Showing papers in "Autonomous Robots in 1995"
TL;DR: The importance of communication in robotic societies is investigated through experiments on both simulated and real robots, finding that in cases where communication helps, the lowest level of communication is almost as effective as the more complex type.
Abstract: Multiple cooperating robots are able to complete many tasks more quickly and reliably than one robot alone. Communication between the robots can multiply their capabilities and effectiveness, but to what extent? In this research, the importance of communication in robotic societies is investigated through experiments on both simulated and real robots. Performance was measured for three different types of communication for three different tasks. The levels of communication are progressively more complex and potentially more expensive to implement. For some tasks, communication can significantly improve performance, but for others inter-agent communication is apparently unnecessary. In cases where communication helps, the lowest level of communication is almost as effective as the more complex type. The bulk of these results are derived from thousands of simulations run with randomly generated initial conditions. The simulation results help determine appropriate parameters for the reactive control system which was ported for tests on Denning mobile robots.
561 citations
TL;DR: An integrated physical system including vision, sound input and output, and dextrous manipulation, all controlled by a continuously operating large scale parallel MIMD computer is described to capitalize on newly available levels of computational resources to understand human cognition.
Abstract: We describe a project to capitalize on newly available levels of computational resources in order to understand human cognition. We will build an integrated physical system including vision, sound input and output, and dextrous manipulation, all controlled by a continuously operating large scale parallel MIMD computer. The resulting system will learn to ``think'''' by building on its bodily experiences to accomplish progressively more abstract tasks. Past experience suggests that in attempting to build such an integrated system we will have to fundamentally change the way artificial intelligence, cognitive science, linguistics, and philosophy think about the organization of intelligence. We expect to be able to better reconcile the theories that will be developed with current work in neuroscience.
411 citations
TL;DR: Two low-cost robotic wheelchair prototypes that assist the operator of the chair in avoiding obstacles, going to pre-designated places, and maneuvering through doorways and other narrow or crowded areas are described.
Abstract: Many people who are mobility impaired are, for a variety of reasons, incapable of using an ordinary wheelchair. In some instances, a power wheelchair also cannot be used, usually because of the difficulty the person has in controlling it (often due to additional disabilities). This paper describes two low-cost robotic wheelchair prototypes that assist the operator of the chair in avoiding obstacles, going to pre-designated places, and maneuvering through doorways and other narrow or crowded areas. These systems can be interfaced to a variety of input devices, and can give the operator as much or as little moment by moment control of the chair as they wish. This paper describes both systems, the evolution from one system to another, and the lessons learned.
177 citations
TL;DR: This work has developed a complete system that integrates local and global navigation that was tested on a real robot and successfully drove it 1.4 kilometers to find a goal given no a priori map of the environment.
Abstract: Most autonomous outdoor navigation systems tested on actual robots have centered on local navigation tasks such as avoiding obstacles or following roads. Global navigation has been limited to simple wandering, path tracking, straight-line goal seeking behaviors, or executing a sequence of scripted local behaviors. These capabilities are insufficient for unstructured and unknown environments, where replanning may be needed to account for new information discovered in every sensor image. To address these problems, we have developed a complete system that integrates local and global navigation. The local system uses a scanning laser rangefinder to detect obstacles and recommend steering commands to ensure robot safety. These obstacles are passed to the global system which stores them in a map of the environment. With each addition to the map, the global system uses an incremental path planning algorithm to optimally replan the global path and recommend steering commands to reach the goal. An arbiter combines the steering recommendations to achieve the proper balance between safety and goal acquisition. This system was tested on a real robot and successfully drove it 1.4 kilometers to find a goal given no a priori map of the environment.
133 citations
TL;DR: In this paper, the authors present a decomposition of rover navigation into four major functions: goal designation, rover localization, hazard detection, and path selection, and present results to date of evaluating the performance of each function, and outline an approach to enhancing performance for future missions.
