SMUG Planner: A Safe Multi-Goal Planner for Mobile Robots in Challenging Environments

Robotic exploration or monitoring missions require mobile robots to autonomously and safely navigate between multiple target locations in potentially challenging environments. Currently, this type of multi-goal mission often relies on humans designing a set of actions for the robot to follow in the form of a path or waypoints. In this work, we consider the multi-goal problem of visiting a set of pre-defined targets, each of which could be visited from multiple potential locations. To increase autonomy in these missions, we propose a safe multi-goal (SMUG) planner that generates an optimal motion path to visit those targets. To increase safety and efficiency, we propose a hierarchical state validity checking scheme, which leverages robot-specific traversability learned in simulation. We use LazyPRM* with an informed sampler to accelerate collision-free path generation. Our iterative dynamic programming algorithm enables the planner to generate a path visiting more than ten targets within seconds. Moreover, the proposed hierarchical state validity checking scheme reduces the planning time by 30% compared to pure volumetric collision checking and increases safety by avoiding high-risk regions. We deploy the SMUG planner on the quadruped robot ANYmal and show its capability to guide the robot in multi-goal missions fully autonomously on rough terrain

Better consumer protection when buying newly produced tenant-ownership apartments : A review of the changes proposed in SOU 2017:31 and bill 2021/22:171

Ett köp av en nyproducerad bostadsrätt är en tidskrävande process som består av flera olika steg. Det är också en transaktion som står för ett stort värde. Därför är det extra viktigt att köparen känner till vilka risker som finns och de många problem som kan uppstå under processen, innan avtal ingås om att köpa den nya lägenheten. Dessa risker och problem kan vara både av privatekonomisk och associationsrättslig natur. Det är således viktigt att köparen är informerad om hur processen genomförs, dess delar och ur vilka situationer som nämnda risker och problem kan uppkomma. I denna uppsats utreder vi de situationer en köpare kan utsättas för under köpprocessen, fråntidigt intresse till inflyttning. Vi för också fram de för köp av nyproduktion relevanta regleringarsom föreslagits i SOU 2017:31 samt prop. 2021/22:171. Vilka konsumentskyddande egenskaper de har och hur de förhåller sig till gällande lagstiftning på området. Vi djupdyker även i dessa regleringar för att förstå bakgrunden till dem samt de konsumenträttsliga situationer som de är tänkta att lösa. Vikt läggs även vid de remissyttranden som myndigheter och intresseorganisationer har lämnat på både SOU och propositionens promemoria. En analys görs av de väsentliga förbättringar som innehållet i förarbetena kan komma att innebära för konsumentskyddet vid köp av nyproducerade bostadsrätter. Förbättringarna analyseras i flera av de steg som köpprocessen består av. Slutligen identifieras kvarstående särskilda brister i konsumentskyddet och en diskussion kring hur dessa kan lösas förs fram.

Better consumer protection when buying newly produced tenant-ownership apartments : A review of the changes proposed in SOU 2017:31 and bill 2021/22:171

Ett köp av en nyproducerad bostadsrätt är en tidskrävande process som består av flera olika steg. Det är också en transaktion som står för ett stort värde. Därför är det extra viktigt att köparen känner till vilka risker som finns och de många problem som kan uppstå under processen, innan avtal ingås om att köpa den nya lägenheten. Dessa risker och problem kan vara både av privatekonomisk och associationsrättslig natur. Det är således viktigt att köparen är informerad om hur processen genomförs, dess delar och ur vilka situationer som nämnda risker och problem kan uppkomma. I denna uppsats utreder vi de situationer en köpare kan utsättas för under köpprocessen, fråntidigt intresse till inflyttning. Vi för också fram de för köp av nyproduktion relevanta regleringarsom föreslagits i SOU 2017:31 samt prop. 2021/22:171. Vilka konsumentskyddande egenskaper de har och hur de förhåller sig till gällande lagstiftning på området. Vi djupdyker även i dessa regleringar för att förstå bakgrunden till dem samt de konsumenträttsliga situationer som de är tänkta att lösa. Vikt läggs även vid de remissyttranden som myndigheter och intresseorganisationer har lämnat på både SOU och propositionens promemoria. En analys görs av de väsentliga förbättringar som innehållet i förarbetena kan komma att innebära för konsumentskyddet vid köp av nyproducerade bostadsrätter. Förbättringarna analyseras i flera av de steg som köpprocessen består av. Slutligen identifieras kvarstående särskilda brister i konsumentskyddet och en diskussion kring hur dessa kan lösas förs fram.

