This study introduces an innovative K-/Ka-band planar active shared-aperture phased array (ASAPA), advancing low earth orbit (LEO) terminal design through synergistic innovations in shared-aperture topology and three-dimensional (3D) integration. Breaking from conventional shared-aperture topologies plagued by cross-band interference and radiation pattern distortion, we propose a partial-element-reuse-based (PER) topology that strategically repurposes 50% of dual-band dual-polarized elements for simultaneous transmit and receive (STAR) operation. This configuration eliminates active element pattern distortion while achieving a reduction in element count, enabling wide-angle beam scanning essential for dynamic satellite tracking. Furthermore, a sandwich-structured printed circuit board (PCB) lamination method is further employed to streamline integration by partitioning functional modules into antenna, coupler, and active circuit layers interconnected via ball grid array (BGA) technology. This 3D integration strategy simplifies vertical interconnects, minimizes PCB layer requirements, and enhances thermal dissipation through embedded air gaps. Experimental results validate robust beamforming performance across ±60° scanning ranges for both transmitting and receiving arrays, achieving high transceiver isolation and signal integrity, which are imperative for high-capacity satellite links. By addressing key bottlenecks in LEO terminal design, the proposed innovations can accelerate the deployment of energy-efficient, cost-effective satellite networks, thus advancing the 6G vision of ubiquitous global connectivity.

A low-cost millimeter-wave wideband filtenna integrating filtering and radiation performance for next-generation millimeter-wave (mmWave) Internet of Things (IoT) devices is proposed in this article. The filtering performance is achieved by utilizing the intrinsic high-pass property of a microstrip-fed magneto-electric dipole (ME-dipole) and filtering feeding mechanism. Several shorted parasitic patches are settled around the E-dipole to enhance the radiation performance within the operating band and develop suppression levels at both the lower and upper bands. A stepped cross-shaped microstrip-line structure is added in the center of the radiating aperture to generate two resonances, so that the in-band impedance performance and the selectivity can be improved. Measurement results indicate that the proposed filtenna achieves a wide operating bandwidth of 30.26% (22.8-31.4 GHz), a peak gain of 8.21 dBi and an out-of-band gain suppression better than 23 dB. Furthermore, a 2×2 filtenna subarray is constructed with some shorted parasitic patches being shared, and then, a 4×4 circularly-polarized (CP) sequential rotated (SR) array is also delicately designed using the 2×2 filtenna subarray. Remarkable operating bandwidths and appropriate out-of-band suppression performance with simplistic structures are all confirmed well through experiments. The outstanding performance of the proposed filtenna and its arrays makes them potential candidates for the B5G/6G mmWave communications.

BACKGROUND: Combinatorial drug therapy for complex diseases, such as HSV infection and cancers, has a more significant efficacy than single-drug treatment. However, one key challenge is how to effectively and efficiently determine the optimal concentrations of combinatorial drugs because the number of drug combinations increases exponentially with the types of drugs. RESULTS: In this study, a searching method based on Markov chain is presented to optimize the combinatorial drug concentrations. In this method, the searching process of the optimal drug concentrations is converted into a Markov chain process with state variables representing all possible combinations of discretized drug concentrations. The transition probability matrix is updated by comparing the drug responses of the adjacent states in the network of the Markov chain and the drug concentration optimization is turned to seek the state with maximum value in the stationary distribution vector. Its performance is compared with five stochastic optimization algorithms as benchmark methods by simulation and biological experiments. Both simulation results and experimental data demonstrate that the Markov chain-based approach is more reliable and efficient in seeking global optimum than the benchmark algorithms. Furthermore, the Markov chain-based approach allows parallel implementation of all drug testing experiments, and largely reduces the times in the biological experiments. CONCLUSION: This article provides a versatile method for combinatorial drug screening, which is of great significance for clinical drug combination therapy.

Bio-syncretic robots made up of living biological systems and electromechanical systems may have the potential excellent performance of natural biological entities. Therefore, the study of the bio-syncretic robots has got lots of attention in recent years. The 3D skeletal muscles have been used widely, due to the considerable contraction force and the controllability. However, the low differentiation quality of the C2C12 in the tissues hinders the broad application in the development of the skeleton muscle actuated bio-syncretic robots. In this work, an approach based on circular mould and rotary electrical stimulation to build high-quality muscle rings, which can be used to actuate various bio-syncretic robots, has been proposed. Firstly, the advantage of the proposed circular mould for the muscle rings culture has been shown by simulation. Then, the muscle rings have been fabricated with different moulds using the experiment-optimized compositions of the biological mixture. After that, the muscle rings in the circular moulds with different electrical stimulations have been cultured, to show the superiority of the proposed rotary electrical stimulation. Moreover, the contractility of the muscle rings have been measured under the different electrical pulses stimulation, for the study of the control property of the muscle rings. This work may be meaningful not only the development of bio-syncretic robots actuated by 3D muscle tissues but also the muscle tissue engineering.

