Miniature Mobile Robot Research Articles

An Integrated Triangulation Laser Scanner for Obstacle Detection of Miniature Mobile Robots in Indoor Environment

The miniaturization of an autonomous robot requires the integration of components that not only need to satisfy strict spatial constraints, but also need to demonstrate useful functionalities and performance, while demanding low power. For miniaturized autonomous robots that aim at exploring unknown environments, sensors for navigation and for the understanding of basic geometrical features of the environment are of utmost importance for a robot's survival and mission. This paper presents a miniaturized triangulation laser scanner that was developed and characterized for use on a 10 × 10 × 10 cm3 robot. The optimal configurations of the laser sensor on two sides of the robot are discussed, and measurement formulas as well as theoretical resolution are deduced. For indoor applications, the measurement range of the system runs from approximately 80 mm, with 1 mm resolution, up to 600 mm, with 12 mm resolution. The aim of the work is to demonstrate the possibility of extracting basic information from the robot surroundings by means of small, simple, low-power, and low-cost demanding devices, which, in addition, can be scaled down in order to equip even smaller robots.

From swarm robotics to smart materials

Swarm intelligence refers to the phenomenon of a system of spatially distributed individuals that coordinate their actions in a decentralized and self-organized manner, so as to exhibit complex collective behavior. Such systems tend to have large numbers of individual agents that interact with each other in simple ways. This allows swarm-intelligent systems to be inherently robust and flexible. As these principles are scale-free, systems with these properties can range in size from the nano to the macro scale. Swarm-intelligent systems are common throughout nature. Examples are bacteria colonies, neural networks, social insects, and flocks/herds of vertebrates. In addition, humans have produced a variety of (artificial) swarm systems ranging from swarm-based optimization algorithms to sensor networks, swarms of robots, and smart materials. In each of these natural or artificial systems, populations of agents change their spatiotemporal configuration solely based on the agents’ local interactions with each other and the environment. This special issue on ‘‘Swarm Robotics’’ provides an overview of recent results and trends in this emerging field. Contributions to this special issue range from programming paradigms for swarming systems to specific distributed algorithms and modular robotic systems. The unifying theme of these works is individual simplicity: complex global behavior emerges from purely local interactions and simple local rules. Examples covered in this special issue range from spatial behaviors such as flocking and dispersion, computational behaviors such as shortest-path routing and collective decisions, up to full-body behaviors of modular robot ensembles. In their paper, ‘‘Composable continuous-space programs for robotic swarms’’, Bachrach, Beal, and McLurkin present the functional programming language Proto that allows individual behavior to be described by expressions over a global field. By computing the global field not only from local measurements but also based on data received from other swarm members within the local neighborhood, previous state, and control logic, Proto allows complex swarming behaviors to be composed with highly compact code. Proto code is then compiled into op-codes for the Proto Virtual Machine, which needs to provide abstractions for sensing, actuation, estimation of the geometric relations between neighboring swarm members, and local communication. Algorithms such as shortest-path routing are demonstrated on a swarm of 40 miniature mobile robots, as well as in computer simulations. In their paper, ‘‘Collective decision-making based on social odometry’’, Gutierrez, Campo, Monasterio-Huelin, Magdalena, and Dorigo investigate a novel collective decision-making mechanism using a colony of mobile robots that accomplish a foraging task. The robots are required to establish a path from a central place to the closest of multiple resource sites. To reach a consensus, they make use of social odometry. The latter mechanism enables the robots to estimate the position of resource sites by exchanging and aggregating odometry-based positional information and confidence levels. The collective decisionmaking mechanism is successfully validated by experiment N. Correll (&) Department of Computer Science, University of Colorado at Boulder, 430 UCB, Boulder, CO 80309, USA e-mail: nikolaus.correll@colorado.edu

Experiments and Resonant Locomotion Principle Based on Impact Force

Double pendulum with unilateral constraints is a complex system, which has many dynamic behaviors. The dynamics of a double pendulum contacting with constraints in initial conditions is studied, and it is found that only very small excitation is needed to separate the pendulum and the constraint when the excitation frequency is appropriate, then the system enters vibro-impact state. In this state, the probability distribution of tangential impulse generated by every impact is invariable. The impact force shows the ability of driving robot to move. Based on this principle, by simulating the characteristic of double pendulum, resonant legs and a prototype robot are developed. Experiment results show that the impact force between resonant leg and ground do have driving effect, and a velocity of 172 mm/s can be got with 10 V driving voltage. The resonant locomotion principle can fit the micro and miniature mobile robots well for it is simple, easy to implement and fast.

