Smart Navigation in Surgical Robotics

La cirugía mínimamente invasiva, y concretamente la cirugía laparoscópica, ha supuesto un gran cambio en la forma de realizar intervenciones quirúrgicas en el abdomen. Actualmente, la cirugía laparoscópica ha evolucionado hacia otras técnicas aún menos invasivas, como es la cirugía de un solo puerto, en inglés Single Port Access Surgery. Esta técnica consiste en realizar una única incisión, por la que son introducidos los instrumentos y la cámara laparoscópica a través de un único trocar multipuerto. La principal ventaja de esta técnica es una reducción de la estancia hospitalaria por parte del paciente, y los resultados estéticos, ya que el trocar se suele introducir por el ombligo, quedando la cicatriz oculta en él. Sin embargo, el hecho de que los instrumentos estén introducidos a través del mismo trocar hace la intervención más complicada para el cirujano, que necesita unas habilidades específicas para este tipo de intervenciones. Esta tesis trata el problema de la navegación de instrumentos quirúrgicos mediante plataformas robóticas teleoperadas en cirugía de un solo puerto. En concreto, se propone un método de navegación que dispone de un centro de rotación remoto virtual, el cuál coincide con el punto de inserción de los instrumentos (punto de fulcro). Para estimar este punto se han empleado las fuerzas ejercidas por el abdomen en los instrumentos quirúrgicos, las cuales han sido medidas por sensores de esfuerzos colocados en la base de los instrumentos. Debido a que estos instrumentos también interaccionan con tejido blando dentro del abdomen, lo cual distorsionaría la estimación del punto de inserción, es necesario un método que permita detectar esta circunstancia. Para solucionar esto, se ha empleado un detector de interacción con tejido basado en modelos ocultos de Markov el cuál se ha entrenado para detectar cuatro gestos genéricos. Por otro lado, en esta tesis se plantea el uso de guiado háptico para mejorar la experiencia del cirujano cuando utiliza plataformas robóticas teleoperadas. En concreto, se propone la técnica de aprendizaje por demostración (Learning from Demonstration) para generar fuerzas que puedan guiar al cirujano durante la resolución de tareas específicas. El método de navegación propuesto se ha implantado en la plataforma quirúrgica CISOBOT, desarrollada por la Universidad de Málaga. Los resultados experimentales obtenidos validan tanto el método de navegación propuesto, como el detector de interacción con tejido blando. Por otro lado, se ha realizado un estudio preliminar del sistema de guiado háptico. En concreto, se ha empleado una tarea genérica, la inserción de una clavija, para realizar los experimentos necesarios que permitan demostrar que el método propuesto es válido para resolver esta tarea y otras similares

Path planning for reconfigurable rovers in planetary exploration

This paper introduces a path planning algorithm that takes into consideration different locomotion modes in a wheeled reconfigurable rover. Such algorithm, based on Fast Marching, calculates the optimal path in terms of power consumption between two positions, providing the most appropriate locomotion mode to be used at each position. Finally, the path planning algorithm is validated on a virtual Martian scene created within the V-REP simulation platform, where a virtual model of a planetary rover prototype is controlled by the same software that is used on the real one. Results of this contribution also demonstrate how the use of two locomotion modes, wheel-walking and normal-driving, can reduce the power consumption for a particular area.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Multi-scale path planning for a planetary exploration vehicle with multiple locomotion modes

Planetary exploration vehicles (rovers) can encounter with a great variety of situations. Most of them are related to the terrain, which can cause the end of the mission if these vehicles are not able to traverse it. It was the case of Spirit rover, which got stuck in loose sand, making it impossible to continue advancing. A solution to this is to make rovers capable of modifying their locomotion to traverse terrains with particular terramechanic parameters.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Path Planning for Reconfigurable Rovers in Planetary Exploration

This paper introduces a path planning algorithm that takes into consideration different locomotion modes in a wheeled reconfigurable rover. Power consumption and traction are estimated by means of simplified dynamics models for each locomotion mode. In particular, wheel-walking and normaldriving are modeled for a planetary rover prototype. These models are then used to define the cost function of a path planning algorithm based on fast marching. It calculates the optimal path, in terms of power consumption, between two positions, providing the most appropriate locomotion mode to be used at each position. Finally, the path planning algorithm was implemented in V-REP simulation software and a Martian area was used to validate it. Results of this contribution also demonstrate how the use of these locomotion modes would reduce the power consumption for a particular area.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

