Showing papers on "Obstacle published in 1993"

An obstacle detecting device for a vehicle

Abstract: An obstacle detecting device for a vehicle comprises a pair of image sensors for taking an image of an object surrounding a vehicle, a display image plane for displaying an image data taken by said pair of image sensors as an image, and a plurality of windows designating regions of said image on said display image plane. The device further comprises an optical obstacle detecting device for detecting distances from said vehicle to said object in said regions of the image designated by said plurality of windows for the respective windows to thereby detect an obstacle, a laser radar device mounted on the vehicle for radiating a radar beam to the object surrounding the vehicle to thereby detect said obstacle, and an obstacle selecting device for selecting either the obstacle detected by said optical obstacle detecting device or the obstacle detected by said laser radar device mounted on the vehicle.

Obstacle detection device for vehicle

Abstract: An obstacle detection device for a vehicle includes an area determining section for determining a detection area extended forward of a running vehicle and provided for detecting an obstacle, a split section for splitting the area into a plurality of small split zones, a detecting section for detecting an obstacle in each of the small split zones, inferring section for an inferring a path of the vehicle in the obstacle detection area, and a judging section for judging a rank of danger of an obstacle in the detection area. The obstacle can be properly detected so that the vehicle can take a responsive and appropriate action for avoiding the obstacle.

Driving environment surveillance apparatus

Abstract: A driving environment surveillance apparatus is provided to specify a region where an obstacle is present depending upon an azimuth detected by an obstacle detecting unit so as to derive a two-dimensional image corresponding to the specified region from an image detecting unit, and to extract the obstacle from the two-dimensional image so as to calculate a size index of the obstacle, thereby detecting a relative distance or the azimuth to the obstacle from a vehicle with high accuracy and at a high speed.

Controlled Motion in an Elastic World

Abstract: The flexibility of the drives and structures of controlled motion systems are presented as an obstacle to be overcome in the design of high performance motion systems, particularly manipulator arms. The task and the measure of performance to be applied determine the technology appropriate to overcome this obstacle. Included in the technologies proposed are control algorithms (feedback and feed forward), passive damping enhancement, operational strategies, and structural design. Modeling of the distributed, nonlinear system is difficult, and alternative approaches are discussed. The author presents personal perspectives on the history, status, and future directions in this area.

Obstacle sensing apparatus for vehicles

Abstract: An obstacle sensing apparatus for vehicles which enables efficient obstacle sensing and improves sensing precision. The apparatus comprises a section for predicting a deduced traveling-passage on which the vehicle will travel, based on a steering angle, a yaw rate and a velocity of the vehicle, a section having a CCD camera, for detecting a current traveling-passage on which the vehicle is currently moving, a scanning-type radar unit for sensing obstacles within a predetermined area, and a danger level judging section for judging danger levels of the sensed obstacles, based on the deduced traveling-passage and the current traveling-passage. The danger level judging section sets the danger level of the obstacle sensed within an area, where the deduced traveling-passage and the current traveling-passage overlap with each other, to the highest danger level; the obstacle sensed in an area within the current traveling-passage and without the deduced traveling-passage, to an intermediate danger level; the obstacle sensed in an area within the deduced traveling-passage and without the current traveling-passage, to a lower danger level; and the obstacle sensed in an area without the current and deduced traveling-passages, to the lowest danger level.

The hydraulics of steady two-layer flow over a fixed obstacle

Abstract: This paper reports the results of a theoretical and experimental study of steady two-layer flow over a fixed two-dimensional obstacle. A classification scheme to predict the regime of flow given the maximum height of the obstacle, the total depth of flow, and the density and flow rate of each layer, is presented with experimental confirmation. There are differences between this classification scheme and that derived for flow over a towed obstacle by Baines (1984, 1987). These differences are due to the motion of upstream disturbances in towed obstacle flows. Approach-controlled flows, i.e. flows with an internal hydraulic control in the flow just upstream of the obstacle are studied in detail for the first time. This study reveals that non-hydrostatic forces, rather than a shock solution (called an internal hydraulic drop by previous investigators), need to be considered to explain the behaviour of Approach-controlled flows.

