Insect-type MEMS microrobot with mountable bare chip IC of artificial neural networks

This paper discussed insect-type MEMS microrobot system which could locomote without using computer programs. Locomotion of the MEMS microrobot was generated using the analog circuit of artificial neural networks. We constructed the artificial neural networks as a bare chip integrated circuit (IC) which could mount on top of the MEMS microrobot. As a result, the MEMS microrobot system could perform the locomotion using constructed bare chip IC of artificial neural networks. The insect-type MEMS microrobot system was 0.079 g in weight and less than 5.0 mm in size. Only the power source was outside of the robot. In addition, we analyze the heat conduction of the shape memory alloy-type actuator. It was shown that the heat of shape memory alloy conducts to the mechanical parts of the MEMS microrobot; therefore, locomotion becomes slowly after 30 s. The slow locomotion was 2 mm/min. We constructed the less conduction shape memory alloy-type actuator. The locomotion speed of the insect-type MEMS microrobot using less conduction shape memory alloy-type actuator was 90.8 mm/min.     

Four-leg independent mechanism for MEMS microrobot

In this paper, the development of a quadruped micro-electro mechanical system (MEMS) microrobot with a four-leg independent mechanism is described. As the actuator mechanism inside small robot bodies is difficult to realize, many microrobots use external field forces such as magnetism and vibration. In this paper, artificial muscle wires that are family of shape memory alloy are used for the force of the actuator. The artificial muscle wire shows the large displacement by passing the electrical current through the material itself. The double four-link mechanism is adopted for the leg system. The link mechanism transforms the linear motion of the artificial muscle wire to the foot step-like pedaling motion. The location of the backward swing motion is lower than that of forward swing motion. This motion generates the locomotion force. As a result, the total length of the constructed quadruped MEMS microrobot was 6 mm. The microrobot could perform similar gait pattern changes as the quadruped animal.     

IC design of driving circuit of MEMS microrobot using pulse-type hardware neuron model

This paper presented a driving circuit which can output a driving waveform of the piezoelectric element impact-type actuator. The piezoelectric element impact-type actuator generates the rotational movement which is necessary to move the legs of the micro electro mechanical systems (MEMS) microrobot. The MEMS microrobot is made from silicon wafers fabricated by micro fabrication technology. The size of the fabricated MEMS microrobot is 4.0 mm × 4.6 mm × 3.6 mm. The driving circuit consists of a bare chip IC of the pulse-type hardware neuron model (P-HNM) and a peripheral circuit. P-HNM is an electrical oscillating model which has the same basic features of biological neurons. Therefore, P-HNM can output the driving waveform of the piezoelectric element impact-type actuator using electrical oscillation as biological neuron. As a result, we showed that the driving circuit can output the driving waveform of the piezoelectric element impact-type actuator without using any software programs or analog digital converters.     

Design and Optimization of an Omnidirectional Permanent-Magnetic Wheeled Wall-Climbing Microrobot with MEMS-Based Electromagnetic Micromotors

The paper presents a compact omnidirectional permanent-magnetic wheeled wall-climbing microrobot. A millimeter-sized axial flux electromagnetic micromotor based on MEMS technology has been specially fabricated for the microrobot and its size is 6.8 mm × 7.8 mm × 3.9 mm. A novel permanent-magnetic wheel is designed, which is directly integrated with the stators and rotor of the electromagnetic micromotor. The omnidirectional wall-climbing mechanism is realized by a set of steering gears and three standard permanent-magnetic wheels. By static and dynamic force analysis of the microrobot, the required magnetic force and the required torques for its translational and steering movements are derived. To reduce the unnecessary torque consumption of the microrobot, its structural parameters are optimized in combination with its design constraints by ANSOFT and Pro/Engineer simulation. A prototype of the proposed microrobot with the maximum designed load capacity of 3 g is developed, whose size is 26 mm in diameter and 16.4 mm in height. Experimental and simulation results demonstrate the feasibility of these concepts.     

Neural networks IC controlled multi-legged walking MEMS robot with independent leg mechanism

In this paper, we will compare the walking behavior of quadruped and hexapod walking MEMS robots. These robots are fabricated by connecting same modules, which are composed of a couple of independent leg mechanisms. Independent leg mechanisms can actuate the single leg by a single artificial muscle wire. The neural networks IC that mimics real living organisms controls the mechanical systems. The length and weight of the quadruped MEMS robot were 7.2 mm and 95.8 mg, respectively. The quadruped robot showed the walking speed of 24.6 mm/min. The robot tended to lose its balance and the weight balance is quite important for the moving quadruped. On the other hand, the length and weight of the hexapod MEMS robot were 9.0 mm and 162 mg, respectively. The hexapod robot showed stable walking. The speed was 27.0 mm/min.     

