Showing papers on "Obstacle published in 1985"

Obstacle Avoidance for Kinematically Redundant Manipulators in Dynamically Varying Environments

Abstract: The vast majority of work to date concerned with obstacle avoidance for manipulators has dealt with task descriptions in the form ofpick-and-place movements. The added flexibil ity in motion control for manipulators possessing redundant degrees offreedom permits the consideration of obstacle avoidance in the context of a specified end-effector trajectory as the task description. Such a task definition is a more accurate model for such tasks as spray painting or arc weld ing. The approach presented here is to determine the re quired joint angle rates for the manipulator under the con straints of multiple goals, the primary goal described by the specified end-effector trajectory and secondary goals describ ing the obstacle avoidance criteria. The decomposition of the solution into a particular and a homogeneous component effectively illustrates the priority of the multiple goals that is exact end-effector control with redundant degrees of freedom maximizing the distance to obstacles. An efficient numerical ...

A Three-Dimensional Vision by Off-Shelf System with Multi-Cameras

Abstract: A three-dimnensional vision system for on-line operation that aids a collision avoidance system for an industrial robot is developed. Because of the real-time requirement, the process that locates and describes the obstacles must be fast. To satisfy the safety requirement, the obstacle model should always contain the physical obstacle entirely. This condition leads to the bounding box description of the obstacle, which is simple for the computer to process. The image processing is performed by a Machine Intelligence Corporation VS-100 machine vision system. The control and object perception is performed by the developed software on a host Digital Equipment Corporation VAX 11/780 Computer. The resultant system outputs a file of the locations and bounding descriptions for each object found. When the system is properly calibrated, the bounding descriptions always completely envelop the obstacle. The response time is data-dependent. When using two cameras and processed on UNIX time sharing mode, the average response time will be less than 2 s if eight or fewer objects are present. When using all three cameras, the average response time will be less than 4 s if eight or fewer objects are present.

Obstacle detection system

Abstract: An obstacle detection system has a sensor unit including a plurality of ultrasonic transducers and sequentially changes the number of pulses provided to groups of transducers, thereby performing front center sensing, front right sensing and front left sensing. The time between emission of ultrasonic waves and reception of waves reflected by an obstacle is calculated by a timer. A microcomputer computes the distance data and position data of the obstacle in accordance with obtained timer data and sensing region data.

Ultrasonic obstacle location apparatus and method

Abstract: An obstacle sensing area ahead of a mobile robot is divided into a plurality of sensing regions. A number of ultrasonic transmitters and plural receivers on the robot cooperate to detect the presence of obstacles in the sensing regions. Coordinates representing four corners of each sensing region, and time data representing a time period from emission of ultrasonic waves from selected transmitters to reception of the waves by each receiver when the waves are reflected by an obstacle at each corner point, are prestored in data ROMs. The data ROMs are retrieved by a CPU in response to obtained time data, and precise position data of the obstacle in the sensing area is determined.

Controller of moving robot

Abstract: PURPOSE:To run a moving robot efficiently throughout the whole area efficiently without any collision against an obstacle even if the obstacle is present by deciding an area where the robot is not run yet from an area where the robot is already run and an area where the obstacle is present. CONSTITUTION:A previously learnt movement area is fractionized into longitudinal and lateral blocks in a matrix on two-dimensional coordinates and stored on a map. A CPU9 repeats a run longitudinally or laterally, line by line, and the area where the robot run is is stored and held in a storage part 10 successively. Thus, a linear run is made and ultrasonic sensors 4 on both flanks detect whether there is an obstacle on the right and left sides of a run block and stores the result in the storage part 10. When a sensor 4 on the front surface senses an obstacle in front, the run is repeated within a range wherein the robot collides against it while the position of the obstacle is stored; when the sensor does not sense it any more, a decision on an area where the robot is not run so far is made from the area where the robot is already run and the obstacle area, and the robot is moved to the part to continue to run, line by line.

