Materials that respond to external stimuli by expanding or contracting provide a transduction route that integrates sensing and actuation powered directly by the stimuli. This motivates us to build colloidal scale robots using these materials that can morph into arbitrary configurations. For intelligent use of global stimuli in robotic systems, computation ability needs to be incorporated within them. The challenge is to design an architecture that is compact, material agnostic, stable under stochastic forces and can employ stimuli-responsive materials. We present an architecture that computes combinatorial logic using mechanical gates that use muscle-like response - expansion and contraction - as circuit signal with additional benefits of logic circuitry being physically flexible and able to be retrofit to arbitrary robot bodies. We mathematically analyze gate geometry and discuss tuning it for the given requirements of signal dimension and magnitude. We validate the function and stability of the design at the colloidal scale using Brownian dynamics simulations. We also demonstrate the gate design using a 3D printed model. Finally, we simulate a complete robot that folds into Tetris shapes.
When a human performs a given specific task, it has been known that the central nervous system controls modularized muscle group, which is called muscle synergy. For human-robot interface design problem, therefore, the muscle synergy can be utilized to reduce the dimensionality of control signal as well as the complexity of classifying human posture and motion. In this paper, we propose an approach to design a human-robot interface which enables a human operator to transfer a kinodynamic control command to robotic systems. A key feature of the proposed approach is that the muscle synergy and c…
This paper shows a detailed modeling of three-link robotic finger that is actuated by nylon artificial muscles and a simulink model that can be used for numerical study of a robotic finger. The robotic hand prototype was recently demonstrated in recent publication Wu, L., Jung de Andrade, M., Saharan, L.,Rome, R., Baughman, R., and Tadesse, Y., 2017, Compact and Low-cost Humanoid Hand Powered by Nylon Artificial Muscles, Bioinspiration & Biomimetics, 12 (2). The robotic hand is a 3D printed, lightweight and compact hand actuated by silver-coated nylon muscles, often called Twisted and coiled P…
An Efficient Learning Control Framework With Sim-to-Real for String-Type Artificial Muscle-Driven Robotic Systems
Department of Advanced Manufacturing and Robotics, College of Engineering（先进制造与机器人学院）；State Key Laboratory of Turbulence and Complex Systems, Peking University（湍流与复杂系统国家重点实验室）
Southern University of Science and Technology（南方科技大学）；Massachusetts Institute of Technology（麻省理工学院）；Shenzhen Institute of Artificial Intelligence and Robotics for Society（深圳市人工智能与机器人研究院）；The Chinese University of Hong Kong（香港中文大学）
Supernumerary Robotics Device (SRD) is an ideal solution to provide robotic assistance in overhead manual manipulation. Since two arms are occupied for the overhead task, it is desired to have additional arms to assist us in achieving other subtasks such as supporting the far end of a long plate and pushing it upward to fit in the ceiling. In this study, a method that maps human muscle force to SRD for overhead task assistance is proposed. Our methodology is to utilize redundant DoFs such as the idle muscles in the leg to control the supporting force of the SRD. A sEMG device is worn on the op…
University of Stuttgart（斯图加特大学）；Max Planck Institute for Intelligent Systems（马克斯·普朗克智能系统研究所）；Hertie-Institute for Clinical Brain Research, University of Tübingen（赫蒂临床脑研究所，图宾根大学）
Humans are able to outperform robots in terms of robustness, versatility, and learning of new tasks in a wide variety of movements. We hypothesize that highly nonlinear muscle dynamics play a large role in providing inherent stability, which is favorable to learning. While recent advances have been made in applying modern learning techniques to muscle-actuated systems both in simulation as well as in robotics, so far, no detailed analysis has been performed to show the benefits of muscles when learning from scratch. Our study closes this gap and showcases the potential of muscle actuators for …
University of California, Santa Barbara（加州大学圣巴巴拉分校）；University of New South Wales（新南威尔士大学）
Conformable robotic systems are attractive for applications in which they can be used to actuate structures with large surface areas, to provide forces through wearable garments, or to realize autonomous robotic systems. We present a new family of soft actuators that we refer to as Fluidic Fabric Muscle Sheets (FFMS). They are composite fabric structures that integrate fluidic transmissions based on arrays of elastic tubes. These sheet-like actuators can strain, squeeze, bend, and conform to hard or soft objects of arbitrary shapes or sizes, including the human body. We show how to design and …
