Survey of Visual and Force/Tactile Control of Robots for Physical Interaction in Spain

Sensors provide robotic systems with the information required to perceive the changes that happen in unstructured environments and modify their actions accordingly. The robotic controllers which process and analyze this sensory information are usually based on three types of sensors (visual, force/torque and tactile) which identify the most widespread robotic control strategies: visual servoing control, force control and tactile control. This paper presents a detailed review on the sensor architectures, algorithmic techniques and applications which have been developed by Spanish researchers in order to implement these mono-sensor and multi-sensor controllers which combine several sensors

A Robust approach to control robot manipulators by fusing visual and force information

In this paper, a method to combine visual and force information using the information obtained from the movement flow-based visual servoing system is proposed. This method allows not only to achieve a given desired position but also to specify the trajectory that the robot will follow from its initial position to its final one in the 3D space. This paper also extends the visual servoing system in order to increase the robustness when errors in the camera calibration parameters appear. Experiments using an eye-in-hand robotic system demonstrate the correct behaviour when important errors exist in the camera intrinsic parameters. After the description of this strategy, we then describe its application to an insertion task to be performed by the robotic system in which the joint use of visual and force information is required. To combine both sensorial systems, a position-based impedancecontrol system is implemented, which modifies the trajectory generated by the visual system depending on the robot’s interaction with its setting. This modification is performed without knowledge of the exact camera calibration parameters. Furthermore, the visual-force approach based on impedance control does not require having previous knowledge about the contact geometry.This work was funded by the Spanish MCYT project “Diseño, Implementación y Experimentación de Escenarios de Manipulación Inteligentes para Aplicaciones de Ensamblado y Desensamblado Automático” (DPI2005-06222) and by the project GV05/007: “Diseño y experimentación de estrategias de control visual-fuerza para sistemas flexibles de manipulación”