Development of IR-Based Short-Range Communication Techniques for Swarm Robot Applications

This paper proposes several designs for a reliable infra-red based communication techniques for swarm robotic applications. The communication system was deployed on an autonomous miniature mobile robot (AMiR), a swarm robotic platform developed earlier. In swarm applications, all participating robots must be able to communicate and share data. Hence a suitable communication medium and a reliable technique are required. This work uses infrared radiation for transmission of swarm robots messages. Infrared transmission methods such as amplitude and frequency modulations will be presented along with experimental results. Finally the effects of the modulation techniques and other parameters on collective behavior of swarm robots will be analyzed.

Intelligent wheeled mobile robot navigation

The paper deals with the wireless sensor-based remote control of mobile robots motion in an unknown environment with obstacles using the Sun SPOT technology and gives the fuzzy velocity control of a mobile robot motion in an unknown environment with obstacles. When the vehicle is moving towards the target and the sensors detect an obstacle, an avoiding strategy and velocity control are necessary. We proposed the wireless sensor-based remote control of mobile robots motion in an unknown environment with obstacles using the Sun SPOT technology and a fuzzy reactive navigation strategy of collision-free motion and velocity control in an unknown environment with obstacles. The simulation results show the effectiveness and the validity of the obstacle avoidance behavior in an unknown environment. The proposed method have been implemented on the miniature mobile robot Khepera® that is equipped with sensors.

A Miniature Mobile Robot for Navigation and Positioning on the Beating Heart

Robotic assistance enhances conventional endoscopy; yet, limitations have hindered its mainstream adoption for cardiac surgery. HeartLander is a miniature mobile robot that addresses several of these limitations by providing precise and stable access over the surface of the beating heart in a less-invasive manner. The robot adheres to the heart and navigates to any desired target in a semiautonomous fashion. The initial therapies considered for HeartLander generally require precise navigation to multiple surface targets for treatment. To balance speed and precision, we decompose any general target acquisition into navigation to the target region followed by fine positioning to each target. In closed-chest, beating-heart animal studies, we demonstrated navigation to targets located around the circumference of the heart, as well as acquisition of target patterns on the anterior and posterior surfaces with an average error of 1.7 mm. The average drift encountered during station-keeping was 0.7 mm. These preclinical results demonstrate the feasibility of precise semiautonomous delivery of therapy to the surface of the beating heart using HeartLander.

Preface to the Journal of Micro-Nano Mechatronics

We are very happy to start the Journal of Micro-Nano Mechatronics, which is a quarterly journal devoted to the theory and applications of micro and nanotechnologies. Although there have been very significant research achievements and advancements related to microand nanotechnologies in the last decade, there is a significant gap in system level microand nanoscale research for high impact real world applications of these technologies. Therefore, the field of microand nanomechatronics has emerged as a new field to fill this gap. The mission of this journal is to report the research advances and achievements of this new field. This journal is rooted from the Journal of MicroMechatronics published by VSP. In the Journal of Micro-Nano Mechatronics, the topics are extended to nanoscale mechatronic systems, and Springer became the new publisher. We have very dynamic and active new editorial board members from experts in the field around the world. The Journal of Micro-Nano Mechatronics promotes both theoretical and practical engineering research based on analysis and synthesis from the micro level to the nano level. Some example topics of interest include design, manufacturing, control, and applications of miniature mobile robots down to microand nanometer sizes, micro/nanoscale manipulation systems, precision or directed self-assembly based micro/nano-assembly, micro/nanoscale precision positioning, micro/nanoelectromechanical systems (M/NEMS), bio-MEMS, micro/ nano-manufacturing, micro/nanoscale dynamics, automation and control, micro/nanoscale sensors and actuators, modeling of micro/nanoscale physics and mechanics, adhesion and friction at the micro/nanoscale, distributed, reconfigurable, emergent and self-organizing micro/ nano-systems, energy and power sources at the micro/ nanoscale, human-machine interfaces for micro/nanosystems, and applications of micro/nano-mechatronic systems in health care, biology, information technology, environment, manufacturing, space; and others. The journal includes survey papers, technical papers, short papers, and news items. Many special issues are planned, similar to the one in this first issue by guest editors Sergej Fatikow and Quan Zhou. The journal will be included in the Web of Science database after few years depending on our success of publishing high impact papers regularly. We look forward to receiving high quality papers from all of our colleagues to make this journal a leading publication in the field of microand nanomechatronics. J. Micro-Nano Mech. (2008) 4:1 DOI 10.1007/s12213-008-0014-x

