Pseudo-passive dynamic walkers designed by coupled evolution of the controller and morphology

In this paper we investigated the morphology and controller of biped robots. We viewed them as design components that together can induce dynamically stable bipedal locomotion. We conducted coupled evolution of the morphology and controller of a biped robot, consisting of nine links and eight joints, actuated by oscillators without sensor feedback in three-dimensional simulation. As a result, both pseudo-passive dynamic walkers and active-control walkers emerged, but the pseudo-passive dynamic walkers showed more dynamic stability than the active-control walkers. This is because compliant components in morphology function as noise filters and passive oscillators. Analysis on this latter class of walkers revealed that this was achieved by two novel functions: self-stabilization and self-regulation. Because these functions were handled by the passive dynamics induced in the robot morphology, due to its compliance, we concluded that a computational trade-off between the controller and morphology occurs in these devices. Finally, we have concluded that appropriate compliance is a key to achieving dynamical stability during locomotion.     

Nonlinear analysis of an indirectly controlled limit cycle walker

Towards controlling the frequency of limit cycle locomotion as well as adapting to rough terrain and performing specific tasks, a novel and indirect method has been recently introduced using an active wobbling mass attached to limit cycle walkers. One of the strongest advantages of the method is the easiness of its implementation, prompting its applicability to a wide variety of locomotion systems. To deeply understand the nonlinear dynamics for further enhancement of the methodology, we use a combined rimless wheel with an active wobbling mass as an example to perform nonlinear analysis in this paper. First, we introduce the simplified equation of motion and the gait frequency control method. Second, we obtain Arnold tongue, which represents region of entrained locomotion. In regions where the locomotion is not entrained, we explore chaotic and quasi-periodic gaits. To characterize bistability of two different locomotions that underlie hysteresis phenomena, basins of attraction for the two locomotions were computed. The present nonlinear analysis may help understanding the detailed mechanism of indirectly controlled limit cycle walkers.     

Design and control of an IPMC wormlike robot.

This paper presents an innovative wormlike robot controlled by cellular neural networks (CNNs) and made of an ionic polymer-metal composite (IPMC) self-actuated skeleton. The IPMC actuators, from which it is made of, are new materials that behave similarly to biological muscles. The idea that inspired the work is the possibility of using IPMCs to design autonomous moving structures. CNNs have already demonstrated their powerfulness as new structures for bio-inspired locomotion generation and control. The control scheme for the proposed IPMC moving structure is based on CNNs. The wormlike robot is totally made of IPMCs, and each actuator has to carry its own weight. All the actuators are connected together without using any other additional part, thereby constituting the robot structure itself. Worm locomotion is performed by bending the actuators sequentially from "tail" to "head," imitating the traveling wave observed in real-world undulatory locomotion. The activation signals are generated by a CNN. In the authors' opinion, the proposed strategy represents a promising solution in the field of autonomous and light structures that are capable of reconfiguring and moving in line with spatial-temporal dynamics generated by CNNs.     

Cooperative linear cargo transport with molecular spiders

Molecular spiders are nanoscale walkers made with DNA enzyme legs attached to a common body. They move over a surface of DNA substrates, cleaving them and leaving behind product DNA strands, which they are able to revisit. Simple one-dimensional models of spider motion show significant superdiffusive motion when the leg-substrate bindings are longer-lived than the leg-product bindings. This gives the spiders potential as a faster-than-diffusion transport mechanism. However, analysis shows that single-spider motion eventually decays into an ordinary diffusive motion, owing to the ever increasing size of the region of cleaved products. Inspired by cooperative behavior of natural molecular walkers, we propose a symmetric exclusion process model for multiple walkers interacting as they move over a one-dimensional lattice. We show that when walkers are sequentially released from the origin, the collective effect is to prevent the leading walkers from moving too far backwards. Hence, there is an effective outward pressure on the leading walkers that keeps them moving superdiffusively for longer times, despite the growth of the product region. Multi-spider systems move faster and farther than single spiders or systems with multiple simple random walkers.     