Abstract: In 1996, NASA will launch the Mars Pathfinder spacecraft, which will carry an 11 kg rover to explore the immediate vicinity of the lander. To assess the capabilities of the rover, as well as to set priorities for future rover research, it is essential to evaluate the performance of its autonomous navigation system as a function of terrain characteristics. Unfortunately, very little of this kind of evaluation has been done, for either planetary rovers or terrestrial applications. To fill this gap, we have constructed a new microrover testbed consisting of the Rocky 3.2 vehicle and an indoor test arena with overhead cameras for automatic, real-time tracking of the true rover position and heading. We create Mars analog terrains in this arena by randomly distributing rocks according to an exponential model of Mars rock size frequency created from Viking lander imagery. To date, we have recorded detailed logs from over 85 navigation trials in this testbed. In this paper, we outline current plans for Mars exploration over the next decade, summarize the design of the lander and rover for the 1996 Pathfinder mission, and introduce a decomposition of rover navigation into four major functions: goal designation, rover localization, hazard detection, and path selection. We then describe the Pathfinder approach to each function, present results to date of evaluating the performance of each function, and outline our approach to enhancing performance for future missions. The results show key limitations in the quality of rover localization, the speed of hazard detection, and the ability of behavior control algorithms for path selection to negotiate the rock frequencies likely to be encountered on Mars. We believe that the facilities, methodologies, and to some extent the specific performance results presented here will provide valuable examples for efforts to evaluate robotic vehicle performance in other applications.
92 citations
TL;DR: A dependent-user recognition voice system and ultrasonic and infrared sensor systems has been integrated in this wheelchair which can be driven with using voice commands and with the possibility of avoiding obstacles and downstairs or hole detection.
Abstract: This paper describes a wheelchair for physically disabled people developed within the UMIDAM Project. A dependent-user recognition voice system and ultrasonic and infrared sensor systems has been integrated in this wheelchair. In this way we have obtained a wheelchair which can be driven with using voice commands and with the possibility of avoiding obstacles and downstairs or hole detection. The wheelchair has also been developed to allow autonomous driving (for example, following walls). The project, in which two prototypes have been produced, has been carried out totally in the Electronics Department of the University of Alcala (Spain). It has been financed by the ONCE. Electronic system configuration, a sensor system, a mechanical model, control (low level control, control by voice commands), voice recognition and autonomous control are considered. The results of the experiments carried out on the two prototypes are also given.
85 citations
TL;DR: A vision guidance system which steers a tractor relative to the rows of a crop such as cotton shows great promise for cost effective commercial exploitation and further sensing systems are outlined for performing related guidance tasks when vision is inappropriate.
Abstract: A vision guidance system has been designed, built and commissioned which steers a tractor relative to the rows of a crop such as cotton. It was required to be insensitive to additional visual “noise” from weeds, while tolerating the fading out of one or more rows in a barren patch of the field. The system integrates data from several crop rows, testing for image quality. At the same time, the data processing requirements have been limited by the use of frame-sequential strategies to reduce the image space which must be processed. The design has been developed to the stage where six evaluation prototypes have been installed to test farmer-acceptance. The present prototypes employ a 486 PC motherboard embedded in a custom housing, together with a 68HC11 microcomputer to which the task of closing the steering servo loop is delegated. The system shows great promise for cost effective commercial exploitation.
69 citations
TL;DR: A behavior-based control paradigm that allows a distributed collection of autonomous mobile robots to control the lifting and lowering processes of payload transportation is proposed and then tested with computer simulations, which demonstrates an ability to function with inaccurate sensor data.
Abstract: A behavior-based control paradigm that allows a distributed collection of autonomous mobile robots to control the lifting and lowering processes of payload transportation is proposed and then tested with computer simulations. This control paradigm, which represents an approach to solving the cooperative load-bearing problem inherent in multi-agent payload transportation, is based upon a control structure we term thebehavior pathway controller. The behavior pathway controller emphasizes simple, feasible methodologies over complex, optimal methodologies, although we show that with some global self-organization of the collective, the feasible solutions approach and become optimal solutions. Using this controller in simulated environments, our robots demonstrate an ability to function with inaccurate sensor data, which is an important consideration for real world implementations of an autonomous mobile robot control paradigm. The simulated robots also demonstrate an ability to learn their place, or role, within the collective. They must learn their relative roles because they possess no predetermined knowledge about pallet mass, pallet inertia, collective size, or their positions relative to the pallet's center of gravity.
