Result
The result of the codesign are 3 products which addresses different issues within the bigger problem of (de)coupling the handbike. For the problem of aligning the handbike a laser setup was created. For the problem of coupling the handbike an automated jack system was modelled. Lastly for the problem of decoupling an extended lever was created.
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Alignment – Laser Bracket
Prototype
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For a more in depth view of the laser bracket see: Conceptualisation – alignment.
The laser bracket is a solution to the first problem encountered by the case owner when coupling the handbike to the wheelchair. The connecting bar of the handbike needs to be pulled accurately onto a bracket that is mounted, out of view, underneath the wheelchair.
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With this prototype, the case owner can flick a switch mounted to the wheelchair to project two red laser lines onto the floor in front of them, that offer a visual aid when pulling the handbike towards the wheelchair. These lasers are projected from the prototype, mounted onto a horizontal bar underneath the wheelchair.
Testing
Testing the laser bracket consisted of verifying that the prototype technically functions as intended, and that it fits the desires of the case-owner. The whole protocol can be found here.
Conclusion
The laser bracket was successfully made, mounted and adjusted as intended and worked as expected. Besides this the case owner expressed his fondness of the lasers. Nonetheless the only way to truly measure the improvement of the alignment process with the lasers, as compared to the situation beforehand, would be to time the process several times with and without the lasers turned on. For this there was no time during the final testing session, meaning that no truly sound conclusion can be reached at this time.
Discussion
Although the laser bracket worked as expected, many recommendations can be made for further developing the product, both in terms of functionality and aesthetics. Another area of improvement would be testing, where the current circumstances prevented thorough testing, a continuation of the project could feature more in depth testing allowing for a product that is even more personalized for the case owner.
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Functionality:
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The laser lights could be a bit stronger, they were visible during the daytime as is, but may not be useful outside on a sunny day.
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The laser bracket should be made water and dirt resistant to allow the case owner to keep it mounted onto his wheelchair when driving outside.
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The diameter of the inside cylinder had purposely been designed with a tolerance to ensure that the bracket would fit over the tube during testing, in a more refined design, the inside of the bracket would perfectly fit the tube and may feature some rubber to further secure the fit.
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Wiring between the bracket and the switch should be improved, in the current model 4 wires run loosely between the bracket and the switch. These wires were designed slightly too long to ensure a fit, but in a more refined design the wires would be exactly the right length, bundled together and neatly mounted to the wheelchair.
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Wiring between the lasers and the electronics housing should be improved, in the current model 2 wires run from the lasers to the electronics housing. This was done to ensure access to the lasers at all times, but in a more refined prototype these wires should be internally routed through the bracket.
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The holes for the bolts used in the prototype did not match any available bolts in the designlab, so slightly smaller bolts had to be used. To further improve the secureness of the attachment, better fitting bolts should be sourced.
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The current design featured 4 separate parts (2 for the main body of the bracket, and 2 for the laser holders) this was done to be able to fit the separate parts on the UT printers, ideally the bracket would be made of 2 or less parts to improve strength.
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Aesthetics:
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The current design features a square shape that is designed with manufacturing in mind. When further developing the product, it can be recommended to redesign the shape in a more streamlined way.
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The picture is a 3d rendering of a suggestion how the aesthetics could be improved.
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Testing:
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The current prototype features 2 lasers mounted on the wheelchair as this was deemed the most suitable and feasible option considering the time and resources. When further developing the Idea, other laser layouts may be considered and tested (eg a laser attached to the handbike, and a laser attached to the wheelchair, where both lasers would need to overlap when aligning)
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When further developing the prototype, it would be highly recommended to source a wheelchair of the same make and model, to be able to test the fitment throughout the process. Since much of the development effort for this project was spent on ensuring maximum flexibility and adjustability of the prototype, so that it would fit on the one opportunity to test the fitment.
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Coupling – Static Ramp
Prototype:
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The ramp is a solution which is mainly to solve the problem of coupling the handbike, however because of its design it also addresses the alignment issue. With the ramp the wheelchair is tilted already and the final push the case owner needs to give requires less force. With this prototype the case owner can drive up the ramp, align the handbike and click it in place.
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Testing
Testing the ramp consisted of verifying that the prototype functions as intended, and that the coupling is indeed easier for the case owner. The whole protocol can be found here.
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Conclusion
The static ramp was made as a simplified prototype and worked as expected. There were some issues when testing, these will be touched upon in the discussion. The main focus when testing the ramp was to check if the coupling would go easier for the case owner, and from the testing it can be concluded that this is true.
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Discussion
When testing the prototype some alterations were made in the set up. To make sure it was safe and comfortable to test the ramp the handbike was help in place by the POCO and the ramp pieces by the group members. Based on this some recommendations could be made:
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The ramp is prone to slide over the floor which interrupts the coupling. Also, if it moves it needs to be moved back in the correct position which is not possible for the case owner to do by himself. So, in order to make sure that the ramp stays, a rubber base can be included to provide more grip.