An adaptive, self-organizing dynamical system for hierarchical control of bio-inspired locomotion

In this paper, dynamical systems made up of locally coupled nonlinear units are used to control the locomotion of bio-inspired robots and, in particular, a simulation of an insect-like hexapod robot. These controllers are inspired by the biological paradigm of central pattern generators and are responsible for generating a locomotion gait. A general structure, which is able to change the locomotion gait according to environmental conditions, is introduced. This structure is based on an adaptive system, implemented by motor maps, and is able to learn the correct locomotion gait on the basis of a reward function. The proposed control system is validated by a large number of simulations carried out in a dynamic environment for simulating legged robots.     

A Framework for Augmented Reality using Non-Central Catadioptric Cameras

This paper proposes a strategy for a group of swarm robots to self-assemble into a single articulated(legged) structure in response to terrain difficulties during autonomous exploration. These articulated structures will have several articulated legs or backbones, so they are well suited to walk on difficult terrains like animals. There are three tasks in this strategy: exploration, self-assembly and locomotion. We propose a formation self-assembly method to improve self-assembly efficiency. At the beginning, a swarm of robots explore the environment using their sensors and decide whether to self-assemble and select a target configuration from a library to form some robotic structures to finish a task. Then, the swarm of robots will execute a self-assembling task to construct the corresponding configuration of an articulated robot. For the locomotion, with joint actuation from the connected robots, the articulated robot generates locomotive motions. Based on Sambot that are designed to unite swarm mobile and self-reconfigurable robots, we demonstrate the feasibility for a varying number of swarm robots to self-assemble into snake-like and multi-legged robotic structures. Then, the effectiveness and scalability of the strategy are discussed with two groups of experiments and it proves the formation self-assembly is more efficient in the end.     

Development of an underwater biomimetic microrobot with compact structure and flexible locomotion

Compact structure and flexibility is normally considered as a pair of incompatible characteristics for legged microrobots. Most robots choose complex structure of multi-joint legs to attain the flexibility, while some microrobots have poor flexibility for miniaturization. To attain a microrobot with both compact structure and flexible locomotion, we designed a novel type of biomimetic locomotion employing ionic conducting polymer film (ICPF) actuators as one-DOF legs. We developed several prototype microrobots using this locomotion. In this paper, a microrobot using this biomimetic locomotion, named Walker-3, utilizing six ICPF actuators with two-DOF motion is developed. It is 30 mm in length, 55 mm in width and 8 mm in height (in static state). Experimental results indicate that Walker-3 can attain 6 mm/s of walking speed and 7.1 deg/s of rotating speed and climb on a 30° ascent at a speed of 0.5 mm/s with control signal of 10 V, 0.5 Hz. It is also suitable for uncertain terrain, such as climbing on a stairs less than 2 mm high and striding over a pit less than 5 mm wide. It has better flexibility, balance and load ability than its predecessors. We compared it with some legged microrobots and the result shows a microrobot with this biomimetic locomotion can have both compact structure and multi DOF locomotion.     

System Design and Testing of the Hominid Robot Charlie

Current and future application scenarios for mobile robots deal with increased requirements regarding autonomy and flexibility in the locomotor system. To cope with these demands, a high sensor quantity and quality allows us to perform robust locomotion. The authors present a hominid robotic system that is equipped with multi‐point‐contact feet and an active artificial spine to incorporate extended sensing and locomotion capabilities for walking robots. In the proposed robotic system, the front and rear part are connected via an actuated spinal structure with six degrees of freedom. To increase the robustness of the system's locomotion in terms of traction and stability, a footlike structure equipped with various sensors has been developed. Altogether, the robot embodies more than 330 sensors. In terms of distributed local control, the structures feature their own local intelligence and are as autonomous as possible regarding sensing, sensor preprocessing, control, and communication. This allows the robot to respond to external disturbances with minor latency. Within this paper, the proposed robotic system and its distributed and hierarchical control method are presented. To validate the electromechanical and software approach, the authors present results verified experimentally in different environments (in‐ and outdoor) with differing walking speeds on various substrates and in varying inclinations from to 20°. The results show that the presented approach is viable and improves the flexibility of the locomotor system. A hominid design was chosen in order to perform various types of locomotion. To demonstrate the entire functionality of the developed hardware, two different motion modes (quadrupedal and bipedal locomotion) are investigated. This also includes a stable transition from a four‐legged posture to an upright posture and vice versa.     

