Running control system for mobile robot provided with multiple sensor information integration system

• US 5,400,244 A
• Filed: 06/25/1992
• Issued: 03/21/1995
• Est. Priority Date: 06/25/1991
• Status: Expired due to Fees

• Current Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Original Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Inventors: Onoguchi, Kazunori, Kweon, In S., Watanabe, Mutsumi
• Primary Examiner(s): Teska, Kevin J.
• Assistant Examiner(s): LOUIS JACQUES, JACQUES H
• Application Number:
  US07/904,039
• Time in Patent Office: 999 Days
• Field of Search: 364/424.02, 364/443, 364/444, 364/449, 364/461, 364/424.01, 901/1, 901/9, 901/10, 901/11, 318/587, 318/580, 318/570, 318/574, 180/79.1, 180/98, 180/167, 180/168, 180/169
• US Class Current: 701/28
• CPC Class Codes: G05D 1/0242 using non-visible light signals, e.g. IR or UV signals
• CPC Class Codes: G05D 1/0246 using a video camera in combination with image processing means
• CPC Class Codes: G05D 1/0255 using acoustic signals, e.g. ultra-sonic singals sonar systems designed for anti-collision purposes G01S15/93

Abstract

A running control system for a mobile robot has the functions necessary for motion clustered into a danger avoidance portion, a safe region advance portion and an interest region follow portion, and these are coupled to a motion actuator control portion which directly controls each movement of the robot, and fused in the motion actuator control portion. Operation commands are configured from a moving distance and a moving direction of the mobile robot. In addition, there is also a coupling in the direction of the safe region advance portion from the danger avoidance portion but internal situations such as the failure and end of processing and like are transmitted using these couplings of portions. Interference between intelligent behavior and reflexive behavior is basically performed via the motion actuator control portion. The control amount for the motion actuator is determined by fusing a plural number of types of operation commands relating to the various types of behavior of the mobile robot, and it is possible to have real-time running of the mobile robot. In addition, when there is a failure in the various types of processing and which can occur in a dynamic environment, the inducing of a operation command of an auxiliary function portion enables the positive escape from a status of failure.

Claims

1. A running control system at least including a mobile robot having a motion actuator and capable of running, and obstacle sense means provided on the robot for sensing obstacles existing in a predetermined area in which the robot is running, said system comprising:

danger avoidance means for avoiding said mobile robot from a danger of said obstacles by detecting said danger of said obstacles on the basis of an output of said obstacle sense means and by outputting operation commands for an avoidance;

safe region advance means for outputting operation commands for advancing said mobile robot for the safest region which is obtained for said mobile robot on the basis of said output of said obstacle sense means;

interest region follow means for outputting operation commands for following said mobile robot toward an object within an interest region which is determined and includes an objective point to be reached and a moving object to be chased on the basis of said output of said obstacle sense means; and

motion actuator control means for controlling running of said mobile robot after parallel receiving said operation commands outputted from said danger avoidance means, safe region advance means and interest region follow means to unitedly process said commands and to determine an control amount of said motion actuator provided in said mobile robot.

2. The running control system for said mobile robot according to claim 1, wherein said motion actuator control means comprises:

an operation analysis circuit for analyzing each of said operation commands supplied from said danger avoidance means, safe region advance means and interest region follow means, thereby dividing operation commands with respect to a direction and operation commands with respect to a distance;

a steering angle determining circuit for determining a moving direction of said mobile robot on the basis of said operation commands with respect to said direction divided by said operation analysis circuit; and

a speed determining circuit for determining a running speed of said mobile robot on the basis of said operation commands with respect to said distance divided by said operation analysis circuit.

3. The running control system for said mobile robot according to claim 2, wherein said steering angle determining circuit comprises:

a weighting memory for storing a plurality of weighting values which are set for correlatively weighting said operation commands to avoid a local-portion optimum condition when the mobile robot becomes in the local-portion optimum condition after analyzing an operation history of said mobile robot, and for outputting a weighting value corresponding to said operation commands with respect to said direction supplied from said operation analysis circuit;

a plurality of multipliers for respectively multiplying said weighting value outputted from said weighting memory by said operation commands with respect to said direction outputted from said operation analysis circuit; and

an adder obtaining a steering angle control amount by adding respective outputs of said plurality of multipliers.

