Exoskeleton Controller With Visual Feedback

Team Members: Christina Yee, Seema Puthyapurayil, Priya Iyer
 
Description
Our project aims to improve the user interface of an existing wired controller for an exoskeleton (exo) which helps paraplegics walk with more natural strides. Aside from converting to a wireless controller, we plan to design a more intuitive user interface which not only removes the “unknown” for users during exo operations by providing instant feedback to instill a sense of security, but also accommodates varying stride lengths during walking. To accomplish our goals, we will combine user input and mechanical output with visual feedback.
 
Design Components
Existing hardware for our project is the exo itself and two crutches for user balance/support. We plan to incorporate new technology into this hardware to improve the user interface. In particular, we envision our new user interface to have four main features:
1. The user enters commands for the exo (walk forward, sit down, stand up) using buttons on the crutches
2. The user sets or controls the exo’s stride length using buttons on the crutches equipped with FSRs (sliders or dials are alternative options to FSRs)
3. The user receives visual feedback regarding exo session usage time, distance covered, current stride length, current speed setting, etc. on a small digital monitor attached to each shoe
4. The user visualizes subsequent foot placement location on the ground through a projection of laser beams mounted on the exo at the waist, thigh or crutches
 
Alternative Solutions
Before deciding on the above solutions to accomplish our project goals, we brainstormed various methods to accomplish each design component. Below we’ve listed alternative solutions and a brief explanation of why we ruled out each one.

• Using voice commands to control the stride length and successive step speed
  • Voice commands would not allow users to “blend-in” to their surroundings, especially in quiet settings like a library. Societal acceptance is an important benefit of exos by allowing users to leave their wheelchairs and we do not want to jeopardize this by adding voice commands.
• Using brain-machine interfacing (BMI) to control exo commands and stride length
  • At this time, we are not convinced that BMI technology has developed enough to accomplish a simple, discreet design, which is an important theme of the exo that we want to maintain.
• Using finger-controlled sensors to point to the exact location of the next step when setting the stride length
  • Since users balance themselves with both crutches, this could compromise safety during exo use.
• Using auditory feedback through an earpiece instead of digital feedback for stride length and speed settings, distance covered, etc.
  • Most of the digital feedback is a “luxury” to augment the user’s security/confidence with the exo. Therefore, auditory feedback could become annoying to some users. Furthermore, an earpiece could be uncomfortable.
• Using glasses, augmented reality, or projectors in order to visualize the next step location instead of a laser beam
  • In keeping with the overall trend of the exo, we want a simple, minimal, discrete, natural solution. Glasses are an unnecessary added component to the exo while augmented reality and projectors are an over-design for our goals.