Assistive mobility devices focusing on Smart Walkers: Classification and review

In an aging society it is extremely important to develop devices, which can support and aid the elderly in their daily life. This demands means and tools that extend independent living and promote improved health.Thus, the goal of this article is to review the state of the art in the robotic technology for mobility assistive devices for people with mobility disabilities. The important role that robotics can play in mobility assistive devices is presented, as well as the identification and survey of mobility assistive devices subsystems with a particular focus on the walkers technology. The advances in the walkers’ field have been enormous and have shown a great potential on helping people with mobility disabilities. Thus it is presented a review of the available literature of walkers and are discussed major advances that have been made and limitations to be overcome.     

Maximal entanglement from quantum random walks

The conditions under which entanglement becomes maximal are sought in the general one-dimensional quantum random walk with two walkers. Moreover, a one-dimensional shift operator for the two walkers is introduced and its performance in generating entanglement is analyzed as a function of several free parameters, some of them coming from the shift operator itself and some others from the coin operator. To simplify the investigation an averaged entanglement is defined.     

Design and control of tensegrity robots for locomotion

The static properties of tensegrity structures have been widely appreciated in civil engineering as the basis of extremely lightweight yet strong mechanical structures. However, the dynamic properties and their potential utility in the design of robots have been relatively unexplored. This paper introduces robots based on tensegrity structures, which demonstrate that the dynamics of such structures can be utilized for locomotion. Two tensegrity robots are presented: TR3, based on a triangular tensegrity prism with three struts, and TR4, based on a quadrilateral tensegrity prism with four struts. For each of these robots, simulation models are designed, and automatic design of controllers for forward locomotion are performed in simulation using evolutionary algorithms. The evolved controllers are shown to be able to produce static and dynamic gaits in both robots. A real-world tensegrity robot is then developed based on one of the simulation models as a proof of concept. The results demonstrate that tensegrity structures can provide the basis for lightweight, strong, and fault-tolerant robots with a potential for a variety of locomotor gaits.     

Localization of two-particle quantum walk on glued-tree and its application in generating Bell states

Studies on two-particle quantum walks show that the spatial interaction between walkers will dynamically generate complex entanglement. However, those entanglement states are usually on a large state space and their evolutions are complex. It makes the entanglement states generated by quantum walk difficult to be applied directly in many applications of quantum information, such as quantum teleportation and quantum cryptography. In this paper, we firstly analyse a localization phenomena of two-particle quantum walk and then introduce how to use it to generate a Bell state. We will show that one special superposition component of the walkers’ state is localized on the root vertex if a certain interaction exists between walkers. This localization is interesting because it is contrary to our knowledge that quantum walk spreads faster than its classical counterpart. More interestingly, the localized component is a Bell state in the coin space of two walkers. By this method, we can obtain a Bell state easily from the quantum walk with spatial interaction by a local measurement, which is required in many applications. Through simulations, we verify that this method is able to generate the Bell state \(\frac{1}{\sqrt{2}}(|A \rangle _1|A\rangle _2 \pm |B\rangle _1|B\rangle _2)\) in the coin space of two walkers with fidelity greater than \(99.99999\,\%\) in theory, and we have at least a \(50\,\%\) probability to obtain the expected Bell state after a proper local measurement.     