Micro operation system based on miniature mobile robot

A newly developed micro operation system assisted by a conceptual 5-DOF (degree of freedom) macro/micro dual driven micro robot is presented. With the macro motion mode, the robot is a typical wheeled mobile robot and with the micro motion mode the robot is an inchworm robot. A manipulator is mounted on the top of robot platform for the robot accomplishing micro operation task. To navigate the robot automatically, an intelligent vision sensor system is developed. The vision system includes two parts that are the global vision system and the local vision system. The global visual system guides the robot to accomplish large workspace rapid motion. The local vision system guides the robot to accomplish small workspace precision positioning for micro operation task. Experiments show that the proposed system succeeds in providing micro operation task such as micro part gripping and assembly.

An In Vivo Mobile Robot for Surgical Vision and Task Assistance

Current laparoscopic surgical robots are expensive, bulky, and fundamentally constrained by the small entry incisions. A potential new approach to minimally invasive surgery is to place the robot completely within the patient. We have developed several such miniature mobile robots and conducted tests during animal surgeries. These robots can provide vision and task assistance to the surgeon without being constrained by the entry port. We used a mobile biopsy and camera robot to sample hepatic tissue from an anesthetized porcine animal model. This successful test demonstrated the capability of performing a single port laparoscopic biopsy procedure. In the future, a family of such robots could be remotely controlled and used to perform surgical procedures without the need for conventional laparoscopic tools.

SELF-ORGANIZATION OF SPIKING NEURAL NETWORK THAT GENERATES AUTONOMOUS BEHAVIOR IN A REAL MOBILE ROBOT

In this paper, we propose self-organization algorithm of spiking neural network (SNN) applicable to autonomous robot for generation of adoptive and goal-directed behavior. First, we formulated a SNN model whose inputs and outputs were analog and the hidden unites are interconnected each other. Next, we implemented it into a miniature mobile robot Khepera. In order to see whether or not a solution(s) for the given task(s) exists with the SNN, the robot was evolved with the genetic algorithm in the environment. The robot acquired the obstacle avoidance and navigation task successfully, exhibiting the presence of the solution. After that, a self-organization algorithm based on a use-dependent synaptic potentiation and depotentiation at synapses of input layer to hidden layer and of hidden layer to output layer was formulated and implemented into the robot. In the environment, the robot incrementally organized the network and the given tasks were successfully performed. The time needed to acquire the desired adoptive and goal-directed behavior using the proposed self-organization method was much less than that with the genetic evolution, approximately one fifth.

Modelling the Environment of a Mobile Robot with the Embedded Flow State Machine

A type of topological approach to mobile robot navigation is discussed and experimentally evaluated. The environment as experienced by a moving robot is treated as a dynamical system. Simple types of reactive behavior are supplemented with eventual decisions to switch between them. When switching criteria are defined, the system may be described in the form similar to a finite state machine. Since it is embedded in the environment and dependent on the sensory flow of the robot, we introduce the term "Embedded flow state machine" (EFSM). We implemented it with a recurrent neural network, trained on a sequence of sensory contents and actions. One of the main virtues of this approach is that no explicit localization is required, since the recurrent neural network holds the state implicitly. The EFSM is applicable to multi-step prediction of sensory information and the travelled distances between decision points, given a sequence of decisions at decision points. Thus, the optimal path to a specified goal can be sought. One of the main issues is, for how many steps ahead the prediction is reliable enough. In other words, is it feasible to perform environment modelling and path planning in this manner? The approach is tested on a miniature mobile robot, equipped with proximity sensors and a color video camera. Decision `points,' where deviations from the wall-following behavior are allowed, are based on color object recognition. In the case of an experimental environment of medium complexity, this approach was successful.

Device Server for a Miniature Mobile Robot

This paper describes a device server for a miniature mobile robot. Generally, miniature robots have low-size memory and relatively slow microcontroller to realize complicated tasks. Therefore, a device server for small sized mobile robots is proposed with the intention of increasing their capabilities. The proposed software system runs on the microcontroller of the robot, and serves a collection of sensors and actuators over serial rf transceiver to authorized clients. The system has modularity and multi-tasking capability. The proposed system is implemented on a Z-80 microprocessor-controlled mobile robot. It is shown that proposed system is capable of serving one client and two processes.