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There was some difficulty with driving the handbike onto the ramp because the wheel kept slipping. To solve this either the wheel of the handbike or the ramp could be revised with a different material.
Coupling – Jack
Prototype
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The jack is a solution which tackles the problem of coupling the handbike to the wheelchair. The jack should provide the force needed to tilt the wheelchair and click in place. For the project the jack was worked out as a theoretical model due to time restrictions and complexity. Because the jack was not worked out as a working prototype it was not included in the testing.
However, there is a prototype made which lets the straight gear move up and down. This proves that the concept works and shows the working to others. This is a medium-fidelity prototype and can be used to develop a high-fidelity prototype to really test if it couples the hand bike to the wheelchair. This can be made by changing the used materials to stronger ones and by using a stronger motor. Also, attaching a button, one for moving the straight gear up, and one for moving the straight gear down, needs to be attached to make it workable for the case owner.
Decoupling – extended lever
Prototype
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The extended lever is a solution to make the decoupling of the handbike easier. The handbike is normally decoupled with an integrated lever however it required quite some force to do this. To make this easier an extended lever was created which fits over the existing lever and reduces the force needed by providing extra lever/ arm. The lever includes a personalized grip making the it more comfortable to hold it.
Testing
Testing the extended lever consisted of verifying that the prototype functions as intended, understand which dimension tube would be better, and that the decoupling is indeed easier for the case owner. The whole protocol can be found here.
Conclusion
The lever was successfully made, assembled and tested. The lever worked as expected and there were no hick-ups in the process of testing it. The lever made it easier for the case owner to decouple his handbike and the grip was comfortable for his hand. From this it can be concluded that the extended lever is a successful functioning product.
Discussion
Because the test setup was to check the different lengths of the lever recommendation can be made for the optimal length. In addition to this there were some small points which if tweaked would improve and finetune the product.
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The shorter length of the tube was optimal. As the longer tube had some deformation and kept hitting the computer of the handbike while decoupling.
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The diameter of some holes can be smaller or even removed. The holes were not needed for the lever to function and looked a bit odd.
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When using the extended lever the paint on the existing lever could get damaged. This can be fixed by including a rubber layer inside the extended lever.
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Reflection on Requirements
Based on the testing the requirements can be reflected on and checked if they are included in the current design:​​​
Overview Completion Requirements:
Requirement number
Completed?
Decoupling Aid
1.1
Not fully
The CO says that it feels that he needs less force to couple, and it also enables him to do it. However, the power measurement is not done and can give more clearance about this.
1.2
Yes
The CO removed the decoupler within 5 seconds, which is less then 10 seconds.
1.3
Yes
A system for the decoupling ad to be stored on the wheelchair was created.
1.4
Yes
The CO removed the decoupler himself.
1.5
Yes
The CO said holding the personalized grip was comfortable and this made the decoupling process overall quite comfortable.
2.1
Not considered
Not tested and not considered.
2.2
Yes
No battery is used, so it can be used more then 5 times without recharging, since it does not need to recharge.
2.3
Yes
The decoupler is fully manufactured with the tooling available from the UT.
2.4
Not fully
It has been removed and putted on around 10 times, this had no effect on the wheelchair. However, wear over time has not been tested.
3.1
Yes
During the testing no harm was done to the CO when using the decoupler.
3.2
Not considered
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3.3
Not fully
A working system for the holder was created, however it was not tested yet so there is no definite answer is this is to work or not.
4.1
Yes
The part which is mainly fragile for bending is fully made of metal. The handle is made for plastic to reduce weight and for comfort when holding.
4.2
The decoupling aid itself lies on the edge of having a sufficient difficulty level to meet the requirement for this set by the university. The handle is personalized and modelled with certain complexity. The tube is just a tube.
Not fully
4.3
Not looked at and not calculated, no conclusion can be made.
Not considered
4.4
Every part of the decoupler is accessible for maintenance. It also consists of 2 parts, when the bolt on top is removed the handle can be removed from the metal tube, which makes maintenance even easier.
Yes
5.1
5.2
A drop test has been conducted where the decoupler is dropped from 1.5 meters, here it did not break.
Not fully
Has not been tested with the CO, but a simulation has been made which shows that it would last more than 500 uses.
Yes
5.3
Has not been tested physically, but a simulation has been made which shows that it would last more than 100 uses without maintenance.
Not fully
Coupling Aid
1.1
Theoretically the only force the CO has to make is pressing a button, which is less force then coupling now.
Yes
1.2
The coupling aid stays on the handbike, which makes that it does not need to be removable and also probably is not doable within 1 minute, but this has not been tested.
No
1.3
When the CO was sitting in his wheelchair and the hand bike was attached, the coupling aid could been attached and not stand in the way because of his legs position.
Yes
1.4
The CO does not need to remove the coupling aid.
