Visual servoing of aerial manipulators

The final publication is available at link.springer.comThis chapter describes the classical techniques to control an aerial manipulator by means of visual information and presents an uncalibrated image-based visual servo method to drive the aerial vehicle. The proposed technique has the advantage that it contains mild assumptions about the principal point and skew values of the camera, and it does not require prior knowledge of the focal length, in contrast to traditional image-based approaches.Peer ReviewedPostprint (author's final draft

Hierarchical task control for aerial inspection

This paper presents a task oriented control strategy for aerial vehicles equipped with a robotic arm and a camera attached to its end-effector. With this setting the camera can reach a new set of orientations previously not feasible for the quadrotor. The over-actuation of the whole system is exploited with a hierarchical control law to achieve a primary task consisting on a visual servoing control, whilst secondary tasks can also be attained to minimize gravitational effects or undesired arm configurations. Results are shown in a Robot Operating System (ROS) simulation.Peer ReviewedPostprint (author’s final draft

Autonomous Motion Planning for Avatar Limbs

In this work, a new algorithm for autonomous avatar motion is presented. The new algorithm is based in the Rapidly-exploring Random Tree (RRT) and an appropriate ontology. It uses a novel approach for calculating the motion sequence planning for the different avatar limbs: legs or arms. First, the algorithm uses the information stored in the ontology concerning the avatar structure and the Degrees Of Freedom (DOFs) to obtain the basic actions for motion planning. Second, this information is used to perform the growth process in the RRT algorithm. Then, all this information is used to produce planning. The plans are generated by a random search for possible motions that respect the structural restrictions of the avatar on kinesiology studies. To avoid a big configuration space search, exploration, exploitation, and hill climbing are used in order to obtain motion plans

Exploiting the robot kinematic redundancy for emotion conveyance to humans as a lower priority task

Current approaches do not allow robots to execute a task and simultaneously convey emotions to users using their body motions. This paper explores the capabilities of the Jacobian null space of a humanoid robot to convey emotions. A task priority formulation has been implemented in a Pepper robot which allows the specification of a primary task (waving gesture, transportation of an object, etc.) and exploits the kinematic redundancy of the robot to convey emotions to humans as a lower priority task. The emotions, defined by Mehrabian as points in the pleasure–arousal–dominance space, generate intermediate motion features (jerkiness, activity and gaze) that carry the emotional information. A map from this features to the joints of the robot is presented. A user study has been conducted in which emotional motions have been shown to 30 participants. The results show that happiness and sadness are very well conveyed to the user, calm is moderately well conveyed, and fear is not well conveyed. An analysis on the dependencies between the motion features and the emotions perceived by the participants shows that activity correlates positively with arousal, jerkiness is not perceived by the user, and gaze conveys dominance when activity is low. The results indicate a strong influence of the most energetic motions of the emotional task and point out new directions for further research. Overall, the results show that the null space approach can be regarded as a promising mean to convey emotions as a lower priority task.Postprint (author's final draft