仿蛇变体机器人运动机理研究

本文设计了一种蛇形机器人，分析了蛇形机器人的结构，详细讨论了蛇形机器人的运 动机理和几何结构关系，并推导出蛇形机器人的控制算法和相应的控制程序，蛇形机器人在 程序控制下能够向前、向后运动，在一定程度上实现了蛇的运动．     

Reflex-oscillations in evolved single leg neurocontrollers for walking machines

As a prerequisite for developing neural control for walking machines that are able to autonomously navigate through rough terrain, artificial structure evolution is used to generate various single leg controllers. The structure and dynamical properties of the evolved (recurrent) neural networks are then analysed to identify elementary mechanisms of sensor-driven walking behaviour. Based on the biological understanding that legged locomotion implies a highly decentralised and modular control, neuromodules for single, morphological distinct legs of a hexapod walking machine were developed by using a physical simulation. Each of the legs has three degrees of freedom (DOF). The presented results demonstrate how extremely small reflex-oscillators, which inherently rely on the sensorimotor loop and e.g. hysteresis effects, generate effective locomotion. Varying the fitness function by randomly changing the environmental conditions during evolution, neural control mechanisms are identified which allow for robust and adaptive locomotion. Relations to biological findings are discussed.     

A lattice-type reconfigurable robotic system for achieving gaits of chain-type robots

Traditional lattice-type reconfigurable robots can only achieve the flow-style locomotion with low efficiency. Since gaits of chain-type robots are proved to be efficient and practical, this paper presents a novel lattice distortion approach for lattice-type reconfigurable robots to achieve locomotion gaits of chain-type robots. Using this approach, the robotic system can be actuated by local lattice distortion to move as an ensemble. In this paper, a rule that makes the lattice distortion equivalent to joint rotation is presented firstly. Then, a kind of module structure is designed according to requirements of the lattice distortion. Finally, a motion planning for achieving locomotion is developed, which works well in physics-based simulations of completing a serpentine locomotion gait of a snake-like robot and a tripod gait of a hexapod robot.     

Multimode locomotion via SuperBot reconfigurable robots

One of the most challenging issues for a self-sustaining robotic system is how to use its limited resources to accomplish a large variety of tasks. The scope of such tasks could include transportation, exploration, construction, inspection, maintenance,in-situ resource utilization, and support for astronauts. This paper proposes a modular and reconfigurable solution for this challenge by allowing a robot to support multiple modes of locomotion and select the appropriate mode for the task at hand. This solution relies on robots that are made of reconfigurable modules. Each locomotion mode consists of a set of characteristics for the environment type, speed, turning-ability, energy-efficiency, and recoverability from failures. This paper demonstrates a solution using the SuperBot robot that combines advantages from M-TRAN, CONRO, ATRON, and other chain-based and lattice-based robots. At the present, a single real SuperBot module can move, turn, sidewind, maneuver, and travel on batteries up to 500 m on carpet in an office environment. In physics-based simulation, SuperBot modules can perform multimodal locomotions such as snake, caterpillar, insect, spider, rolling track, H-walker, etc. It can move at speeds of up to 1.0 m/s on flat terrain using less than 6 W per module, and climb slopes of no less 40 degrees. Harris Chi Ho Chiu is a PhD Student in Computer Science at the University of Southern California and a research assistant in Polymorphic Robotics Laboratory of Information Science Institute. He received his Master in Computer Science from the University of Southern California and his Bachelor of Engineering from the University of Hong Kong. His research interests include intelligent automated systems, modular self-reconfigurable systems, artificial intelligence, and machine learning. Michael Rubenstein is currently a PhD student at the Polymorphic Robotics Laboratory, working on the CONRO and Superbot self-reconfigurable robotic systems. He has received his bachelors in Electrical Engineering from Purdue University, and his masters in Electrical Engineering from the University of Southern California, and is currently working towards his PhD in Computer Science from the University of Southern California. His interests include modular self-reconfigurable systems, autonomous robots, self-healing systems, and self-replicating systems. Jagadesh B Venkatesh is a member of the Polymorphic Robotics Laboratory at the Information Sciences Institute. He is currently a Master’s candidate in the Product Development Engineering program at the University of Southern California. He received his MS in Computer Science with specialization in Intelligent Robotics, also at the University of Southern California in 2005. His current interest is the commercialization of robotic technologies, specifically in the consumer robotics sector.     

