Development of an integrated staircase lift for home access

Abstract

Purpose

Stairways into buildings present a significant environmental barrier for those with mobility impairments, including older adults. A number of home access solutions that allow users to safely enter and exit the home exist, however these all have some limitations. The purpose of this work was to develop a novel, inclusive home access solution that integrates a staircase and a lift into one device.

Method

The development of an integrated staircase lift followed a structured protocol with stakeholders providing feedback at various stages in the design process, consistent with rehabilitation engineering design methods.

Results

A novel home access device was developed. The integrated staircase-lift has the following features: inclusivity, by a universal design that provides an option for either use of stairs or a lift; constant availability, with a lift platform always ready for use on either level; and potential aesthetic advantages when integrating the device into an existing home. The potential also exists for emergency descent during a power outage, and self-powered versions.

Conclusions

By engaging stakeholders in a user centred design process, insight on the limitations of existing home access solutions and specific feedback on our design guided development of a novel home access device.

Introduction

Stairways into buildings have been reported amongst the most challenging environmental barriers for users of wheeled mobility devices [1]. Further, older adults have identified stair climbing as the activity most requiring assistive devices [2]. The significance of this problem should not be underestimated. Reporting on findings from the National Health Interview Survey and the Census Bureau’s Survey of Income and Program Participation, Maisel et al. note that approximately 1.7 to 2.3 million people in the US use wheeled mobility devices and an additional 6.1 million individuals use other devices, such as canes, crutches, or walkers. Quoting statistics from the National Center for Health Statistics 2006, Maisel also notes that that in the US, 11.5 million persons aged 65 and older reported difficulty climbing ten steps without resting [3].

With estimates of home inaccessibility as high as 90% in the US [3], home access presents a significant barrier to people with mobility impairments and those wanting to age-in-place [4–7]. Traditional solutions to addressing home inaccessibility have typically involved either moving to alternate housing or modifying the home to remove accessibility barriers [3]. The complex challenges associated with a move and the failure of many to adequately modify their homes [8] have serious implications for people with mobility limitations. Inaccessible housing has been associated with premature institutionalization, increased care costs, deteriorating health and well-being, dislocated family relations, and recourse to higher dependency housing [3, 9–11].

Home access solutions (HAS) aim to address the architectural barrier that stairs present and allow users to safely enter and exit the home while maintaining as much independence as possible [8]. Existing HAS range from relatively inexpensive handrails and ramps to more costly elevators and lifts. Lifts can be categorized into three broad groups: 1) vertical platform lifts - designed to transport the user vertically between 2 or 3 floor levels; 2) inclined platform lifts (also referred to as a wheelchair platform lifts) - designed to transport the user between levels on an incline such as along a stairway; and 3) stair glides (also referred to as stair lifts, stair-chair lifts, and stair climbers) - designed to transport a seated user between floor levels while traveling on an incline such as along a stairway [12]. It is apparent that innovation in HAS over recent years is limited; the changing demographics have done little to spur innovation in this area, and these ‘traditional’ HAS that have been used for many years continue to dominate the market. While a few new solutions have been developed in recent years [13–15], the uptake of these solutions is limited to specific niche applications.

Studies looking at the benefits and limitations of ‘traditional’ HAS point to several drawbacks with these solutions. While ramps typically offer a lower cost access solution, their large foot print and impact on home aesthetics limits the locations in which they can be used and reduces their desirability for many [16, 17]. Safety concerns such as the grade of the ramp, challenges negotiating tight ramp corners, and the effects of weather on ramp slipperiness have also been reported[17–19]. Elevators have been identified as effective solutions in terms of speed, capacity, rise and usability, however the need for adequate space, and the high costs associated with their purchase, installation, and maintenance are significant drawbacks, thus limiting their use in typical home settings [12]. Platform lifts and stair glides remain the ‘devices of choice’ for small elevation changes [12] in existing homes however these also have their limitations. For platform lifts, limitations relating to use, size, speed, capacity, and rise have been identified [12]. For stair glides, the need to transfer on and off the chair (often at the top of the stairs- one of the most dangerous places in a house) poses risks for those with transfer, balance or visual limitations [20], and the fact that they do not provide access for wheeled mobility devices limits their usability for many [12]. In addition, anecdotally, stair glides do not provide quality access, marginalizing individual dignity with their slow cumbersome use.

