在这项工作中,我们开发了一种数学模型和用于鱼类机器人的机器人模板的仿真平台,即磁性,模块化,过度的机器人($ \ MU $机器人)。通过这个平台,我们通过加固学习系统地探索了设计和流体参数对游泳性能的影响。数学模型由两个相互作用的子系统,机器人动力学和流体动力学组成,并且流体动力学模型由反应性组分(加压和压力)和电阻部件(阻力和摩擦力)组成,然后为导出键而流动化机器人流体相互作用的“控制参数”。 $ \ mu $机器人通过控制谐波电压信号控制的磁执行器驱动,通过基于EM的政策超参数探索(EPHE)进行了优化,以最大化游泳速度。通过改变控制参数,通过ephe模拟和优化具有不同机器人模板变化的36例具有不同机器人模板变化(致动(NOA)和刚度)和流体动力学参数。结果表明,优化的Gaits(即,沿着身体的行波波的波长与模板变化和流体动力学参数无关。较高的NOA产生更高的速度,但每体长度较低,然而,每体长度的增益和较低的速度降低。身体和尾鳍步态动态由流体添加质量,弹簧和致动扭矩之间的相互作用,具有可忽略的流体电阻阻力的贡献。相比之下,推力产生由作用在尾鳍上的压力,因为稳定的游泳是由电阻力和压力之间的平衡导致的,从增加的群众和身体阻力的少量贡献。因此,添加质量力仅通过尾部动力学间接影响推力生成和游泳速度。
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微生物,特别是微型游泳者,对生物学和流体动力学的领域感兴趣的运动效率和机械效率。设计鞭打的微型和宏观机器人的挑战是从弹性和流体动力学的相互作用中随后的细长结构(例如棒状鞭毛)的几何非线性变形。某些类型的细菌如大肠杆菌通过在低雷诺流中旋转多个丝状结构来推动自己。这种多鞭状的推进机制与其他类型的细菌(如富轴霍乱)呈现的单鞭状机制定性不同。差异包括鞭毛形成束,以提高细胞运动性的方向稳定性,为细胞移动提供冗余,并提供鞭毛成为递送材料本身的能力。最重要的是,多鞭状的生物系统可以激发新型软机器,用于在人体内施用药物运输和递送。我们提出了一种宏观软机械硬件平台和用于多鞭状机器人的物理合理的仿真模型的计算框架。流体结构相互作用仿真将离散弹性棒算法与正则化的阶段段的方法耦合。由于Spillmann和Teschner,两个鞭毛之间的联系由基于惩罚的方法处理。我们在我们的实验和仿真结果之间显示比较,并验证模拟工具是否可以捕获此问题的基本物理。将多抹布机器人的稳定性和效率与单鞭状的对应物进行比较。
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我们探索粒状介质(GM)中软机器的运动,由细长杆的弹性变形产生。提出了由细菌的生理结构的低成本,迅速制造的机器人。它由刚性头部,带有电动机和电池的嵌入式和电池,以及多个弹性杆(我们的灯泡模型)来调查通用汽车的运动。弹性鞭毛在电机一端旋转,它们由于从GM的拖动而变形,推动机器人。外部拖动由鞭毛形状决定,而后者由于外部负载和弹力之间的竞争而改变。在该耦合的流体结构相互作用问题中,我们观察到增加鞭毛的数量可以减小或增加机器人的推进速度,这取决于系统的物理参数。这种简单机器人之间的功能关系中的这种非线性激励我们利用理论,数值模拟和实验来从根本上分析其力学。我们提出了一个简单的欧拉伯努利光束理论的分析框架,其能够定性地捕获这两种情况。当鞭毛变形小时,理论预测定量匹配实验。为了考虑经常在软机器人和微生物中遇到的几何非线性变形,我们实施了一种仿真框架,该框架包括弹性杆的离散微分几何形状模拟,这是一种基于电阻理论的拖曳模型,以及用于流体动力学的改进的斯托克斯法机器人头。与实验数据的比较表明模拟可以定量地预测机器人运动。总的来说,本文中提出的理论和数值工具可以在粒状或流体介质中的这类清晰的机器人的设计和控制来阐明。
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飞行动物具有高度复杂的物理特征,能够使用翅膀进行敏捷操作。拍打翅膀会产生影响空气动力的复杂唤醒结构,这可能很难建模。尽管可以使用流体结构相互作用对这些力进行建模,但它在计算上非常昂贵且难以制定。在本文中,我们遵循一种更简单的方法,通过使用相对较少的状态得出空气动力,并以简单的状态空间形式呈现它们。该公式利用PrandTL的提升线理论和Wagner的功能来确定作用在机翼上的不稳定空气动力学,然后将其与蝙蝠风格的机器人的实验数据进行比较,称为Aerobat。可以从该模型中评估模拟的尾边涡流脱落,然后可以分析基于尾流的步态设计方法,以改善机器人的空气动力学性能。
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Snakes and their bio-inspired robot counterparts have demonstrated locomotion on a wide range of terrains. However, dynamic vertical climbing is one locomotion strategy that has received little attention in the existing snake robotics literature. We demonstrate a new scansorial gait and robot inspired by the locomotion of the Pacific Lamprey. This new gait allows a robot to steer while climbing on flat, near-vertical surfaces. A reduced-order model is developed and used to explore the relationship between body actuation and vertical and lateral motions of the robot. Trident, the new wall climbing lamprey-inspired robot, demonstrates dynamic climbing on flat vertical surfaces with a peak net vertical stride displacement of 4.1 cm per step. Actuating at 1.3 Hz, Trident attains a vertical climbing speed of 4.8 cm/s (0.09 Bl/s) at specific resistance of 8.3. Trident can also traverse laterally at 9 cm/s (0.17 Bl/s). Moreover, Trident is able to make 14\% longer strides than the Pacific Lamprey when climbing vertically. The computational and experimental results demonstrate that a lamprey-inspired climbing gait coupled with appropriate attachment is a useful climbing strategy for snake robots climbing near vertical surfaces with limited push points.
