Showing papers in "Advanced Robotics in 1997"
Journal Article•
TL;DR: A novel formulation for the estimation of the coordinates of a wave source based on the differences in the time-of-flights from a single transmitter to various receivers fixed in 3D space, which leads to a robust system that is insensitive to changes in the environmental conditions.
Abstract: This paper presents a novel formulation for the estimation of the coordinates of a wave source based on the differences in the time-of-flights from a single transmitter to various receivers fixed in 3D space. The formulation is closed form linear, and estimates the speed of sound at every ranging operation. This leads to a robust system that is insensitive to changes in the environmental conditions. Typical applications that will benefit from this technology are 3D position sensing systems that may be used in robotics, navigation of autonomously guided vehicles, tracking of objects for virtual reality cells, and vibration analysis.
122 citations
TL;DR: The cooperative navigation system (CNS) algorithm described here is based on a Kalman filter which uses inter-robot position sensing to update the collective position estimates of the group.
Abstract: The navigation capability of a group of robots can be improved by sensing of relative inter-robot positions and intercommunication of position estimates and planned trajectories. The cooperative navigation system (CNS) algorithm described here is based on a Kalman filter which uses inter-robot position sensing to update the collective position estimates of the group. Assuming independence of sensing and positioning errors, the CNS algorithm always improves individual robot estimates and the collective navigation performance improves as the number of robots increases. The CNS algorithm computation may be distributed among the robot group. Simulation results and experimental measurements on two Yamabico robots are described.
75 citations
TL;DR: It is first clarified through simulational analysis that co-activation between agonist an muscle and its antagonist both having nonlinear elasticity is indispensable for the stiffness adjustment on an articulator movement.
Abstract: It is first clarified through simulational analysis that co-activation between agonist an muscle and its antagonist both having nonlinear elasticity is indispensable for the stiffness adjustment on...
41 citations
TL;DR: This paper proposes to use a reconfigurable gripper equipped with two parallel plates to immobilize objects through frictionless contacts with three of the pins and the bottom plate, and to manipulate an object within a grasp by planning the sequence of pin configurations that will bring this object to a desired position and orientation.
Abstract: This paper addresses the problem of grasping and manipulating three-dimensional objects with a reconfigurable gripper equipped with two parallel plates whose distance can be adjusted by a computer-controlled actuator. The bottom plate is a bare plane and the top one carries a rectangular grid of actuated pins that can translate in discrete increments under computer control. We propose to use this gripper to immobilize objects through frictionless contacts with three of the pins and the bottom plate, and to manipulate an object within a grasp by planning the sequence of pin configurations that will bring this object to a desired position and orientation. A detailed analysis of the problem geometry in configuration space was used in a previous paper to devise simple and efficient algorithms for grasp and manipulation planning. We have constructed a prototype of the gripper and this paper presents our experiments.
30 citations
TL;DR: This paper tries to incorporate an offline metadynamics function into their previously proposed mechanism, and uses a genetic algorithm with a devised crossover operator to accomplish this function.
Abstract: We have been investigating a new behavior arbitration mechanism based on the biological immune system. The behavior arbitration mechanism and the biological immune system share certain similarities since both systems deal with various sensory inputs (antigens) through interactions among multiple competence modules (lymphocytes and/or antibodies). We have demonstrated the flexible arbitration abilities of our proposed method; however, we have not shown a solution to the problem: how do we prepare an appropriate repertoire of competence modules? In this paper, in order to construct an appropriate immune network without human intervention, we try to incorporate an offline metadynamics function into our previously proposed mechanism. The metadynamics function is an adaptation realized by varying the structure of the immune network. To accomplish this function, we use a genetic algorithm with a devised crossover operator. Finally, we verify our method by carrying out simulations.
29 citations
TL;DR: Extensions to the distributed control architecture KAMARA (KArlsruhe Multi-Agent Robot Architecture) are described that are used to overcome coordination problems, e.g. path planning for collision avoidance between both manipulators in a two-arm system.
Abstract: The main advantage of distributed controlled robots and subsystems is the decentralized task execution by the system components In this way, properties for the design of flexible control architectures like modularity, fault-tolerance, integrability and extendibility are easily obtained; furthermore, it is possible to use the concepts of distributed knowledge and decentralized world representation On the other hand, coordination between the components, eg path planning for collision avoidance between both manipulators in a two-arm system, is very difficult to guarantee To explain these concepts, the Karlsruhe Autonomous Mobile Robot (KAMRO), which is being developed at our institute, is considered The robot system consists of several subcomponents like two manipulators, hand-eye cameras, one overhead camera and a mobile platform Extensions to the distributed control architecture KAMARA (KArlsruhe Multi-Agent Robot Architecture) are described that are used to overcome coordination problems, eg as c
26 citations
TL;DR: A new control strategy for robot manipulators is presented, which utilizes visual information to direct the manipulator in its working space, to pick up an object of known shape, but with arbitrary position and orientation.