Two other significant drawbacks inherent with existing HAS are their lack of inclusivity and the fact that they appear to many as obvious symbols of disability. These have been reported to negatively impact the self-identity of residents and their relationship with neighbours, as well as make residents feel less secure, even vulnerable[21, 22]. It has been suggested that these factors may compromise the functionality and expected benefits of HAS [21].

This work aimed to address some of the drawbacks of existing HAS through the development of a new solution- the ARISE integrated staircase lift. This novel design aims to: address inclusivity by providing a staircase and lift in the same access location and footprint; encourage stair use whenever possible (e.g. by seniors for exercise), as well as offer the safety and convenience of a lift when necessary (e.g. when the person is encumbered or using a wheelchair); and provide repeatable emergency descent from a house in times of power outages. The device allows for use of stairs or the lift to access the same entrance whether walking, using a wheelchair, using a walker or pushing a stroller.

Methodology

Design

The development of the ARISE was based on a structured, user-driven design process that involved obtaining feedback from stakeholders during the design cycle, and using these results to inform subsequent stages of development. The design and development of the ARISE was done under the structure of the International Organization for Standardization (ISO) 9001Quality Management System (QS), in the context of rehabilitation engineering design that includes user feedback at various stages. The QS provides a systematic framework for product development and evaluation that includes the development of design requirements, a risk management process (including hazard analysis), as well as verification and validation (ensuring design requirements are met and system fulfills intended purpose).

A schematic of the iterative process used for this project is presented in Figure 1. The first stage of the design process involved developing preliminary design requirements and creating a Phase I (‘proof of concept’) prototype to demonstrate the basic functionality of the ARISE design. Next, stakeholder perspectives were explored through a series of interviews with occupational therapists (OTs) and two focus groups with end users. (Note- As the ARISE development was still in the early concept stage, OTs (rather than end users) were first interviewed to provide a broad perspective of home access needs of a number of disability groups and to help narrow potential end user groups.) Findings were used to revise design requirements, which were then used as a framework for the design and construction of a Phase II (‘evaluation’) prototype. After verifying and validating the Phase II prototype and conducting the hazard analysis, the final stage of this work involved end users evaluating a full-scale working model of the ARISE against other commercially available HAS.

Figure 1.

Iterative design process used for the development of the ARISE.

Stakeholder feedback

Sample

Purposive sampling was employed to recruit eight OTs with experience practicing in community care for interviews and eight wheelchair users with a range of physical disabilities who had past experience using HAS for the focus groups.

Methods

Protocols for the interviews and focus groups were approved by our Ethics Review Board and all participants were required to sign informed consent prior to participation. For the interviews, OTs were presented with images of the ARISE and a semi-structured interview script was used to guide 60–90 sessions. For the focus groups, participants were shown an animated model and video of the ARISE Phase I prototype and a semi-structured focus group script was used to elicit feedback. Both the interviews and the focus groups were audio taped then transcribed verbatim; thematic analysis was performed to identify salient findings. Member checking (by email or phone) was utilized to verify the accuracy of the initial findings.

Results

Phase I (‘proof of concept’) prototype

At the outset of the project, preliminary design requirements were developed based on a concept envisioned by the principal investigator (a wheelchair user) and supported by anecdotal feedback from end users. Notable requirements for the concept are listed in Table 1.

Table 1.