Micro-robots have a great application prospect in the biomedical field due to the feature of small size. To solve the issues of energy supply and bio-compatibility of micro-robots, bio-syncretic micro-robots composed of biological materials and electromechanical systems have been studied widely. The skeletal muscle is a potential material to develop bio-actuator for the bio-syncretic robots on account of the great contraction force and the controllability. However, the low differentiation quality of C2C12s and the control of the bio-syncretic robots are the two of the main challenges for the development of the bio-syncretic robots based on the skeleton muscle. In this paper, an approach based on circularly distributed multiple electrodes (CDMEs) was proposed to improve the differentiation of C2C12 myoblast cells and characterize the electro-responsive beating behavior of myotubes for the development of bio-syncretic robots. Three groups of C2C12 blasts were used to fulfill the differentiation experiments without electrical stimulation and with electrical stimulation using parallel electrodes and CDMEs respectively, for evaluating the effect of CDMEs on C2C12 differentiation. It was demonstrated that electrical field through CDMEs can improve the differentiation quality of C2C12 blasts into myotubes in terms of intensity, length, and widths. Then, the effect of electrical stimulation on the beating behaviors of myotubes was also investigated with CDMEs, and it was shown that the beating amplitudes of myotubes were significantly affected by the frequencies, amplitude and direction of electrical stimulation with respect to the myotubes, which is fundamental for the control of the micro-robot based on skeletal muscle cells. The proposed approach is useful for not only the development of the bio-syncretic robots, but also the study of muscle tissue engineering.

Bio-syncretic robots, consisting of living biological materials and traditional electromechanical systems, have attracted lots of attention due to the potentialities of self-sensing, self-actuation and self-repairing with intrinsic safety and high energy conversion efficiency. However, most of current researches focus on the movement of the devices, and have ignored the study on the control of actuation unit “cells”, which is as important as motors for traditional electromechanical robots. In this work, the effects of cell culturing time, seeding concentration and functional drugs (cytochalasin and adrenalin) on contractile frequency and force strength of cardiomyocytes have been studied using scanning ion conductance microscope (SICM) and arrays of micro-pillars made of PDMS. This work will lay the foundation for the further study of quantitatively control of bio-syncretic robots actuated by cardiomyocytes and is also meaningful for the development of cytology, medicine, and clinical science.

In atomic force microscopy (AFM)-based nanomanipulation, the tip position uncertainties still exist due to the parameter inaccuracies in the open-loop compensation of the piezo scanner, the noise in the closed-loop control and thermal drift. These spatial uncertainties are very challenging to be directly estimated owing to the lack of real-time feedback, and its effects are more significant in performing an automatic nanomanipulation/assembly task than macro world manipulations. In this paper, we propose a stochastic framework for feature-based localization and planning in nanomanipulations to cope with these uncertainties. In the proposed framework, some features in the sample surface are identified to calculate their positions in statistics, and detected by using the AFM tip as the sensor itself through a local scan-based motion. In the localization, the Kalman filter is used through incorporating the tip motion model and the local scan-based observation model to estimate the on-line tip position in the task space. The simulation and experiments about tip positioning are carried out to illustrate the validity and feasibility of the proposed algorithm. Then, positioning tip for effective nanomanipulation is presented by using several experiments. Finally, a carbon nanotube is followed to show that the proposed method can provide a great potential for improving the position accuracy.

Cellular mechanical properties as the main physical performance characteristics have been actively studied in the past years for the study of cytobiology and the development of medicine. In this study, by combining Hertz model, a novel strategy is proposed to simultaneously measure the cellular mechanical properties including cellular mass, elasticity and viscosity, based on the principle of forced vibration stimulated by simple harmonic force, with piezoelectric transducer (PZT) as vibrator and Atomic Force Microscope (AFM) as detector. The corresponding theoretical model was derived and the simulation was realized based on the proposed model. The experiments of indentations and vibrations with myoblasts and myotubes were implemented to calculate the three mechanical parameters of cells according to the proposed strategy. The results validated the proposed approach. This work would be useful for the development of cytology, medicine, previously diagnose, specific therapy and so on.

The determination of the mechanical properties of cells plays an important role in biological studies and has gained acceptance recently as a possible label-free biomarker for cell status determination or diseases detection. Investigations on how external cellular properties affect cell mechanics are helpful in understanding cell disease processes and cell morphogenesis, which are of large significance in medical science. Although most researchers have focused on individual cell mechanics, or the effect of substrate stiffness on cells, cell mechanical response due to interactions among cells is yet to be examined. A reason for this is that the study of cell mechanical response to cell shape requires one to use a cell patterning process. However, existing cell patterning methods are very complex and time-consuming. In this paper, we describe a practical and rapid technique that can easily pattern cells into desired shapes, which allows investigations of the effect of external environment on cell stiffness. In the new technique, Poly-(ethylene) glycol diacrylate (PEGDA) hydrogel film with thickness 70–100 nm is controllably patterned on a hydrogenated amorphous silicon (a-Si:H) substrate by polymerizing PEGDA molecules in-situ using programmable visual light patterns. The idea is to enable the confinement of cells cultured on the hydrogels into special areas. The elastic modulus of the patterned cells is measured using an atomic force microscope. Experimental results have demonstrated the versatility of the technique as a tool for cell pattering and exploration of cell mechanics under external mechanical stimuli.

