get the scaled prototype flying. All of this is part of a
larger goal to miniaturize a flapping flying robot of which this project is only a part.
“ … i ABSTRACT ADVISOR: William Keat Aerogels are solid, porous and light materials … to be … . Union College. 15 July. 2012. [8] Xie Lutao and William D. Keat “ Characterization of Microstructure from … New York: McGraw-Hill, 2010. Print. [16] Courtesy of Prof. Keat William . … ”
Abstract
Aerogels are solid, porous and light materials that are 90-99% air by volume, with particularly small pore sizes and large specific surface areas. According to previous studies, silica aerogels have appeared to be typical fractal materials. Its microstructure can be described as a fractal network in the length scale 10-1000Å, which is considered to be the result of an aggregation mechanism. To model the behavior of this material, a non-linear finite element code was developed to determine the sequence in which elements fail under compressive load for different starting pore distributions. The 2D geometry of the brittle silica lattice was represented by a single strand of bar elements interconnected by transverse beam elements. As pores collapsed, broken elements were replaced by non-linear contact springs to efficiently model fragmentation of the lattice. Results agreed with the expectation.
“ … of Mechanical Engineering, June 2023 ADVISOR: Dr. William Keat This thesis will discuss the process of … ”
Abstract
This thesis will discuss the process of designing, manufacturing, and testing of a two-wheeled, front-wheel drive, adjustable recumbent bicycle. The design aims to create a more accessible, comfortable, efficient, and utilitarian bicycle. The design utilizes a two-wheeled, front-wheel drive system, and is adjustable for riders of different heights. The two-wheeled design was chosen for its simplicity, cost-effectiveness, and accessibility. The front-wheel drive system that this bicycle utilizes was chosen over a more traditional rear-wheel drive because it significantly reduced the length of the chain. The increased chain length from rear-wheel drive models is the primary cause of large frictional losses in the power transmission. Furthermore, the bicycle was designed with current road bike standards in mind, as wheel spacings, chain length, and gearing are all cross-compatible with upright bicycles. The frame is TIG welded and made from 4130 chromoly steel tubing. Steel was chosen for its high strength, manufacturability, and low cost. Testing was done on varied grades against a traditional drop-bar road bike, and the recumbent bike was ~30% faster than the road bike on flat to downhill terrain but lagged behind on steep uphills.
“ … Design of a Robotic Cownose Ray Mark Marzotto, Professor William Keat Ph.D. Union College, Mechanical Engineering … ”
Abstract
Nature often inspires advances in science and technology and a promising example of this is mimicking locomotion of underwater animals. The main ways in which manmade aquatic vehicles propel themselves are water jets and propellers, which are inconsistent with how underwater animals swim. The cownose ray displays very efficient thrust with low frequency strokes by using a combination of oscillations and undulations with its pectoral fins. The goal of this paper is to mechanically replicate the actual fin motion of the cownose ray in order to capture these attractive features. The design will account for both the oscillations by designing a cabling mechanism that simulates muscle and the undulations by using a flexible shaft to control the twist present in the fin. Integrating these two mechanisms will achieve an accurate model of the true motion.
“ … contributed to the completion of this project: • Professor WilliamKeat, Professor, Department of Mechanical Engineering • … ”
Abstract
The overall goal of this research project is to fully design, manufacture, and test a robot for tick collection. The robot will be designed to collect ticks in regions with thickly branched vegetation, specifically including shrubs, trees, and leaf liter. The robot will be useful to biologists who collect ticks for research or disease control purposes, because it will reach areas that are inaccessible to human-powered collection methods and thus provide them with a more accurate estimate of the tick density in a given region. Obtaining a more precise tick density is crucial, because it provides more detailed information about certain regions and the likelihood of encountering a tick species that transmits a harmful disease. The robot design incorporates several features that will enable it to succeed in tick collection. The small compact size of the robot will allow the robot to maneuver in between obstacles such as branches and trees in the environment. The primary method of collection that will be implemented is dragging. The environment that the robot is designed to navigate is the Albany Pine Bush, which contains an uneven terrain mainly consisting of dirt, shrubs, and leaf liter, and the robot chassis is designed for this environment.