Vehicle obstacle avoidance system

Abstract: A system for warning a vehicle driver of obstacles to the front, rear and sides of the vehicle. If the vehicle is stopped and a front or rear obstacle is detected, the vehicle is prevented from moving forward or reverse, respectively. The inhibition of movement can be overridden by the driver once he acknowledges the obstacle. Similarly, the driver is warned of front, rear and side obstacles while the vehicle is moving. In the case of side obstacles, only when it appears that the driver will move the vehicle toward the obstacle is he warned.

Sliding mode control for an obstacle avoidance strategy based on an harmonic potential field

Abstract: This paper introduces a new integrated path control strategy (combined path planning and motion control) for autonomous systems of arbitrary dimension. A harmonic artificial potential field is used to specify admissible trajectories leading around obstacles. Using a sliding mode controller, motion is generated along the gradient lines of the potential field, avoiding collisions with the obstacles. The extremely low computational complexity of the proposed method makes it very suitable for online applications. The strategy is applied to mobile robots moving amidst known obstacles. Only the obstacle closest to the robot is considered at each time instance. The switching of the two respective gradient fields along the equi-distance line between two obstacles leads to the interesting phenomenon of an additional "spatial" sliding surface, which is examined in detail. The algorithm guarantees approaching the goal point continuously, following a reasonably short path. Numerical examples are presented to demonstrate the utility of this new strategy. >

Planning a time-minimal motion among moving obstacles

Abstract: Motion planning for a point robot is studied in a time-varying environment. Each obstacle is a convex polygon that moves in a fixed direction at a constant speed. The point to be reached (referred to as the destination point) also moves along a known trajectory. The concept of “accessibility” from a point to a moving object is introduced, and is used to define a graph on a set of moving obstacles. If the point robot is able to move faster than any of the obstacles, then the graph exhibits an important property: a time-minimal motion is given as a sequence of edges in the graph. An algorithm is described for generating a time-minimal motion and its execution time is analyzed.

Obstacle Detection By Vision System For An Autonomous Vehicle

Abstract: In this paper, a method to detect an obstacle on unstructured roads using a vision system and a technique for camera calibration is presented. The effectiveness is demonstrated by using a real road image obtained by two cameras mounted on a vehicle.

Headlight device for vehicle

Abstract: PURPOSE:To control the light distribution in front of a vehicle so as to recognize an obstacle by a driver of the own vehicle in the running condition. CONSTITUTION:A scope setting process is made to an image taken by a TV camera (200), and after an obstacle detecting process is carried out, the existence of an obstacle is decided (202 and 204). When there is no obstacle, a normal light distribution control to improve the visibility and to prevent a glare is carried out (214). On the other hand, when there is an obstacle, the upper end of the obstacle is measured (206). Then, the position of the cut line by the present shade position is stored (208), and by deciding whether the upper end of the obstacle is near the cut line or not, it is decided whether the normal light distribution control will do or not (210). When the answer is no, a light distribution control to light on the obstacle is carried out (212). By placing the priority to the light distribution to light on the obstacle in such a way, the driver can recognize an obstacle such as a walker securely.

Obstacle detecting device

Abstract: PURPOSE: To correctly estimate an obstacle area by judging the possibility of continuity of the obstacle area including even the far/near relation of a small area noticed at on an image. CONSTITUTION: A distance image calculating means A calculates a distance image having a distribution of distance values from a reference position to an obstacle and respective points. An obstacle selecting means B retrieves the calculated distance image and selects the small area as an object of estimation of the obstacle area. An obstacle continuity decision means (c) compares the distance value of the selected small area with the distance value of an evaluation part for evaluating the continuity to the small area, thereby deciding the possibility of continuity between the small area and evaluation part. An obstacle area estimating means D estimates the obstacle area on the basis of the decision on the possibility of continuity. Consequently, plural obstacles can accurately be separated and estimated even in a distance image including absence of and an error in distance value obtained by stereoscopic, observation using images, etc., in the actual state of obstacles on a road. COPYRIGHT: (C)1995,JPO

Travel environment monitoring device

Abstract: PURPOSE:To provide a travel environment monitoring device capable of detecting a relative distance and azimuth between a vehicle and an obstacle at high speed even when detecting accurately. CONSTITUTION:An area when an obstacle exists is specified based on an azimuth detected by an obstacle detecting means 15, a two-dimensional image corresponding to that specified area is obtained from an image detecting means 16, and the obstacle is extracted from the two-dimensional image to calculate the index of magnitude of the obstacle.