Key Design Requirements
Inclusive design usable by people with a range of mobility impairments, including those with wheelchairs and walkers
Is “always available”, i.e. doesn’t need to be called from another floor
Provides the option for users to use stairs
Stair tread rise to run ratio consistent with current building codes
Form factor that allows aesthetic integration with North American bungalow homes
Potential for a self-powered version (i.e. no external power required)
Usable for emergency descent in absence of power

Based on these requirements, a basic proof of concept prototype was built to demonstrate the concept feasibility. Figure 2 depicts our first full scale Phase I prototype, designed to elevate approximately 0.9m (5 stairs). This design has two major home access characteristics: 1) it is inherently a conventional staircase; and 2) each end of the staircase can operate as a platform lift. A person (e.g. in a wheelchair or otherwise) can enter either the top or bottom staircase platform, thus there is never a need to ‘call’ or wait for the platform. Each platform is similar in size to a conventional vertical platform lift, and large enough to accommodate two people or a wheelchair. Each platform is hinged to the frame of the staircase in such a manner that a levered platform lift is realized, operationally analogous to a ‘see-saw’. The frame of the stairs, handrails, and vertical platform posts form a parallelogram linkage (see Figure 3). The entire symmetrical structure pivots around two horizontal axes placed at the centre of the stairs and handrails (red arrows in Figure 3). The parallelogram linkage allows the user to quickly raise or lower to a different level while still maintaining each of the platforms in a horizontal orientation at all times.

Figure 2.

First full scale prototype of the ARISE. It is inherently a conventional staircase but each end of the staircase also can operate as a platform lift.

Figure 3.

The ARISE design. The entire structure moves about two pivot axes (red arrows), providing the pivoting lift action. The bottom cutaway model shows the internal linkage (blue arrow) of the staircase treads.

The ARISE design also maintains a normal staircase for use by others when the lift is not in use, regardless of which platform is in the upper position. To prevent falls, especially by the elderly, the literature recommends that stair-riser heights and tread lengths conform to specific asymmetrical geometries (e.g. a rise to run ratio of ~7:11) [23, 24]. In order to maintain proper stair geometry when the ARISE swaps positions, the ARISE utilizes a pivoting mechanism that links each stair riser to another parallel linkage (blue arrow in Figure 3). We were able to validate the feasibility of this stair pivot mechanism, demonstrating the ability to maintain stair treads in a horizontal position throughout the lift, while still preserving the appropriate rise to run ratio when either end of the platform is raised; in addition, it was found by the research team that this dynamic structure still provided a conventional stiff feel when walking up or down the stairs. This stair design has the added benefit of providing adjustability for various heights of entry levels as the entire structure can accommodate changes in elevation of several inches (by slightly altering the 7:11 ratio), or until another step needs to be added to the staircase.

To address potential home design integration, a number of bungalow style houses with 5–6 steps were identified locally (although heights greater than 6 stairs may also be appropriate for this design). An Architectural Sciences student modeled several alternatives for aesthetically and functionally integrating the ARISE into these homes (see Figure 4 for a sample rendering of an early ARISE configuration).

Figure 4.

Early rendering of the ARISE integrated into front porch of a bungalow home.

To simplify installation and removal, a concept for a removable porch landing that could be constructed over an existing staircase for installation of the ARISE was developed. For a home entrance elevation served by 5 stairs, the ARISE requires a landing (e.g. front porch) of about 4 m in length. The landing size only grows about 30 cm per additional stair; e.g. for 10 stairs, the landing is approximately 5.4 m long. This footprint is much smaller than a comparable ramp. For example, a 1:12 ramp serving a home of 5 stairs has a footprint of 16m and an equivalent ramp serving a home of 10 stairs has a foot print of almost 32 m. (If a gentler, 1:16 rise to run ratio is utilized, the ramp footprints increase to 19 m and 38 m for 5 and 10 stair heights respectively).

The Phase I prototype was tested with loads up to 140 kg and it was demonstrated that the platforms could easily be moved the entire vertical distance in a very smooth and quick manner (2–3 seconds from bottom to top). When in a balanced condition (e.g. a person on one side and an equivalent weight on the opposite platform), very little effort is required to manually move the platforms from one position to the other (i.e. as with a balanced see-saw, only the force required to overcome frictional forces in the pivots is required). It is possible that low- or self-powered versions of the ARISE design may be feasible by counterbalancing the lift in some fashion. For example, a counterbalancing weight could shoulder the load of one side of the ARISE, providing the bulk of the lifting force necessary to raise the occupant, with only a little effort from the occupant necessary to pull him/herself and the lift from one position to another. We tested this concept using gas springs (sized for a 180kg load) as a counterweight, demonstrating that not only did gas springs greatly reduce the forces required to raise a user, the damping they provided while lowering the user resulted in a smoother, gentler ride and also provided a means of powerless emergency egress.