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串联连接的机器人是希望在大规模灾害中的搜索和救援等限制空间中执行任务的候选人。这种机器人通常是韧带,我们假设肢体的添加可以改善移动性。然而,在设计和控制这种装置方面的挑战在于以提高移动性的方式协调高维冗余模块。在这里,我们开发了一个控制串联连接的多腿机器人的一般框架。具体地,我们结合了两种方法来构建一般的形状控制方案,其可以为各种机器人形态的有效运动提供自变形(“Gaits”)的基线模式。首先,我们从维度降低和生物步态分类方案中获取灵感,以产生身体变形和脚提升/降低的循环模式,其促进了任意基板接触图案的产生。其次,我们使用几何力学方法来促进识别这些起伏的最佳相位,以最大化速度和/或稳定性。我们的方案允许在扁平摩擦地形上的多腿机器人机车上的有效Gaits开发有多种数量的四肢(4,6,16,甚至0四肢)和身体致动能力(包括在Limbless设备上的侧壁Gaits)。通过适当协调身体波动和腿部放置,我们的框架结合了Limbless机器人(模块化)和腿机器人(移动性)的优势。我们预计我们的框架可以提供一般的控制方案,以便快速部署一般的多腿机器人,铺平往达在现实条件下遍历复杂环境的机器的方式。
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This study proposed a novel robotic gripper that can achieve grasping and infinite wrist twisting motions using a single actuator. The gripper is equipped with a differential gear mechanism that allows switching between the grasping and twisting motions according to the magnitude of the tip force applied to the finger. The grasping motion is activated when the tip force is below a set value, and the wrist twisting motion is activated when the tip force exceeds this value. "Twist grasping," a special grasping mode that allows the wrapping of a flexible thin object around the fingers of the gripper, can be achieved by the twisting motion. Twist grasping is effective for handling objects with flexible thin parts, such as laminated packaging pouches, that are difficult to grasp using conventional antipodal grasping. In this study, the gripper design is presented, and twist grasping is analyzed. The gripper performance is experimentally validated.
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A reduced order model of a generic submarine is presented. Computational fluid dynamics (CFD) results are used to create and validate a model that includes depth dependence and the effect of waves on the craft. The model and the procedure to obtain its coefficients are discussed, and examples of the data used to obtain the model coefficients are presented. An example of operation following a complex path is presented and results from the reduced order model are compared to those from an equivalent CFD calculation. The controller implemented to complete these maneuvers is also presented.
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Accurate simulation of soft mechanisms under dynamic actuation is critical for the design of soft robots. We address this gap with our differentiable simulation tool by learning the material parameters of our soft robotic fish. On the example of a soft robotic fish, we demonstrate an experimentally-verified, fast optimization pipeline for learning the material parameters from quasi-static data via differentiable simulation and apply it to the prediction of dynamic performance. Our method identifies physically plausible Young's moduli for various soft silicone elastomers and stiff acetal copolymers used in creation of our three different robotic fish tail designs. We show that our method is compatible with varying internal geometry of the actuators, such as the number of hollow cavities. Our framework allows high fidelity prediction of dynamic behavior for composite bi-morph bending structures in real hardware to millimeter-accuracy and within 3 percent error normalized to actuator length. We provide a differentiable and robust estimate of the thrust force using a neural network thrust predictor; this estimate allows for accurate modeling of our experimental setup measuring bollard pull. This work presents a prototypical hardware and simulation problem solved using our differentiable framework; the framework can be applied to higher dimensional parameter inference, learning control policies, and computational design due to its differentiable character.