Generating stable walking gaits that yield natural locomotion when executed on robotic-assistive devices is a challenging task that often requires hand-tuning by domain experts. This paper presents an alternative methodology, where we propose the addition of musculoskeletal models directly into the gait generation process to intuitively shape the resulting behavior. In particular, we construct a multi-domain hybrid system model that combines the system dynamics with muscle models to represent natural multicontact walking. Provably stable walking gaits can then be generated for this model via t…
North Carolina State University（北卡罗来纳州立大学）；University of North Carolina at Chapel Hill（北卡罗来纳大学教堂山分校）
Existing robotic lower-limb prostheses use autonomous control to address cyclic, locomotive tasks, but they are inadequate to operate the prosthesis for daily activities that are non-cyclic and unpredictable. To address this challenge, this study aims to design a novel electromyography (EMG)-driven musculoskeletal model for volitional control of a robotic ankle-foot prosthesis. This controller places the user in continuous control of the device, allowing them to freely manipulate the prosthesis behavior at will. The Hill-type muscle model was used to model a dorsiflexor and a plantarflexor, wh…
The Hong Kong Polytechnic University（香港理工大学）；Delft University of Technology（代尔夫特理工大学）
Biological muscles have always attracted robotics researchers due to their efficient capabilities in compliance, force generation, and mechanical work. Many groups are working on the development of artificial muscles, however, state-of-the-art methods still fall short in performance when compared with their biological counterpart. Muscles with high force output are mostly rigid, whereas traditional soft actuators take much space and are limited in strength and producing displacement. In this work, we aim to find a reasonable trade-off between these features by mimicking the striated structure …
City University of Hong Kong（香港城市大学）；the University of Hong Kong（香港大学）
To achieve human-like dexterity for anthropomorphic robotic hands, it is essential to understand the biomechanics and control strategies of the human hand, in order to reduce the number of actuators being used without loosing hand flexibility. To this end, in this article, we propose a new interpretation about the working mechanism of the metacarpal (MCP) joint's extension and the underlying control strategies of the human hand, based on which we further propose a highly flexible finger design to achieve independent movements of interphalangeal (IP) joints and MCP joint. Besides, we consider t…
Soft robotics technologies have gained growing interest in recent years, which allows various applications from manufacturing to human-robot interaction. Pneumatic artificial muscle (PAM), a typical soft actuator, has been widely applied to soft robots. The compliance and resilience of soft actuators allow soft robots to behave compliant when interacting with unstructured environments, while the utilization of soft actuators also introduces nonlinearity and uncertainty. Inspired by Cerebellum's vital functions in control of human's physical movement, a neural network model of Cerebellum based …
Imitation Learning for Adaptive Control of a Virtual Soft Exoglove
Department of Informatics, King’s College London（信息学院，伦敦国王学院）；MyoLab；Harvard Medical School（哈佛医学院）；Spaulding Rehabilitation Hospital（斯波林康复医院）；Department of Bioengineering, Faculty of Engineering, Imperial College London（生物工程系，伦敦帝国理工学院工程学院）；John A. Paulson School of Engineering and Applied Sciences, Harvard University（哈佛大学约翰·A·保罗森工程与应用科学学院）
Multi-Mode Pneumatic Artificial Muscles Driven by Hybrid Positive-Negative Pressure
Department of Mechanical Engineering（机械工程系）；Tsinghua University（清华大学）；Beijing Key Laboratory of Transformative High-end Manufacturing Equipment and Technology（北京 transformative 高端制造装备与技术重点实验室）
Learning to Control Emulated Muscles in Real Robots: Towards Exploiting Bio-Inspired Actuator Morphology
Max Planck Institute for Intelligent Systems（马克斯·普朗克智能系统研究所）；Hertie Institute for Clinical Brain Research（赫特希临床脑研究所在）；Centre for Integrative Neuroscience（整合神经科学中心）；University of Tübingen（图宾根大学）；Distributed Intelligence（分布式智能）；Institute of Computer Engineering (ZITI)（计算机工程研究所）
University of Southern California（南加利福尼亚大学）；Google Brain（谷歌大脑）
Passive elastic elements can contribute to stability, energetic efficiency, and impact absorption in both biological and robotic systems. They also add dynamical complexity which makes them more challenging to model and control. The impact of this added complexity to autonomous learning has not been thoroughly explored. This is especially relevant to tendon-driven limbs whose cables and tendons are inevitably elastic. Here, we explored the efficacy of autonomous learning and control on a simulated bio-plausible tendon-driven leg across different tendon stiffness values. We demonstrate that inc…