Comparison of Legged Single-Robot and Multi-Robot Planetary Analog Exploration Systems

The development of ongoing and future planetary exploration missions calls for novel, effective robotic exploration technologies. Inspired by the recent developments in terrestrial robotic teams, we investigate the design and deployment of heterogeneous robotic teams and the accompanying operation concepts in planetary analog missions. Specifically, we describe a single-robot and a multi-robot system we developed for analog exploration missions using legged robots. We focus on the field trials using these systems at the ESA/ESRIC Space Resources Challenge. We show a performance comparison of our approaches, including payload utilization, mapping performance, redundancy, and human-robot interaction metrics. Furthermore, we present our lessons learned on developing and testing single-robot and multi-robot exploration systems. Our work shows that a heterogeneous robotic team allows higher payload utilization and a safer redundancy concept than single-robot approaches. However, a higher level of autonomy per robot is required to scale up the multi-robot approach

SMUG Planner: A Safe Multi-Goal Planner for Mobile Robots in Challenging Environments

Robotic exploration or monitoring missions require mobile robots to autonomously and safely navigate between multiple target locations in potentially challenging environments. Currently, this type of multi-goal mission often relies on humans designing a set of actions for the robot to follow in the form of a path or waypoints. In this letter, we consider the multi-goal problem of visiting a set of pre-defined targets, each of which could be visited from multiple potential locations. To increase autonomy in these missions, we propose a safe multi-goal (SMUG) planner that generates an optimal motion path to visit those targets. To increase safety and efficiency, we propose a hierarchical state validity checking scheme, which leverages robot-specific traversability learned in simulation. We use LazyPRM* with an informed sampler to accelerate collision-free path generation. Our iterative dynamic programming algorithm enables the planner to generate a path visiting more than ten targets within seconds. Moreover, the proposed hierarchical state validity checking scheme reduces the planning time by 30% compared to pure volumetric collision checking and increases safety by avoiding high-risk regions. We deploy the SMUG planner on the quadruped robot ANYmal and show its capability to guide the robot in multi-goal missions fully autonomously on rough terrain.ISSN:2377-376

Physiologic Data-Driven Iterative Learning Control for Left Ventricular Assist Devices

Continuous flow ventricular assist devices (cfVADs) constitute a viable and increasingly used therapy for end-stage heart failure patients. However, they are still operating at a fixed-speed mode that precludes physiological cfVAD response and it is often related to adverse events of cfVAD therapy. To ameliorate this, various physiological controllers have been proposed, however, the majority of these controllers do not account for the lack of pulsatility in the cfVAD operation, which is supposed to be beneficial for the physiological function of the cardiovascular system. In this study, we present a physiological data- driven iterative learning controller (PDD-ILC) that accurately tracks predefined pump flow trajectories, aiming to achieve physiological, pulsatile, and treatment-driven response of cfVADs. The controller has been extensively tested in an in-silico environment under various physiological conditions, and compared with a physiologic pump flow proportional-integral-derivative controller (PF-PIDC) developed in this study as well as the constant speed (CS) control that is the current state of the art in clinical practice. Additionally, two treatment objectives were investigated to achieve pulsatility maximization and left ventricular stroke work (LVSW) minimization by implementing copulsation and counterpulsation pump modes, respectively. Under all experimental conditions, the PDD-ILC as well as the PF-PIDC demonstrated highly accurate tracking of the reference pump flow trajectories, outperforming existing model-based iterative learning control approaches. Additionally, the developed controllers achieved the predefined treatment objectives and resulted in improved hemodynamics and preload sensitivities compared to the CS support.ISSN:2297-055

