Terug naar overzicht ASSAM - Autonomie en mobiliteit voor senioren

iHandlebars of the ASSAM walking assistant

Usability research by Bartiméus and the Accessibility Foundation

Are vibrations a convenient way to send navigation instructions to blind and partially sighted people? The ASSAM Walking Assistant aims to transform navigation instructions into nonvisual information. Notifications and information about the environment is given via intelligent sensing and vibrating handlebars and through auditive feedback. What do blind people think about the possibility of vibro-tactile stimulation for indicating directions and navigation? 

The Walking Assistant is developed as part of the European project Assistance for Safe Mobility (ASSAM), and aims to help blind and partially sighted people, in need of a walker, to find their way in an indoor and outdoor environment. Our blind test users include Hans (63), Roel (64) and Bianca (39). They have tested the ASSAM Walking Assistant during usability research at the Accessibility Foundation in Utrecht, The Netherlands. 

Assam Walking assistant various functions of iHandlebarsASSAM describes the iHandlebar as a help technology that is filled with innovative technology and that can detect user presence and provide feedback from the navigation software. The navigation software is aided by intelligent wheels that send information about direction, speed, distance and tilt. The walker will stop the wheels if nobody is holding the handlebar.

Blind users tested the vibration notifications of the iHandlebar for navigation. Mobility experts of the Bartiméus foundation in the Netherlands also tested the vibration feedback.

In academic literature a lot has already been written about the possibilities of vibrating elements in navigation aids for blind people. Different scholars agree that vibro-tactile stimulation can be of great use for indicating directions and navigation. According to Schätzle and Weber, vibro-tactile stimulation has different advantages:

  • It is an intuitive form of feedback.
  • It is a possible modality for sensory substitution.
  • It can be used in situations where auditory or visual presentation is not possible, for example in noisy environments.
  • It avoids overloading the auditory and visual perception channels usually involved.
  • Information is displayed in an unobtrusive way, without                                                                                                                                               annoying others or drawing their attention.

Assam walking assistant iHandlebarsIn this article we draw special attention to the vibrating handlebars of the ASSAM Walking Assistant. Can these iHandlebars help blind and visual impaired people with navigation? First, let us have a closer look at the handlebars. What do they consist of?

1: A vibrating element inside the handlebar can be used for notifications to the user.
2: Feedback by a LED light is possible, also on the user’s grasp of the handlebar.
3: A battery is integrated inside the handlebar.
4: With the handbrake you can stop the walker.

The iHandlebars communicate, together with the OdoWheels, with the Navigation Aid software through a Bluetooth connection.

Warnings about obstacles

During the usability research the navigation application and the vibrating handlebars did not fully work yet. We installed a small vibrating element ourselves to start the discussion with the test users. With a remote control we sent vibrations to the handlebars in order to give the test users instructions. We attached the vibrating element in the right handlebar and asked the test users to indicate the meaning of the vibration pulse. We asked them what they thought the vibration pulse means, without giving them instruction in advance. Roel, Bianca and Hans all thought the vibration pulse was giving warnings about an obstacle on the right side of their walking path. They did not associate navigation instructions with the vibrating pulses. So, their natural impulse was to think they received a warning about an obstacle or something that was blocking their way. After we explained that the vibrating handlebars are intended to give information about the environment and more precisely about directions, we tested the ASSAM Walking Assistant in an outdoor situation.

Clear instructions

Because vibrations do not have a direct meaning that we automatically associate with a message, it is important to make clear instructions about the meaning of the vibrating pulses. In the focus group session, Hans pointed out the importance of receiving clear instructions about the meaning of the vibrations. When using the iHandlebars of the ASSAM Walking Assistant, blind and partially sighted people need a training to understand the variety of vibrating pulses that correspondent with certain messages.

Hans said it is just a matter of giving fixed meanings to the different vibrating pulses. For example: If a vibrating pulse in the right handlebar means ‘go to the right’, it is still not clear how much to the right a person has to go. A blind person cannot see the walking path and needs precise instructions about a turn in a path. A solution can be the use of different vibro-tactile stimulation patterns such as waves, knocks or impulses that correspond to different directions.