One of the major limitations for Atomic Force Microscopy (AFM)-based nanomanipulation is that AFM only has one sharp tip as the end-effector, and can only apply a point force to the nanoobject, which makes it extremely difficult to achieve a stable manipulation. For example, the AFM tip tends to slip-away during nanoparticle manipulation due to its small touch area, and there is no available strategy to manipulate a nanorod in a constant posture with a single tip since the applied point force can make the nanorod rotate more easily. In this paper, a robotic nano-hand method is proposed to solve these problems. The basic idea is using a single tip to mimic the manipulation effect that multi-AFM tip can achieve through the planned high speed sequential tip pushing. The theoretical behavior models of nanoparticle and nanorod are developed, based on which the moving speed and trajectory of the AFM tip are planned artfully to form a nano-hand. In this way, the slip-away problem during nanoparticle manipulation can be get rid of efficiently, and a posture constant manipulation for nanorod can be achieved. The simulation and experimental results demonstrate the effectiveness and advantages of the proposed method.

Stair-climbing is a necessary capacity for mobile robots. This paper presents an online control method for the stair-climbing of a transformable tracked robot, Amoeba-II, and this robot is also an isomerism-modules robot with different mechanism modules. Based on the reasonable compartmentalization and kinematics analysis of the stair-climbing process, the coordination of the rotations of modules can reduce the slippage between tracks and terrain. To ensure that the robot can climb stairs with enough capability and stability, the stair-climbing criterion for the robot has been established based on the force analysis of each stage of the stair-climbing procedure. Meanwhile, the interference-avoiding criterion has been set up to avoid the interference between the non-tracked module of the robot and the stair. The experiment for the stair-climbing of the robot has been implemented to certify the validity of the online stair-climbing control method for a transformable tracked robot.

This paper presents an optimal design method for a new robot called amphibious transformable robot which can not only perform reconfiguration but also implement tasks in amphibious environment. To satisfy a range of performance requirements for the robot in aquatic and terrestrial environments, the multi-objective optimization method is adopted to design the robot which can achieve the optimal comprehensive performance in the amphibious environment. Based on the kinematics and dynamic analysis of the robot, the multi-objective optimization problem of the mechanism parameters design is established on the mapping relationships between the performance indexes, and then Multi-Objective Genetic Algorithm is proposed to get Pareto solution. Based on combination weighting method of multi-attribute decision-making, the result can be extracted and used to direct the mechanism design of the amphibious transformable robot, Amoeba-II. The experiment for the maneuverability of Amoeba-II in the amphibious environment is performed to verify the validity and applicability of the mechanism-parameters design method of amphibious transformable robot based on Multi-Objective Genetic Algorithm.

Robotic teleoperation constitutes a key technique for networked manufacturing system. Since Internet is noisy and performance of telerobotic systems strongly depends on communication conditions, control strategies which could be used to distribute computation and communication resource properly and require less data transmission are required. Motion description language (MDL) is an appropriate solution. In this paper, comparison study between MDL-based and the traditional direct control method under randomly varying time-delay condition has been pursued which show that the MDL-based method has the ability to guarantee the stability of the whole telerobotic system under randomly varying time-delay condition. Furthermore, MDL-based method provides an uniform mathematical description on discrete control on the master site and continuous execution on the slave site. Simulation results indicate that the proposed method is promising for Networked Manufacturing development.

Our amphibious snake-like robot conquers the terrestrial and aquatic environments with different kinds of gait. Future work has been planned to apply the robot in inspection tasks in complicated wild environments.

Making biomimetic robots move like natural animals is an interesting problem, because this topic involves not only the low level algorithm that controls the movement of robots' bodies and limbs but also the high level control strategy that deals with different kinds of situations. Based on a certain biological assumption, a self-tuning multi-phase CPG for snake robots is proposed. This method imitates the control strategy of natural snake's movement in different environments, which enables the snake robot to move more quickly and naturally. Through kinematic and dynamic analysis of snake robots, optimal control parameters are chosen for the decision strategy. Due to the intrinsic property of the multi-phase CPG, this model can change the movement patterns and control parameters autonomously according to external information. As a result, such neural control provides a powerful but simple way to self-tune adaptable behaviors in snake robots.