Automatic searching method of path

Abstract: PURPOSE:To search automatically at a high speed a practical path by executing a temporary wiring between a designated source and target by using a computer, applying and connecting a prescribed pattern, and using a mesh just before an obstacle, as a new source, when the obstacles exists. CONSTITUTION:When an operator designates a source S1 and a target T1 which are two points to be connected, a computer applies a pattern P1 between these two points and executes a temporary wiring. As for the pattern P1, however, in case an obstacle O3 exists on the way, a mesh just before the obstacle O3 is used as a new source S2, and a pattern for connecting this source S2 and the target T1 is searched in the next time. Subsequently, a pattern P8 is applied. Since an obstacle O1 exsits on the way of this line l2, a mesh just before the obstacle O1 is used as a new source S3, and a pattern for connecting the source S3 and the target T1 is searched. Next, the computer uses the S3 as a source, applies the pattern P1, and fetches the pattern P8 from a source S4 of a mesh just before an obstacle O2 in the same way.

Coincidence sets in the obstacle problem for the p-harmonic operator

Abstract: We consider the obstacle problem for the p-harmonic operator div(Iv I 2v *) withp > 1, and show that the coincidence set is star shaped under certain conditions on the obstacle

Automatic running service car

Abstract: PURPOSE:To avoid exactly and automatically an obstacle by a simple operation, by changing automatically front wheels, rear wheels and a steering operating angle in accordance with a result of a distance detection by a distance detecting sensor CONSTITUTION:A control device 5 inputs a result of a detection of a distance extending from an ultrasonic sensor A to an obstacle X, and basing on it, this device calculates and outputs a control signal for driving solenoid valves 8, 9 for operating front wheels 2, rear wheels 3, and hydraulic cylinders 6, 7 which execute a steering operation at a prescribed steering angle, and a control signal for driving a motor 11 for operating a speed change position of a speed changing device 10 In this way, a car body can be avoided by a result of a detection of the obstacle X by only one sensor A In this regard, in case when the obstacle cannot be avoided, an alarm is generated by an alarm device 12

Obstacle evading device for unmanned conveyance vehicle

Abstract: PURPOSE: To increase the safety during a run by sensing an obstacle in the front and carrying out evading run operation in a run following up a guiding means, and returning the original run path and restarting a follow-up run. CONSTITUTION: An unmanned conveyance vehicle is equipped with a photoelectric sensor on its frame and a light reflection tape for guidance installed on the run path previously is sensed by the sensor to make a run on the run path while correcting the direction to right and left. In this case, an obstacle sensing means is provided on the front surface of the unmanned conveyance vehicle and on both right and left flanks and when an obstacle is sensed in the front, the guidance run is stopped and the vehicle begins to run to one side. When there is no obstacle sensed in the front after said obstacle is evaded, the sideward run is stopped and a forward run is started. Further, the obstacle sensing means on one flank senses an obstacle and then turns off, the forward run is stopped and a run to the other side is made until the position of the guide means on the run path. Consequently, the vehicle returns to the run path and begins to make the follow-up run. COPYRIGHT: (C)1987,JPO&Japio

Detection of obstacle in moving body

Abstract: PURPOSE:To attain the cost reduction in the detection of an obstacle, by arranging a plurality of distance measuring instruments each using a medium such as an ultrasonic wave on a moving body such as a moving robot and performing the detection of the obstacle to impart a running control signal to the moving body CONSTITUTION:In a moving body in a running state, under a usual state wherein no obstacle is discovered, the signal from a control apparatus operates a distance measuring apparatuses in a front monitoring mode When the obstacle is detected, an object is tracked by one distance measuring apparatus and the scanning range of the other distance measuring apparatus is enlarged or the subsequent trend of the tracked obstacle is detected A running control signal necessary for the moving body is outputted to allow said moving body to avoid the obstacle By this method, the highly practicable detection of the obstacle can be performed inexpensively