“ … 43(7):859–881, 2008. [17] Mark Khazanov, Ben Humphreys, William D Keat, and John Rieffel. Exploiting dynamical complexity in a … ”
Abstract
Soft robotics is an emerging field of research due to its potential to explore and operate in unstructured, rugged, and dynamic environments. However, the properties that make soft robots compelling also make them difficult to robustly control. Here at Union, we developed the world's first wireless soft tensegrity robot. The goal of my thesis is to explore effective and efficient methods to explore the diverse behavior our tensegrity robot. We will achieve that by applying state-of-art machine learning technique and a novelty search algorithm.
“ … Becker, Stan Gorski, and Professor William Keat . Rhonda was extremely helpful in ordering all … of … quite stuck. I would also like to thank Professor Keat, who assisted me with setting up the load test analysis, … ”
Abstract
Each year, the American Society of Mechanical Engineers (ASME) sponsors the Human Powered Vehicle Challenge. The purpose of the competition is to provide a continued source of research into human powered vehicles. Generally, the vehicles for this competition consist of faired recumbent tricycles and bicycles, capable of reaching high speeds in an efficient manner.
The subject of this report is the design and analysis of a new vehicle frame for Union's 2014 competition entry. The frame is the structural skeleton of the vehicle, supporting the rider and all vehicle components. The frame is what withstands the majority of the loads applied to the vehicle during riding, and needs to be able to distribute them safely around the vehicle without failure. In addition, the frame is meant to act as a safety device. The frame is required to include a roll protection system (RPS), which prevents any injury to the rider during a rollover scenario.
Growing up in Maine, the trucking industry is an ever-present part of life. With a very sparse, lightly used rail system, almost all of the raw materials and goods that enter and leave the state do so by truck. Truckers in Maine are constantly challenged by Maine's roads, which can often be difficult or even treacherous to navigate. The rough logging roads near Jackman or Millinocket, or the sharp ninety degree turns near the Portland oil docks, can ruin a trucker's day, or even worse, cause an accident. For example, there is a tiny four-way intersection on Broadway in South Portland, where full-length oil semi-trucks have to turn ninety degrees as they leave the massive oil storage tanks at the docks. Broadway is a very busy road; as soon as the trucks get the signal to turn, there are lines of cars stopped at the light. The trucks have to turn wide, right into the stopped line of cars. This means the cars then have to coordinate and back up to allow the truck to turn. After much confusion and after the light has turned green, then red, then green again about ten times with the trailer completely cutting off the intersection, the truck can move on. The same thing happens along the backroads of Millinocket. When trucks come off the logging roads they usually have to turn ninety degrees onto the main road. This is tricky to do at best, and dangerous at worst. The roads usually aren't wide enough for the truck to turn onto them without going over the other side. If the logging companies don't build pulloffs on the side of the road for the trucks to run through, then eventually a trucker is going to try to turn on to the main road and end up in the ditch on the other side, with the trailer completely blocking the way until the truck can be moved.
“ … Khazanov, Ben Humphreys, WilliamKeat, and John Rieffel. Exploiting dy- namical … ”
Abstract
Creating e?ective designs for soft robots is extremely di?cult due to the large number of di?erent possibilities for shape, material properties, and movement mechanisms. Due to the lack of methods to design soft robots, previous research has used evolutionary algorithms to tackle this problem of overwhelming options. A popular technique is to use generative encodings to create designs using evolutionary algorithms because of their modularity and ability to induce large scale coordinated change. The main drawback of generative encodings is that it is di?cult to know where along the ontogenic trajectory resides the phenotype with the highest ?tness. The two main approaches for addressing this issue are static and scaled developmental timings. In order to compare the e?ectiveness of each of these two approaches, I have implemented a framework capable of evolving soft robot designs that utilize vibration as a movement mechanism.
