Retrograde-assisted Percutaneous Cystolitholapaxy versus Transurethral Cystolithotripsy with Holmium-YAG Laser, A Retrospective Study

Introduction: The retrograde approach is a modification that makes the percutaneous cystolitholapaxy (PCCL) a more trendy method, especially in operating rooms with limited facilities. The transurethral approach for bladder calculi lithotripsy by a laser has become popular among urologists. In this study, we investigate the feasibility and safety of retrograde assisted access for PCCL in comparison with transurethral cystolithotripsy by the holmium-YAG laser (Ho:YAG).Methods: According to the type of intervention, the patients were stratified to two matched groups. In the retrograde-assisted percutaneous cystolitholapaxy (RPCCL) group, a Benique was conducted through the urethra into the bladder; palpating the suprapubic region, an about 1.5 cm incision was done over the tip, then an Amplatz sheath was placed over it, treading into the bladder; further cystolitholapaxy was done by a routine order. In transurethral Ho: YAG laser lithotripsy (TULL) via 200 μm fiber vaporize the stone.Results: A total of 124 male patients with the mean age of 50.33 ± 9.64 years and the average stone burden of 3.35 ± 1.07 cm were included in the study. The most common cause of vesical calculi was spinal cord injury. Statistically significant differences were found in terms of the mean operation time in favor of the RPCCL group (P ≤ 0.05) and the mean hospital stay in favor of the TULL group (P ≤ 0.05). The stone-free rate (SFR) was 100% in both methods after a one month follow-up. None of the interventions changed to open surgery. There were not any major complications in both methods.Conclusion: RPCCL is a safe and effective method in bladder stone treatment and is applicable inmedical centers without Ho: YAG equipment

Dynamic Manipulability of the Center of Mass: A Tool to Study, Analyse and Measure Physical Ability of Robots

Azad M, Babic J, Mistry M. Dynamic Manipulability of the Center of Mass: A Tool to Study, Analyse and Measure Physical Ability of Robots. In: Proc. International Conference on Robotics and Automation (ICRA). Accepted

Uncertainty Averse Pushing with Model Predictive Path Integral Control

Planning robust robot manipulation requires good forward models that enable robust plans to be found. This work shows how to achieve this using a forward model learned from robot data to plan push manipulations. We explore learning methods (Gaussian Process Regression, and an Ensemble of Mixture Density Networks) that give estimates of the uncertainty in their predictions. These learned models are utilised by a model predictive path integral (MPPI) controller to plan how to push the box to a goal location. The planner avoids regions of high predictive uncertainty in the forward model. This includes both inherent uncertainty in dynamics, and meta uncertainty due to limited data. Thus, pushing tasks are completed in a robust fashion with respect to estimated uncertainty in the forward model and without the need of differentiable cost functions. We demonstrate the method on a real robot, and show that learning can outperform physics simulation. Using simulation, we also show the ability to plan uncertainty averse paths.Comment: Humanoids 2017. Supplementary video: https://youtu.be/LjYruxwxkP

Enhancement of the Thermal Energy Storage Using Heat-Pipe-Assisted Phase Change Material

Usage of phase change materials' (PCMs) latent heat has been investigated as a promising method for thermal energy storage applications. However, one of the most common disadvantages of using latent heat thermal energy storage (LHTES) is the low thermal conductivity of PCMs. This issue affects the rate of energy storage (charging/discharging) in PCMs. Many researchers have proposed different methods to cope with this problem in thermal energy storage. In this paper, a tubular heat pipe as a super heat conductor to increase the charging/discharging rate was investigated. The temperature of PCM, liquid fraction observations, and charging and discharging rates are reported. Heat pipe effectiveness was defined and used to quantify the relative performance of heat pipe-assisted PCM storage systems. Both experimental and numerical investigations were performed to determine the efficiency of the system in thermal storage enhancement. The proposed system in the charging/discharging process significantly improved the energy transfer between a water bath and the PCM in the working temperature range of 50 & DEG;C to 70 & DEG;C

Model Estimation and Control of Compliant Contact Normal Force

This paper proposes a method to realize desired contact normal forces between humanoids and their compliant environment. By using contact models, desired contact forces are converted to desired deformations of compliant surfaces. To achieve desired forces, deformations are controlled by controlling the contact point positions. Parameters of contact models are assumed to be known or estimated using the approach described in this paper. The proposed methods for estimating the contact parameters and controlling the contact normal force are implemented on a LWR KUKA IV arm. To verify both methods, experiments are performed with the KUKA arm while its end-effector is in contact with two different soft objects

Kinematics-Based Estimation of Contact Constraints Using Only Proprioception

Robots are increasingly being required to perform tasks which involve contacts with the environment. This paper addresses the problem of estimating environmental constraints on the robot's motion. We present a method which estimates such constraints, by computing the null space of a set of velocity vectors which differ from commanded velocities during contacts. We further extend this method to handle unilateral constraints, for example when the robot touches a rigid surface. Unlike previous work, our method is based on kinematics analysis, using only proprioceptive joint encoders, thus there is no need for either expensive force-torque sensors or tactile sensors at the contact points or any use of vision. We first show results of experiments with a simulated robot in a variety of situations, and we analyse the effect of various levels of observation noise on the resulting contact estimates. Finally we evaluate the performance of our method on two sets of experiments using a KUKA LWR IV manipulator, tasked with exploring and estimating the constraints caused by a horizontal surface and an inclined surface

The CoDyCo Project achievements and beyond: Towards Human Aware Whole-body Controllers for Physical Human Robot Interaction

International audienceThe success of robots in real-world environments is largely dependent on their ability to interact with both humans and said environment. The FP7 EU project CoDyCo focused on the latter of these two challenges by exploiting both rigid and compliant contacts dynamics in the robot control problem. Regarding the former, to properly manage interaction dynamics on the robot control side, an estimation of the human behaviours and intentions is necessary. In this paper we present the building blocks of such a human-in-the-loop controller, and validate them in both simulation and on the iCub humanoid robot using a human-robot interaction scenario. In this scenario, a human assists the robot in standing up from being seated on a bench