4. The running control system for said mobile robot according to claim 1, wherein said safe region advance means comprises:

an obstacle circumference follow portion for outputting operation commands for moving said mobile robot so as to follow a periphery of an obstacle; and

an open space detection portion for outputting operation commands for moving said mobile robot in a direction in which there is open space; and

wherein

said obstacle circumference follow portion and open space detection portion mutually operates as failure notification means and auxiliary function means.

5. The running control system for said mobile robot according to claim 4, wherein said danger avoidance means comprises:

touch detection means for detecting as to whether said mobile robot touches the other objects or not, and for outputting a stop command to said motion actuator control means when a touch is detected;

approaching object detection means for outputting a stop command when the other object has entered into the proximity of said mobile robot;

stationary object avoidance means for transmitting an avoidance operation command of said mobile robot responsive to said other objects to said motion actuator control means; and

wherein

when said stationary object avoidance means activates said obstacle circumference follow portion when said mobile fails avoidance operation, thereby causing said mobile robot to escape from a danger condition for a collision.

6. A running control system at least including a mobile robot having a driving actuator and capable of running, and obstacle sense means provided on the robot for sensing obstacles existing in a predetermined area in which the robot is running, said system comprising:

imaging means for photographing an image in a running direction of said mobile robot for sensing obstacles of a robot advancing direction as a part of said obstacle sense means;

observed object pursuit means for pursuing an object to be observed in the image photographed by said imaging means;

observed object selection means for selecting two observed objects near said mobile robot after judging front and rear relationship on the basis of a motion of said observed object in said image when there are a plurality of object to be observed in the image;

running control amount calculation means for calculating a running amount in the manner that an advancing direction of said mobile robot is to be center between said two observed objects on the basis of the motion of said observed objects in the image; and

running control means for controlling running of said mobile robot on the basis of said running control amount calculated by said running control amount calculation means.

7. The running control means for said mobile robot according to claim 6, wherein:

said running control amount calculation means obtains a steering control angle which is formed by two directions of an advancing direction of said mobile robot and a direction from a present position of said mobile robot to a center position of said two observed objects on the basis of a motion on the image of said two observed objects when said mobile robot straightly advances a predetermined distance, and calculate said running control amount according to said steering control angle in the manner that said mobile robot passes in the center position through said two observed objects.

8. A running control system at least including a mobile robot having a driving actuator and capable of running, and obstacle sense means provided on the robot for sensing obstacles existing in a predetermined area in which the robot is running, said control system comprising:

a complex sensor system having a plurality of sensor sets including a plurality of kinds of non-touch sensors and touch sensors which are mounted on said mobile robot, and for outputting sensor data from said plurality of sensor sets as control data candidates;

a system error removing circuit for outputting as control data optimum sensor data which are formed by removing system errors from said sensor data from said plurality of sensor sets of said complex sensor system after an investigation;

a mobile robot guidance system provided for a prediction of a position of said mobile robot by receiving said control data outputted from said system error removing means and by minimizing an internal energy in said mobile robot corresponding to a control content of said control data on the basis of a reference of a path smoothness and an external force by distance data from said complex sensor system, and including various operation calculation circuits for respectively performing an extraction of the safest running region of said mobile robot, an avoidance of a collision of said mobile robot to said obstacles, follow of said mobile robot along a boundary of a stationary obstacle, and an extraction of an open space for said mobile robot to be moved; and

an operation determination circuit for selecting any of operation patterns of said mobile robot on the basis of various operation commands outputted from said various operation calculation circuits forming said mobile robot guidance system, and for outputting an operation command with respect to a selected operation pattern to a moving actuator driving controller of said mobile robot.

