A New Controller for a Smart Walker Based on Human-Robot Formation

Abstract

This paper presents the development of a smart walker that uses a formation controller in its displacements. Encoders, a laser range finder and ultrasound are the sensors used in the walker. The control actions are based on the user (human) location, who is the actual formation leader. There is neither a sensor attached to the user’s body nor force sensors attached to the arm supports of the walker, and thus, the control algorithm projects the measurements taken from the laser sensor into the user reference and, then, calculates the linear and angular walker’s velocity to keep the formation (distance and angle) in relation to the user. An algorithm was developed to detect the user’s legs, whose distances from the laser sensor provide the information necessary to the controller. The controller was theoretically analyzed regarding its stability, simulated and validated with real users, showing accurate performance in all experiments. In addition, safety rules are used to check both the user and the device conditions, in order to guarantee that the user will not have any risks when using the smart walker. The applicability of this device is for helping people with lower limb mobility impairments.

A Novel Coordinated Motion Fusion-Based Walking-Aid Robot System

“…Furthermore, human footsteps were captured by a camera and pressure sensors. Valado [ 19 ] designed a laser range finder and ultrasound sensors-based walker. In this human-robot system, the distance relationship between the robot and the user was considered as a formation.…”

Extending the Application of an Assistant Personal Robot as a Walk-Helper Tool

“…Similarly, Jun et al [18] presented a sit-to-stand support system and Morris et al [19] proposed one of the first robotic walkers with an embedded autonomous navigation system capable of reaching a destination point by itself. Other reference works include that of Nejatbkhsh et al [20] who proposed the use of an omnidirectional motion system for optimal guidance, Yu et al [21] who proposed a kinematic adaptation of the robotic walker to the user gait and formation by using a dedicated laser range sensor to detect user legs, and Valadão et al [22] who proposed a kinematic controller for a robot walker based on user pose and interaction. Finally, in another direction, Hou et al [23] proposed the development of an electric energy model applied to increase the reliability and autonomy of a mobile robot.…”

Adaptation of a smart walker for stroke individuals: a study on sEMG and accelerometer signals

“…In the opposite case, i.e., if the user is closer than the set-point, the walker moves away to make him/her catch the set-point. In general, the walker makes the user stays always on the central angle and at the predefined set-point posture (distance: 70 cm; orientation: 0°) (Valadão et al, 2016).…”

“…A smart walker from UFES/Brazil (Valadão et al, 2016) (Figure 1) was used in the experiments, which was built from a conventional four-legged walker adapted to a robotic mobile platform. The smart walker structure has forearm bars to provide weight support and comfort during its use, also allowing the user to guide it.…”

“…To enhance the experience with the walker, all tests were carried out using a classical PID controller together with a safety supervisor system composed of a set of rules (Table 1) to avoid harmful situations for the user while using the walker (Valadão et al, 2016).…”