This paper presents a framework for creating a 3D map of an environment that contains the probability of a geometric feature to emit a sound. The goal is to provide an automated tool for condition monitoring of plants. The map is created by a mobile platform equipped with a microphone array and laser range sensors. The microphone array is used to estimate the sound power received from different directions whereas the laser range sensors are used for estimating the platform pose in the environment. During navigation, a ray casting method projects the audio measurements made onboard the mobile platform to the map of the environment. Experimental results show that the created map is an efficient tool for sound source localization.

This work introduces a 3D visibility model for comfortable autonomous vehicles. The model computes a visibility index based on the pose of the wheelchair within the environment. We correlate this index with human navigational comfort (discomfort) and we discuss the importance of modeling visibility to improve human riding comfort. The proposed approach models the 3D visual field of view combined with a two-layered environmental representation. The field of view is modeled with information from the pose of the robot, a 3D laser sensor and a two-layered environmental representation composed of a 3D geometric map with traversale area information. Human navigational discomfort was extracted from participants riding the autonomous wheelchair. Results show that there is fair correlation between poor visibility locations (e.g., blind corners) and human discomfort. The approach can model places with identical traversable characteristics but different visibility and it differentiates visibility characteristics according to traveling direction.

This paper presents a framework for making a mobile robot aware of an entity in the blind region of its laser range finders when that entity emits sound. First in a mapping stage, a 3D description of the environment that contains information about acoustic reflection is created. Then during operation, the robot combines estimated directions of arrival of sound with this 3D description to detect entities that are not visible by line of sight sensors but could be heard because of sound reflections. Using this approach, it is possible to restrict the hypothesis about the position of a sound emitting entity in the blind region to a small set of candidate depth values.

This paper presents a multi-modal sensor approach for mapping sound sources using an omni-directional microphone array on an autonomous mobile robot. A fusion of audio data (from the microphone array), odometry information and the laser range scan data (from the robot) was used to precisely localize and map the audio sources in an environment. An audio map is created while the robot is autonomously navigating through the environment by continuously generating audio scans with a steered response power (SRP) algorithm. Using the poses of the robot, rays are cast in the map in all directions given by the SRP. Then each occupied cell in the geometric map hit by a ray is assigned a likelihood of containing a sound source. This likelihood is derived from the SRP at that particular instant. Since the localization of the robot is probabilistic, the uncertainty in the pose of the robot in the geometric map is propagated to the occupied cells hit during the ray casting. This process is repeated while the robot is in motion and the map is updated after every audio scan. The generated sound maps were reused and the changes in the audio environment were updated by the robot as it identifies these changes.

This paper presents a method for mapping the radiated sound intensity of an environment using an autonomous mobile platform. The sound intensities radiated by the objects are estimated by combining the sound intensity at the platform's position (estimated with a steered response power algorithm) and the distances to the objects (estimated using laser range finders). By combining the estimated sound intensity at the platform's position with the platform's pose obtained from a particle filter based localization algorithm, the sound intensity radiated from the objects is registered in the cells of a grid map covering the environment. This procedure creates a map of the radiated sound intensity that contains information about the sound directivity. To illustrate the effectiveness of the proposed method, a map of radiated sound intensity is created for a test environment. Then the position and the directivity of the sound sources in the test environment are estimated from this map.

This paper presents a method for detecting moving entities that are in the robot's path but not in the field of view of sensors like laser scanners, cameras or ultrasonic sensors. The proposed system makes use of passive acoustic localization methods which receive information from occluded regions (at intersections or corners) because of the multipath nature of sound propagation. Contrary to the conventional sensors, this method does not require line of sight. In particular, specular reflections in the environment make it possible to detect moving entities that emit sound such as a walking person or a rolling cart. This idea was exploited for safe navigation of a mobile platform at intersections. The passive acoustic localization output is combined with a 3D geometric map of the environment that is precise enough to estimate sound propagation and reflection using ray casting methods. This gives the robot the ability to detect a moving entity out of the field of view of the sensors that require line of sight. Then the robot is able to recalculate its path and waits until the detected entity is out of its path so that it is safe to move to its destination. To illustrate the performance of the proposed method, a comparison of the robot's navigation with and without the audio sensing is provided for several intersection scenarios.

The noninvasive brain-machine interface (BMI) is anticipated to be an effective tool of communication not only in laboratory settings but also in our daily livings. The direct communication channel created by BMI can assist aging societies and the handicapped and improve human welfare. In this paper we propose and experiment a BMI framework that combines BMI with a robotic house and autonomous robotic wheelchair. Autonomous navigation is achieved by placing waypoints within the house and, from the user side, the user performs BMI to give commands to the house and wheelchair. The waypoint framework can offer essential services to the user with an effectively improved information-transfer rate and is an excellent examples of the fusion of data measured by sensors in the house, which can offer insight into further studies.

Reliable autonomous navigation is an active research topic that has drawn the attention for decades, however, human factors such as navigational comfort has not received the same level of attention. This work proposes the concept of “comfortable map” and presents a navigation approach for autonomous passenger vehicles which in top of being safe and reliable is comfortable. In our approach we first extract information from users preference related to comfort while sitting on a robotic wheelchair under different conditions in an indoor corridor environment. Human-comfort factors are integrated to a geometric map generated by SLAM framework. Then a global planner computes a safe and comfortable path which is followed by the robotic wheelchair. Finally, an evaluation with 29 participants using a fully autonomous robotic wheelchair, showed that more than 90% of them found the proposed approach more comfortable than a shortest-path state of the art approach.