Abstract: —In robotic applications, tasks of picking and placing are the most fundamental ones. Also, for a robot manipulator, the recognition of its working environment is one of the most important issues t...
24 citations
Journal Article•
TL;DR: An efficient kinematic position control for the center of mass of an articulated arm by integrating the context of multiple joints reaching their limit value together with a singular configuration on the remaining joint space is proposed.
Abstract: We propose an efficient kinematic position control for the center of mass of an articulated arm. The algorithm integrates the context of multiple joints reaching their limit value together with a singular configuration on the remaining joint space. We demonstrate the resulting fine control by interactively outlining the reachable area borders of the center of mass (in a 2D context for clarity). Moreover, the identification is also possible under any position or orientation constraint of an end effector. This tool can easily be integrated in the early conception stage of mobile articulated structures combining strong requirements on reachability and balance.
23 citations
TL;DR: Two types of the controller are derived to compensate the full Lagrangian manipulator dynamics using the Lyapunov stability theory to have real-time computational advantages, and a robustness against the miscalibration of the camera intrinsic parameters, focal length, etc.
Abstract: In this paper, we deal with a planar manipulator control problem using camera information. We derive two types of the controller to compensate the full Lagrangian manipulator dynamics using the Lyapunov stability theory. One controller uses the image Jacobian, and the other controller requires the manipulator Jacobian and the direct kinematics. Hence these controllers are expected to have real-time computational advantages, and a robustness against the miscalibration of the camera intrinsic parameters, focal length, etc. In order to analyze the stability of the latter controller, we exploit the property of the rotational matrix and propose a new type of potential function of the image feature parameter space. The controller based on the image feature parameter potential has a nonlinear saturated potential term. Experimental results are presented to illustrate the controllers performance.
23 citations
TL;DR: An effective adaptive neural network feedback controller for force control of robot manipulators in an unknown environment by applying damping neurons which possess elastic-viscous properties is presented.
Abstract: _This paper presents an effective adaptive neural network feedback controller for force control of robot manipulators in an unknown environment by applying damping neurons which possess elastic-viscous properties. The unexpected overshooting and oscillation caused by the unknown and/or unmodeled dynamics of a robot manipulator and an environment can be decreased efficiently by the effect of the proposed damping neurons. Furthermore, a fuzzy controlled evaluation function is applied for the learning of the proposed neural network controller, so that the controller is able to adapt to the unknown environment more effectively. The effectiveness of the proposed neural network controller is evaluated by experiment with a 3 d.o.f. direct-drive planar robot manipulator.
20 citations
TL;DR: A new idea for an obstacle recognition method for mobile robots by analyzing optical flow information acquired from dynamic images by using a normalized square residual error value that is calculated in the process of estimating the FOE.
Abstract: —This paper presents a new idea for an obstacle recognition method for mobile robots by analyzing optical flow information acquired from dynamic images. First, the optical flow field is detected in...
TL;DR: A neuro-fuzzy expert system E_S_CO_V (Expert System COntrolling Vehicles) for the IAV obstacle avoidance behavior is suggested and improves Maeda's obstacle avoidance approach by handling size and number of obstacles.
Abstract: The use of Hybrid Intelligent Systems (HIS) is becoming necessary to bring the behavior of Intelligent Autonomous Vehicles (IAV) near to that of humans in terms of recognition, learning, decision making and action. First, combining Expert Systems (ES), Neural Networks (NN) and Fuzzy Logic (FL) to provide IAV with more autonomy and intelligence is discussed. Second, a neuro-fuzzy expert system E_S_CO_V (Expert System COntrolling Vehicles) for the IAV obstacle avoidance behavior is suggested. Indeed, E_S_CO_V improves Maeda's obstacle avoidance approach by handling size and number of obstacles, on the one hand. On the other hand, the fuzzy reasoning and inference to decide static and dynamic obstacle danger degrees are carried out using Fuzzy Neural Networks (FNN_1) and (FNN_2) respectively, while the decision table of avoidance direction is carried out using NN_3. Third, simulation results illustrate the efficiency of E_S_CO_V in handling several obstacles with different sizes and display its ability to ac...