While counterbalancing (with weights or gas springs) was shown to reduce the lift forces, a drive mechanism for the ARISE was still required. Prototype self-powered drive mechanisms were developed, including a simple hand crank drive, and a lever drive attached to chain and sprockets.

Using these drive mechanisms, users were able to raise themselves 0.9m in approximately 12 seconds and 14 seconds respectively. Later, a scale prototype of an improved lever system was developed. This lever mechanism incorporated a gearing system with one-way bearings that translated both fore-aft lever motions into a unidirectional lifting or lowering action. It is estimated that such a system would allow a user to rise about 1 meter with 4 movements of the lever, taking approximately 7 seconds.

Feedback from OTs

OTs were interviewed and asked for feedback on the Phase I prototype. Several key factors emerged from an analysis of the interviews. OTs, without exception, identified cost as the most commonly cited concern influencing an end users’ choice of HAS. In order for the ARISE to be a viable solution it was noted that the cost must be within a manageable price range or the device must become eligible for funding. Safety was also brought up as an important factor. For the ARISE, OTs noted the importance of including a full range of safety features such as gates, railings, emergency stop, etc.

The importance of aesthetics and the access solution ‘fitting’ the house (i.e. the height of the entry, the footprint, landscaping issues) were also brought up as important. Apart from end users wanting the front of their home to look nice, they are also looking for more subtle and unobtrusive solutions that don’t create the stigma that is often associated with disability related products. OTs noted that solutions that ‘advertise’ disability can make end users feel vulnerable, as they perceive themselves as a potential target for criminal activity. Overall, feedback on the visibility of the ARISE was very positive. One OT commented that the ARISE design doesn’t ‘scream out disability’, while another stated that it looked ‘more normalizing’. The fact that the ARISE embraces universal design and provides solutions for people with a range of disabilities was also well received.

The end users’ condition and prognosis (i.e. relating to both physical and cognitive abilities), as well as the potential presence of a caregiver, were stated as important factors that influenced choice of HAS. OTs suggested that the ARISE would be particularly well suited for people with energy issues (e.g. those with Multiple Sclerosis, Chronic Fatigue, and the elderly), or for people whose mobility may vary or decline over time (e.g. walking now but may need a wheelchair down the road). Ease of installation and having the ability to remove the access solution if the house is sold were also noted as important considerations.

Finally, the possibility that the ARISE could be self-powered, or at least operational for emergency egress, was considered to be a benefit as it was noted that people like something that doesn’t necessarily rely on an external power source that could occasionally be out of service.

Feedback from end users

End users confirmed that HAS are an essential component for providing the opportunity to engage in activities outside the home and that similarly, ineffective HAS can create barriers to participation, including limiting activities related to self-care (e.g. bringing groceries into the home). When comparing the benefits and limitations of existing HAS, important characteristics identified included: cost, safety, feelings of security, durability (especially for outdoors), dependability, usability, speed, noise, and maintenance.

As in the interviews with OTs, cost was identified as an important factor that often determined choice of one HAS over another. The importance of factoring in repair and maintenance costs was also discussed, with some participants citing stair-lifts and elevators as examples of solutions with high servicing costs. When participants were asked if they would consider using the ARISE, there was an overall preference for the manual self-powered ARISE version, in part due to perceived lower maintenance needs.

The importance of the assistive technology-human fit was also discussed, with a number of users highlighting the value of designing a device that can accommodate a diverse array of end-user needs. There were some concerns that the ARISE may only benefit individuals with a certain degree of functional mobility. In particular, it was noted that a self-powered version of the ARISE would not fit all end users as some would not have the strength to operate it. On the other hand, when asked if they would consider using the ARISE, most participants preferred the self-powered version of the ARISE because of the sense of control and independence it could provide to the end user.

