Animals run robustly in diverse terrain. This locomotion robustness is puzzling because axon conduction velocity is limited to a few ten meters per second. If reflex loops deliver sensory information with significant delays, one would expect a destabilizing effect on sensorimotor control. Hence, an alternative explanation describes a hierarchical structure of low-level adaptive mechanics and high-level sensorimotor control to help mitigate the effects of transmission delays. Motivated by the concept of an adaptive mechanism triggering an immediate response, we developed a tunable physical damper system. Our mechanism combines a tendon with adjustable slackness connected to a physical damper. The slack damper allows adjustment of damping force, onset timing, effective stroke, and energy dissipation. We characterize the slack damper mechanism mounted to a legged robot controlled in open-loop mode. The robot hops vertically and planar over varying terrains and perturbations. During forward hopping, slack-based damping improves faster perturbation recovery (up to 170%) at higher energetic cost (27%). The tunable slack mechanism auto-engages the damper during perturbations, leading to a perturbation-trigger damping, improving robustness at minimum energetic cost. With the results from the slack damper mechanism, we propose a new functional interpretation of animals' redundant muscle tendons as tunable dampers.

大多数腿部机器人都是由串行安装链路和执行器的腿部结构构建的，并通过复杂的控制器和传感器反馈来控制。相比之下，动物发展了多段腿，关节之间的机械耦合以及多段的脚。它们在所有地形上运行敏捷，可以说是通过更简单的运动控制。在这里，我们专注于开发抗原在自然地形上也滑落和下沉的脚步机制。我们提出了安装在具有多接头机械肌腱耦合的鸟类灵感机器人腿上的多段脚的首先结果。我们的单段和两段机械自适应的脚显示在开始滑动之前，在多个软和硬质基材上显示了可行的水平力。我们还观察到，与球形和圆柱 - 脚相比，分割的脚减少了软底物上的下沉。我们报告了多段脚如何提供非常适合双皮亚机器人的可行压力点的范围范围，还适用于斜坡和自然地形上的四倍机器人。我们的结果还提供了对诸如级别鸟类等动物的分段脚的功能理解。

人类的腿部运动受人体和神经控制的自然动态的控制。假定有助于人类行走效率高的一种机制是冲动的脚踝推断，它可能为挥杆腿弹射器提供动力。然而，尚不清楚人类下腿的机制，其复杂的肌肉弯曲单元跨越了单个关节和多个关节。腿部机器人允许在实际步行步态中测试复杂的腿力学，控制和环境之间的相互作用。我们开发了一个高0.49m，2.2千克的拟人化型双足机器人，带有比目鱼和甲壳虫肌肉弯曲单元，由线性弹簧代表，在机器人的踝关节和膝关节周围充当单型和二子弹性结构。我们测试了三个比目鱼和胃弹簧螺旋形构型对踝关节功率曲线的影响，踝关节和膝关节运动的协调，总运输成本和步行速度。我们用前馈中央模式发生器控制了机器人，在1.0Hz运动频率下，步行速度在0.35m/s和0.57m/s之间，腿长为0.35m。我们发现所有三种配置之间的差异。比目鱼弹簧刺刺调节机器人的速度和能量效率可能是通过踝关节放大的，而胃刺的弹簧螺旋体在推下时改变了脚踝和膝关节之间的运动配位。

Object detectors are conventionally trained by a weighted sum of classification and localization losses. Recent studies (e.g., predicting IoU with an auxiliary head, Generalized Focal Loss, Rank & Sort Loss) have shown that forcing these two loss terms to interact with each other in non-conventional ways creates a useful inductive bias and improves performance. Inspired by these works, we focus on the correlation between classification and localization and make two main contributions: (i) We provide an analysis about the effects of correlation between classification and localization tasks in object detectors. We identify why correlation affects the performance of various NMS-based and NMS-free detectors, and we devise measures to evaluate the effect of correlation and use them to analyze common detectors. (ii) Motivated by our observations, e.g., that NMS-free detectors can also benefit from correlation, we propose Correlation Loss, a novel plug-in loss function that improves the performance of various object detectors by directly optimizing correlation coefficients: E.g., Correlation Loss on Sparse R-CNN, an NMS-free method, yields 1.6 AP gain on COCO and 1.8 AP gain on Cityscapes dataset. Our best model on Sparse R-CNN reaches 51.0 AP without test-time augmentation on COCO test-dev, reaching state-of-the-art. Code is available at https://github.com/fehmikahraman/CorrLoss

This paper expounds the design and control of a new Variable Stiffness Series Elastic Actuator (VSSEA). It is established by employing a modular mechanical design approach that allows us to effectively optimise the stiffness modulation characteristics and power density of the actuator. The proposed VSSEA possesses the following features: i) no limitation in the work-range of output link, ii) a wide range of stiffness modulation (~20Nm/rad to ~1KNm/rad), iii) low-energy-cost stiffness modulation at equilibrium and non-equilibrium positions, iv) compact design and high torque density (~36Nm/kg), and v) high-speed stiffness modulation (~3000Nm/rad/s). Such features can help boost the safety and performance of many advanced robotic systems, e.g., a cobot that physically interacts with unstructured environments and an exoskeleton that provides physical assistance to human users. These features can also enable us to utilise variable stiffness property to attain various regulation and trajectory tracking control tasks only by employing conventional controllers, eliminating the need for synthesising complex motion control systems in compliant actuation. To this end, it is experimentally demonstrated that the proposed VSSEA is capable of precisely tracking desired position and force control references through the use of conventional Proportional-Integral-Derivative (PID) controllers.