TL;DR: This work developed and simulated some sample programs for the vision chip architecture and proved that they can be processed within 1 ms/frame, a rate that is high enough for high-speed visual feedback for robot control.
Abstract: To solve the I/O bottleneck problem in existing vision systems and to realize versatile processing adaptive to various and changing environments, we propose a new vision chip architecture for appli...
TL;DR: The design, fabrication and operation of a fluidic micro-axel array for the 2D conveyance system was described and the developed system was capable of performing the positioning task and experiments to convey objects to the fixed desired position were performed successfully.
Abstract: We have proposed the concept of distributed micro motion systems (DMMS) in order to coordinate simple motions of many microactuators arranged on a wafer so as to perform a more complicated task. A two-dimensional conveyance system in a plane is studied as an example of DMMS. A system design has been presented with the aim of controlling many microactuators in a similar way as the cellular automaton. In this paper, we focus on a microactuator and define a micro-axel as an elemental unit of DMMS. As the first step towards the implementation of the designed two-dimensional (2D) system, we have previously reported the development and operation of a one-dimensional conveyance system using a fluidic micro-axel array. Here, this paper describes the design, fabrication and operation of a fluidic micro-axel array for the 2D conveyance system. The developed system was capable of performing the positioning task and experiments to convey objects to the fixed desired position by the system were performed successfully....
TL;DR: A computational model based on the hypothesis that human movements minimize the integral of the norm of the rate of change of actuator torques is proposed and shows that the computational model predicts the trajectories and the distribution of forces (torques) for a certain class of trajectories.
Abstract: —The main objective of this paper is to study human dual-arm manipulation tasks and to develop a computational model that predicts the trajectories and force distribution for the coordination of two arms moving an object between two given positions and orientations in a horizontal plane. Our ultimate goal is to understand the dynamics of human dual-arm coordination in order to develop better robot control algorithms. We propose a computational model based on the hypothesis proposed by Uno et al. that suggests that human movements minimize the integral of the norm of the rate of change of actuator torques. We compare the experimental trajectories and force distributions with those obtained from the computational model. The observed trajectories show a significant degree of repeatability across trials and across subjects. We show that the computational model predicts the trajectories and the distribution of forces (torques) for a certain class of trajectories. However, the trajectories in the sagittal and f...
TL;DR: The resulting multimodal HuMan-Robot Interface (MRI) allows specification of various types of robot activities by use of an advanced system for natural spoken user-independent speech understanding and flexible robot command generation.
Abstract: This paper discusses requirements for information exchange between a human operator and a semi-autonomous service robot operating in a remote indoor environment The resulting multimodal HuMan-Robot Interface (MRI) allows specification of various types of robot activities by use of an advanced system for natural spoken user-independent speech understanding and flexible robot command generation Visual screen-based monitoring and support of complex operations is achieved by means of an animated three-dimensional environmental model augmented by the image of an onboard CCD camera Typical features of the MRI are demonstrated through experiments performed with the mobile manipulator ROMAN
TL;DR: A high-speed motion tracking system based on full-search correlation matching that is compact and economical, and well suited for a wide variety of applications such as automatic surveillance, traffic monitoring and sports play analysis.
Abstract: This paper describes a high-speed motion tracking system based on full-search correlation matching. Incorporating the Advanced Correlation Processor, which computes more than 500 motion vectors per frame, the system enables the detection and tracking of moving objects at a video rate. The system is implemented on a single board and can be mounted inside a PC. Thus, it is compact and economical, and is well suited for a wide variety of applications such as automatic surveillance, traffic monitoring and sports play analysis.
TL;DR: All the five levels of behavior were successfully shown by experiment with the use of two small mobile robots and the basic idea of the software architecture realizing the five-layered hierarchical model of consciousness and behavior is that a level in the hierarchy of consciousness is activated when an action on the immediately lower level is obstructed.
Abstract: This paper proposes an aproach to designing animal-like behavior of autonomous robots with use of a five-layered hierarchical model of the relation between consciousness and behavior. The hierarchy of behavior includes reflex motion, detour, and a limited use of temporal and spatial information of environments. The corresponding consciousness has an emotion-valued coordinate system, stably lasting emotion that enables an animal to detour an obstacle for a prey, and symbolic information on time and space. The basic idea of the software architecture realizing the above model of consciousness and behavior is that a level in the hierarchy of consciousness is activated when an action on the immediately lower level is obstructed and that the activated level of consciousness selects and drives a higher behavior. With this software architecture, all the five levels of behavior were successfully shown by experiment with the use of two small mobile robots. Their instantaneous consciousness is visualized on the scre...