Stochastic performance modeling and evaluation of obstacle detectability with imaging range sensors

Abstract: Statistical modeling and evaluation of the performance of obstacle detection systems for unmanned ground vehicles (UGVs) is essential for the design, evaluation, and comparison of sensor systems. This issue is addressed for imaging range sensors by dividing the valuation problem into two levels, i.e., the quality of the range data itself and the quality of the obstacle detection algorithms applied to the range data. Existing models of the quality of range data from stereo vision and AM-CW laser range-finders (LADAR) are reviewed. These are used to derive a new model for the quality of a simple obstacle detection algorithm. This model predicts the probability of detecting obstacles and the probability of false alarms, as functions of the size and distance of the obstacle, the resolution of the sensor, and the level of noise in the range data. These models are evaluated experimentally using range data from stereo image pairs of a gravel road with known obstacles at several distances. The results show that the approach is a promising tool for predicting and evaluating the performance of obstacle detection with imaging range sensors. >

Vehicular obstacle complying device

Abstract: PURPOSE:To enable accurate information to be reliably given to an occupant according to the degree of damages by obstacles to one's own vehicle and also to enable protection for the occupant in relation to collision to the obstacles to be performed in advance CONSTITUTION:A vehicular obstacle complying device is provided with an obstacle detecting means 2 for detecting an obstacle A existing on the periphery of a vehicle 1, an obstacle degree judging means 4 for judging the obstacle degree of the detected obstacle A to one's own vehicle on the basis of the relative distance D and the relative velocity V between the obstacle A and one's own vehicle, a seat belt device 5 capable of adjusting the belt tension in fitting, and a belt adjusting means 16 for increasing the belt tension of the seat belt device 5 according to the obstacle degree so that the belt tension of the seat belt device 5 may be increased as the obstacle degree judged by the obstacle degree judging means 4 is large

Fast path planning available for moving obstacle avoidance by use of Laplace potential

Abstract: Describes the theory and an experiment for a fast path planning method that is available for moving obstacle avoidance for an autonomous mobile robot by the use of the Laplace potential. This new navigation function for path planning is feasible to guide, in real time, a mobile robot avoiding arbitrarily moving obstacles and reaching the goal. The experiment is conducted to verify the effectiveness of the navigation function in obstacle avoidance in the real world. The experimental systems are composed of a position sensing camera, a mobile robot and a computer for processing the position signal and for controlling the velocity vector of the robot. Three examples are presented; firstly the avoidance of a standing obstacle, secondly the avoidance of a moving obstacle in parallel lines-bounded space, and thirdly the avoidance of one moving obstacle and another standing obstacle. The robot can reach the goal after successfully avoiding the obstacles in all cases.

An on-line algorithm for navigating in an unknown environment

Abstract: Suppose that a robot is required to traverse a two-dimensional scene with impenetrable rectangular obstacles. The robot has no information about the obstacles in advance and the size, location, and orientation of each obstacle in the scene are arbitrary, yet the robot can see and move in any direction. In this paper we construct an on-line algorithm for the robot to determine an obstacle-free path to its destination dynamically. The primary concern for such on-line algorithm is the competitiveness coefficient which essentially compares the actual distance traversed to the length of the shortest path. We show that if the aspect ratio of every rectangular obstacle in the scene is bounded by a constant r, then our algorithm achieves the optimal competitiveness coefficient which is r/2+1.

Safety device for vehicle

Abstract: PURPOSE: To evade unnecessary safety securing operation by restricting the safety securing operation unless an obstacle is positioned on a going path that a going path estimating means estimates when the obstacle almost in a stop state is detected on a travel path that a travel path estimating means detects. CONSTITUTION: When the obstacle almost in the stop state is present on the travel path of this vehicle that the travel path estimating means 14 as a result of the calculation of, for example, the relative speed as a value larger than a set value, a restricting means 16 restricts the safety securing operation by, for example, inhibition, delay, basic preparation alteration, or selection unless the obstacle is on the going path of this vehicle that the going path estimating means 8 estimates. Consequently, when the driver judges that the obstacle almost in the stop state such as a parking vehicle or pedestrian by the travel path can be passed by, the unnecessary safety securing operation can be evaded. COPYRIGHT: (C)1995,JPO