Although abdominal operation is a kind of important clinical surgery, recovery of the post-operative is usually evaluated by the judgment of doctors. This traditional medical care mode may take much time of medical staffs and meanwhile increase the expense of patients. In this paper, a recovery evaluation system is established for the abdominal post-operative by using body sensor networks (BSN). The evaluation system can collect acceleration signals from five parts of human body and surface electro myographic (sEMG)signals from abdomen muscle group (AMG) during a user'sdaily activities. An experiment as a pilot study has been conducted to test the validity and feasibility of the system. The experimental results showed the evaluation system may effectively acquire the relationship between a user's daily activities and intensity of AMG. The study work in this paper may be used as a basis for further study on evaluating recovery level of the actual post-operative.

A MDL-based control method for tele-robotic systems over internet is presented in this paper. Internet-based tele-robotic systems are characterized by the fact that the operator and the remote robotic system are connected by Internet. Since limited bandwidth, random time delay and other transmission problems deteriorate performance of tele-robotic systems severely, control strategies which can be used to settle transmission problems are expected. The obvious characteristic of the new method introduced in this paper is that control commands have a linguistic flavor, data transferred between operator and remote robot can be reduced accordingly. The framework presented in this paper has the potential of reducing operator's working pressure and enhancing the performance of the system. Furthermore, the existing motion description language modal is expanded to deal with the packet loss and disorder problem. The main contribution of this paper is the development of a novel framework for tele-robotics and its implementation in a real tele-manipulator system.

This paper presents a self-rescue mechanism for a screw drive in-pipe robot, which only uses one DC motor. The robot has two working modes, Normal Working Mode and Self-rescue Mode. Under normal working mode, the robot propels itself in the pipe just as other classical screw drive robots. When the robot encounters the obstacle and gets jammed, the lock up mechanism and motion control mechanism of the robot are activated. Then, the robot changes from working mode to self-rescue mode and moves away in the reverse direction to avoid jamming in the pipe. The change of the working mode is determined by the characteristics of the mechanism. The proposed mechanism can be used as a safety protection method for the pipe robot. Experiments have been conducted to testify the proposed mechanism. Compared with those with screw drive mechanisms, robots with self-rescue mechanism are able to avoid jamming in the pipe.

The mobile robots often perform the dangerous missions such as planetary exploration, reconnaissance, anti-terrorism, rescue, and so on. So it is required that the robots should be able to move in the complex and unpredictable environment where the ground might be soft and hard, even and uneven. To access to such terrains, a novel robot (NEZA-I) with the self-adaptive mobile mechanism is proposed and developed. It consists of a control system unit and two symmetric transformable wheel-track (TWT) units. Each TWT unit is driven only by one servo motor, and can efficiently move over rough terrain by changing the locomotion mode and transforming the track configuration. It means that the mobile mechanism of NEZA-I has self-adaptability to the irregular environment. The paper proposes the design concept of NEZA-I, presents the structure and the drive system of NEZA-I, and describes the self-adaptive principle of the mobile mechanism to the rough terrains. The locomotion mode and posture of the mobile mechanism is analyzed by the means of simulation. Finally, basic experiments verify the mobility of NEZA-I.

The control of a snake-like robot is a challenging problem because of the complex dynamics and the unknown environment. We have proposed an energy-based method, called passive creeping, to control the serpentine locomotion. This paper lays emphasis on the stability and the adaptability of the method. First, the local orbital stability of the movement is explicated based on the maximal Lyapunov exponent and the recurrence plot. Second, the adaptability to the environment is analyzed, and an optimal adaptive law based on the energy proportion is put into use to perfect the method. The particular advantages of the passive creeping include the comprehensive concept, the explicit control, and the inherent adaptability.

One of the prerequisite conditions for making a successful manipulation is that the relative position between the AFM tip and the objects can be sensed and controlled accurately. While this prerequisite is grandly hampered by the PZT nonlinearity and thermal drift. Although the PZT nonlinearity can be compensated to a certain extent through mounting a position sensor on the PZT scanner, this method leads to a higher system noise and a higher cost. In addition, this method can not handle the positioning error caused by thermal drift due to the lack of sensing ability to the displacement between the AFM tip and the sample stage. This paper propose a newly developed strategy to solve these problems. Its pivotal idea is the tip position is localized based on the sensing information to sample features, not PZT driving voltage or sensor signal. In this way, the positioning error aroused from PZT nonlinearity and thermal drift can be effectively suppressed. Experimental results demonstrate the advantage and effectiveness of the proposed method.

A snake-like robot can locomote in various environments; and it can manipulate objects when one end is fixed. A method of dynamic modeling for locomotion-manipulation of the snake-like robot is developed in order to unify the dynamic equations of two states. A virtual structure for orientation and position and the product-of-exponentials formula describe the mechanism and the kinematics of the robot. The dynamics of the robot are established in a Riemannian manifold. Furthermore, the dynamics of manipulation can be directly degenerated from those of locomotion. This method unifies the dynamics of locomotion and manipulation of the snake-like robot in the differential geometry formulation. Finally, simulation results of the method are presented.