TL;DR: A general measure to estimate the mechanical controllability both qualitatively and quantitatively, even if any control scheme is applied is provided.
Abstract: The posture stability driving control of a human riding-type unicycle has been realized. The robotic unicycle is considered as a biomechanical system using an internal world representation with a description of emotion, instinct and intuition mechanisms. We introduced intelligent control methods based on soft computing, and confirmed that such an intelligent control and biological instinct as well as intuition together with a fuzzy inference is very important for emulating human behaviors or actions. For the fitness function of the generic algorithm, a new physical measure of the minimum entropy production for a description of the intelligent behavior in a biological model is introduced. The calculation of robustness and controllability of the robotic unicycle is presented. This paper provides a general measure to estimate the mechanical controllability both qualitatively and quantitatively, even if any control scheme is applied. The measure can be computed using a Lyapunov function coupled with the therm...
TL;DR: The paper presents a novel path planning method for non-point, non-holonomically constrainted mobile robots and proposes specific updating and coding procedures for the environmental information and introduces the Ageing function to insert time parameterization in the path-planning results.
Abstract: The paper presents a novel path planning method for non-point, non-holonomically constrainted mobile robots. The proposed method, named the Active Kinematic Histogram (AKH) method, is a potential f...
TL;DR: A programming method is employed with the help of recent powerful computers to obtain two kinds of gaits which can maintain the gait stability margin at a high level for a duty factor in the range of 0.6 ≤ β < 1.6.
Abstract: —As a remarkably strong point of a hexapod walking robot, it is considered that even if one of the six legs is disabled, static walking may be maintained by the remaining five legs. However, to maintain the static stability at maximum, a gait study for five-legged walking is a necessary factor. Hence, this paper describes a method of gait study for such a situation. Since it is very difficult to find a suitable gait by use of an analytical method without any model, such as a model based on insects' walking, we employed a programming method with the help of recent powerful computers. Some devices are applied to reduce the number of computations. As a result, we have obtained two kinds of gaits which can maintain the gait stability margin at a high level for a duty factor in the range of 0.6β < 1.
TL;DR: A tactile display for presenting the moving or the strain direction to the skin of the human finger and a suitable way to present vibro-tactile stimulation is described.
Abstract: This paper proposes a tactile display for presenting the moving or the strain direction to the skin of the human finger. Of the many types of sense which the human finger has, we consider to stimulate the tactile sense by vibration and to develop a tactile feedback system. The proposed vibro-tactile stimulator employs a number of vibrating pins to provide a ticking sensation to the human operator's skin. We use micro resonators which are driven by electromagnetic force to the vibrating pins. We performed an experiment to present vibro-tactile stimulation using a single micro resonator and confirmed the ability to perform vibro-tactile stimulation. Next we arrayed the micro resonators in a matrix state and constructed the tactile display. We performed the tactile feedback experiment using this display. From these results, we describe a suitable way to present vibro-tactile stimulation.
TL;DR: In the present work, a new kinematic model is proposed, to overcome the drawbacks of the models currently available and possesses a zero-initial position characteristic in the sense that the various joint displacements can be assigned the value of zero at any desired initial configuration.
Abstract: Kinematic modeling of robotic arms is essential for robot control and calibration. The models used usually encompass matrix representation of the geometric behavior of the robot joints. The parameters of kinematic models should be designed such that the spatial relations between the successive joint axes are adequately described. However, most of the models currently available for users either suffer from numerical singularities (both apparent and hidden) or do not possess certain properties required for robot calibration. In the present work, a new kinematic model is proposed, to overcome the drawbacks of the models currently available. The proposed model, which is referred to as the Φ-model. possesses a zero-initial position characteristic in the sense that the various joint displacements can be assigned the value of zero at any desired initial configuration. The Φ-model is also equipped with a parameter-control tool which is presented as a new concept in the field of robot kinematic modeling and is des...
TL;DR: This paper describes the design concept and the details of the system, and introduces an experiment in which the robot reaches and grasps an object on a table through coordinating legs and arms.
Abstract: We present a 35 d.o.f. humanoid which can perform a reach-and-grasp motion through coordinating legs and arms. The humanoid robot is designed to be a research testbed to integrate research tools. Each leg and arm has 6 d.o.f. The neck has 3 d.o.f. Each hand has 4 d.o.f. The key idea of the system architecture is a remote-brained approach. In this paper we describe the design concept and the details of the system, and introduce an experiment in which the robot reaches and grasps an object on a table through coordinating legs and arms.