54 citations
TL;DR: This paper investigates how an industrial mobile robot can respond to unexpected static obstacles while following a path planned by a global path planner.
Abstract: Real-time obstacle avoidance is essential for the safe operation of mobile robots in a dynamically changing environment. This paper investigates how an industrial mobile robot can respond to unexpected static obstacles while following a path planned by a global path planner. The obstacle avoidance problem is formulated using decision theory to determine an optimal response based on inaccurate sensor data. The optimal decision rule minimises the Bayes risk by trading between a sidestep maneuver and backtracking to follow an alternative path. Real-time implementation is emphasised here as part of a framework for real world applications. It has been successfully implemented both in simulation and in reality using a mobile robot.
49 citations
TL;DR: Practical, effective approaches to stereo perception and dead reckoning are described, and results from systems implemented for a prototype lunar rover operating in natural, outdoor environments are presented.
Abstract: This paper describes practical, effective approaches to stereo perception and dead reckoning, and presents results from systems implemented for a prototype lunar rover operating in natural, outdoor environments. The stereo perception hardware includes a binocular head mounted on a motion-averaging mast. This head provides images to a normalized correlation matcher, that intelligently selects what part of the image to process (saving time), and subsamples the images (again saving time) without subsampling disparities (which would reduce accuracy). The implementation has operated successfully during long-duration field exercises, processing streams of thousands of images. The dead reckoning approach employs encoders, inclinometers, a compass, and a turn-rate sensor to maintain the position and orientation of the rover as it traverses. The approach integrates classical odometry with inertial guidance. The implementation succeeds in the face of significant sensor noise by virtue of sensor modelling, plus extensive filtering. The stereo and dead reckoning components are used by an obstacle avoidance planner that projects a finite number of arcs through the terrain map, and evaluates the traversability of each arc to choose a travel direction that is safe and effective. With these components integrated into a complete navigation system, a prototype rover has traversed over 1 km in lunar-like environments.
42 citations
TL;DR: In the US-German Spacelab mission D2 (April/May 1993), a new level of automation capabilities has been achieved with the ROTEX-‘freeflyer’-experiment of DLR and the contributions of UniBwM in the fields of monocular motion-stereo vision, state prediction and fully automatic grasping under long delay times are discussed in detail.
Abstract: In the US-German Spacelab mission D2 (April/May 1993) a new level of automation capabilities has been achieved with the ROTEX-‘freeflyer’-experiment of DLR. For the first time, a combined human/robotic task force on the ground succeeded in visually controlled tele-grasping of a free floating object on board the Space Shuttle Columbia within a working cell of the German Spacelab by a remotely controlled robot arm. The contributions of UniBwM in the fields of monocular motion-stereo vision, state prediction and fully automatic grasping under long delay times (5 to 7 seconds) are discussed in detail.
TL;DR: The Stored Waste Autonomous Mobile Inspector (SWAMI) is a prototype mobile robot designed to perform autonomous inspection of nuclear and hazardous waste storage facilities.
Abstract: The Stored Waste Autonomous Mobile Inspector (SWAMI) is a prototype mobile robot designed to perform autonomous inspection of nuclear and hazardous waste storage facilities. The onboard control system, consisting of three Motorola 68030-based microcomputers, controls a number of subsystem components including barcode readers, cameras, and a radiation detector. The control system software, running under the VxWorks real-time operating system, is designed toward the client-server model and is implemented in C++. GENISAS, a communication library developed by the Sandia National Laboratories, is used extensively. Much of the onboard software was generated by a custom code generation tool called Moses.