Based on the geometry features of lunar terrain, this paper treats lunar terrain reconstruction as a surface reconstruction problem. We define an energy functional model consisting of local energy term and smooth energy term for lunar terrain reconstruction. The solution to minimize the functional (by partial differential equations) is defined as the optimal surface. In the smooth energy term, we design a vector field of depth discontinuousness likelihood (VFDDL) to control the direction and degree of smoothing. Experiments indicate that accurate VFDDL can lead to an exact reconstructed surface. Thus, VFDDL transfers 3D terrain reconstruction into a 2D image processing problem. An innovative method is proposed to estimate VFDDL, using image local and statistical features. Experiments verify our method and show a good performance in terrain reconstruction.

In this paper, a mobile mechanism with driving capability and detecting function is proposed for in-pipe inspection task. Based on this mechanism, a robot is designed and fabricated. The advantage of this robot is that it has mobile ability in the pipe and detecting function for inspection, while only one DC motor is installed. This results in low energy consumption and low cost to make. The robot propels itself in the pipe under a driving mode, and it is used for finding the defect of the pipe under a detecting mode. By switching these two working modes, the robot performs the inspection task without other extra DC motors. Moreover, a velocity change mechanism is introduced to adapt the change of the payload through adjusting the incline angle of the roller. The characteristics of this mechanism are analyzed by comparison with a classical screw drive robot and a direct drive robot. Finally, basic experiments are conducted to testify the mobility and efficiency of this robot.

One of the main roadblocks to Atomic Force Microscope (AFM) based nanomanipulation is lack of real time visual feedback. Although the model based visual feedback can partly solve this problem, its unguaranteed reliability due to the inaccurate models in nano-environment still limits the efficiency of AFM based nanomanipulation. This paper introduce a Real-time Fault Detection and Correction (RFDC) method to improve the reliability of the visual feedback. By utilizing Kalman filter and local scan technologies, the RFDC method not only can real-time detect the fault display caused by the modeling error, but also can on-line correct it without interrupting manipulation. In this way, the visual feedback keeps consistent with the true environment changes during manipulation, which makes several operations being finished without a image scanning in between. The theoretical study and the implementation of the RFDC method are elaborated in this paper. Experiments of manipulating nano-particles have been carried out to demonstrate the effectiveness and efficiency of the proposed method.

The variable time delay and the packet loss degrade the performance of Internet based teleoperation system seriously, even make the system unstable. To overcome the trouble, an idea that using CARIMA model of the linearized slave robot to design a controller based on the Generalized Predictive Control (GPC) method is proposed in this paper. We place the GPC controller at the remote site. First of all, The CARIMA model of the linearized slave robot is derived. Secondly, a GPC controller is designed at slave site to generate the redundant control information to diminish the influence of the packet loss and the large time delay in the internet to the system. Moreover, in order to solve the problem caused by the variable time delay, the reference information signed with time stamp is used and feedback to the operator, so the operator can predict the next round trip time delay(RTT) according to the preceding RTT we got. Finally, stability condition is achieved. Simulation results show that these strategies can dynamically compensate for the variable time delay and reduce the performance degradation induced by packet loss.

Robots are efficient and economic for in-pipe inspection tasks. In this paper, we deal with versatility and multifunction of in-pipe inspection robots. A versatile platform equipped with one driving motor is the main body of multifunctional mobile unit (MMU) that performs inspection tasks. We have developed three kinds of MMU by fixing different assemblies on the proposed versatile platform. MMU1 is an adaptive mobile mechanism that changes its working mode autonomously and gets over the obstacle without any extra motorpsilas help, in the case that the pipe diameter changes. MMU2 is a mechanism that has both driving ability and detecting function; MMU3 is equipped with assemblies that integrate the wheel and propeller function together, thus, MMU3 is able to propel both in dry pipe and watery pipe. These MMUs are all constructed from a same platform, which makes little increase of the cost but realizes of more kinds of robots. Several basic experiments have been conducted to confirm the effectiveness and mobility of the MMUs.

A robot, which is composed of adaptive mobile mechanism, is developed for the purpose of performing the internal inspection tasks of pipelines. Adaptability and efficiency are the basic considerations for this robot. Based on these concepts, a prototype is designed and fabricated. The proposed adaptive mobile mechanism equipped with one actuator can perform two working modes, a normal working mode and an assistant enhanced mode. Robot under the normal working mode is used for moving in pipe or monitoring the inner surface of the pipe. On the other hand, robot under the assistant enhanced mode will produce a larger torque to help itself surmount an obstacle in the pipe without any other driving actuator. This special feature is achieved by applying a power transmission mechanism. The rotation problem of the stator is solved according to the calculation results of the robot kinematics. Basic experiments have been conducted to testify the adaptability and efficiency of the robot.