Gait pattern changing of quadruped robot using pulse-type hardware neural networks

This paper studied about gait pattern changing of the constructed quadruped robot system using pulse-type hardware neural networks (P-HNN). We constructed the 20 cm in size prototype quadruped robot system. Quadruped robot system consisted of mechanical components and electrical components. The mechanical components consisted of four legs, body frames and four servo motors. Quadruped animal-like locomotion could realize by only four servo motors using link mechanisms to each leg. The electrical components consisted of P-HNN, power supply circuit, control board and battery. P-HNN was constructed by analog discrete circuits which could mount on top of the quadruped robot. As a result, constructed P-HNN could output the locomotion rhythms which were necessary to generate the gait pattern of the quadruped robot. P-HNN could output the locomotion rhythms without using software programs or analog digital converter. In addition, P-HNN could change the locomotion rhythms by inputting the trigger pulse to the P-HNN. Our constructed quadruped robot system could perform the locomotion without using external devices.     

Development of a novel type of microrobot for biomedical application

This paper proposes a new type of microrobot that can move along a narrow area such as blood vessels which has great potential for application in microsurgery. Also, the development of a wireless microrobot that can be manipulated inside a pipe by adjusting an external magnetic field has been discussed. The model microrobot utilizes an electromagnetic actuator as the servo actuator to realize movement in biomedical applications. The structure, motion mechanism, and evaluation characteristic of motion of the microrobot have been discussed, and the directional control can be realized via the frequency of the input current. The moving experiments have been carried out in branching points in the horizontal direction, and the moving speed of the robot has been measured in vertical direction by changing frequency. Based on the results, the microrobot has a rapid response, and it can clear out dirt which is adhering to the inner wall of pipe. This microrobot will play an important role in both industrial and medical applications such as microsurgery.     

A Modular Self-Reconfigurable Robot with Enhanced Locomotion Performances: Design,Modeling, Simulations,and Experiments

This paper presents the design and implementation of a modular self-reconfigurable robot with enhanced locomotion capabilities. It is a small hexahedron robot which is 160 mm × 140 mm × 60 mm in size and 405 g in weight. The robot is driven by three omnidirectional wheels, with up and down symmetrical structure. The robot can perform rectilinear and rotational locomotion, and turn clockwise and counterclockwise without limitation. A new docking mechanism that combines the advantages of falcula and pin-hole has been designed for attaching and detaching different modules. The communication and image data transmission are based on a wireless network. The kinematics and dynamics of the single module has been analyzed, and the enhanced locomotion capabilities of the prototype robot are verified through experiments. The maximum linear velocity is 25.1cm/s, which is much faster than other modular self-reconfigurable robots. The mobility of two connected modules is analyzed in the ADAMS simulator. The locomotion of the docking modules is more flexible. Simulations on the wheel and crawling locomotion are conducted, the trajectories of the robot are shown, and the movement efficiency is analyzed. The docking mechanisms are tested through docking experiments, and the effectiveness has been verified. When the transmission time interval between the adjacent packets is more than 4 ms, the wireless network will not lose any packet at the maximum effective distance of 37 m in indoor environments.     

An omni-directional mobile millimeter-sized microrobot with 3-mm electromagnetic micromotors for a micro-factory

This paper presents an omni-directional mobile microrobot for micro-assembly in a micro-factory. A novel structure is designed for omni-directional movement with three normal wheels. The millimeter-sized microrobot is actuated by four electromagnetic micromotors whose size is 3.1 mm × 3.1 mm × 1.4 mm. Three of the micromotors are for translation and the other one is for steering. The micromotor rotors are designed as the wheels to reduce the microrobot volume. A piezoelectric micro-gripper is fabricated for grasping micro-parts. The corresponding kinematics matrix is analyzed to prove the omni-directional mobility. A control system composed of two CCD cameras, a host computer and circuit board is designed. The macro camera is for a global view and the micro camera is for local supervision. Unique location methods are proposed for different scenarios. A microstep control approach for the micromotors is presented to satisfy the requirement of high positioning accuracy. The experiment demonstrates the mobility of the microrobot and the validity of the control system.     