TL;DR: A fuzzy model approach is applied to the control of a time-varying rotational angle, in which multiple linear models are obtained by utilizing the original nonlinear model in some representative angles and they are used to derive the optimal type 2 servo gain matrices.
Abstract: It is known that the equation of motions for an omnidirectional mobile robot is nonlinear with respect to the rotational angle between the moving and absolute coordinate systems In this paper, a fuzzy model approach is applied to the control of a time-varying rotational angle, in which multiple linear models are obtained by utilizing the original nonlinear model in some representative angles and they are used to derive the optimal type 2 servo gain matrices The effectiveness of the proposed method is illustrated by giving some simulations for the trajectory tracking control problem
TL;DR: A new autonomous consideration method of joint torque saturation for robust manipulator motion control that consists of three on-line autonomous algorithms that realizes smooth and robust robot motion response.
Abstract: As each joint actuator of a robot manipulator has a limit value of torque, the motion control system should consider the torque saturation. Conventional motion control based on robust acceleration controller cannot consider the torque saturation and it often causes an oscillated or wrong response. This paper proposes a new autonomous consideration method of joint torque saturation for robust manipulator motion control. The proposed method consists of three on-line autonomous algorithms. These algorithms are the torque limitation algorithm in joint space, the adjustment algorithm of motion control in Cartesian space, and the adjustment algorithm of motion reference in Cartesian space. The robot motion control using the proposed algorithms realizes smooth and robust robot motion response.
TL;DR: A new neuronactivation function suitable for vehicle lateral guidance control is suggested, a feed-forward multilayer neural network (FMNN) with the suggested neuron activation function is proposed and a vehicle lateral Guidance Controller (VLGC) is proposed.
Abstract: An advanced vehicle lateral guidance control technology is necessary in order to develop intelligent transportation and manufacturing systems with flexibility and immediate adaptability. PID contro...
TL;DR: A new scheme for the design of a neural oscillatory network which can be used to generate the desired walking pattern trajectories is presented, based on the evolutionary computation concept, and has the advantages of simplicity, flexibility, and high calculation speed.
Abstract: Humanoid biped walking patterns attracts more and more attention both in the fields of robotics and prosthetics. This paper presents a new scheme for the design of a neural oscillatory network which can be used to generate the desired walking pattern trajectories. The scheme is based on the evolutionary computation concept, and has the advantages of simplicity, flexibility, and high calculation speed. The scheme proved to be effective from the results of simulations. This research also established the foundation for research on expressing various human walking patterns in mathematical models.
TL;DR: This paper proposes a new fusion approach which uses the ultrasonic sensor aided by an omni-directional vision sensor to give a grid-based free space around the robot.
Abstract: For robot navigation, it is important to have a local map which gives the free space around the robot. Various sensing and fusion methods have been developed to detect the free space. In this paper we propose a new fusion approach which uses the ultrasonic sensor aided by an omni-directional vision sensor to give a grid-based free space around the robot. By use of the ultrasonic sensor, the robot can obtain conservative range information based on our nearby range filtering method. The filtering can give a more reliable result considering the sensor's problem of specular reflection. Also, by use of the special omni-directional vision sensor we developed, color and edge information can be obtained in a single picture and mapped to the ground plane by the inverse perspective transformation. Thus the range, color and edge information can all be expressed on a metric grid-based representation which forms the basis of our fusion processing. From the filtered range information in this metric representation, we o...
TL;DR: In this article, a heuristic approach towards fast planning of precision grasps for realistic, arbitrarily shaped 3-D objects is presented, where a number of feasible grasp candidates are generated heuristically.
Abstract: —In the near future, more and more robots will be used for servicing tasks, tasks in hazardous environments or space applications. Dextrous hands are a powerful and flexible tool to interact with these real world environments that are not specially tailored for robots. In order to grasp and manipulate real world objects, grasp planning systems are required. Grasp planning for general three-dimensional (3-D) objects is quite a complex problem requiring a large amount of computing time. Fast algorithms are required to integrate grasp planners in online planning systems for robots. This paper presents a heuristic approach towards fast planning of precision grasps for realistic, arbitrarily shaped 3-D objects. In this approach a number of feasible grasp candidates are generated heuristically. These grasp candidates are qualified using an efficiently computable grasp quality measure and the best candidate is chosen. It is shown that only a relatively small number of grasp candidates has to be generated in orde...