In this paper, we deal with the yaw control problem of a small-scale helicopter mounted on an experimental platform. The yaw dynamics of helicopter involve input nonlinearity, time-varying parameters and the couplings between main and tail rotor. An attractive control strategy that combines neural networks with traditional adaptive controls has been successfully used for yaw control with input nonlinearities. In contrast to conventional adaptation law, the sliding condition is taken as the objective function instead of the error function used in MIT rule. From the concept of the sliding mode control, the adaptive controller guarantees the stability of the closed-loop system and convergence of the output tracking error to a desired bound, even if the model parameters are unknown or in the presence of disturbance. The simulation results are further compared with those obtained by normal PID control to demonstrate the improvements of the proposed algorithm

With 3D (3-dimensional) movement's ability and rhythmic locomotion mode, a nature snake makes itself survive in rugged terrains. The rhythmic activities of most creatures are generated by the CPG (central pattern generator). Based on this fact, the sustained-type neuron has been adopted to construct a cyclic inhibitory CPG model for a snake-like robot whose joints are perpendicularly connected in series. Having compared with the sustained-type neuron and the mutual inhibitory CPG, the cyclic inhibitory CPG was proven to generate capably rhythmic output with the least number of differential equations. In this paper, we introduce the neuron network organized by the cyclic inhibitory CPGs connected in line with unilateral excitation to control the 3D locomotion of a snake-like robot, and present the necessary condition for the CPG neuron network to sustain a rhythmic output. By implementing this control architecture to a simulator with consideration of mechanical dynamics of a real snake-like robot "Perambulator", preliminary parameter setting of the CPG neuron network for its 3D locomotion is obtained. Moreover, it is shown that "Perambulator" can successfully exhibit 3D locomotion by using the output of the proposed CPG network. The obtained results have also provided a bran new approach to understand the unknown neuron network of nature snakes

For AFM based robotic nanomanipulation system without displacement sensor, one of the key technical problems is to realize high accurate positioning of the AFM probe. To solve the problem, based on the hysteresis and nonlinear characteristics analysis of AFM PZT actuator, a new actuating method called "actuating method based on reappearing the scanning trajectory" is presented to actuate the PZT actuator. Then two kinds of probe positioning errors, namely kinematics coupling errors due to the tube actuator's bend motion and probe tip's positioning errors caused by cantilever deflections, are compensated to further improve the probe's positioning accuracy. Nanopatterning experiments are performed to verify the effectiveness of the new actuating method and the compensation methods of probe positioning errors

A reconfigurable modular planetary robot system (RMPRS) consists of the parent body and multiple asymmetric wheel-manipulator child-robot modules. The module, which can independently locomote and manipulate, possesses the orientation of posture and the direction of locomotion. The modules have reconfiguration capability so that a group of the modules can construct a variety of configurations. The aim of the robot reconfiguration is to generate better configuration with respect to the directional locomotion adapted to the environment. Module state vector (MSV) and configuration state matrix (CSM) are presented and constructed for representing the asymmetric module and the configurations, and supporting the transformation operation for triggering the elementary motions of the module and the reconfiguration. The algorithm for optimizing the assembly reconfiguration of discrete modules is proposed and the result is evaluated through numerical simulation in an example

A reconfigurable planetary rover system (RPRS) is presented, including the parent body and some child robots. The child robot composed with the arm part and the wheel part has two moving modes: locomotion mode and manipulation mode. According to the mechanical characteristics, we proposed the two methods for the motion planning of swerving locomotion. The results of experiments showed that the robot can achieve turn during locomotion by adjusting the arm's attitude. But the child robot's radius of left-hand turning motion during locomotion is bigger much than the radius of right-hand turning motion during locomotion and the effect is not obvious. The method of spot turning is presented by use of the difference between radial frictional force and tangential frictional force of ground and direction wheel, which is important for robot for autonomous locomotion.

Based on the structure of both biological snakes and snake-like robots and their rhythm locomotion, the theory of the cyclic inhibitory CPG is adopted as a control method to construct a neuron network model of the snake-like robot. The relation between the CPG parameters and the serpentine locomotion of the snake-like robot is defined in this paper. The validity of the serpentine locomotion controlled by the CPG model is verified through a snake-like robot model. The modulating methods of the CPG parameters are brought forward and simulated to realize the required turn motion and the reconfiguration. Moreover, we present that real snake-like robot can successfully exhibit serpentine locomotion by using controller output of the proposed architecture. Finally, the aspects of future researches are discussed.

Based on the structure of both biological snakes and snake-like robots and their rhythmic locomotion, the musical theory is adopted as a control method to study on a snake-like robot. The relation between the rules and symbols of the musical theory and the control process of the snake-like robot is defined in this paper. Thus the data sequence of the relative angles in the serpentine locomotion is melodized. The gait score of the serpentine locomotion is utilized to control a snake-like robot named "Perambulator-I". Finally, the aspects of the future researches are discussed.