Detection for obstacle of autonomous moving robot

Abstract: PURPOSE:To detect obstacles in a high speed without erroneous recognition by setting a window which limits the range of obstacle detection and calculating lengths to objects in this window to detect obstacles. CONSTITUTION:When a robot 1 goes straightly into a visual field 7, segments 11 and 12 which its both faces pass are set, and an area 13 surrounded with these segments 11 and 12 is defined as the window for detection of obstacles. When the height of a viewpoint 19 of the robot, the angle of robot's eyes to a horizontal plane 22, the length between the viewpoint 19 and the lower end of an obstacle 5, the angle of a segment 23 connecting the viewpoint 19 and the lower end of the obstacle to a floor surface 24 are denoted as (h), theta, (x), and beta respectively, the length (x) is obtained by dividing the height (h) by the tangent of the angle beta. The image obtained by vision is processed continuously in this manner to generate a histogram in the window, thereby determining the position of the obstacle.

Obstacle detecting system for vehicle

Abstract: PURPOSE:To detect a relative position of an obstacle and a vehicle by providing a display panel partitioned into plural block units being proportional to an actual size of the periphery of the vehicle. CONSTITUTION:A microcomputer (MC)5 drives a stepping motor 7 through a motor driver 6, and executes initializing for turning the measuring direction of an ultrasonic sensor 8 to a reference position. Subsequently, the MC5 turns the motor 7 by an angle theta1, and sets the detecting direction of the sensor 8 to a direction of 1'. In case an obstacle has been detected, a distance l between the sensor 8 and the obstacle is measured, and the distance l is compared with a distance to each intersection point (a), (b) and (c) stored in advance. As a result, if the distance l to the obstacle is shorter than the first intersection point (a), a lamp of a display block I is trned on, and its display block is lighted. In such a way, a driver can recognize instantaneously a block in which the obstacle exists, and can grasp exactly the relative position relation of the obstacle and the vehicle.

Confirming device of side part obstacle of vehicle

Abstract: PURPOSE:To make the confirmation of information of the side part of a car body easier by offering to a driver as a numerical information a runner of the side part of a car body and the existing condition of a substance. CONSTITUTION:Plural sets of ultrasonic transmitters 1 and ultrasonic receivers 2 are constituted of an alarm switch 6 which is opened and closed with linking to the movement of a handle of the case of the operation at more than the prescribed steering angle by a battery 4 and power source switch 5 and steering device or to the motion of a turn signal lever, etc. A controlling unit 8 controls the timing of transmitting and receiving, calculates the distance between a vehicle 3 and obstacle 7 and judges the approaching condition of the obstacle 7. The unit 8, then, indicates to a visualizing device 9 the judgement result thereof. An outline shape 9a looked from the upper part of a vehicle, distance figures 9b upto the obstacle 7 and turning on-and-off lamps 9c classified by colors according to the distances, are lined on the same surface in the device 9 contained in the dash board at the front of a drivers seat. A driver can therefore visualize easily.

Trajectory control and obstacle avoidance for robot manipulators with bounded inputs

Abstract: The dynamic equations for a robot manipulator are generally represented by coupled, non-linear state equations. A non-linear controller is developed in this thesis that considers the complete non-linear system dynamics. In addition, the control allows for bounds on the system inputs, such as limited input torque from the joint motors. The control is based upon the application of an Optimal Decision Strategy, a pointwise optimization process. This results in the design of the control being reduced to the solution of a quadratic programming problem at each sample point. The robustness of the control scheme to unmodeled dynamics is examined and a robust control is presented. A real-time implementation of this control is developed for a three degree of freedom robot manipulator. The control is implemented using 16 bit microprocessor and is programmed in a high level language. The manipulator dynamics are computed using the Euler-Lagrange formulation and the control system is run with a sample period of 16 milliseconds. A path planning strategy for a two degree of freedom Cartesian manipulator with obstacles in the workspace is developed. Previous path planning strategies have usually neglected manipulator dynamics, with the potential result of a trajectory that cannot be followed by the manipulator. The concept of an extended obstacle is presented where the obstacle is defined in both position and velocity space. This allows for the consideration of bounded inputs in the obstacle avoidance strategy. A control is computed based upon the Optimal Decision Strategy, and then examined to see if the resulting trajectory hits the extended obstacle. If so, an avoidance control is then applied. The obstacle avoidance strategy results in a trajectory that can always be tracked by the manipulator, and has the potential to be implemented on-line.