WIRELESS MINIATURE ROBOT AND ITS CONTROL SYSTEM

A miniature mobile robot facing on precision manipulation is developed and the wireless control system is designed. This robot is composed of moving allocation unit basing on macro/micro dual moving manner and spherical manipulator with three degrees of freedom. The whole robot occupies a volume of 90 mm×70 mm×60 mm. In the macro-moving manner, using the micro motor with the diameter of 3 mm, the robot can move at high speed up to 100 mm/s. And the positioning accuracy is up to 0.5 mm as well as the moving resolution is 0.1 mm. In the micro-moving manner, according to prin- ciple of inchworm, the robot can move at a speed of 200 μm/s with 50μm positioning accuracy and 2μm resolution. Three pizeo-ceramic tubes basing on the principle of stick-slip drive the spherical manipulator. The manipulator can rotate around z-axis or move up and down. The accuracy of spherical manipulator is 0.001°. All driving circuits are integrated in the body of robot. Two polymeric lithium-metal cells are selected as the power source. The robot communicates with the image processing system through a blue tooth model. For convenient control, the locomotion of robot is decomposed several sample motion modes. By applying the multiple threads technology to program, the performance of real time operation is good.

Preliminary evaluation of a mobile robotic device for navigation and intervention on the beating heart

This article describes the development and preliminary testing of a mobile robotic device to facilitate minimally invasive beating-heart intrapericardial intervention. The HeartLander robot will be introduced beneath the pericardium via subxiphoid incision, adhere to the epicardium, navigate to any location, and administer therapy under the control of the physician. As compared to current robotic cardiac surgical techniques, this novel paradigm obviates immobilization of the heart and eliminates access limitations. Furthermore, it does not require lung deflation and differential ventilation and thus could enable outpatient cardiac surgery. The current HeartLander prototypes use suction to maintain prehension of the epicardium and wire actuation to perform locomotion. A fiber optic videoscope displays visual feedback to the physician, who controls the device through a joystick interface. The initial prototype demonstrated successful prehension, turning, and locomotion on open-chest, beating-heart porcine models where the pericardium was removed (N = 3). A smaller second-generation prototype with an injection system demonstrated locomotion and myocardial injection of dye, both performed with the pericardium intact (N = 3). These trials illustrate the feasibility of using a miniature mobile robot to navigate upon the beating heart and perform intrapericardial therapy.

The HeartLander: A novel epicardial crawling robot for myocardial injections

Myocardial infarction is the leading cause of congestive heart failure and death in the industrialized world. Stem cell transplantation to failing myocardium appears to improve heart function following myocardial infarction, but further refinement of the delivery methodology is required. The HeartLander miniature mobile robot has the ability to adhere to the epicardium, travel to the operative site, and perform intramyocardial injections under direct control of the surgeon. This paradigm obviates sternotomy, cardiopulmonary bypass, mechanical stabilization and lung deflation, while granting improved access. To facilitate movement under the pericardium, a small prototype with a tapered front has been constructed that is 11 mm tall and fits through a 15-mm cannula. This prototype was tested in beating-heart porcine trials via median sternotomy, but with the pericardium intact ( N = 2). The HeartLander was able to maintain prehension and travel without being displaced by the overhead motion of the pericardium. Myocardial injections of tissue dye were performed successfully at several locations. These experiments show the feasibility of navigating under the pericardium and performing needle injections into the myocardium using video feedback. Future research will move toward minimally invasive testing without sternotomy, including both locomotion and therapy.

Autonomous Stair-Climbing With Miniature Jumping Robots

The problem of vision-guided control of miniature mobile robots is investigated. Untethered mobile robots with small physical dimensions of around 10 cm or less do not permit powerful onboard computers because of size and power constraints. These challenges have, in the past, reduced the functionality of such devices to that of a complex remote control vehicle with fancy sensors. With the help of a computationally more powerful entity such as a larger companion robot, the control loop can be closed. Using the miniature robot's video transmission or that of an observer to localize it in the world, control commands can be computed and relayed to the inept robot. The result is a system that exhibits autonomous capabilities. The framework presented here solves the problem of climbing stairs with the miniature Scout robot. The robot's unique locomotion mode, the jump, is employed to hop one step at a time. Methods for externally tracking the Scout are developed. A large number of real-world experiments are conducted and the results discussed.