Webots平台的仿人机器人仿真的研究

仿人机器人是机器人研究领域的热点,可以应用于工业、医疗和家庭服务等领域。机器人仿真技术可以帮助研究者更好地研究机器人的结构和运动控制。本文基于Webots软件,构建HOAP2机器人的运动仿真平台,详细说明了机器人仿真环境的构建过程以及运动控制的仿真过程。仿真结果说明,本研究构建的仿真平台是有效的。     

Fighting exclusion: a multimedia mobile app with zombies and maps as a medium for civic engagement and design

This paper presents a study on urban data crowdsourcing driven by Geo-Zombie, a multimedia mobile application we designed and developed to engage pedestrians in taking note of urban architectural impediments and facilities by documenting them through pictures and multimedia data. Geo-Zombie aims at transforming the civic activity of contributing into a virtual gamified experience where players attempt to escape from horrific situations in which zombies are ready to cannibalize unsuspecting walkers. In some sense, walkers that kill zombies deeply reconnect with the concept of imminent danger which can be fought resorting to appropriate civic actions. To challenge our initial hypotheses we conducted a design process, starting with a concept generation where three different concepts were discussed which gave rise to five different multimedia mobile apps including the one with zombies. Then, focus group, experience prototyping, application design and implementation, and finally field trials were exploited to refine the design and to select the best apps out of the five that better responded to the need of involving common people in collecting urban accessibility data. It is worth noting that the experiences of use with 50 avid walkers have demonstrated that a multimedia mobile app with maps and zombies can be a concrete step towards a social inclusion strategy while inviting new reflections and discussions on the issue of urban data crowdsourcing.     

仿人机器人相似性运动研究进展

针对仿人机器人模仿人体运动问题, 从运动轨迹角度比较了基于运动解析方程方法与基于人体运动相似性方法的特点, 阐述了相似性运动系统基本结构, 分析了图像捕捉与处理、相似性特征处理、相似性运动约束与优化等模块功能, 阐述了相似性运动中的人体运动捕获与处理、运动关节解算、运动模型简化与重定向、关键姿势处理与相似度评价、关节空间位姿计算、动力学匹配约束等方面的研究现状, 最后提出了研究展望。     

仿蚯蚓移动机器人离散步态控制与相位差控制特性比较

从机器人的运动特征、稳态平均速度和波动特性3个方面,对仿蚯蚓移动机器人的离散步态控制策略和相位差控制策略进行比较研究．首先,通过学习蚯蚓的形态学特征,基于舵机－弹簧钢片复合结构,设计并制作了可以执行拮抗变形的仿蚯蚓机器人单元,并将其串联得到一个8单元仿蚯蚓移动机器人．以该机器人为平台,从理论和实验角度研究了机器人在离散步态控制和等相位差控制下的平均速度和运动特征．研究发现,对于2种控制策略,实验得到的平均速度都与理论预测定性吻合,但机器人单元在运动过程中有可能发生显著的向后滑动,使得实验得到的平均速度低于理论预测的平均速度．随后,从波传播的角度对2种控制策略进行了比较．2种控制策略都使得机器人单元的变形以波动的形式沿机器人进行传播,传播方向与机器人运动方向相反,与蚯蚓的后退蠕动波机理保持一致．对于离散步态控制,波传播的波形、波速、波长和周期都与步态参数密切相关;对于相位差控制,波形和周期都由作动规律决定,不能通过相位差进行调节,但波速和波长与相位差成反比．从控制效果来看,机器人在最优的等相位差控制模式下可以实现更高的平均速度,且与蚯蚓的连续特征保持一致,具有一定的优势．