Simulating soft robots in cluttered environments remains an open problem due to the challenge of capturing complex dynamics and interactions with the environment. Furthermore, fast simulation is desired for quickly exploring robot behaviors in the context of motion planning. In this paper, we examine a particular class of inflated-beam soft growing robots called "vine robots", and present a dynamics simulator that captures general behaviors, handles robot-object interactions, and runs faster than real time. The simulator framework uses a simplified multi-link, rigid-body model with contact constraints. To narrow the sim-to-real gap, we develop methods for fitting model parameters based on video data of a robot in motion and in contact with an environment. We provide examples of simulations, including several with fit parameters, to show the qualitative and quantitative agreement between simulated and real behaviors. Our work demonstrates the capabilities of this high-speed dynamics simulator and its potential for use in the control of soft robots.
NVIDIA（英伟达）；University of Southern California（南加州大学）；University of Toronto（多伦多大学）；Vector Institute（向量研究所）；University of Washington（华盛顿大学）；University of Sydney（悉尼大学）
Robotic cutting of soft materials is critical for applications such as food processing, household automation, and surgical manipulation. As in other areas of robotics, simulators can facilitate controller verification, policy learning, and dataset generation. Moreover, differentiable simulators can enable gradient-based optimization, which is invaluable for calibrating simulation parameters and optimizing controllers. In this work, we present DiSECt: the first differentiable simulator for cutting soft materials. The simulator augments the finite element method (FEM) with a continuous contact m…
In recent years, Evolutionary Strategies were actively explored in robotic tasks for policy search as they provide a simpler alternative to reinforcement learning algorithms. However, this class of algorithms is often claimed to be extremely sample-inefficient. On the other hand, there is a growing interest in Differentiable Robot Simulators (DRS) as they potentially can find successful policies with only a handful of trajectories. But the resulting gradient is not always useful for the first-order optimization. In this work, we demonstrate how DRS gradient can be used in conjunction with Evol…
University of Southern California（南加州大学）；NVIDIA（英伟达）；University of Washington（华盛顿大学）；University of Toronto（多伦多大学）；Vector Institute（向量研究所）；University of Sydney（悉尼大学）
Robotic cutting of soft materials is critical for applications such as food processing, household automation, and surgical manipulation. As in other areas of robotics, simulators can facilitate controller verification, policy learning, and dataset generation. Moreover, differentiable simulators can enable gradient-based optimization, which is invaluable for calibrating simulation parameters and optimizing controllers. In this work, we present DiSECt: the first differentiable simulator for cutting soft materials. The simulator augments the finite element method (FEM) with a continuous contact m…
A Digital Twin Simulator of a Pastillation Process with Applications to Automatic Control based on Computer Vision
University of Wisconsin-Madison（威斯康星大学麦迪逊分校）；University of Waterloo（滑铁卢大学）；Princeton University（普林斯顿大学）；ExxonMobil Technology and Engineering（埃克森美孚技术与工程公司）
RAFL: Generalizable Sim-to-Real of Soft Robots with Residual Acceleration Field Learning
Department of Computer Science, Duke University（达特茅斯大学计算机科学系）；Department of Mechanical Engineering and Material Science（机械工程与材料科学系）；Department of Electrical and Computer Engineering（电气与计算机工程系）
Simulation is an important step in robotics for creating control policies and testing various physical parameters. Soft robotics is a field that presents unique physical challenges for simulating its subjects due to the nonlinearity of deformable material components along with other innovative, and often complex, physical properties. Because of the computational cost of simulating soft and heterogeneous objects with traditional techniques, rigid robotics simulators are not well suited to simulating soft robots. Thus, many engineers must build their own one-off simulators tailored to their syst…
Due to their ability to move without sliding relative to their environment, soft growing robots are attractive for deploying distributed sensor networks in confined spaces. Sensing of the state of such robots would also add to their capabilities as human-safe, adaptable manipulators. However, incorporation of distributed sensors onto soft growing robots is challenging because it requires an interface between stiff and soft materials, and the sensor network needs to undergo significant strain. In this work, we present a method for adding sensors to soft growing robots that uses flexible printed…
Soft growing robots are proposed for use in applications such as complex manipulation tasks or navigation in disaster scenarios. Safe interaction and ease of production promote the usage of this technology, but soft robots can be challenging to teleoperate due to their unique degrees of freedom. In this paper, we propose a human-centered interface that allows users to teleoperate a soft growing robot for manipulation tasks using arm movements. A study was conducted to assess the intuitiveness of the interface and the performance of our soft robot, involving a pick-and-place manipulation task. …
Linking Exteroception and Proprioception through Improved Contact Modeling for Soft Growing Robots
School of Mechanical Engineering, Purdue University, West Lafayette, IN, USA（帕克大学机械工程学院）；Department of Computer Science, Purdue University, West Lafayette, IN, USA（帕克大学计算机科学系）
Stanford University（斯坦福大学）；Korea University of Technology and Education（韩国技术教育大学）
Pneumatically operated soft growing robots that extend via tip eversion are well-suited for navigation in confined spaces. Adding the ability to interact with the environment using sensors and tools attached to the robot tip would greatly enhance the usefulness of these robots for exploration in the field. However, because the material at the tip of the robot body continually changes as the robot grows and retracts, it is challenging to keep sensors and tools attached to the robot tip during actuation and environment interaction. In this paper, we analyze previous designs for mounting to the t…
We present a user-friendly interface to teleoperate a soft robot manipulator in a complex environment. Key components of the system include a manipulator with a grasping end-effector that grows via tip eversion, gesture-based control, and haptic display to the operator for feedback and guidance. In the initial work, the operator uses the soft robot to build a tower of blocks, and future works will extend this to shared autonomy scenarios in which the human operator and robot intelligence are both necessary for task completion.