Traveling apparatus for preventing collision with obstacle

Abstract: PURPOSE:To detect the certainty for a true obstacle and the possibility of getting-over the obstacle, by installing a detector which contacts the obstacle at the height which a traveling body can get-over and a detector which projects forward at the position higher than the above-described former detector CONSTITUTION:Onto a bracket 3 installed at the front part of the traveling body 1 such as tractor, a working machine 5 raised and lowered by a cylinder apparatus 4 is installed in swingable ways Onto said working machine 5, the detecting apparatuses 10 and 11 which detect the possibility of getting-over are installed by utilizing side plates 8 The detecting apparatus 10 is constituted through the connection of a detecting switch 13 and a detector 12 whose upper edge is positioned at the height H which the traveling body 1 can get-over While, the detecting apparatus 11 is constituted through the connection of a detecting switch 16 and the detector 15 whose lower edge is positioned at the above-described height H Therefore, the detecting apparatuses 10 and 11 are allowed to contact an obstacle in succession, and it is detected that the obstacle is a true obstacle or not, and the possibility of getting-over the obstacle is detected

Method and device for determining the distance between a motor vehicle and an obstacle

Abstract: A method for determining the distance between a motor vehicle and an obstacle situated in its lane is characterised by the use of a light source which is mounted on the vehicle and casts onto the obstacle a light spot which has a limited outer contour and whose greatest horizontal extent is always equal to the distance of the vehicle from the obstacle. A device suitable for carrying out the method consists of a spotlight mounted on the vehicle which has on the emitting side a light exit opening having defined dimensions.

Obstacle detecting apparatus for vehicle

Abstract: PURPOSE:To facilitate steering judgment, by providing a means, which detects a distance from a vehicle to an obstacle and the direction from the vehicle to the position of the obstacle, and providing a means, which displays the positional relation between the vehicle and the obstacles around the vehicle as a bird's-eye view. CONSTITUTION:An obstacle detecting apparatus for a vehicle is provided with the following devices: distance measuring parts 7-1-7-4, which are provided at, e.g., front and rear and right and left of a body, and detect the distances to an obstacle; direction control parts 9-1-9-4, which are provided at front and rear and right and left of the body and control the obstacle detecting directions of the distance measuring parts 7-1-7-4; a display part 13, which receive the signals from the distance measuring parts 7-1-7-4 and the directions control parts 9-1-9-4 and displays the positional relation of the own vehicle and the surrounding objects as a bird's-eye view on a CRT screen and the like; and a microcomputer 11, which performs picture-signal processing for the display on said display part 13. Thus, a drive can judge the steering direction readily based on the positional relation with the surrounding obstacle.

Obstacle detecting device

Abstract: PURPOSE:To obtain necessary information with a simple device by deriving the height of an obstacle and a moving distance before than time, from an angle of rocking and the moving distance information of a non-contact time and a contact time to the obstacle of a searching body installed so as to be rockable to the front of a moving body. CONSTITUTION:A searching body 2 is usually held so as to maintain an angle alpha in front of a moving body 1, and outputs it to an operating device by the first limit switch 5. In this state, the moving body 1 is advanced, and searching body 2 contacts an obstacle in front of said body, and when its angle reaches beta, the second limit switch 8 is operated. As a result, the second limit switch 8 outputs information of the angle beta to the operating device. On the other hand, a moving extent of the moving body before that time is detected by a distance detector 14, and outputted to the operating device. The operating device calculates the height of the obstacle 3 and a distance to the obstacle basing on the detected information, and outputs them to a control device.