Preliminary evaluation of a mobile robotic device for navigation and intervention on the beating heart

This article describes the development and preliminary testing of a mobile robotic device to facilitate minimally invasive beating-heart intrapericardial intervention. The HeartLander robot will be introduced beneath the pericardium via subxiphoid incision, adhere to the epicardium, navigate to any location, and administer therapy under the control of the physician. As compared to current robotic cardiac surgical techniques, this novel paradigm obviates immobilization of the heart and eliminates access limitations. Furthermore, it does not require lung deflation and differential ventilation and thus could enable outpatient cardiac surgery. The current HeartLander prototypes use suction to maintain prehension of the epicardium and wire actuation to perform locomotion. A fiber optic videoscope displays visual feedback to the physician, who controls the device through a joystick interface. The initial prototype demonstrated successful prehension, turning, and locomotion on open-chest, beating-heart porcine models where the pericardium was removed (N = 3). A smaller second-generation prototype with an injection system demonstrated locomotion and myocardial injection of dye, both performed with the pericardium intact (N = 3). These trials illustrate the feasibility of using a miniature mobile robot to navigate upon the beating heart and perform intrapericardial therapy.

Chaotic dynamics of a behavior-based miniature mobile robot: effects of environment and control structure

To study the regularity and complexity of autonomous behavior, the flow of sensory information obtained in autonomous mobile robots under various conditions was analyzed as a complex system. Sensory information time series X n was collected from a miniature mobile robot during free navigation, and plotted on the return map, the graph of X n+τ vs. X n . The plot exhibited a characteristic trajectory, representing the regularity of the time series. Correlation integral and Lyapunov exponent analysis also showed properties of deterministic chaos; the presence of fractal dimension and positive Lyapunov exponent. Analysis of sensory information obtained in the robot with three different neural controllers revealed that the autonomous robot behaves in such a way that the flow of sensory information is governed by a deterministic rule, and this pattern is unique to each controller. Furthermore, the analysis in various environments exhibited that transitions from one trajectory to another on the return map occur during the course of autonomous behavior. The fractal and Lyapunov dimensions calculated in various conditions indicate that these dimension could be utilized to quantify the complexity of autonomous behavior and the relative difficulty of tasks. Analyses at different evolutionary stage revealed that behavioral performance correlates with fractal dimension. These studies using a miniature mobile robot that allowed to idealize the experimental conditions demonstrated firmly that the complex analysis could be utilized in evaluation and optimization of autonomous systems and the behavior.

Grasping and Tracking Using Constant Curvature Dynamic Contours

In this paper we present our constant curvature dynamic contours (snakes) and three applications of these: visual servoing and grasping, occluding contour depth extraction, and localization of miniature mobile robots. For the first application, a novel deformable contour model is implemented for the automatic determination of plausible grasp axes of unknown objects using an eye-in-hand robotic system. The system finds potential grasp point pairs, ranks them based upon measurements taken from the contour, and executes a vision-guided grasp using the highest ranked grasp point pair to determine the gripper alignment. Our method is based upon statistical active deformable models. We have developed a new snake model that is applicable to real-time vision problems. The grasping method is experimentally verified using both simple and complex unknown grasping targets. These experiments demonstrate the effectiveness of using the proposed snakes to grasp previously unknown objects in minimally structured environments. We also present a novel method for active monocular depth recovery (second application of our snakes). It combines new, highly stable active deformable models with a structured camera motion along the optical axis to produce depth estimates for all snake control points. The method has a simple formulation and is suitable for real-time, vision-based robotic applications. Experiments with a variety of objects and depths demonstrate the practicality of the method. Finally, we present a novel method for localizing miniature mobile robots (Scouts) using dynamic contours. The miniature robot is tracked as it moves and jumps in the environment. The proposed dynamic contours are very effective in tracking the fast accelerations and decelerations of this small robot. We show initial experimental results emphasizing the task of monitoring a Scout's jumps.

Fuzzy Behavior-Based Control. 3rd Report. Module Learning and Behavioral Coordination by an Adaptive Fusion Unit with External Sensor Information.

In order to obtain more effective coordinated behaviors against changes in environments or unlearned environments, we here propose a new fusion unit using external sensor information for a fuzzy behavior-based control system trained in the framework of module learning. The present fusion unit falls into a class of adaptive priority-based architecture in which the fusion between behavioral elements is carried out by a cooperation or comnetition strategy, depending on whether an objective point or obstacle can be detected or not. Some experimental results of a miniature mobile robot Khepera show that the proposed metcod is superior to the conventional method that applies a fusion unit based on a fixed priority-based architecture.