Vehicle run safety apparatus

Abstract: When information of an obstacle is not outputted from a radar device, a presumption device presumes at least a present value of a distance between a vehicle and the obstacle based on information in a memory part obtained until the time, and a contact-possibility judgment device judges a possibility of contact of the vehicle with the obstacle based on the information from the presumption device. A detection device is provided for detecting conditions at the time when the information of the obstacle is not outputted from the radar device, for example, a relation of relative position of the obstacle to the vehicle. Further, a restriction device is provided for restricting the presumption by the presumption device according to the relation of relative position. Thus, a possibility of contact of the vehicle with the obstacle running forward of the vehicle is appropriately judged and mis-operations of an alarm, an automatic braking and the like are prevented, while ensuring running safety.

Obstacle detector for vehicle

Abstract: PURPOSE: To indicate the position and direction of an obstacle without requiring the substantial shift of line of sight of a driver. CONSTITUTION: The driver's eye ball irradiated with infrared illumination light is imaged by an infrared camera 14, and based on the picture, line of sight is detected, and then on a front windshield 14, driver's observation area V is set. Using an infrared radar head, the position and direction of an obstacle B around a car is detected, and between the position/direction of the obstacle B and the center C of the observance area, a warning mark M is displayed by a head-up display. Since the warning mark M is displayed near the line of sight of the driver, the appearance of the obstacle is surely known. As the direction of the obstacle is also indicated by the direction toward which the warning mark M is displayed, from the center C of the observance area, the obstacle is easily confirmed. COPYRIGHT: (C)1994,JPO&Japio

Perception control for obstacle detection by a cross-country rover

Abstract: Perception control consists of optimally tuning sensor or processing parameters in order to increase perception efficiency under requirement constraints or while adjusting to the environment. Perception control in the task of obstacle detection from cross-country navigation is addressed. The authors show how to maximize the vehicle safety at a given velocity, or inversely how to derive the maximum speed for a given safety. This optimization problems requires the joint analysis of how the vehicle velocity sets look-ahead requirements, how the computational cost of perception is related to the perception variables, the window of attention and image resolution, and how the reliability of the obstacle detection system is related to these variables. This criterion relies on experimental performance statistics. This system has been implemented and tested in outdoor operation. >

Obstacle avoidance apparatus

Abstract: An obstacle avoidance apparatus including a target data generator for outputting observation values of a target, a static obstacle driver for expressing a static obstacle by a turning acceleration of the target, a characteristic amount extractor for outputting characteristic amounts for representing first control amounts of a destination direction and a static obstacle avoidance by the turning acceleration, and a control amount determiner for outputting a second control amount of the target based on the first control amounts. A three-dimensional obstacle is expressed by the turning acceleration looked at from the target and the control amount for avoiding the obstacle until the target reaches a destination is determined.

Generation system for obstacle avoiding path

Abstract: PURPOSE:To efficiently search for an optimum path to a destination as to an obstacle avoiding path system which makes a mobile robot avoid an obstacle by autonomously generating the path. CONSTITUTION:The mobile robot 1 performs specific mobile operation by having its driving wheels 12 controlled according to commands from an autonomous travel control unit 2. A laser range finder 11 is mounted on this robot 1 and the laser range finder 11 measures distances in its front direction and sends information on them to the autonomous control unit 2. The map generating means 21 of the autonomous travel control unit 2 processes the received information into geographic data to generate a geographic map. A path generating means 22 generates a potential field on the geographic map wherein an obstacle area is a ridge and a travelable area is a valley, redefines an area whose potential value is larger than a specific value as the obstacle area and an area whose potential value is less than the specific value as the travelable area, and generates the path of the moving robot 1 in the travelable area. Further, a polygonal path for obstacle avoidance is generated. A travel control means 23 generates travel commands on the basis of information regarding the path and outputs the travel commands to the driving wheels 12 of the mobile robot 1.

Technologies for automating rotorcraft nap-of-the-earth flight

Abstract: This paper discusses the technologies required for automating rotorcraft nap-of-the-earth flight, where the use of natural obstacles for masking from the enemy is intentional and the danger of undesirable obstacles such as enemy traps is real. Specifically, the automatic guidance structure is modeled by three decision-making levels: the far-field mission planning and the mid-field terrain-masking trajectory shaping are both driven by prestored terrain data, whereas the nearfield obstacle detection/avoidance is driven by real-time on-board sensor data. This paper summarizes the far-field and mid-field accomplishments, and reports on the status of the more-recent efforts in obstacle detection and avoidance development. Obstacle detection is based primarily on passive imaging sensors for the desirable properties of covertness and wide field of view, although active sensors are included in the structure to provide the much needed high resolution for thin-wire detection.