TL;DR: The rover, its operational environment and the implementation of the on-board autonomous functions of navigation and hazard avoidance are described.
Abstract: When the Mars Pathfinder (MPF) spacecraft lands on Mars, the Microrover Flight Experiment (MFEX) will be deployed and perform its mission to conduct technology experiments verifying the engineering design, to deploy an alpha proton x-ray spectrometer (APXS) to measure elemental properties of rocks and soil, and to image the MPF lander. In accomplishing this mission the MFEX rover must determine a safe path to goal locations traversing over a poorly known Martian surface. The rover does this mission with a capable mobile platform executing on-board autonomous functions of navigation and hazard avoidance. In this paper we describe the rover, its operational environment and the implementation of the on-board autonomous functions.
TL;DR: It is shown how to compute hybrid potential fields in real time and use them to control the motions of a real robot and a simulated one, and a feature matching approach for position error correction is presented.
Abstract: We propose a new type of artificial potential field, that we call hybrid potential field, to navigate a robot in situations in which the environment is known except for unknown and possibly moving obstacles. We show how to compute hybrid potential fields in real time and use them to control the motions of a real robot. Our method is tested on both a real robot and a simulated one. We present a feature matching approach for position error correction that we have validated experimentally with our mobile robot. We show extensive simulation results with up to 50 randomly moving obstacles.
TL;DR: A complete approach that encompasses the major aspects involved in the design of a robotic system for planetary exploration, which includes mission teleprogramming and supervision at a ground station, and autonomous mission execution by the remote mobile robot is presented.
Abstract: Sending mobile robots to accomplish planet exploration missions is scientifically promising and technologically challenging. We present in this paper a complete approach that encompasses the major aspects involved in the design of a robotic system for planetary exploration. It includes mission teleprogramming and supervision at a ground station, and autonomous mission execution by the remote mobile robot. We have partially implemented and validated these concepts. Experimental results illustrate the approach and the results.
TL;DR: It is found that implementing a complicated global control task with cooperating local controllers can effectively control complex robots.
Abstract: The purpose of this paper is twofold. First, we outline important issues in designing real-time controllers for robots with numerous sensors, actuators, and behaviors. We address these issues by implementing a behavior based controller on a sophisticated autonomous robot. Hence, this work provides a point of reference for the scalability, ease of design, and effectiveness of the behavior based control for complex robots. Second, we explore the viability of using cooperation among local controllers to achieve coherent global behavior. Our approach is to decompose a difficult control task for a complex robot into a multitude of simpler control tasks for robotic subsystems. We illustrate and examine the effectiveness of this approach via rough terrain locomotion using an autonomous hexapod robot. Traversing rough terrain is a good task to test the viability of this approach because it requires a considerable amount of leg coordination. We found that implementing a complicated global control task with cooperating local controllers can effectively control complex robots.
TL;DR: Control strategies are developed for thetakeoff, flight and thelanding phases of a standing jump using a simplified planar model and the concept of effective linear momentum to remove linear and angular momentum of the body during landing.
Abstract: In this paper the control of a quadruped standing jump over irregular terrain obstacles is investigated. Control strategies are developed for thetakeoff, flight and thelanding phases of a standing jump. Using a simplified planar model and the concept ofeffective linear momentum, simple feedforward leg force profiles are planned to remove the linear and angular momentum of the body during landing. Super real-time simulation, which involves predicting landing conditions based on faster than real-time simulation using the simplified model, is used to select leg touchdown angles for landing. Using the principle of symmetry, the leg forces during takeoff are derived from those predicted for landing. Leg motions are planned to maximize clearance during flight and stability during landing. Using these strategies, the quadruped is able to clear a variety of obstacles including isolated walls, terrain steps, and ditches. Simulation results are compared with experimental data of an animal jump from the literature.
TL;DR: It is concluded that there is an inadequate basis for predicting the reliability and behavior of robots operating in unengineered environments and a new approach to the study of autonomous mobile robot performance based on formal statistical analysis of independently reproducible experiments conducted on real robots is presented.