Department of Engineering and Architecture, University of Trieste, Italy（的里雅斯特大学工程与建筑系，意大利）
Voxel-based soft robots (VSRs) are aggregations of soft blocks whose design is amenable to optimization. We here present a software, 2D-VSR-Sim, for facilitating research concerning the optimization of VSRs body and brain. The software, written in Java, provides consistent interfaces for all the VSRs aspects suitable for optimization and considers by design the presence of sensing, i.e., the possibility of exploiting the feedback from the environment for controlling the VSR. We experimentally characterize, from a mechanical point of view, the VSRs that can be simulated with 2D-VSR-Sim and we d…
Developing Simulation Models for Soft Robotic Grippers in Webots
Faculty of Science and Engineering, University of Groningen（格罗宁根大学科学与工程学院）；School of Electrical Engineering and Informatics, Bandung Institute of Technology（班达理工大学电气工程与信息学院）
Purdue University（普渡大学）；Stanford University（斯坦福大学）；University of California, Santa Barbara（加利福尼亚大学圣巴巴拉分校）
Continuum and soft robots can leverage complex actuator shapes to take on useful shapes while actuating only a few of their many degrees of freedom. Continuum robots that also grow increase the range of potential shapes that can be actuated and enable easier access to constrained environments. Existing models for describing the complex kinematics involved in general actuation of continuum robots rely on simulation or well-behaved stress-strain relationships, but the non-linear behavior of the thin-walled inflated-beams used in growing robots makes these techniques difficult to apply. Here we d…
The University of Manchester（曼彻斯特大学）；Delft University of Technology（代尔夫特理工大学）
Soft robots can safely interact with environments because of their mechanical compliance. Self-collision is also employed in the modern design of soft robots to enhance their performance during different tasks. However, developing an efficient and reliable simulator that can handle the collision response well, is still a challenging task in the research of soft robotics. This paper presents a collision-aware simulator based on geometric optimization, in which we develop a highly efficient and realistic collision checking / response model incorporating a hyperelastic material property. Both act…
Massachusetts Institute of Technology（麻省理工学院）；Tsinghua University（清华大学）
Physical simulators have been widely used in robot planning and control. Among them, differentiable simulators are particularly favored, as they can be incorporated into gradient-based optimization algorithms that are efficient in solving inverse problems such as optimal control and motion planning. Simulating deformable objects is, however, more challenging compared to rigid body dynamics. The underlying physical laws of deformable objects are more complex, and the resulting systems have orders of magnitude more degrees of freedom and therefore they are significantly more computationally expe…
Stanford University（斯坦福大学）；University of North Carolina Chapel Hill（北卡罗来纳大学教堂山分校）；University of California Santa Barbara（加州大学圣巴巴拉分校）
Navigation and motion control of a robot to a destination are tasks that have historically been performed with the assumption that contact with the environment is harmful. This makes sense for rigid-bodied robots where obstacle collisions are fundamentally dangerous. However, because many soft robots have bodies that are low-inertia and compliant, obstacle contact is inherently safe. As a result, constraining paths of the robot to not interact with the environment is not necessary and may be limiting. In this paper, we mathematically formalize interactions of a soft growing robot with a planar…
SoMA: A Real-to-Sim Neural Simulator for Robotic Soft-body Manipulation
Fudan University, China（复旦大学）；Shanghai Artificial Intelligence Laboratory, China（上海人工智能实验室）；Shanghai Jiao Tong University, China（上海交通大学）；The Chinese University of Hong Kong, China（香港中文大学）；The University of Hong Kong, China（香港大学）
Stanford University（斯坦福大学）；University of California, Santa Barbara（加利福尼亚大学圣巴巴拉分校）
Tip-extending soft robots that "grow" via pneumatic eversion of their body material have demonstrated applications in exploration of cluttered environments. During growth, the motion and force of the robot tip can be controlled in three degrees of freedom using actuators that direct the tip in combination with extension. However, when reversal of the growth process is attempted by retracting the internal body material from the base, the robot body often responds by buckling rather than inverting the body material, making control of tip motion and force impossible. We present and validate a mod…
Shared-Control Teleoperation Paradigms on a Soft Growing Robot Manipulator
Kadir Has University（卡迪尔哈斯大学）；University of Naples Federico II（那不勒斯费德里科二世大学）；Stanford University（斯坦福大学）；Washington State University（华盛顿州立大学）；Purdue University（普渡大学）；UC Santa Barbara（加州大学圣巴巴拉分校）
High-Fidelity Multi-Body Simulator for Autonomous Racing
University of Modena and Reggio Emilia（摩德纳与雷焦艾米利亚大学）；Megaride S.r.l.（Megaride 有限责任公司）；University of Naples Federico II（那不勒斯费德里科二世大学）；Claytex（Claytex 公司）