During imaging and nanomanipulation with a sample-scanning AFM based nanomanipulator, because of bend motion of tube scanner, two important errors will be generated, namely scanning size error and cross coupling error, and they are destructive to both image quantitative analysis and nanomanipulation accuracy. To minimize the errors, a kinematics model of the scanner is presented, which shows that lateral and vertical displacements at any point on sample depend on its onset to tube axis, applied voltage and sample thickness besides scanner geometric parameters and piezoelectric constant. According to the model, the two errors are quantitatively analyzed. Imaging and nanolithography experiments verify the kinematics model and errors calculation formulas, and some methods are also proposed for minimizing the errors.

During the control of teleoperation via Internet, an operator cannot obtain the real-time data in a timely and accurate fashion. This is due to the uncertain time delays, which are unavoidable in the Internet-based communication and cause instability and poor system performance. This paper deals with the modelling and control of Internet-based teleoperation systems using the hybrid dynamic system approach. A supervisory controller is implemented to overcome the uncertain time delays. This method provides an efficient way to model the concurrence and complexity of the Internet-based robotic teleoperation.

A reconfigurable modular snake robot has been developed, which can not only move on a plane but aIso achieve some f-dimensional motions while reconfigured. Control equations of 3-dimensional locomotion were established by the composition of two bending motions in mutual orthogonal plane. Three types of lateral rolling locomotion, flapping, linear rolling and curved rolling, were achieved by controlling the amplitudes and the number of two waves in the two bending motions. Using the three types of locomotion the snake robot can realize net lateral translation, alternation of its contact base and rolling over some obstacles. The lateral rolling locomotion obtains its driving force through the interaction with the environment. The rolling shape and its direction depend on the transferring direction and phase difference of the two waves respectively.

This paper presents a modeling and analysis method for the motion planning and control of mobile robot systems in a hybrid fashion. Robotic systems obtain environmental information from perceptive sensors and respond to the perceptions to execute the task through decision and control process. The hybrid perceptive model of the robotic system has one continuous and two discrete layers, and it also has continuous and discrete perceptive references. The discrete layers enable the robot system to plan and modify original path through switching. Stability can be guaranteed in switching. The hybrid perceptive references can not be stopped by blocking the continuous reference, including obstacles. The model is verified by experiments.

With high adaptability to environments snakelike robots offer a variety of advantages over other mobile robots. Such a robot with passive wheels has quite different mechanism in locomotion from that of other locomotion systems. We have developed a snakelike robot for rescue applications. The unit composing the snakelike robot of Shenyang Institute of Automation (SIA) is a module including actuating system and control system. To let the snakelike robot perform turning motion and compensate offset and orientation errors of the robot, we propose an amplitude modulation method and a phase modulation method based on analysis of the serpenoid curve. The side motion of the snakelike robot can also be generated by the amplitude modulation. The tracking control method is also proposed based on sensor information. Computer simulations and experimental tests are performed to show the validity of the proposed methods.

This paper describes the motion planning problems of mobile robots in uncertain dynamic environments with no restrictions on the shape of obstacles. A new approach based on the behavior dynamics of collision-avoidance is proposed to deal with the real-time collision-free motion planning using the local coordinates of the mobile robot. The behavior dynamics of a dynamic collision-avoidance process was modeled, and then the motion-planning problem was transformed into a simple optimization problem with some inequality constraints based on control of the behavior dynamics. The decision-making space of this optimization problem is right the acceleration space of the mobile robot. By solving this optimization problem, the optimal behavior of the mobile robot to avoid obstacles and go to the desired target can be obtained easily. Simulations are given to illustrate the main ideas.

Hyper-redundant manipulator has more degrees of freedom than the least necessary to perform a given task, thus it has the features of overcoming conventional industrial robot's limitation such as improving its kinematics and dynamic performances. Crucial as it is, effective control of hyper-redundant manipulator is difficult for its redundancy. A novel shape control technique based on the concept of variable structure regular polygon and subsystem has been proposed. This technique, using variable structure regular polygon and neural networks models, is completely capable of solving the control problem of a planar hyper-redundant manipulator with any number of links following any desired path. With regular polygon side number's variety and its shape's transformation, the manipulator's configuration changes accordingly and moves actively to perform the task form point to point or following a path. Compared with other methods to our knowledge, this technique has such superiorities as fewer control parameters, higher precision and less computation. Simulation of a six-link modularized manipulator's inspection work in a bottle-like concave has demonstrated that this control technique is available and effective.

It is essential to design a joint mechanism for snake-like robots to exhibit more mobility, no singularity and powerful actuation for many applications. By adding a series of passive wheels to the perimeter of the newly designed joint mechanism with 3 DOFs, a snake-like robot provided with the characteristic of omnidirectional mechanism can traverse rough terrain and compensate the lack of actuation due to passive wheels. The nonholonomic constraints and kinematics are analyzed as well as the redundancy. The composite motion method and grouping alternation motion control method are thus proposed for the locomotion of robot and the avoidance of singularity. Also, the grouping alternation motion adds a new explanation to the sinus lifting locomotion of natural snake. Computer simulations validate both mobility of mechanism and effectiveness of control methods.