Abstract: We review the current state of research in autonomous mobile robots and conclude that there is an inadequate basis for predicting the reliability and behavior of robots operating in unengineered environments. We present a new approach to the study of autonomous mobile robot performance based on formal statistical analysis of independently reproducible experiments conducted on real robots. Simulators serve as models rather than experimental surrogates. We demonstrate three new results: 1) Two commonly used performance metrics (time and distance) are not as well correlated as is often tacitly assumed. 2) The probability distributions of these performance metrics are exponential rather than normal, and 3) a modular, object-oriented simulation accurately predicts the behavior of the real robot in a statistically significant manner.
TL;DR: The Russian rover Marsokhod, designed by Babakin Center for Mars exploration and the navigation sub-system based on stereovision developed by the French Space Agency C.N.E.S.S., is described to provide the rover with autonomous motion ability, improving thus its exploration range on the surface of Mars.
Abstract: This paper describes the Russian rover Marsokhod, designed by Babakin Center for Mars exploration and the navigation sub-system based on stereovision developed by the French Space Agency C.N.E.S. to provide the rover with autonomous motion ability, improving thus its exploration range on the surface of Mars. Tests of the complete vehicle, including autonomous locomotion, has been recently fulfilled on a Mars-like area build in C.N.E.S. for this purpose by a joined Russian-French team; the main results and conclusions of these test are related.
TL;DR: A new class of spherically symmetric, high degree of freedom robots called “platonic beasts” are described, which are kinematically equivalent to a symmetric polyhedron, such as one of the Platonic solids, with identical multi-purpose limbs attached to its vertices.
Abstract: We describe a new class of spherically symmetric, high degree of freedom robots called “platonic beasts.” A robot in this family is kinematically equivalent to a symmetric polyhedron, such as one of the Platonic solids, with identical multi-purpose limbs attached to its vertices. The symmetry and regularity of the design have several advantages including robustness to toppling, novel gaits such as therolling gait, and fault tolerance.
TL;DR: GANESHA (Grid based Approach for Navigation by Evidence Storage and Histogram Analysis), a system using sonar that was implemented for the autonomous land vehicle Navlab, and its implementation for collision avoidance, parallel parking and its integration with other vehicle systems are described.
Abstract: Detecting unexpected obstacles and avoiding collisions is an important task for any autonomous mobile system. This article describes GANESHA (Grid based Approach for Navigation by Evidence Storage and Histogram Analysis), a system using sonar that we implemented for the autonomous land vehicle Navlab. The general hardware configuration of the system is shown, followed by a description of how the system builds a local grid map of its environment. The information collected in the map can then be used for a variety of applications in vehicle navigation like collision avoidance, feature tracking and parking. An algorithm was implemented that can track a static feature such as a rail, wall or an array of parked cars and use this information to drive the vehicle. Methods for filtering the raw data and generating the steering commands are discussed and the implementation for collision avoidance, parallel parking and its integration with other vehicle systems is described.
TL;DR: The application of aerobots to Venus exploration is explored and a Planetary Aerobot Testbed is discussed which will conduct Earth atmospheric flights to validate autonomous-state-estimator techniques and flight-path-control techniques needed for future planetary missions.