Generative models learned from training using deep learning methods can be used as priors in inverse under-determined inverse problems, including imaging from sparse set of measurements. In this paper, we present a novel hierarchical deep-generative model MrSARP for SAR imagery that can synthesize SAR images of a target at different resolutions jointly. MrSARP is trained in conjunction with a critic that scores multi resolution images jointly to decide if they are realistic images of a target at different resolutions. We show how this deep generative model can be used to retrieve the high spatial resolution image from low resolution images of the same target. The cost function of the generator is modified to improve its capability to retrieve the input parameters for a given set of resolution images. We evaluate the model's performance using the three standard error metrics used for evaluating super-resolution performance on simulated data and compare it to upsampling and sparsity based image sharpening approaches.

Measuring and monitoring soil organic carbon is critical for agricultural productivity and for addressing critical environmental problems. Soil organic carbon not only enriches nutrition in soil, but also has a gamut of co-benefits such as improving water storage and limiting physical erosion. Despite a litany of work in soil organic carbon estimation, current approaches do not generalize well across soil conditions and management practices. We empirically show that explicit modeling of cause-and-effect relationships among the soil processes improves the out-of-distribution generalizability of prediction models. We provide a comparative analysis of soil organic carbon estimation models where the skeleton is estimated using causal discovery methods. Our framework provide an average improvement of 81% in test mean squared error and 52% in test mean absolute error.

Self-supervised learning (SSL) methods such as WavLM have shown promising speech separation (SS) results in small-scale simulation-based experiments. In this work, we extend the exploration of the SSL-based SS by massively scaling up both the pre-training data (more than 300K hours) and fine-tuning data (10K hours). We also investigate various techniques to efficiently integrate the pre-trained model with the SS network under a limited computation budget, including a low frame rate SSL model training setup and a fine-tuning scheme using only the part of the pre-trained model. Compared with a supervised baseline and the WavLM-based SS model using feature embeddings obtained with the previously released 94K hours trained WavLM, our proposed model obtains 15.9% and 11.2% of relative word error rate (WER) reductions, respectively, for a simulated far-field speech mixture test set. For conversation transcription on real meeting recordings using continuous speech separation, the proposed model achieves 6.8% and 10.6% of relative WER reductions over the purely supervised baseline on AMI and ICSI evaluation sets, respectively, while reducing the computational cost by 38%.

Sociability is essential for modern robots to increase their acceptability in human environments. Traditional techniques use manually engineered utility functions inspired by observing pedestrian behaviors to achieve social navigation. However, social aspects of navigation are diverse, changing across different types of environments, societies, and population densities, making it unrealistic to use hand-crafted techniques in each domain. This paper presents a data-driven navigation architecture that uses state-of-the-art neural architectures, namely Conditional Neural Processes, to learn global and local controllers of the mobile robot from observations. Additionally, we leverage a state-of-the-art, deep prediction mechanism to detect situations not similar to the trained ones, where reactive controllers step in to ensure safe navigation. Our results demonstrate that the proposed framework can successfully carry out navigation tasks regarding social norms in the data. Further, we showed that our system produces fewer personal-zone violations, causing less discomfort.

从示范中学习（LFD）提供了一种方便的手段，可以在机器人固有坐标中获得示范时为机器人提供灵巧的技能。但是，长期和复杂技能中复杂错误的问题减少了其广泛的部署。由于大多数此类复杂的技能由组合的较小运动组成，因此将目标技能作为一系列紧凑的运动原语似乎是合理的。在这里，需要解决的问题是确保电动机以允许成功执行后续原始的状态结束。在这项研究中，我们通过提议学习明确的校正政策来关注这个问题，当时未达到原始人之间的预期过渡状态。校正策略本身是通过使用最先进的运动原始学习结构，条件神经运动原语（CNMP）来学习的。然后，学识渊博的校正政策能够以背景方式产生各种运动轨迹。拟议系统比学习完整任务的优点在模拟中显示了一个台式设置，其中必须以两个步骤将对象通过走廊推动。然后，通过为上身类人生物机器人配备具有在3D空间中的条上打结的技巧，显示了所提出的方法在现实世界中进行双重打结的适用性。实验表明，即使面对校正案例不属于人类示范集的一部分，机器人也可以执行成功的打结。