Car-mounted equipment

Abstract: PURPOSE:To perform an image recognition by means of a camera surely even at night by installing a device detecting an obstacle or the like from an image of the camera and a distance measuring instrument in a gap with an object, and controlling the distance measuring instrument and the lighting direction of head lamps directively to the side of the object. CONSTITUTION:This car-mounted equipment is provided with a lane sensor, an obstacle sensor, an image recognizer by means of a camera, through which a travel lane, an obstacle on the lane, a car distance and relative speed with a preceding car, a distance or the like with the obstacle are detected, judging a degree of traveling safety on the basis of the secured data, and thereby a steering wheel, an accelerator, a brake or the like are operated, and thus any possible dangerousness is avoided. In the car-mounted equipment like that, at night in partuclar, the lighting direction of headlights or the like is compensated according to the curved status of a road. In brief, the lighting direction of the headlights of one's own car 5b is controlled in a 7e direction so as to light up a preceding car 5a at the curved road. In addition, simultaneously the lighting direction of a beam of a device measuring a car distance and a relative speed is also controlled in the 7e direction too.

Modeling, control and obstacle avoidance of a mobile robot with an onboard manipulator

Abstract: A systematic approach for modeling and base motion control of a mobile vehicle with an onboard robot is presented. Feedback linearization is used to take into account the complete dynamics with nonholonomic constraints. Methods from potential field theory are incorporated to provide resolution among possibly conflicting performance goals (e.g. maintaining a desired course and speed plus obstacle avoidance). The feedback linearization provides an inner loop that accounts for possible motion of the onboard arm. The case of maintaining a desired course and speed is considered. The outer control loop is designed using potential field theory, with the two objectives of homing and avoiding an obstacle. >

Numerical determination of optimal non-holonomic paths in the presence of obstacles

Abstract: The problem of numerically finding an optimal path for a robot with nonholonomic constraints is addressed. A carlike robot whose tuning radius is lower bounded is considered as an example, where the arc length and the change in steering angle are optimized. The carlike robot is kinematically constrained and is modeled as a 2-D object translating and rotating in the horizontal plane in the midst of well-defined static obstacles. Given the initial and final configurations of the car and a complete description of the obstacles, the procedure directly generates a nonholonomic path as a function of the control variables in an environment of reasonable obstacle clutter. Nonholonomic paths in the midst of more complex obstacle clutter have been generated by identifying grid points on a geometric road map and by applying the procedure between successive grid points. >

Obstacle detecting device

Abstract: PURPOSE: To provide an obstacle detecting device which can detect only an obstacle which interferes with traveling. CONSTITUTION: An obstacle detecting device has a measuring part 3, which measures the time in which a light receiving part 2 receives the reflection light. In a control part 5, the measured time and the threshold time which is previously memorized in the second memory 11 are compared. If the measured time is longer, a detection permission signal is outputted into a distance detection part 4, and the distance data from the obstacle which is detected by the distance detection part 4 is outputted into an alarm lamp 9 and a display unit 10. Accordingly, only the obstacle which interferes with traveling can be detected, and only the information necessary for a driver can be obtained, and the safety during drive can be improved. COPYRIGHT: (C)1994,JPO

An approach to robot motion planning for time-varying obstacle avoidance using the view-time concept

Abstract: An analytic solution approach to the time-varying obstacle avoidance problem is adopted. The problem considers the collision between any link of the robotic manipulator and the time-varying obstacle. The information on the motion and shape change of the obstacle is given prior to robot motion planning. To facilitate the problem, we analyze and formulate it mathematically in a robot joint space. We then introduce the view-time concept and analyze its properties. Using the properties of the view-time, a view-time based motion planning method is proposed. The view-time based method plans the robot motion by units of the view-time. In every view-time, it uses a stationary obstacle avoidance scheme. The proposed method is applied to the motion planning of a 2 DOF robotic manipulator in an environment with a polyhedral moving obstacle.