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虽然在各种应用中广泛使用刚性机器人,但它们在他们可以执行的任务中受到限制,并且在密切的人机交互中可以保持不安全。另一方面,软机器鞋面超越了刚性机器人的能力,例如与工作环境,自由度,自由度,制造成本和与环境安全互动的兼容性。本文研究了纤维增强弹性机壳(释放)作为一种特定类型的软气动致动器的行为,可用于软装饰器。创建动态集参数模型以在各种操作条件下模拟单一免费的运动,并通知控制器的设计。所提出的PID控制器使用旋转角度来控制多项式函数之后的自由到限定的步进输入或轨迹的响应来控制末端执行器的方向。另外,采用有限元分析方法,包括释放的固有非线性材料特性,精确地评估释放的各种参数和配置。该工具还用于确定模块中多个释放的工作空间,这基本上是软机械臂的构建块。
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Humans can balance very well during walking, even when perturbed. But it seems difficult to achieve robust walking for bipedal robots. Here we describe the simplest balance controller that leads to robust walking for a linear inverted pendulum (LIP) model. The main idea is to use a linear function of the body velocity to determine the next foot placement, which we call linear foot placement control (LFPC). By using the Poincar\'e map, a balance criterion is derived, which shows that LFPC is stable when the velocity-feedback coefficient is located in a certain range. And that range is much bigger when stepping faster, which indicates "faster stepping, easier to balance". We show that various gaits can be generated by adjusting the controller parameters in LFPC. Particularly, a dead-beat controller is discovered that can lead to steady-state walking in just one step. The effectiveness of LFPC is verified through Matlab simulation as well as V-REP simulation for both 2D and 3D walking. The main feature of LFPC is its simplicity and inherent robustness, which may help us understand the essence of how to maintain balance in dynamic walking.
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This work presents an actuation framework for a bioinspired flapping drone called Aerobat. This drone, capable of producing dynamically versatile wing conformations, possesses 14 body joints and is tail-less. Therefore, in our robot, unlike mainstream flapping wing designs that are open-loop stable and have no pronounced morphing characteristics, the actuation, and closed-loop feedback design can pose significant challenges. We propose a framework based on integrating mechanical intelligence and control. In this design framework, small adjustments led by several tiny low-power actuators called primers can yield significant flight control roles owing to the robot's computational structures. Since they are incredibly lightweight, the system can host the primers in large numbers. In this work, we aim to show the feasibility of joint's motion regulation in Aerobat's untethered flights.
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机器人社区在为软机器人设备建模提供的理论工具的复杂程度中看到了指数增长。已经提出了不同的解决方案以克服与软机器人建模相关的困难,通常利用其他科学学科,例如连续式机械和计算机图形。这些理论基础通常被认为是理所当然的,这导致复杂的文献,因此,从未得到完整审查的主题。Withing这种情况下,提交的文件的目标是双重的。突出显示涉及建模技术的不同系列的常见理论根源,采用统一语言,以简化其主要连接和差异的分析。因此,对上市接近自然如下,并最终提供在该领域的主要作品的完整,解开,审查。
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In unstructured environments, robots run the risk of unexpected collisions. How well they react to these events is determined by how transparent they are to collisions. Transparency is affected by structural properties as well as sensing and control architectures. In this paper, we propose the collision reflex metric as a way to formally quantify transparency. It is defined as the total impulse transferred in collision, which determines the collision mitigation capabilities of a closed-loop robotic system taking into account structure, sensing, and control. We analyze the effect of motor scaling, stiffness, and configuration on the collision reflex of a system using an analytical model. Physical experiments using the move-until-touch behavior are conducted to compare the collision reflex of direct-drive and quasi-direct-drive actuators and robotic hands (Schunk WSG-50 and Dexterous DDHand.) For transparent systems, we see a counter-intuitive trend: the impulse may be lower at higher pre-impact velocities.