Concept Study of a Small-Scale Dynamic Legged Robot for Lunar Exploration

When it comes to the exploration of the lunar surface, many high-reward targets, such as the craters at the lunar south pole or the Aristarchus Plateau, lie in hard-to-reach areas due to steep slopes, crater rims, and unstructured terrain. Therefore, such high-risk high-reward targets are currently out of human and robotic reach. Legged robots present a promising approach to exploring hard-to-access targets on the Moon. Legged robot prototypes have shown impressive locomotion capabilities in sloped, unstructured terrain in analog environments. However, despite their success in locomotion validation tests, we currently lack a target- and mission-specific analysis and design of the locomotion pattern, the thermal requirements, and the power system. We have set our goal to develop a small-scale, legged, technology demonstration robot. In this paper, we present our conceptual work on such a robot, targeting a traverse distance of 200 m and a payload capability of 1.5 kg. Our study showcases a basic locomotion study that identifies a feasible gait and its power requirements on representative terrain. We then lay our major focus on a thermal and power model considering the environment, the robot, and task schedule with sufficient accuracy to fulfill our self-defined mission success criteria. We also investigate the influence of the system’s emissivity and absorptivity on the regulation of the robot’s temperature. The simulation results suggest feasibility for missions at latitudes of 24°S and 75°S using a small-scale dynamic legged robot. However, it becomes clear that further research is required to validate the accuracy of the model. Research in solar panel degradation due to dust perturbation in legged robots will be necessary as the solar panel degradation shows a significant impact on the mission duration. Furthermore a precise soil-robot view factor needs to be determined. The determination of a realistic multi layer insulation concept for SpaceHopper in a lunar environment will be necessary to validate the assumptions draw based on the results the simulations

Learning-based Design and Control for Quadrupedal Robots with Parallel-Elastic Actuators

Parallel-elastic joints can improve the efficiency and strength of robots by assisting the actuators with additional torques. For these benefits to be realized, a spring needs to be carefully designed. However, designing robots is an iterative and tedious process, often relying on intuition and heuristics. We introduce a design optimization framework that allows us to co-optimize a parallel elastic knee joint and locomotion controller for quadrupedal robots with minimal human intuition. We design a parallel elastic joint and optimize its parameters with respect to the efficiency in a model-free fashion. In the first step, we train a design-conditioned policy using model-free Reinforcement Learning, capable of controlling the quadruped in the predefined range of design parameters. Afterwards, we use Bayesian Optimization to find the best design using the policy. We use this framework to optimize the parallel-elastic spring parameters for the knee of our quadrupedal robot ANYmal together with the optimal controller. We evaluate the optimized design and controller in real-world experiments over various terrains. Our results show that the new system improves the torque-square efficiency of the robot by 33% compared to the baseline and reduces maximum joint torque by 30% without compromising tracking performance. The improved design resulted in 11% longer operation time on flat terrain.ISSN:2377-376

Traversing Steep and Granular Martian Analog Slopes With a Dynamic Quadrupedal Robot

Celestial bodies, such as the Moon and Mars are mainly covered by loose, granular soil, which is a notoriously challenging terrain to traverse with wheeled robots. Here, we present experimental work on traversing steep, granular slopes with the dynamically-walking quadrupedal robot SpaceBok. To adapt to the challenging environment, we developed passive-adaptive, planar feet and optimized studs to reduce sinkage and increase traction. Single-foot experiments revealed that a surface area of 110 cm2 per foot reduces sinkage to an acceptable level for the 22 kg robot, even on highly collapsible soil. Implementing several 12 mm studs increases traction by 22% to 66% on granular media compared to stud-less designs. Together with a terrain-adapting walking controller, we validate — for the first time — static and dynamic locomotion on Mars analog slopes of up to 25° (the maximum of the testbed). We evaluated the performance between point- and planar feet and static and dynamic gaits for safety, velocity, and energy consumption. We show that dynamic gaits are energetically more efficient than static ones, but are riskier on steep slopes. Our tests also revealed that energy consumption with planar feet increases drastically as slope inclination approaches the soil’s angle of repose. Point feet are less affected by slippage due to their excessive sinkage but, in turn, are prone to instabilities and tripping. Based on our findings, we present safe and energy-efficient, global, path-planning strategies for negotiating steep Martian topography.ISSN:2771-398