With the rapid development of information technology, Internet has evolved from a simple data-sharing media to an amazing information world where people can enjoy different kinds of services. Recently, the use of the Internet has been expanded to the field of automation, i.e. using the Internet as a tool to control equipment located at remote sites. This paper presents a cooperative robot system consisting of a robot hand and a mobile robot carrying a stereo vision, which can be tele-operated by operators at different sites via the Internet. To overcome the instability and reliability problem caused by the random time delay of the Internet communication, we adopt an event as the reference for controller design of the system. A vision-based method is adopted to maintain interactions among the operations. Results obtained in teleoperation experiments among Hong Kong, the mainland China, and USA will be demonstrated to confirm the usefulness and effectiveness of the developed method and system.

This paper addresses visual servoing of a robot manipulator with uncalibrated intrinsic and extrinsic parameters of the vision system and unknown physical parameters of the manipulator. A novel sliding mode visual feedback scheme is proposed to solve the problem of the robust trajectory tracking of a planar manipulator in the image frame without calibrating the camera parameters. The controller does not use visual velocity so as to achieve high and robust performance with low sampling rate of the vision system. It is proved by Lyapunov direct method that the tracking error of the robot converges to an arbitrarily small neighborhood of zero. The simulation is included to demonstrate the effectiveness of the controller proposed.

A model identification method for unknown environments has been developed. By the interactions between a mobile manipulator and the unknown object, a nonholonomic cart, sensory information has been collected to estimate the model parameters of the cart, which are used to control the cart. Since the raw data are contaminated by noise they can not be modeled statistically, a wavelet based least square method is proposed to estimate these parameters for the cart. The raw signal has been decomposed into a certain bandwidth to generate a series of new signals, which are used to estimate the parameters. The new signal, which has the minimal estimation residual in least square sense is adopted as the best estimation. The error convergence of the estimation approach is given. The experimental results indicate that the estimation accuracy can be significantly improved by the use of the proposed method.

Snakes perform many kinds of movement that are adaptable to the environment. Utilizing the snake (its forms and motion) as a model to develop a snake-like robot that emulates a snakes' function is important for generating a new type of locomotor and expanding the possible use of robots. We developed a simulator to simulate the creeping locomotion of a snake-like robot, in which the robot dynamics is modeled and its interaction with the environment is considered through Coulomb friction. This simulator makes it possible to analyze the creeping locomotion with the normal-direction slip coupled to gliding along the tangential direction. Through the developed simulator, we investigated the snake-like robot creeping locomotion which is generated only by swinging each of the joints from side to side, and discussed the optimal creeping locomotion of the snake-like robot that is adaptable to a given environment.

Now a number of advanced control systems take advantage of networks such as Ethernet, Fieldbus and Internet as their communication channel. Transmission time delay of these networks may lead unstable problems to system. In this paper, the prediction of network delay using neural network is presented first. Then the analysis of the control oriented quality of service (CO-QoS) specially with the Internet-based teleoperation is considered and fuzzy inference is used to construct a quantification of CO-QoS. At last, the simulation results show that this method provides a practical way for the judgment of the network's characteristics.

Classical PD control for a direct drive motor system is enhanced to suppress disturbing torque by incorporating an acceleration feedback loop. This is intended to achieve a stable and high stiffness control without the need of adjusting the PD controller, either the structure or the parameters. The acceleration feedback control is presented with a focus on designing the acceleration closed-loop in terms of its stability and ability in resisting the dynamic disturbances. The sensing and modeling of angular acceleration via servo-type linear accelerometers is dealt with from the viewpoint of practical implementation. Extensive experiments are conducted on the second joint of a three-link direct drive robot. Results are compared to those obtained by classical PD control without the acceleration feedback loop, to mainly investigate the ability of the acceleration feedback control in resisting disturbing torque, and its influence on conventional PD control.

This paper is concerned with the stabilization problem of multiple chained form control systems with input constraints. A new controller presented can stabilize the system to an arbitrarily, small /spl epsi/-neighborhood of its equilibrium in a finite time. This is achieved by the sliding mode approach and a multi-step control strategy. The application of it to a nonholonomic wheeled mobile robot is described. Simulation result shouts that the proposed controller is effective.

Joint acceleration feedback control is employed to damp oscillations during the contact transition with non-zero approaching speed. A classical integral force controller is refined by means of joint acceleration and velocity feedback. The intention is to achieve a stable contact transition without need of adjusting the controller parameters adaptive to the unknown or changing environments. Extensive experiments are conducted on the third joint of a three-link direct-drive robot to verify the proposed scheme for various stiffness of the contacted environments, including elastic (sponge), less elastic (hardboard) and hard (steel plate) surfaces. Results are compared with those experimental ones by the transition control with only velocity feedback damping. The advantages offered by our approach are addressed.