“ … 41 Acknowledgements I would like to thank Professor William Keat for advising me throughout the course of this … Mechanical Engineering Senior Thesis 2023 Professor William Keat i … provided in the google drive link that … ”
Abstract
A hybrid loop, dual axis solar tracking system was developed to increase the efficiency of a stationary solar panel by continuously tracking the highest solar radiation point of the sun. The design features two systems that work to find and track the sun vector, the independent sensing unit and main panel unit. The first detects the optimal point of the sun without expending energy moving the large solar panel. The sensing unit consists of 3D printed ASA plastic parts designed to hold and move single photovoltaic cells, ultraviolet sensors, and light dependent resistors. Once the sensing unit has accurately tracked the sun the optimal point is translated to the second unit for energy collection. The second unit, or main panel system, is made of 3003 Aluminum with 1045 steel shafts that control the movement. It collects solar energy using a 50W mono-crystalline photovoltaic panel and stores it in a 12V lithium polymer battery for self-sustaining operation. The motion is achieved using four Pololu gearbox motors for the elevation and azimuth control of both the sensor and main panel units. Worm gears are utilized on all four shafts to achieve a self-locking structure that can sustain winds up to 60 MPH. An Arduino Mega 2560 microcontroller implements a controller algorithm for accurate positional feedback and motion. The proposed system will begin data collection in the spring to determine the energy gain compared to a stationary panel. A 20% increase in energy collection is the expected minimum value that will result from the use of the independent sensing unit paired with the main panel system.
“ … and guidance of this research exploration: Professor WilliamKeat, Paul Tompkins, Robert … ”
Abstract
The steering system within a vehicle is a vital aspect of operation and performance. The Baja society of automotive engineering (SAE) challenges students to design and manufacture an off-road vehicle to compete in a series of racing challenges. The team of engineers works together to discover challenges in design, manufacturing, and business. The steering system for the Union College Baja Team 2023 vehicle is designed as a rack and pinion mechanism, fulfilling the team designated requirement of 1.5 inches of travel per side. The mechanism has a link-to-link distance of 17 inches, and a steering wheel rotation of 172 degrees to account for the length of travel. The system consists of a round gear rack, a 16 teeth metal gear, high load ball bearing, ultra-low friction oil embedded sleeve bearings, a press-fit drill bushing, and inline ball joint linkages. One of the focus points of the steering system was the durability of the middle housing, where failure has occurred in previous years. Using a static load of 3g (2100 lbf) the housing portion of the steering system achieved a factor of safety of 7.2 discovered using finite element analysis, while the key receiving a shear stress applied by the torque of the wheel achieved a factor of safety of 1.5. The manufacturing techniques for this system include CNC machining, water jet techniques, and various assembly and fitting methods. A bearing and support system was put in place to emphasize the stability of the system. On May 4-7, 2023, the vehicle competed at the annual competition in Oshkosh, Wisconsin, with a final overall score of 208.41.
“ … Advisors: Professor Ashok Ramasubramanian, Ph.D. Professor William D. Keat, Ph.D. Machinists: Paul Tompkins Faculty/Staff: Bradford … and uphill climbing situations. With the help of Professor Keat, the calculations showed that the … ”
Abstract
The Union College Human Powered Vehicle Team has designed, built and tested Chester's Chariot for the 2014 American Society of Mechanical Engineers Human Powered Vehicle Challenge. The goal of this year's team was produce an efficient, sustainable, and practical human powered vehicle with a high degree of safety. The team conducted gear ratio analysis, beam bending analysis, aerodynamic analysis using computational and analytical methods. In addition, physical testing was completed to demonstrate the safety and performance of Chester's Chariot.
Chester's Chariot has the capability of obtaining higher speeds due to an optimized gear set. Last year's vehicle did not have enough high gears and were not able to reach their desired speeds. This year's vehicle drivetrain is consisted of a 2 chainring crankset of 39 and 53 teeth, and a 9 speed 11-34 teeth cassette. The gears were chosen through optimization and performance testing. The maximum calculated velocity is 35 mph whereas the previous team's was 26 mph. In addition, two disc brakes are used on each side of the vehicle instead of single caliper brake at the rear wheel. The steering component of the vehicle is comprised of a single tie rod that connects the two front wheels and was designed using the Ackermann Steering Geometry. With these changes, Chester's Chariot is capable of making tighter turns, obtaining higher speeds while still maintaining low speeds for uphill climbs and a more reliable braking system.