Abstract: Planetary aerobots are a new type of telerobotic science platform that can fly and navigate in a dynamic 3-dimensional atmospheric environment, thus enabling the global in situ exploration of planetary atmospheres and surfaces. Aerobots are enabled by a new concept in planetary balloon altitude control, developed at JPL, which employs reversible-fluid changes to permit repeated excursions in altitude. The essential physics and thermodynamics ofreversible-fluid altitude control have been demonstrated in a series of altitude-control experiments conducted in the Earth's atmosphere, which are described. Aerobot altitude-control technology will be important in the exploration of seven planets and satellites in our solar system. Three of these objects—Venus, Mars, and the Saturnian satellite Titan—have accessible solid surfaces and atmospheres dominated by the dense gases nitrogen or carbon dioxide. They will be explored with aerobots using helium or hydrogen as their primary means of buoyancy. The other four planets—Jupiter, Saturn, Uranus, and Neptune—have deep atmospheres that are predominantly hydrogen. It may be possible to explore these atmospheres with aerobots inflated with atmospheric gas that is then radiatively heated from the hotter gaseous depths below. To fulfill their potential, aerobots to explore the planets will need autonomous state estimators to guide their observations and provide information to the altitude-control systems. The techniques of acquiring these data remotely are outlined. Aerobots will also use on board altitude control and navigation systems to execute complex flight paths including descent to the surface and exploiting differential wind velocities to access different latitude belts. Approaches to control of these systems are examined. The application of aerobots to Venus exploration is explored in some detail: The most ambitious mission described, the Venus Flyer Robot (VFR), would have the capability to make repeated short excursions to the high-temperature surface environment of Venus to acquire data and then return to the Earth-like upper atmosphere to communicate and recool its electronic systems. Finally a Planetary Aerobot Testbed is discussed which will conduct Earth atmospheric flights to validate autonomous-state-estimator techniques and flight-path-control techniques needed for future planetary missions.
TL;DR: The autonomous development of cutaneo-motor coordination is investigated in the case of a robotic finger mounted on a robotic manipulator, for a particular class of micromovements.
Abstract: The capability of autonomously discovering relations between perceptual data and motor actions is crucial for the development of robust adaptive robotic systems intended to operate in an unknown environment. In the case of robotic tactile perception, a proper interaction between contact sensing and motor control is the basic step toward the execution of complex motor procedures such as grasping and manipulation. In this paper the autonomous development of cutaneo-motor coordination is investigated in the case of a robotic finger mounted on a robotic manipulator, for a particular class of micromovements. A neural network architecture linking changes in the sensed tactile pattern with the motor actions performed is described and experimental results are analyzed. Examples of application of the developed sensory-motor coordination in the generation of motor control procedures for the estimate of surface curvature are considered.
TL;DR: It is demonstrated the necessity and usefulness of an autonomous mobile robot simulator as a programming tool which simulates all robot functions and environments including dynamic motion of a robot, control software of robot's subsystems, sensor characteristics and behavior level software and why such a simulator can act as the center of a programming environment for developing robot behavior algorithms.
Abstract: An autonomous mobile robot must achieve its goal in very complex environments with uncertainties of sensors and actuators. Due to such uncertainties, the control algorithm of robot behavior must have the ability to cope with various possible environmental situations and robot status. To develop such a control algorithm of robot behavior, the algorithm must be tested under numerous conditions of the robot's environment. Such a process requires a large number of experiments using real robots and because of high experimental cost and environmental complexity, a realistic simulator should be developed for verification of behavior algorithms. In this paper, we demonstrate the necessity and usefulness ofan autonomous mobile robot simulator as a programming tool which simulates all robot functions and environments including dynamic motion of a robot, control software of robot's subsystems, sensor characteristics and behavior level software. And we point why such a simulator can act as the center of a programming environment for developing robot behavior algorithms. Accordingly, we describe Autonomous Mobile RObot Simulator (AMROS) which is developed as a programming tool for sensor based behavior. AMROS consists of simulation of vehicle controller process, simulation of vehicle motion based on dynamics model, simulation of ultrasonic range sensor, simulation of ROBOL/0 behavior program execution and simulation of indoor environment. To realize AMROS, synchronization method among all parts of the simulation is considered. Synchronization mechanism that a behavior description language ROBOL/0 has, is utilized for this synchronization. Due to the fact that sensory information is the only way to know environmental conditions, a realistic simulation of sensor interaction with robot's environment is necessary. Based on this concept, an ultrasonic range sensor simulator, which simulates propagation process of ultrasonic wave, is developed and described in this paper. AMROS targets the real mobile robot “Yamabico” operating in an indoor environment. The efficiency of the results obtained through simulation are presented by comparing to the results obtained by real experiment. Lastly, we present our experience of implementing behaviors of the mobile robot with some examples that show the high performance of the developed simulator.