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.     

新型仿生水下子母机器人系统设计

传统的水下子母机器人在水下作业时母机器人会有噪音大、体积大和隐蔽性差的缺点,而且子机器人作为提高水下机器人位置精度和续航时间的重要手段大多采用尾部摆动、机身两侧划水、小型螺旋桨推进等方式,造成运动过程中稳定性差、噪音大而且尺寸难以微型化的缺点.为了克服这些不足,设计一种新型仿生水下子母机器人系统.该系统球形母机器人采用喷水电机进行喷水推进,减少噪音,增加隐蔽性,并为微型子机器人提供控制信号和能源.微型子机器人以樽海鞘为原型基于仿生原理设计,在水下运动透明度高、隐蔽性强、稳定性高.建立球形母机器人的喷水推进器和微型子机器人的微型驱动器的驱动力计算模型,同时建立微型子机器人的水下转向模型.最后制作子母机器人样机并进行子母机器人的水下运动实验,以验证所设计的子母机器人系统的有效性.     

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.     

Experimentally Verified Optimal Serpentine Gait and Hyperredundancy of a Rigid-Link Snake Robot

In this study, we examine, for a six-link snake robot, how an optimal gait might change as a function of the snake- surface interaction model and how the overall locomotion performance changes under nonoptimal conditions such as joint failure. Simulations are evaluated for three different types of friction models, and it is shown that the gait parameters for serpentine motion are very dependant on the frictional model if minimum power expenditure is desired for a given velocity. Experimental investigations then motivate a surface interaction model not commonly used in snake locomotion studies. Using this new model, simulation results are compared to experiments for nominal and nonnominal locomotion cases including actuator faults. It is shown that this model quite accurately predicts locomotion velocities and link profiles, but that the accuracy of these predictions degrades severely at speeds where actuator dynamics become significant.     

压电谐振驱动三足机器人的平面运动

设计并实现了一类利用压电陶瓷片作动,由三条曲梁足支撑的振动驱动机器人.建立了在一条足共振驱动下机器人水平运动的动力学方程,数值计算解释了摩擦作用下的运动机理,寻找到异性摩擦对运动方向、速度的影响和压电激励频率与运动速度间的关系.通过建立圆弧曲梁控制方程求解圆弧型足面内振动的固有频率及振型,设计了三组不同频率的圆弧曲梁足参数,实验制作了机器人模型,利用压电控制三足间振动的共振切换,实现了预想的三个方向的运动以达到平面运动的效果,实验测量了机器人的运动速度与理论计算吻合得较好.     

动态未知环境下一种Hopfield神经网络路径规划方法

针对动态未知环境下移动机器人路径规划问题,采用一种有效的局部连接Hopfiled神经网络(Hopfield Neural Networks,HNN)来表示机器人的工作空间.机器人在HNN所形成的动态数值势场上进行爬山搜索法来形成避碰路径,并且不存在非期望的局部吸引点.HNN权值设计中考虑了路径安全性因素,通过在障碍物附件形成局部虚拟排斥力来形成安全路径.HNN的连接权是非对称的,并且考虑了信号传播时延.分析了HNN的稳定性,所给稳定性条件和时延无关.HNN模型中突出了最大传播激励,从而使得HNN具有更广的稳定性范围并能表示具有更多节点的机器人工作空间.为对该HNN有效仿真求解,结合约束距离变换和HNN的时延性,给出了单处理器上高效的串行模拟方案,规划路径的时间复杂度为O(N)(N是HNN中神经元的数目),使得路径重规划能快速在线进行.仿真和实验表明该方法的有效性.     