Yes
2.1
Not tested and not considered.
Not considered
2.2
The scale model can move up and down, which is the coupling method, more then 5 times when attached to a battery. However, this has not been tested with the real size model since this was not available.
Not fully
2.3
The coupling aid is fully manufactured with the tooling available from the UT.
Yes
2.4
It has been removed and putted on around 1 time, this had no effect on the wheelchair. However, wear over time has not been tested.
Not fully
3.1
During the testing no harm was done to the CO when using the coupling aid.
Yes
3.2
The scale model weights less then 7 kg, the weight of the actual real size model is estimated to stay under 7 kg, but this is not proven.
Not fully
3.3
The scale model was securely attached, however this has not been tested with the real size model.
Not fully
4.1
The scale model mainly consists of wood and plastic. The plan for the real size model is to make the outside of plastic and the gears on the inside of metal.
Not fully
4.2
The coupling aid does have a difficulty level that meets the requirements set by the university, taking into account the attachment, the gears and the motorized system.
Yes
4.3
Not looked at and not calculated, no conclusion can be made.
Not considered
4.4
The scale model does not have a opening to do maintenance, the plan for the real size model is to make such an opening.
Not fully
5.1
Has not been tested so no conclusions can be made.
Not considered
5.2
The scale model will brake when dropped from 1.5 meter (it even broke when dropped from 10 cm), for the real size model no conclusions can be made because of the use of other materials.
Not fully
5.3
Has not been tested so no conclusions can be made.
Not considered
Alignment
1.1
Yes
When tested with the CO, it first took on average 6 tries to align, now it took on average 3 times.
1.2
Yes
The alignment aid could stay on the wheelchair during normal use.
1.3
No
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The CO is not able to attach the alignment aid himself since it is attached at a place that is out of his reach.
2.1
Not considered
Not tested and not considered.
2.2
Yes
The alignment aid was put on and of more than 5 times and still worked.
2.3
Yes
The alignment aid is fully manufactured with the tooling available from the UT.
2.4
Not fully
It has been removed and putted on twice, this had no effect on the wheelchair. However, wear over time has not been tested.
3.1
Yes
During the testing no harm was done to the CO when using the alignment aid.
3.2
Not considered
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3.3
No
This model was not attached tightly enough so did not stay securely attached. An improved model should be attached tighter so it stays securely attached.
3.4
No
This model had the wires just lying around which made that they could been damaged quite easily. An improved model should not have this anymore.
4.1
Yes
Most parts of this model are 3d-printed and plastic, which also makes that it is quite light for its size.
4.2
Yes
The alignment aid does have a difficulty level that meets the requirements set by the university, taking into account the attachment to the wheelchair, the laser attachment and the alignment of the lasers.
4.3
Not considered
Not looked at and not calculated, no conclusion can be made.
4.4
Yes
This model consists of 4 parts and the lasers can also be removed if wanted, which makes it accessible for maintenance.
5.1
Not considered
Has not been tested so no conclusions can be made.
5.2
No
This model will break when dropped from 1.5 meter.
5.3
Not considered
Has not been tested so no conclusions can be made.
Design for the broader audience
The products created are not necessarily made for only the case owner. Some of the measurements are specific for the case owner but the working principle can be used for a broader audience.
Extended lever:
In the current design the extended lever includes some case owner specific features. However, if target to a broader audience these features can be quite easily adapted and optimized. For example, the existing grip is made based on the hand shape of the case owner, this grip can be redesigned to be comfortable for a bigger number of people. Apart from this, measurements like lever diameter, hole diameter, lever length can be adjusted based on use and target group. During the in person meeting the parents of the case owner shared that they are in contact with different groups of people who also experience the same problem. The extended lever is a clean, simple solution which can also address other people with similar problems.
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Static ramp:
From all the different products the static ramp is the most case owner specific product. Meaning that a lot of the different measurements are based on the case owner’s wheelchair and handbike. Because of this the ramp might not be very suitable for a bigger target group. The working mechanism of the ramp holds but right now is worked out to a simplistic extent. Remodelling this idea would certainly be possible however would need a lot of work.
Automated jack:
The automated jack is worked out as theoretical model. The working principle of the jack is also prototyped. The jack is a very good solution to the problem of coupling the handbike to the wheelchair. No force from the user is needed which makes this concept a concept which can still be useful over a period of time. With some minor changes in the specific measurements the jack can be targeted to other handbike users which also experience the problem of difficulty with coupling. As mentioned before the case owner is not the only one who faces this difficulty. One setback however is the complexity of the design. As the design involves electrical elements it will probably also be more expensive which makes it less accessible for everyone.
Laser alignment:
The laser alignment guide is also a design which can easily be implemented in similar situations. The distance between the lasers and the connection of the lasers with the wheelchair or handbike will vary per person but can be easily fixed. Apart from using lasers to align the handbike for the correct coupling set up, lasers can be used for other alignment instances.