Participants also noted that ‘user space’ on HAS, such as floor area inside elevators, is important, noting that there should be enough room to turn around or allow a caregiver to accompany a person in a wheelchair. When participants were shown an animation of the Phase I ARISE design, where users were required to pivot 90 degrees towards the exit upon entering the platform, several participants stated that this small radius turn would be challenging for many. Several participants noted that straight in/straight out access was preferred.

The importance of the aesthetics of HAS was also discussed. Participants noted that solutions that were discreet in appearance and could be integrated into the home were viewed more favorably. As in the OT interviews, participants expressed that HAS that do not advertise disability to the public were considered more desirable as they felt visible solutions could make them targets for criminal activity. Interestingly, although the ARISE was considered to be aesthetically appealing by some, others suggested that making an aesthetically appealing HAS is difficult or impossible to do, noting that most are bulky and don’t ‘blend in’. Some participants questioned the versatility of the ARISE and wondered about its ability to fit to different types of homes.

Phase II (‘evaluation’) prototype

Stakeholder feedback was reviewed by the design team and, where relevant, incorporated into the design of the Phase II prototype. For example, the entry/exit path for the lift was changed to straight through access (rather than the 90 degree turn of the original concept). Also, additional aesthetic details were added to the design, including using composite decking planks for the stair treads/platforms and incorporating planters in front of the ARISE to make the solution look less ‘clinical’.

At this stage, the team decided to focus development of the Phase II prototype on an externally powered version of the ARISE. (In spite of the stakeholder interest and the potential demonstrated in the self-powered prototype, the fact that only end users with good upper extremity function would be able to evaluate it was seen as a significant drawback for user trials. The rest of this paper discusses the more conventional externally powered ARISE, however further work on self-powered options is planned, in particular for possible use as a low cost alternative both in North America and potentially in low resource settings [25]). A number of externally powered drive mechanisms were considered. The final design selected was based on a bi-directional hydraulic actuator that pulled either end down (thus lifting the other platform), and that could be mounted beneath the stairs. A block and tackle pulley mechanism was incorporated into the design to multiply the lift distance by 3 (see Figure 5), thus providing a 0.9 m lift while still keeping the drive mechanism contained in the limited space under the stairs. To create a smoother ride for the user, control algorithms to slow the lift at the beginning and end of the lift cycle were developed. The system was powered by a 12 V battery (trickle-charged through an AC line) that also served as an emergency backup system in the event of a power failure. A push button switch mounted on the side panel of the platform was put in place for the user to control the lift. As a safety feature, the push button operated as a “deadman’s switch’, i.e., the lift stopped the moment the switch was released.

Figure 5.

Drive mechanism for the ARISE: drawing showing location of drive mechanism and one of the drive cables (left), and photo of hydraulic actuator and block and tackle pulley mechanism (right).

A number of safety systems were put in place to ensure safe operation of the ARISE during the evaluation. A total of four gates were included in the ARISE design (one exit gate and one entry gate for each platform). Gates consisted of pivoting bars (anchored to the platform frame uprights), driven by small micro-controller activated motors. The micro-controller was programmed to sequence the opening and closing of gates with the lift operation: i.e. closing the ‘entry’ gates when the operation button was pressed and opening the ‘exit’ gates when the next level was reached. As an additional safety feature, the ARISE was designed to operate only when all of the gates were closed. Other safety features included an external ‘emergency stop’ switch (a system over-ride held by the supervising researcher), rails on both sides of the stairs, and a vertical safety barrier that prevented a user’s wheelchair rolling off the platform when it left the ground. This vertical safety barrier also had a secondary purpose, acting as transition ramp to assist users getting over the lip to the ARISE platform when the platform was on the ground. As operation of the evaluation prototype was limited to the controlled setting of the lab, the team was able to bypass some safeties that would be required for safe operation in a public space. Regardless, further features that simply provided the ‘perception of safety’ and inspired user confidence were also included in the design: visual barriers under the lift platforms (e.g. rolling blinds that unfurled as a platform lifted – see red arrows in Figure 6) were installed to obscure the view of moving parts under the platform.