We present the modeling, design, fabrication and feedback control of an earthworm-inspired soft robot capable of crawling on surfaces by actively manipulating the frictional force between its body and the surface. Earthworms are segmented worms composed of repeating units known as metameres. The muscle and setae structure embedded in each individual metamere makes possible its peristaltic locomotion both under and above ground. Here, we propose a pneumatically-driven soft robotic system made of parts analogous to the muscle and setae structure and can replicate the crawling motion of a single …
Muscle Coactivation in the Sky: Geometry and Pareto Optimality of Energy vs. Aerodynamic Promptness and Multirotors as Variable Stiffness Actuators
Robotics and Mechatronics Department, Electrical Engineering, Mathematics, and Computer Science (EEMCS) Faculty（代尔夫特理工大学机器人与机电系）；Department of Computer, Control and Management Engineering（罗马萨皮恩扎大学计算机、控制与管理工程系）
The objective of this work is to relate muscle effort distributions to the trajectory and resistance settings of a robotic exercise and rehabilitation machine. Muscular effort distribution, representing the participation of each muscle in the training activity, was measured with electromyography sensors (EMG) and defined as the individual activation divided by the total muscle group activation. A four degrees-of-freedom robot and its impedance control system are used to create advanced exercise protocols whereby the user is asked to follow a path against the machine's neutral path and resistan…
Human movement disorders or paralysis lead to the loss of control of muscle activation and thus motor control. Functional Electrical Stimulation (FES) is an established and safe technique for contracting muscles by stimulating the skin above a muscle to induce its contraction. However, an open challenge remains on how to restore motor abilities to human limbs through FES, as the problem of controlling the stimulation is unclear. We are taking a robotics perspective on this problem, by developing robot learning algorithms that control the ultimate humanoid robot, the human body, through electri…
Istituto Italiano di Tecnologia（意大利理工学院）；Fakulta Elektrotechnická, ČVUT v Praze（捷克理工大学电气工程学院）
Somatosensory inputs can be grossly divided into tactile (or cutaneous) and proprioceptive -- the former conveying information about skin stimulation, the latter about limb position and movement. The principal proprioceptors are constituted by muscle spindles, which deliver information about muscle length and speed. In primates, this information is relayed to the primary somatosensory cortex and eventually the posterior parietal cortex, where integrated information about body posture (postural schema) is presumably available. However, coming from robotics and seeking a biologically motivated m…
Cuttlebot: a platform demonstration for complex, autonomous, bio-inspired swimmers
School of Mechanical, Aerospace, and Manufacturing Engineering, University of Connecticut（康涅狄格大学机械、航空航天与制造工程学院）；Department of Mechanical and Industrial Engineering, University of Toronto（多伦多大学机械与工业工程系）；University of Connecticut, Institute of Materials Science（康涅狄格大学材料科学研究所）；Department of Mechanical and Aerospace Engineering, Princeton University（普林斯顿大学机械与航空航天工程系）
A central challenge in building robotic prostheses is the creation of a sensor-based system able to read physiological signals from the lower limb and instruct a robotic hand to perform various tasks. Existing systems typically perform discrete gestures such as pointing or grasping, by employing electromyography (EMG) or ultrasound (US) technologies to analyze muscle states. While estimating finger gestures has been done in the past by detecting prominent gestures, we are interested in detection, or inference, done in the context of fine motions that evolve over time. Examples include motions …
Royal Veterinary College（皇家兽医学院）；DeepMind（深度思维）；University of California, Irvine（加州大学欧文分校）；Imperial College London（帝国理工学院）
Muscle-actuated control is a research topic that spans multiple domains, including biomechanics, neuroscience, reinforcement learning, robotics, and graphics. This type of control is particularly challenging as bodies are often overactuated and dynamics are delayed and non-linear. It is however a very well tested and tuned actuation mechanism that has undergone millions of years of evolution with interesting properties exploiting passive forces and efficient energy storage of muscle-tendon units. To facilitate research on muscle-actuated simulation, we release a 3D musculoskeletal simulation o…