“ … Department of Mechanical Engineering, June 2013. ADVISOR: William Keat The purpose of this project was to design, … ”
Abstract
The purpose of this project was to design, fabricate, and test a maneuverable rolling robot. Although some other rolling robots were researched for this project, a novel approach was taken to design a unique, cheap robot that could turn and was fully enclosed by a rotating outer shell. The design and research phase of this project included the evaluation of several designs, the development of a mathematical model detailing forward motion of the robot, and the derivation of several design equations. Of the possible designs, an interior counterweight was chosen to provide a torque to the outside shell and move the robot forward, while a shifting internal mass was chosen to bank the robot either to the left or the right. The counterweight system applies a torque to the outer shell, and remains stationary during constant speed operation. To turn, a mass shifts to either the right or left side of the robot, changing the center of mass and causing the robot to enter a bank. Two preliminary prototypes were constructed as a feasibility check. One prototype tested forward motion, while the other tested banking. A final, fully functional prototype was fabricated and tested. It was found that the robot satisfied all goals of the project, and could move forward with a top speed of ~6 mph, as well as turn to either the left or right.
“ … Department of Mechanical Engineering, June 2014. ADVISOR: William Keat Many elderly people and injured people suffer … ”
Abstract
Many elderly people and injured people suffer from physical complications that make it difficult or dangerous for them to perform everyday activities, thereby inhibiting their mobility. Some of these activities include walking, standing, and sitting. As a result, it is no surprise that many companies in the medical industry have already attempted to construct an array of options to aid these people, including basic medical walkers, and standing-assist furniture, poles, and machines. Although these options are fair choices, they fail to integrate portability, simplicity, and multi-functionality together. Therefore, this thesis focuses on designing and building a dual purpose machine that can function as a portable medical walker as well as a standing and sitting aid. The purpose of this is to increase the mobility of independent and resilient people who struggle to move around on their own.
A thorough investigation was conducted to determine the natural motion of a person going from the seated to standing position and vice versa. From that analysis, it was determined that both the standing and sitting motions were identical, and that the upper body of a person naturally arced in a manner consistent with a circle. Using the data acquired from this analysis, the natural upper body motion was replicated by designing a crutch mechanism/linkage. Then, a walker frame was modeled around the crutch mechanism. Once the final detailed design was in place, a prototype was constructed and its range of capabilities was examined.
“ … Department of Mechanical Engineering, June 2011 ADVISOR: William Keat Ph.D. There are a variety of fit systems … been possible without the help of my advisor, Professor Keat, and the technical assistance of … ”
Abstract
There are a variety of fit systems available in the outdoor footwear industry. Each of these fit systems tightens the shoe around the wearer's foot in a different way. In this project an apparatus was developed to quantify perpendicular forces between the foot and a shoe. This apparatus utilized piezoresistive sensors that, when combined with an excitation voltage and an inverting operational amplifier, pass a voltage that is proportional to the force applied to the sensing area. A significant section of this project was dedicated to troubleshoot this apparatus in order to produce nearly linear calibration curves.
The apparatus was then used to collect data on the force distribution between four shoes featuring unique fit systems. The shoes were a North Face Ultra 104 GTX XCR laced in a wide set of eyelets, a Treksta Sidewinder, a North Face Ultra 104 GTX XCR laced in a narrow set of eyelets, and a Merrell light hiking shoe. Nine sets of data were collected with these shoes in four conditions: the foot outside of the shoe, the foot inside the shoe with the fit system fully loosened, the foot inside the shoe with the laces tightened only by the loose ends, and finally the foot inside the shoe with the fit system fully tightened.
The data collected was then analyzed to draw conclusions on the effects each fit system had on the force distribution between the foot and the shoe. Specifically, it was found that the North Face shoe laced in the narrow set of eyelets provided the most uniform distribution of force between the foot and the shoe when fully tightened. The data also verified the performance of the low friction eyelets and lace featured on the Treksta. The fit system on the Treksta directly incorporates the heel of the shoe, but this was found to have no effect on the pressure distribution on the heel of the foot. The data also demonstrated that the fit system of the Merrell focuses the force on applied to the foot on the tongue area.
