Low complex sensor-based shared control for power wheelchair navigation

Abstract

Motor or visual impairments may prevent a user from steering a wheelchair effectively in indoor environments. In such cases, joystick jerks arising from uncontrolled motions may lead to collisions with obstacles. We here propose a perceptive shared control system that progressively corrects the trajectory as a user manually drives the wheelchair, by means of a sensor-based shared control law capable of smoothly avoiding obstacles. This control law is based on a low complex optimization framework validated through simulations and extensive clinical trials. The provided model uses distance information. Therefore, for low-cost considerations, we use ultrasonic sensors to measure the distances around the wheelchair. The solution therefore provides an efficient assistive tool that does not alter the quality of experience perceived by the user, while ensuring his security in hazardous situations.

Assisting power wheelchair driving on a sidewalk: A proof of concept

“…Here, as the idea is to provide a proof of concept of the proposed method, the distance to the floor measured by each sensor is used to calculate the distance to the curbside in the horizontal plane. With such a detection, the wheelchair will avoid approaching a curbside the same way it already avoids to collide with a wall, thus bringing us back to the same configuration as in [14]. The detection is such that we can distinguish 3 cases: 1) if we define hip as the minimum height of a positive obstacle we observe, then we detect a positive obstacle when , then, the distance to the obstacle is defined as = sin( ).…”

“…In this article, we present a low-cost semi-autonomous wheelchair control solution for assisting wheelchair navigation on a sidewalk. The proposed method is based on the same mathematical principle as the approach presented in [14] which application has been until now restricted to indoor navigation assistance as the detection of negative obstacles was not ensured yet. This method has been tested and validated by wheelchair regular users within clinical trials whhich have been conducted within the Pôle Saint Hé lier rehabilitation center in Rennes [14,16].…”

“…The proposed method is based on the same mathematical principle as the approach presented in [14] which application has been until now restricted to indoor navigation assistance as the detection of negative obstacles was not ensured yet. This method has been tested and validated by wheelchair regular users within clinical trials whhich have been conducted within the Pôle Saint Hé lier rehabilitation center in Rennes [14,16]. In this paper, we propose to apply this principle to navigation on a sidewalk by considering detected drop-offs as virtual positive obstacles in the horizontal plane thus leading the wheelchair to progressively correct its trajectory to avoid the curbside the same way it avoids colliding with a wall.…”

Probabilistic vs linear blending approaches to shared control for wheelchair driving

“…RELATED WORK As already mentioned, several groups have proposed shared control strategies for wheelchairs that continuously blend the user input signal(s) with some sort of optimal control commands [7]- [11]. Generally these strategies use (variations of) the following equation to blend the user's input with the wheelchair's computed direction [5]:…”

Comparing shared control approaches for alternative interfaces: A wheelchair simulator experiment

“…RELATED WORK The current state of the art in shared control continuous blends of the user's intended velocity and some sort of optimal velocity of a mobile robot [4], [5], [10], [11]. Generally these strategies use (variations of) the following equation to blend the user's intended velocity with the robot's velocity [12]:…”