A behavioural approach to obstacle avoidance for mobile manipulators based on distributed sensing

TL;DR

This paper introduces a reactive, sensor-based obstacle avoidance method for mobile manipulators that uses distributed proximity sensors and a behaviour-based approach to ensure real-time collision avoidance without relying on visual data or detailed models.

Contribution

It presents a novel distributed sensing and behaviour-based control algorithm that enables mobile manipulators to avoid obstacles in dynamic environments without 3D models or visual sensors.

Findings

Real-time collision avoidance achieved using distributed proximity sensors.

The method effectively avoids moving obstacles and self-collisions.

Smooth trajectory adjustments are guaranteed through task combination techniques.

Abstract

A reactive obstacle avoidance method for mobile manipulators is presented. The objectives of the developed algorithm are twofold. The first one is to find a trajectory in the configuration space of a mobile manipulator so as to follow a given trajectory in the task space. The second objective consists in locally adjusting the trajectory in the configuration space in order to avoid collisions with potentially moving obstacles and self-collisions in unstructured and dynamic environments. The perception is exclusively based on a set of proximity sensors distributed on the robot mechanical structure and visual information are not required. Thanks to the adoption of this kind of proximity distributed perception, the approach does not require a 3D model of the robot and allows the real-time collision avoidance without the need of a sensorized environment. To achieve the features cited above, a behaviour-based technique known as Null-Space-Based (NSB) approach has been adopted with some modifications.On one hand, the concept of a total pseudo-energy based on the information from the distributed sensors has been introduced. On the other hand, a method to combine different tasks has been proposed to guarantee the smoothness of the realtime trajectory adjustments. Another significant feature of the method is the strict coordination between the base and the arm exploiting the redundant degrees of freedom, that is a relevant topic in mobile manipulation.