Welcome,

Click a picture or keep scrolling

Permobil

Off-Road Electric Wheelchair

A Study of the Vehicle-to-Ground Interface


The project was performed between January and July 2015 as part of the Master Degree in Industrial Design Engineering at Luleå University of Technology. This text is currently the abstract of the thesis report.

Everyone does not have the ability to walk or transport themselves by their own means at trails or rough terrain due to injuries or other kinds of disabilities. The project aims to investigate how a solution should be designed in order to suffice the needs of these kinds of users. In order to achieve the goals, a series of research questions were determined, one of which read: How does the vehicle-to-ground interface affect the traction of the vehicle and the comfort of the user?

The theoretical framework presents research findings necessary to reach the aim of this project and focuses on topics such as modularity, terrain types, off-road capability, vehicle dynamics and comfort. The overall development process in this project used a method called Pulse Model. The first stage of the project was market research with a primary focus on Permobil’s X850 model, which was put through several tests. The main problems found were that its lack of lateral stability, low ground clearance, and overall harsh and bumpy ride comfort.

The idea generation included both the use of LEGO® Technic bricks, the catalogue method and function prototypes, which resulted in a multitude of different suspension systems. A concept with front and rear trailing arms were chosen for further development and a full-scale prototype was fabricated and tested, which provided important feedback for the final concept.

The prototype enabled a set of key aspects that should be considered when designing an off-road wheelchair. These were a ground clearance of at least 200 mm, four wheel drive, 50/50 weight distribution, 360 degree rear wheel steering, a front pivot bar suspension system and active lateral stability system in the rear which makes it able to maintain a level seat while traversing side slopes.

In this project it was demonstrated that it is possible to design an off-road electric wheelchair which enables people with disabilities to move around more freely and independently in tough terrain. It is also possible achieve this on Permobil’s new modular chassis, which will reduce both manufacturing, stock and production costs for the products overall life cycle.

Media

The complete Master of Science thesis report can be downloaded here!

Permobil
CDV - 14

Compact Demonstration Vehicle 14

A radio controlled 1:6 scale model of the CV90 Armadillo

Background

BAE System Hägglunds AB is a world leading manufacturer and developer of military vehicles. Their tracked vehicles and tanks are delivered and sold to a variety of countries and they often participate in exhibitions and various demonstrations around the world.

Due to rules and regulations, manufacturers of armored vehicles find it increasingly difficult to ship their products to certain countries for participation in various sales exhibitions. As one can imagine, the logistics and efforts required when shipping a 30 ton vehicle halfway around the world is far from cheap. There are a lot of cost saving potential by drastically reducing the size and weight of exhibition models.

There are also various smaller exhibitions that physically restrain them from bringing a full sized vehicle, where a model of smaller size could come to use and improve their impression. The model should be easy to transport and easy to maintain and carry all necessary tools and spare parts with it to each location in the world as one complete and reliable demonstration platform.


Assignment

The most important part was that the model should imitate the original version both visually and dynamically. The model should also work as a platform for both new and current systems to demonstrate how they are used on full sized vehicles. It should be possible to add internal modular systems and an external turret to create a long-term solution that can be modified to each mission. To be a sustainable solution it have to be easy to maintain and repair.


Procedure

The idea of the project was presented to BAE Systems Hägglunds AB, whom liked the idea. Since there is a lot of secrecy, we were not given any blueprints or drawing of the vehicle. This meant we had to use other sources and publicly available photos to make the model as similar as possible to the original. The project involved an extensive product development process that started with stating the initial product specifications, going thru several design and mechanical problems, to end up with manufacturable solutions that we could build and turn in to a final working product. My teammate

Results

A radio controlled 1:6 scale replica of the CV90 Armadillo. The final product was delivered on a custom shipping pallet to make the transportation more convenient.

Media

An article in swedish was published at the university homepage.
More photos and info can be found on my teammate's homepage.
Appearance on the BAE systems Twitter.
New clothes in the SAAB press release on Adaptive camoflauge.

CDV - 14
TukTuk

Hybrid Autorickshaw

An electric Autorickshaw powered by a fuelcell

Background

In the vehicle industry there is an ever-increasing demand for more environmentally friendly solutions and products. The most interesting technology in this area is fuel cells, due to the increasing restriction of air pollution from traditional combustion engines. Auto rickshaws are a very common means of transportation in many countries around the world. In the Indian city of Mumbai alone, there are over 250,000 auto rickshaws in use today. They are cheap and versatile in crowded streets and cities, and are mostly used for public transportation. Therefore, there is a huge market for a more environmentally friendly auto rickshaw.


Assignment

The project focused on creating and testing a fuel cell driven hybrid concept vehicle aimed towards the Indian market. The fuel cell hybrid system was to be implemented in an existing auto rickshaw platform.


Procedure

Initially the project focused heavily on researching and simulating the different requirements that the platform would have to meet, both in terms of environmental aspects and vehicle usage.Afterwards, the project proceeded with an extensive concept development phase which saw us creating and evaluating all kinds of crazy concepts, which eventually resulted in one final concept that met the requirements. The chosen concept was then turned into a fully working product by, amongst other things, adopting it to the existing vehicle platform, making structural finite element calculations and bearing life calculations, and also creating a complete CAD model with accompanying manufacturing material. As the design became finalized, focus shifted towards preparing the electronics ahead of the manufacturing phase and also improving simulations. When components began to arrive, work started on manufacturing the design and implementing it in the vehicle’s platform. As the implementation was completed, the group began testing the vehicle to be able to compare and evaluate the actual results of the concept against the requirements that had been simulated and dictated at the beginning of the project.


Results

A fully working hybrid concept vehicle has been created, tested and delivered to Luleå University of Technology. The concept has also been constructed in such a way that it opens the door for future educational opportunities at the university.

Media

An article in swedish was published at the university homepage.

An article at NyTeknik.se.

The official facebook page han be found here.
More photos and info can be found on my teammate's homepage.

Permobil Permobil
Speaker

Loudspeaker design

Custom louspeakers and amplifiers for home or PA


One of my passions has always been music. During most of my youth it was playing, but now it’s more the technology surrounding it. During my first year at the university I built a PA system that ended up being a little over kill to keep in the apartment, so I started the fraternity LOL – Ljud och Ljus, (Sound and light), where I rented it out to dinners and events at the university. From the money we got we built even bigger speakers to be able to host even bigger events!

The top picture is of some hifi speakers I recently built for my living room. If you have a request for custom speakers for your home, garden or living room I will happily help you out. Just send me a message and I will assist you.

Speaker
about1

About Elias Löthman


This homepage contains a short summary of some of the projects I have been working on over the past years. I recently finished a MSc in Industrial Design Engineering at LTU, during which some of the projects were executed. I currently live in Luleå, which is small town in the north of Sweden, together with my wife Laura, who i met 8 years ago during my years in Mexico. Soon we've been married for two years! I am currently working as a self employed consultant and if you want to know more about my services, I will be happy to hear from you. I am no web designer so please don't let the design scare you. It's a work in progress and will hopefully be better next time you check in!

For updated information, check out my Linked in or download my CV.

about2