Biped Locomotion Control through a Biomimetic CPG-based Controller

Modern concepts of motor learning favour intensive training directed to the neural networks stimulation and reorganization within the spinal cord, the central pattern generator, by taking advantage of the neural plasticity. In the present work, a biomimetic controller using a system of adaptive oscillators is proposed to understand the neuronal principles underlying the human locomotion. A framework for neural control is presented, enabling the following contributions: a) robustness to external perturbations; b) flexibility to variations in the environmental constraints; and c) incorporation of volitional mechanisms for self-adjustment of gait dynamics. Phase modulation of adaptive oscillators and postural balance control are proposed as main strategies for stable locomotion. Simulations of the locomotion model with a biped robot in closed-loop control are presented to validate the implemented neuronal principles. Specifically, the proposed system for online modulation of previous learnt gait patterns was verified in terrains with different slopes. The proposed phase modulation method and postural balanced control enabled robustness enhancement considering a broader range of slope angles than recent studies. Furthermore, the system was also verified for tilted ground including different slopes in the same experiment and uneven terrain with obstacles. Adaptive Frequency Oscillators, under Dynamic Hebbian Learning Adaptation mechanism, are proposed to build a hierarchical control architecture with spinal and supra spinal centers with multiple rhythm-generating neural networks that drive the legs of a biped model. The proposed neural oscillators are based on frequency adaptation and can be entrained by sensory feedback to learn specific patterns. The proposed biomimetic controller intrinsically generates patterns of rhythmic activity that can be induced to sustain CPG function by specific training. This method provides versatile control, paving the way for the design of experimental motor control studies, optimal rehabilitation procedures and robot-assisted therapeutic outcomes.     

微小气动机器人的移动控制

根据仿生尺蠖运动机理研制了一种用于人体腔道微创诊查的气动微机器人系统。该机器人系统由前支撑单元、后支撑单元和具有3个气室的橡胶驱动器三部分组成。设计了控制机器人移动的计算机电-气控制系统,通过控制该电-气系统的继电器和高速开关电磁阀来控制机器人系统的钳位气囊和驱动器气室内的气压。通过分析一个运动周期内机器人的运动状态,给出了机器人移动的控制算法,使机器人前、后支撑单元的气囊和驱动器的气室实现有规律的充气、保持及放气3种状态,从而实现有规律的运动。研究结果表明所设计的机器人具有仿生尺蠖移动机理的柔性结构,通过所设计的电-气控制系统可实现机器人的自动移动。     

A Simplified CPGs Network with Phase Oscillator Model for Locomotion Control of a Snake-like Robot

CPG (Central pattern generator) is a dynamical system of coupled nonlinear oscillators or neural networks inspired by a control mechanism in animal bodies. Without any rhythmic inputs, the CPG has the ability to produce oscillatory patterns. This paper presents a novel structure of a CPG network which can produce rhythmic motion that imitates movement of animals such as snake and lamprey. The focus is on the locomotion control of a snake-like robot, where phase oscillator has been adopted as the dynamical model to control the harmonic motion of the CPG network. There are two main points addressed in this paper: (1) simple network structure of unidirectional coupling oscillators, and (2) a single parameter to control the body shape and to control the forward and backward movement of the snake-like robot. The proposed CPG network is designed to have a simple structure with less complexity, less mathematical computation, fast convergence speed and exhibit limit cycle behavior. In addition, a new parameter, τ is introduced to control the smoothness of the CPG output as well as the speed of the snake-like robot. Simulation and experimental results show that the proposed CPG network can be used to control the serpentine locomotion of a snake-like robot.     

基于改进能量函数的混沌神经网络JSP解法

针对传统Hopfield神经网络(HNN)在求NP类问题的解时易陷入局部最优点的不足,提出基于改进能量函数的模拟退火混沌神经网络算法。通过在Hopfield神经网络中引入混沌机制,并结合退火策略控制混沌动态,有效避免了陷入局部极小的缺陷,因此将其用于求解JSP（作业车间调度）。算法改进了表示JSP的换位矩阵,给出了包含目标函数的能量函数,保证了网络的稳态输出为全局可行解。     

Adaptive Output Feedback Control of Flexible-Joint Robots Using Neural Networks: Dynamic Surface Design Approach

In this paper, we propose a new robust output feedback control approach for flexible-joint electrically driven (FJED) robots via the observer dynamic surface design technique. The proposed method only requires position measurements of the FJED robots. To estimate the link and actuator velocity information of the FJED robots with model uncertainties, we develop an adaptive observer using self-recurrent wavelet neural networks (SRWNNs). The SRWNNs are used to approximate model uncertainties in both robot (link) dynamics and actuator dynamics, and all their weights are trained online. Based on the designed observer, the link position tracking controller using the estimated states is induced from the dynamic surface design procedure. Therefore, the proposed controller can be designed more simply than the observer backstepping controller. From the Lyapunov stability analysis, it is shown that all signals in a closed-loop adaptive system are uniformly ultimately bounded. Finally, the simulation results on a three-link FJED robot are presented to validate the good position tracking performance and robustness of the proposed control system against payload uncertainties and external disturbances.