Figure 6.

Phase II ARISE prototype ready for evaluation with end users. The two platforms are shown in both the raised and lowered positions. The location of the rolling blinds are indicated with red arrows.

Prior to using the ARISE for the evaluation, the prototype was validated against design requirements, and underwent a detailed hazard analysis (see final Phase II prototype, Figure 6). Identified hazards were addressed and safe operating protocols were put in place. ARISE specifications (i.e. time to another level, platform size, and footprint) were recorded and tabulated against specifications from existing HAS) -see Table 2. The next stage of this work involved engaging end users to evaluate the ARISE and compare it with other solutions. Findings from this evaluation will be reported elsewhere.

Table 2.

HAS	Approximate time to another level (seconds) a	Platform size (m)	Footprint (m2)
ARISE	10	1.2 × 0.9	5.3
Savaria Platform lift (Savaria)	17	1.4 × 0.9	2.5
Stair Glide (Bruno Elite)	32	n/a	0.8m width along length of stairs (stair footprint = 2.6m2 including landing)
Ramp (1:12 rise to run ratio)	26	n/a	13.4

^aincludes time to get on the lift and exit.

Discussion

In order to address the limited innovation in home access solutions, we developed a novel home access device that integrated a staircase and vertical platform lift into one inclusive package. The design process followed a structured protocol that involved stakeholders providing feedback during development, consistent with rehabilitation engineering design methods. Using this process, the design team was able to develop an inclusive home access product that is ‘always available’, provides an option for the user to use stairs or a lift, and is usable by people with a range of mobility impairments. This solution is also usable for emergency descent in the absence of power and has potential for low- or self-powered applications.

We believe the involvement of stakeholders in the process added value and led us to a design that was more closely aligned with end user needs. Studies have verified that there are immense benefits to involving end-users when developing innovative yet effective AT [26–28]. While the user driven process takes time and commitment from the research team, the ‘real life’ view point that a variety of end users can provide gives a realistic perspective on potential use that enriches the design process.

Through validation with our prototype, we were able to demonstrate that the ARISE addresses some of the limitations of existing HAS. In particular, significant drawbacks of existing HAS are their lack of inclusivity and the fact that they appear to many as obvious symbols of disability. Stakeholders commented that the ARISE does not appear as a solution for a PWD, and it incorporates universal design principals. Further, the ARISE addresses one of the main drawbacks of ramps- i.e., their large footprint [17]. The ARISE footprint is only slightly larger than a conventional staircase, and much smaller than the footprint of a comparable ramp (while still preserving the use of stairs- see Figure 7).

Figure 7.

Footprint comparison for three HAS servicing a height of 5 stairs: a 1:12 grade ramp (with switchback), the ARISE platform lift, and a conventional staircase.

Frustration with speed of existing HAS (in particular elevators and platform lifts) has been noted both in the literature [12] and by stakeholders participating in this study. We were able to demonstrate that the ARISE is considerably faster than the solutions tested (a platform lift, a stair glide and a ramp). It should be noted that while speed of existing HAS is a frustration for some, speed is in many cases governed by regulation. For this research, the team intentionally set out to create a lift that was faster than current regulation allows in order to explore user perceptions of what is acceptable across a wider range of speeds. While the team felt that the speed of the ARISE was not so fast as to make a user feel insecure, regulatory changes may be required if the faster operational speed were to be incorporated in a commercial product. Regardless, even if the ARISE must be configured to an operational speed that conforms to current regulation, the overall efficiency of the ARISE is still better than existing lifts and stair glides as both these solutions often times require the user to wait while the lift is called.