9. The running control system for said mobile robot according to claim 8, wherein said system error removing circuit comprises:

first system error removing means for removing a system error of a sonar sensor included in said complex sensor system in the manner that a change of a read value as a measured value is calculated by rotating said sonar sensor or said mobile robot when any of sonars corresponds to a distance shorter than an effectively reflective distance, the shortest distance measurement value as sampled data is used when the change becomes larger than a random error of said sonar sensor, and an estimation with respect to a distance uses an average distance which is calculated by using entire effective sonar data;

second system error removing means for ordinarily comparing distance values which are respectively obtained from said sonar data supplied from said sonar sensor to said first system error removing means and sensor data sensed by an infrared radiation sensor included in said complex sensor system, for using a read value of said infrared radiation sensor when both distance values are a disagreement, and for using a read value of said sonar sensor when a distance measurement value of said infrared radiation sensor is inferior, thereby removing said system error of said sonar sensor; and

third system error removing means for removing said system error of said sonar sensor by using both of said sonar data and touch data detected by a touch sensor included in said complex sensor system when both of distance measurement values are inferior which are respectively, obtained from said sonar sensor and said infrared radiation sensor.

10. The running control system for said mobile robot according to claim 8, wherein

said mobile robot guidance system comprises, as one of said various operation calculation circuits, a free space search circuit for extracting the safest running region for said mobile robot:

and wherein

said free space search circuit comprises a Cartesian coordinate conversion circuit for converting sonar distance measurement data from each of said sensors into coordinate data as values of Cartesian coordinates so as to output said coordinate circuit;

an external force calculation circuit for calculating external force as a vector value in a "Snakes" theory on the basis of said coordinate data, a present value and an immediately previous value with respect to robot position data supplied from a motion sensor so as to output external force data;

a robot stop position calculation circuit for calculating robot stop position data for smoothing a path of said mobile robot, in accordance with a principle that when three position data with respect to said present position, one time point previous position and two time points previous position are inputted and when two arcs respectively connecting any of two points in three positions are equal, a curve connecting said three positions is smooth;

an internal force calculation circuit for calculating a first internal force (fs) for smoothly binding said mobile robot on the path, and a second internal force (fc) with respect to a stop obtained by a robot technology by multiplying respective parameters for controlling a smoothness and a motion characteristic, on the basis of said present position data of said mobile robot, said onetime point previous position data and said two time points previous position data;

a new position calculation circuit for calculating a new position of said mobile robot on the basis of said external force as said vector value obtained by said external force calculation circuit and both of said internal force (fs, fc) obtained by said internal force calculation circuit so as to output new position data; and

a polar coordinate conversion circuit for calculating a motion direction and speed of said mobile robot on the basis of said new position data calculated by said new position calculation circuit so as to output said direction and speed as said operation command.

11. The running control system for said mobile robot according to claim 8, wherein:

said mobile robot guidance system comprises, as one of said various operation calculation circuits, an obstacle avoidance circuit for guiding said mobile robot in the direction of avoiding said mobile robot from an obstacle in the manner of preventing a collision of said mobile robot and said obstacle; and

wherein

said obstacle avoidance circuit comprises

a Cartesian coordinate conversion circuit for converting sonar distance measurement data from each of said sensors into coordinate data as values of Cartesian coordinates so as to output said coordinate data;

an approach echo selection circuit for selecting and outputting only close distance data being closer than a certain distance among said sonar distance measurement data supplied with a plurality of data;

an external reaction force calculation circuit for calculating external reaction as a vector value for avoiding said obstacle in accordance with a "Snakes" theory on the basis of said close distance data supplied from said approach echo selection circuit and said present position data as said vector value so as to output external reaction force data as a vector value;

a robot stop position calculation circuit for calculating robot stop position data for smoothing a path of said mobile robot, in accordance with a principle that when three position data with respect to said present position, one time point previous position and two time points previous position are inputted and when two arcs respectively connecting any of two points in three positions are equal, a curve connecting said three positions is smooth;

an internal force calculation circuit for calculating a first internal force (fs) for smoothly binding said mobile robot an the path, and a second internal force (fc) with respect to a stop obtained by a robot technology by multiplying respective parameters for controlling a smoothness and a motion characteristic, on the basis of said present position data of said mobile robot, said onetime point previous position-data and said two time points previous position data;

a new position calculation circuit for calculating a new position of said mobile robot on the basis of said external reaction force data as said vector value obtained by said external reaction force calculation circuit and both of said internal force (fs, fc) obtained by said internal force calculation circuit so as to output new position data; and

a polar coordinate conversion circuit for calculating a motion direction and speed of said mobile robot on the basis of said new position data calculated by said new position calculation circuit so as to output said direction and speed as said operation command.