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在各种条件下行走期间关节阻抗的知识与临床决策以及机器人步态培训师,腿部假体,腿矫形器和可穿戴外骨骼的发展相关。虽然步行过程中的脚踝阻抗已经通过实验评估,但尚未识别步行期间的膝盖和髋关节阻抗。在这里,我们开发并评估了下肢扰动器,以识别跑步机行走期间髋关节,膝关节和踝关节阻抗。下肢扰动器(Loper)由致动器组成,致动器通过杆连接到大腿。 Loper允许将力扰动施加到自由悬挂的腿上,同时站立在对侧腿上,带宽高达39Hz。在以最小的阻抗模式下行走时,Loper和大腿之间的相互作用力低(<5N),并且对行走图案的效果小于正常行走期间的对象内变异性。使用摆动腿动力学的非线性多体动力学模型,在摆动阶段在速度为0.5米/秒的速度的九个受试者期间估计臀部,膝关节和踝关节阻抗。所识别的模型能够预测实验反应,因为分别占髋部,膝关节和踝部的平均方差为99%,96%和77%。对受试者刚度的平均分别在34-66nm / rad,0-3.5nm / rad,0-3.5nm / rad和2.5-24nm / rad的三个时间点之间变化,分别用于臀部,膝部和踝关节。阻尼分别在1.9-4.6 nms / rad,0.02-0.14 nms / rad和0.2-2.4 nms / rad的0.02-0.14 nms / rad供应到0.2-2.4nms / rad。发达的洛普勒对不受干扰的行走模式具有可忽略的影响,并且允许在摆动阶段识别臀部,膝关节和踝关节阻抗。
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Microswimmers can acquire information on the surrounding fluid by sensing mechanical queues. They can then navigate in response to these signals. We analyse this navigation by combining deep reinforcement learning with direct numerical simulations to resolve the hydrodynamics. We study how local and non-local information can be used to train a swimmer to achieve particular swimming tasks in a non-uniform flow field, in particular a zig-zag shear flow. The swimming tasks are (1) learning how to swim in the vorticity direction, (2) the shear-gradient direction, and (3) the shear flow direction. We find that access to lab frame information on the swimmer's instantaneous orientation is all that is required in order to reach the optimal policy for (1,2). However, information on both the translational and rotational velocities seem to be required to achieve (3). Inspired by biological microorganisms we also consider the case where the swimmers sense local information, i.e. surface hydrodynamic forces, together with a signal direction. This might correspond to gravity or, for micro-organisms with light sensors, a light source. In this case, we show that the swimmer can reach a comparable level of performance as a swimmer with access to lab frame variables. We also analyse the role of different swimming modes, i.e. pusher, puller, and neutral swimmers.
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对于宏观尺度的简单机器人平台,对群系统的控制相对良好地理解。然而,关于微型摩托管可以实现类似的结果,仍有几个未解决的问题。本文提出了一种基于全球磁场下磁化自推进Janus Microorobots的动态模型的建模框架。我们通过实验验证我们的模型,并提供了可以旨在准确描述微机器的行为的方法,同时建模他们的同时控制。该模型可以广泛地推广到低雷诺数环境中的其他微生物平台。
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动态运动是机器人武器的关键特征,使他们能够快速有效地执行任务。在任务空间运行时,软连续式操纵器目前尚未考虑动态参数。这种缺点使现有的软机器人缓慢并限制了他们处理外力的能力,特别是在物体操纵期间。我们通过使用动态操作空间控制来解决此问题。我们的控制方法考虑了3D连续体臂的动态参数,并引入了新模型,使多段软机械师能够在任务空间中顺利运行。先前仅为刚性机器人提供的先进控制方法现在适用于软机器;例如,潜在的场避免以前仅针对刚性机器人显示,现在延伸到软机器人。使用我们的方法,柔软的机械手现在可以实现以前不可能的各种任务:我们评估机械手在闭环控制实验中的性能,如拾取和障碍物避免,使用附加的软夹具抛出物体,并通过用掌握的粉笔绘制来故意将力施加到表面上。除了新的技能之外,我们的方法还提高了59%的跟踪精度,并将速度提高到19.3的尺寸,与最新的任务空间控制相比。通过这些新发现能力,软机器人可以开始挑战操纵领域的刚性机器人。我们固有的安全和柔顺的软机器人将未来的机器人操纵到一个不用的设置,其中人和机器人并行工作。
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软机器人技术有可能改变机器人运动,特别是软机器人游泳者提供了一种微创和自适应的解决方案,以探索和保存我们的海洋。不幸的是,当前的软机器人游泳者非常劣于进化的生物游泳者,尤其是在可控性,效率,可操作性和寿命方面。此外,设计软机器人所需的乏味的迭代制造和经验测试阻碍了它们的优化。在这项工作中,我们通过为设计和制造配备静电驱动的软机器人游泳者提供高效且直接的管道来应对这一挑战。我们简化了允许快速增材制造的过程,并显示如何使用可区分的模拟将简化模型与机器人游泳器的真实变形匹配。我们通过改变游泳者的拮抗肌肉的电压和驱动频率来对制造的游泳者进行多个实验。我们展示了在液态油中移动时的电压和频率如何改变游泳者的运动速度,并在前进的游泳速度下观察到明显的最佳选择。我们提出的可区分模拟模型具有各种下游应用,例如游泳者的控制和形状优化;通过我们的SIM到现实匹配,可以将优化结果直接映射回真实机器人。
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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。
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