Cost is another important consideration in the choice of a HAS that was brought up by stakeholders and is also documented in the literature [12, 21]. While we acknowledge that this is important for many, keeping costs low presented many challenges and at times conflicted with other considerations. For example, automated gates were added to the ARISE, even though using manual gates would have been a lower cost option. In this case, the team felt the benefit of increasing the accessibility for a greater number of users outweighed the disadvantages of increased costs. This decision was facilitated by a review of the project design requirements: low cost wasn’t one of the main objectives of this design, however “inclusive design usable by people with a range of mobility impairments…’ was a key requirement.

While reducing cost was not a priority, the design team took heed of this stakeholder feedback and, as much as possible, aimed to minimize costs by reducing the complexity of the solution and reducing the number of custom parts needing to be built. Providing a solution that is flexible and customizable was also seen as a way of mitigating some of these cost concerns. Ideally, HAS should be matched to the individual, based on his/her unique functional abilities, housing situation, personal preferences, family support, resources, and levels of independence and participation [21, 29]. Providing flexible HAS that can be customized to meet end user needs may not only result in better outcomes, but may also help contain costs. For example, with the ARISE, manual gates could be provided to users who could manipulate gates themselves, thus resulting in a simpler and cheaper solution. The fact that the ARISE has the flexibility to be used by users with a range of mobility challenges also provides benefits. As it can be used as a set of stairs by those who are able (thus obtaining valuable exercise [29]), or as a lift (for those requiring assistance), the ARISE is well suited for users with changing conditions. In the longer term, this can prove to be an economical option for users’ whose condition may either improve (through rehabilitation) or deteriorate (with a progressive condition like Multiple Sclerosis) over time. Similarly, providing a self-powered version of the ARISE to those with the upper extremity function to operate it would like provide a lower cost (and more reliable) alternative.

Indeed feedback from stakeholders supports further work on a self-powered version of the ARISE. The premise of the self-powered operation is based on the ability to counterbalance the lift. In many personal home access situations, the lift could be counterbalanced primarily for an individual and their own home. As the occupant would almost always use the same platform, the weight of the counter balance (or force of the gas spring) would be appropriate for this specific user and their wheelchair. In most typical situations, the primary user would be able to operate the lift manually and independently with little or no power. For scenarios where other people (e.g. visitors) would use the lift, and for the situation where the position of the primary lift platform and the typical occupant were mismatched, a relatively small geared motor could be used. Here, the motor could ‘reset’ the lift by slowly moving the un-balanced structure to the opposite position. Low- or self-powered versions of the ARISE could have many different use scenarios, including providing reliability during a power failure, fostering user independence, promoting environmental sustainability, and providing solutions in regions where power is not available. Details of applications in low resource settings are described elsewhere [25].

A review of novel HAS in the marketplace reveals that some of the issues brought up by stakeholders and considered during the design and development of the ARISE are also being considered by others. For example, a company with an integrated HAS that functions as both a staircase and a lift [14] aims to address the importance of providing both a flexible and aesthetic solution. Similarly, a company that boasts a low profile HAS aims to provide an inconspicuous solution that blends into a home [13], while a company with a vacuum elevator touts the benefits of a lower energy solution, including no-power descent [15]. While it is encouraging to see that some of the limitations of HAS that have been discussed in this paper are being considered by others, use of these innovative solutions is not widespread and it is evident that gaps still exist. Innovation in this area is limited, and the market is ripe for new solutions. Results from this work support further development in this area.

Conclusion

By engaging stakeholders in a user centred design process we were able to gain insight on limitations of existing HAS and get valuable feedback on the development of the new ARISE design. We were able to demonstrate that this solution has potential to address shortcomings of existing HAS and provide inclusive home access to a range of end users. Overall, stakeholders expressed enthusiasm for the ARISE. In particular, stakeholders noted advantages of universal design and inclusivity, as well as potential benefits with the aesthetics of the solution. However limitations were also noted. The complexity of the device was likely the most considerable challenge as users felt this would impact both cost and reliability of the solution. Engaging stakeholders in the design cycle proved to add value to the process and emphasized the need for continued feedback from end users through all stages of development.