For many years, the idea of a human with bionic muscles immediately conjures up science fiction images of a TV series superhuman character that was implanted with bionic muscles and portrayed with strength and speed far superior to any normal human. As fantastic as this idea may seem, recent developments in electroactive polymers (EAP) may one day make such bionics possible. Polymers that exhibit large displacement in response to stimulation that is other than electrical signal were known for many years. Initially, EAP received relatively little attention due to their limited actuation capabil…
Machine-Learning-Enhanced Soft Robotic System Inspired by Rectal Functions for Investigating Fecal incontinence
Yamaguchi University（山口大学）；Tokyo Institute of Technology（东京工业大学）；Keio University（庆应义塾大学）；Research Center for Autonomous Systems Materialogy (ASMat), Institute of Innovative Research, Tokyo Institute of Technology（东京工业大学创新研究所自主系统材料学研究中心（ASMat））
Soft robots are promising for manipulation tasks thanks to their compliance, safety, and high degree of freedom. However, the commonly used bidirectional continuum segment design means soft robotic manipulators only function in a limited hemispherical workspace. This work increases a soft robotic arm's workspace by designing, fabricating, and controlling an additional soft prismatic actuator at the base of the soft arm. This actuator consists of pneumatic artificial muscles and a piston, making the actuator back-driveable. We increase the task space volume by 116\%, and we are now able to perf…
Machine Learning Driven Prediction of the Behavior of Biohybrid Actuators
Unconventional Computing Laboratory & School of Computing & Creative Technologies, College of Arts, Technology and Environment, University of the West of England（非常规计算实验室及计算与创意技术学院，艺术、科技与环境学院，西英格兰大学）；School of Computing & Creative Technologies, College of Arts, Technology and Environment, University of the West of England（计算与创意技术学院，艺术、科技与环境学院，西英格兰大学）；Institute for Bioengineering of Catalonia (IBEC), The Barcelona Institute for Science and Technology (BIST), Barcelona, Spain（加泰罗尼亚生物工程研究所（IBEC）、巴塞罗那科学技术研究所（BIST），巴塞罗那，西班牙）；Department of Electrical and Electronic Engineering, University of Cagliari（电子与电气工程系，卡利亚里大学）；Instituciò Catalana de Recerca i Estudis Avancats (ICREA) and Institute for Bioengineering of Catalonia (IBEC), The Barcelona Institute for Science and Technology (BIST), Barcelona, Spain（加泰罗尼亚先进研究中心（ICREA）和加泰罗尼亚生物工程研究所（IBEC）、巴塞罗那科学技术研究所（BIST），巴塞罗那，西班牙）
University of Colorado（科罗拉多大学）；Materials Science and Engineering Program, University of Colorado（科罗拉多大学材料科学与工程项目）；Department of Electrical Engineering, University of Colorado（科罗拉多大学电气工程系）；Department of Computer Science, University of Colorado（科罗拉多大学计算机科学系）
Soft robotics is a field of robotic system design characterized by materials and structures that exhibit large-scale deformation, high compliance, and rich multifunctionality. The incorporation of soft and deformable structures endows soft robotic systems with the compliance and resiliency that makes them well-adapted for unstructured and dynamic environments. While actuation mechanisms for soft robots vary widely, soft electrostatic transducers such as dielectric elastomer actuators (DEAs) and hydraulically amplified self-healing electrostatic (HASEL) actuators have demonstrated promise due t…
Adaptive Control for Triadic Human-Robot-FES Collaboration in Gait Rehabilitation: A Pilot Study
School of Informatics, University of Edinburgh（爱丁堡大学信息学院）；Rey Juan Carlos University（雷伊胡安卡洛斯大学）；Cajal Institute（卡哈尔研究所）；The Alan Turing Institute（艾伦·图灵研究所）
McGowan Institute for Regenerative Medicine（麦高恩再生医学研究所）；Robotics Institute（机器人研究所）；Carnegie Mellon University（卡内基梅隆大学）；Case Western Reserve University（凯斯西储大学）
Living systems can use a single periphery to perform a variety of tasks and adapt to a dynamic environment. This multifunctionality is achieved through the use of neural circuitry that adaptively controls the reconfigurable musculature. Current robotic systems struggle to flexibly adapt to unstructured environments. Through mimicry of the neuromechanical coupling seen in living organisms, robotic systems could potentially achieve greater autonomy. The tractable neuromechanics of the sea slug $\textit{Aplysia californica's}$ feeding apparatus, or buccal mass, make it an ideal candidate for appl…
Nanyang Technological University（南洋理工大学）；Harbin Institute of Technology, Shenzhen（哈尔滨工业大学（深圳））；University of Freiburg（弗莱堡大学）
While most insect-inspired robots come with a simple tarsus such as a hemispherical foot tip, insect legs have complex tarsal structures and claws, which enable them to walk on complex terrain. Their sharp claws can smoothly attach and detach on plant surfaces by actuating a single muscle. Thus, installing insect-inspired tarsus on legged robots would improve their locomotion on complex terrain. This paper shows that the tendon-driven ball-socket structure provides the tarsus both flexibility and rigidity, which is necessary for the beetle to walk on a complex substrate such as a mesh surface.…