12. The running control system for said mobile robot according to claim 8, wherein:

said mobile robot guidance system comprises, as one of said various operation calculation circuits, an obstacle boundary follow circuit for following said mobile robot along a boundary of a stationary obstacle by using a force of the direction of the contact line which is calculated from said distance data reflected from an obstacle near said mobile robot; and

wherein

said obstacle boundary follow circuit comprises

a Cartesian coordinate conversion circuit for converting sonar distance measurement data from each of said sensors into coordinate data as values of Cartesian coordinates so as to output said coordinate data;

an approach echo selection circuit for selecting and outputting only close distance data being closer than a certain distance among said sonar distance measurement data supplied with a plurality of data;

a contact line direction external force calculation circuit for calculating a contact line direction external force as it vector value in accordance with a "Snakes" theory on the basis of said close distance data supplied from said approach echo selection circuit and said present position data as said vector value so as to output contact line direction external force data as a vector value;

a robot stop position calculation circuit for calculating robot stop position data for smoothing a path of said mobile robot, in accordance with a principle that when three position data with respect to said present position, one time point previous position and two time points previous position are inputted and when two arcs respectively connecting any of two points in three positions are equal, a curve connecting said three positions is smooth;

an internal force calculation circuit for calculating a first internal force (fs) for smoothly binding said mobile robot on the path, and a second internal force (fc) with respect to a stop obtained by a robot technology by multiplying respective parameters for controlling a smoothness and a motion characteristic, on the basis of said present position data of said mobile robot, said onetime point previous position, data and said two time points previous position data;

a new position calculation circuit for calculating a new position of said mobile robot on the basis of said contact line direction external force data as said vector value obtained to said contact line direction external force calculation circuit and both of said internal force (fs, fc) obtained by said internal force calculation circuit so as to output new position data; and

a polar coordinate conversion circuit for calculating a motion direction and speed of said mobile robot on the basis of said new position data calculated by said new position calculation circuit so as to output said direction and speed as said operation command.

13. The running control system for said mobile robot according to claim 8, wherein:

said mobile robot guidance system comprises, as one of said various operation calculation circuits, an open space search circuit for extracting an open space such as an open door and an exit of a blind lane; and

wherein

said open space search circuit comprises

a composite sonar data generation circuit for generating increment sonar data by increasing a plurality of ultrasonic search measurement values which are taken in every specified rotation angle while said mobile robot rotates in a predetermined angle, in order to compensate a rough resolution of inputted sonar data;

a Cartesian coordinate conversion circuit for converting said increment sonar data from said composite sensor data generation circuit into coordinate data as values of Cartesian coordinates so as to output said coordinate circuit;

an external force calculation circuit for calculating external force as a vector value in a "Snakes" theory on the basis of said coordinate data and a present value of said mobile robot so as to output external force data;

a robot stop position calculation circuit for calculating robot stop position data for smoothing a path of said mobile robot, in accordance with a principle that when three position data with respect to said present position, one time point previous position and two time points previous position are inputted and when two arcs respectively connecting any of two points in three positions are equal, a curve connecting said three positions is smooth;

an internal force calculation circuit for calculating a first internal force (fs) for smoothly binding said mobile robot on the path, and a second internal force (fc) with respect to a stop obtained by a robot technology by multiplying respective parameters for controlling a smoothness and a motion characteristic, on the basis of said present position data of said mobile robot, said onetime point previous position data and said two time points previous position data;

a new position calculation circuit for calculating a new position of said mobile robot on the basis of said external force as said vector value obtained by said external force calculation circuit and both of said internal force (fs, fc) obtained by said internal force calculation circuit so as to output new position data;

a polar coordinate conversion circuit for calculating a motion direction and speed of said mobile robot on the basis of said new position data calculated by said new position calculation circuit so as to output said direction and speed as said operation command; and

a sonar amplitude change detection circuit for detecting said open space by comparing said direction and speed as said operation command with an amplitude of said increment sonar data.