A guidance robot for the visually impaired: System description and velocity reference generation

This paper presents a guidance robot for the visually impaired along with generation of velocity reference signals. The guidance robot has an interface grip with a force sensor on the top. The robot can be operated intuitively through the interface grip, and at the same time, the position and the behavior of the robot can be provided to the user. An underactuated mobile mechanism is used. It can be moved in X and Y directions and is unconstrained in turning direction. The rotation center of the robot is determined by the user's position. Environmental sensors are equipped for avoiding obstacles and hazards. In addition, the robot has redundant anti-falling systems for safety. The systems work independently from the environmental sensors. The robot is lightweight, foldable, and easy to carry. A versatile time-optimal reference generation algorithm is proposed for the robot's velocity reference. The algorithm can set the bounds for the acceleration, jerk, and snap. Moreover, initial conditions and final conditions of the velocity, acceleration, and jerk can be specified. The switching surfaces are obtained with these parameters in the three-dimensional phase space, which allows the determination of the snap command for easy motion pattern generation. These parameters are changeable online.