Wheelchair Navigation System for Disabled and Elderly People

Abstract

An intelligent wheelchair (IW) system is developed in order to support safe mobility for disabled or elderly people with various impairments. The proposed IW offers two main functions: obstacle detection and avoidance, and situation recognition. First, through a combination of a vision sensor and eight ultrasonic ones, it detects diverse obstacles and produces occupancy grid maps (OGMs) that describe environmental information, including the positions and sizes of obstacles, which is then given to the learning-based algorithm. By learning the common patterns among OGMs assigned to the same directions, the IW can automatically find paths to prevent collisions with obstacles. Second, it distinguishes a situation whereby the user is standing on a sidewalk, traffic intersection, or roadway through analyzing the texture and shape of the images, which aids in preventing any accidents that would result in fatal injuries to the user, such as collisions with vehicles. From the experiments that were performed in various environments, we can prove the following: (1) the proposed system can recognize different types of outdoor places with 98.3% accuracy; and (2) it can produce paths that avoid obstacles with 92.0% accuracy.

A Recursive Algorithm for Indoor Positioning Using Pulse-Echo Ultrasonic Signals

“…The application of ultrasonic sensors in determining the x, y, z coordinates of an object in a working space (e.g., cockpit, robot space) can be used complementarily with optical systems or alone as a valid alternative to optical methods with a reduced sensitivity to noise, dust, lighting conditions, etc. [ 38 ]. In SONAR (Sound NAvigation and Ranging) systems, the resolution can be correlated with the spectral content of the received signals.…”

Sensors and Systems for Physical Rehabilitation and Health Monitoring—A Review

“…A wheelchair that can control and recognize the environment and obstacles can be constructed by fusing data from a camera and ultrasonic sensors [111]. This chair had 98.3% accuracy in recognizing outdoor locations and 92% accuracy in picking pathways to avoid obstacles, reaching a high level of satisfaction from subjects.…”

Generating Comfortable Navigable Space for 3D Indoor Navigation Considering Users’ Dimensions

“…In recent years, several studies have examined the dimensions of indoor navigators, especially wheelchair agents. To improve the safety of navigation, various solutions for smart wheelchairs have been proposed, which implicitly consider agents’ dimensions to avoid obstacles by processing data collected from different sensors (e.g., optical, infrared, and ultrasonic sensors) [ 27 , 28 , 29 ]. Geometrically, the American with Disabilities Act Accessibility Guidelines (ADAAG) provide detailed specifications by considering the required dimensions of wheelchair agents in indoor environments [ 30 ].…”