TL;DR: The first phases of the Eureka project n°969 for the development of an earth robot called IARES are described and two robot movement modes, teleguided and partially-autonomous modes are described.
Abstract: We describe the first phases of the Eureka project n°969 for the development of an earth robot called IARES (Illustrateur Autonome de Robotique mobile pour l'Exploration Spatiale). This project has been initiated in the frame of an international cooperation associating French Laboratories and Industrials to foreign partners (Spanishs, Russians and Hungarians). This demonstrator will show the feasibility of a planetary robot by testing in a realistic environment the robotics axes studied for several years in French and European research centers (Perception, Autonomous Path Generation, Locomotion, Localisation and Navigation, Telemanipulation, Tasks Management system and Ground Operations). Descriptions of the mars and lunar demonstrators are given before describing two robot movement modes, teleguided and partially-autonomous modes.
TL;DR: This paper integrates a vision system, a manipulator, and a force/torque sensor into a hand-eye working system and proposes a method of theAverage Visible Ratio (AVR) to evaluate the viewpoint of the movable camera.
Abstract: This paper deals with the assembly of aSelf-OrganizingManipulator (SOM) by using the method ofActive Sensing. We set a 6-axis force/torque sensor in the wrist of a manipulator and a CCD camera in the hand of another manipulator. By cooperation of hand and eye, human beings can do a variety of versatile work. The eyes guide the motion of the hand, while the hand moves to make the object easy to see. We try to construct a system working in the same way as a human being. We integrate a vision system, a manipulator, and a force/torque sensor into a hand-eye working system. The scene simplification is based on the controlled motion of camera and manipulator. A method of theAverage Visible Ratio (AVR) is proposed to evaluate the viewpoint of the movable camera. A strategy for planning the assembly is presented. The efficiency of the system is illustrated by experiments.
TL;DR: It is shown that spinning capability can be independent of required stability margin and good spinning capability and good terrain adaptability are obtained in a quadruped walking robot.
Abstract: Spinning gaits are used for altering the direction of body in a narrow space. Previous studies reveal thatz type leg-lifting sequence is suitable for spinning motion. In this paper, we focus on anz type aperiodic spinning gait for a quadruped walking robot. We proposed a condition of support pattern suitable for the aperiodicz type spinning motion. Based on the condition, we proposed an aperiodicz type spinning gait planning method. It is shown that spinning capability can be independent of required stability margin. A simulation shows that good spinning capability and good terrain adaptability are obtained.
TL;DR: The paper deals with a set of algorithms including path planning, trajectory planning, and path tracking for a tricycle type wheeled mobile robot using parametric polynomial interpolation using an optimization algorithm based on robot geometric constraints.
Abstract: The paper deals with a set of algorithms including path planning, trajectory planning, and path tracking for a tricycle type wheeled mobile robot. Path planning is carried out with parametric polynomial interpolation using an optimization algorithm based on robot geometric constraints. Trajectory characteristics are then derived from the planned geometric path with time varying parameters. A sliding mode control algorithm combined with an adaptive control law are used to track the planned trajectory. The technique deals with an environment free of obstacles. However, it can be easily integrated in a piecewise non colliding path generation. Simulation results are presented to show the validity of the different algorithms.
TL;DR: This paper focuses on aperiodic forward straight motion having the lifting sequence of wave gait in order for quadruped to adapt to terrain and to have good moving capability.
Abstract: In even terrain, wave gait is the periodic gait having the optimal stability. In this paper, we focus on aperiodic forward straight motion having the lifting sequence of wave gait in order for quadruped to adapt to terrain and to have good moving capability. We investigated the condition of support pattern from which such gait motion can be generated. It is proved that from any support pattern satisfying the condition, it is always possible to transform the given support pattern to the support pattern of wave gait. An aperiodic gait planning method that adapt to terrain and maximize moving capability is proposed. A simulation result shows that the proposed method works well in rough terrain having forbidden areas.