GlSch: Observation Scheduler for the GLORIA Telescope Network

This paper proposes the design and development of a scheduler for the GLORIA telescope network. This network, which main objective is to make astronomy closer to citizens in general, is formed by 18 telescopes spread over four continents and both hemispheres. Part of the management of this network is made by the network scheduler. It receives the observation requests made by the GLORIA users and then sends it to the most suitable telescope. A key module of the network scheduler is the telescope decision algorithm that makes possible to choose the best telescope, and thus avoiding offering an observation to a telescope that cannot execute it. This paper shows two different telescope decision algorithms: the first one is only based on weather forecast, meanwhile the second one uses fuzzy logic and information from each network telescope. Both algorithms were deployed in the GLORIA network. The achieved results coupled with a comparative of their performance is shown. Moreover, the network scheduler architecture, based on a hybrid distributed-centralized schema, is detailed.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Efficient Autonomous Navigation for Planetary Rovers with Limited Resources

Rovers operating on Mars are in need of more and more autonomous features to ful ll their challenging mission requirements. However, the inherent constraints of space systems make the implementation of complex algorithms an expensive and difficult task. In this paper we propose a control architecture for autonomous navigation. Efficient implementations of autonomous features are built on top of the current ExoMars navigation method, enhancing the safety and traversing capabilities of the rover. These features allow the rover to detect and avoid hazards and perform long traverses by following a roughly safe path planned by operators on ground. The control architecture implementing the proposed navigation mode has been tested during a field test campaign on a planetary analogue terrain. The experiments evaluated the proposed approach, autonomously completing two long traverses while avoiding hazards. The approach only relies on the optical Localization Cameras stereobench, a sensor that is found in all rovers launched so far, and potentially allows for computationally inexpensive long-range autonomous navigation in terrains of medium difficulty

Coupled path and motion planning for a rover-manipulator system

This paper introduces a motion planning strategy aimed at the coordination of a rover and manipulator. The main purpose is to fetch samples of scientific interest that could be placed on difficult locations, requiring to maximize the workspace of the combined system. In order to validate this strategy, a simulation environment has been built, based on the VORTEX Studio platform. A virtual model of the ExoTer rover prototype, owned by the European Space Agency, has been used together with the same robot control software. Finally, we show in this paper the benefits of validating the proposed strategy on simulation, prior to its future use on the real experimental rover.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tec

Teleoperación de Instrumentos Quirúrgicos Articulados

En este trabajo se describe la plataforma CISOBOT, desarrollada por la Universidad de Málaga para intervenciones de cirugía mínimamente invasiva, así como su ampliación a través del diseño mecatrónico de un instrumento motorizado que permite mover el extremo de este. El objetivo de esta plataforma es el estudio de nuevos algoritmos de control que permitan la teleoperación bilateral y el empleo de guiado hápticoUniversidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Multi-stage warm started optimal motion planning for over-actuated mobile platforms

This work presents a computationally lightweight motion planner for over-actuated platforms. For this purpose, a general state-space model for mobile platforms with several kinematic chains is defined, which considers dynamics, nonlinearities and constraints. The proposed motion planner is based on a sequential multi-stage approach that takes advantage of the warm start on each step. Firstly, a globally optimal and smooth 2D/3D trajectory is generated using the Fast Marching Method. This trajectory is fed as a warm start to a sequential linear quadratic regulator that is able to generate an optimal motion plan without constraints for all the platform actuators. Finally, a feasible motion plan is generated considering the constraints defined in the model. In this respect, the sequential linear quadratic regulator is employed again, taking the previously generated unconstrained motion plan as a warm start. The motion planner has been deployed into the Exomars Testing Rover of the European Space Agency. This rover is an Ackermann-capable planetary exploration testbed that is equipped with a robotic arm. Several experiments were carried out demonstrating that the proposed approach speeds up the computation time and increases the success ratio for a martian sample retrieval mission, which can be considered as a representative use case of goal-constrained trajectory generation for an over-actuated mobile platform.This work has been partially funded by the EU-H2020 project entitled “Cooperative Robots for Extreme Environments” (CoRob-X) under grant agreement: 101004130. Funding for open access charge: Universidad de Málaga / CBUA”

Dynamic path planning for reconfigurable rovers using a multi-layered grid

Autonomy on rovers is desirable in order to extend the traversed distance, and therefore, maximize the number of places visited during the mission. It depends heavily on the information that is available for the traversed surface on other planet. This information may come from the vehicle’s sensors as well as from orbital images. Besides, future exploration missions may consider the use of reconfigurable rovers, which are able to execute multiple locomotion modes to better adapt to different terrains. With these considerations, a path planning algorithm based on the Fast Marching Method is proposed. Environment information coming from different sources is used on a grid formed by two layers. First, the Global Layer with a low resolution, but high extension is used to compute the overall path connecting the rover and the desired goal, using a cost function that takes advantage of the rover locomotion modes. Second, the Local Layer with higher resolution but limited distance is used where the path is dynamically repaired because of obstacle presence. Finally, we show simulation and field test results based on several reconfigurable and non-reconfigurable rover prototypes and a experimental terrain