The test users suggest using the clock positions for navigation instructions and using the twelve hour markings with the directions in which they point. According to them, the iHandlebars can be used for messages about directions and the presence and distance from obstacles in the traveling space.

Guide dog

A lot of blind and visually impaired people use dogs to guide and help them to follow a walking path. The dogs are trained to navigate around obstacles. Some dogs even know how to get from one place to another. Is the ASSAM Walking Assistant able to replace a guide dog by giving information about directions and obstacles to people in need of a walker?

Bianca and her guide dog using the Assam walking assistantBianca is clear about this question. She does not think a Walking Assistant can replace her dog. She trusts technical aids, but it is more of a social matter. Bianca: “I would never get rid of my dog. It’s a living being that I love. I don’t think I would be able to love a walker.” For her, the social aspect of navigation aid is very important. She feels very attached to her dog that helps her move around. She would only replace her dog for another assistance if she is too old to take care of her dog. “People having problems with mobility are not able to walk the dog four times a day. If this is the case, I would seriously consider a walking assistant. I think then, the ASSAM Walking Assistant can be of great use. Now I feel too young to use the walker. I like my dog too much to replace it for something else.”

During the usability research we tested the ASSAM Walking Assistant together with her guide dog. Bianca likes the idea of making a combination of the two navigation aids. First it was a bit uncomfortable to use the walker with just one hand and hold the line of the dog in the other hand. She felt a bit unbalanced because she had to control both the walker and her dog. After a while, she got used to it and liked the idea of combining the two.

Information through vibrations

The most important question is if the test users want to receive information via vibrations. Three of our users, Roel, Hans and Bianca are all positive about this possibility, but they warn for an information- and signal overload by the different multimodalities of the walker. They prefer speech instructions above vibrating instructions. They think auditive instructions are much more clear. They suggest to use the vibrating handlebars mostly for warnings about obstacles. A lot of different impulses will distract them from traffic noise.

The scholar Ivanow writes that interactions between blind and visually impaired people and their surrounding environment should be simple and intuitive. According to Ivanow we should use blind environment models that are closer to human-to-human interaction than human-computer interaction. This may be an explanation why the test users prefer speech instructions instead of instructions via vibrations.

Yet, vibro-tactile stimulation is currently used in different aids for blind and visual impaired people. For example, the VibroTac is a wrist band with six vibro-tactile actuators and can be used for motion guidance in virtual reality applications and in the context of workstations for blind people. The VibroTac is developed at the German Aerospace Centre. Also some experiments were done with the Personal Radar, which assists blind people in navigating in indoor environments using an ultrasonic sensor combining auditory and vibro-tactile feedback.

Clear, simple and intuitive

Biance her hand on one of the handlebars of the Assam walking assistantIt is clear that modern aids with vibro-tactile stimulation can help blind and visually impaired people. Roel, Bianca and Hans think vibro-tactile stimulation can definitely be of great use. Nevertheless, a few things need to be kept in mind. The natural impulse of the test users was to think a vibrating pulse was a warning about an object in their walking path. They think the vibrating pulses can be used for navigation instructions and/or warnings about obstacles. The most important thing is that the vibrating pulses and their meaning must be very clear, simple and intuitive.

Literature used:

  • Bourbakis, N.
    2008 Sensing Surrounding 3-D Space for Navigation of the Blind
  • Ivanow, R.
    2013 Blind-environment interaction through voice augmented objects
  • Schätzle and Weber
    Towards Vibrotactile Direction and Distance Information for Virtual Reality and Workstations for Blind People
  • Schneider, J. and Stork, W.
    2015 A Multimodal Human Machine Interface for a Robotic Mobility Aid Design – Implementation – Field trials
Tags:
Categorie:
Projecten en publicaties
  • Delen op Facebook
  • Delen op Twitter
  • Delen op LinkedIn