JP4432912B2 - Robot movement control method and mobile robot - Google Patents

Description

  The present invention relates to a method for controlling a robot that moves autonomously and a mobile robot, and more particularly, to a method for autonomously controlling the movement speed and direction of a robot according to surrounding environmental conditions, and a mobile robot.

Conventionally, a method and apparatus for moving in an environment autonomously, that is, based on self-control, have been disclosed. (See Patent Document 1 and Patent Document 2)
Japanese Patent No. 2761454 In the method described in Japanese Patent Laid-Open No. 7-72925, as in Conventional Example 1 shown in FIG. 9, the distance to the obstacles in a plurality of directional areas and the change in distance, that is, the velocity is used as input information to perform the collision. The traveling direction angle and the velocity value are determined so as to avoid the above.

  The apparatus described in Patent Document 2 measures the position of an obstacle and controls movement so as to avoid (FIG. 11-A) or pass (FIG. 11B) as in Conventional Example 2 shown in FIG.

  Each of the methods described in Patent Document 1 and Patent Document 2 is based on the premise that the position of the obstacle or the distance between the obstacle and the autonomous traveling device, that is, the robot itself is accurately input.

  However, the robot is not always placed in a specific environment where the distance can be accurately input, and the distance between the obstacle and the robot itself may not be input correctly. For example, when a camera having a distance measuring function is used as the distance measuring means, accurate distance measurement cannot be performed in an environmental condition where the surroundings are dark field or twilight. Distance measurement may not be possible.

  Even when an expensive active laser distance measuring means is used as the distance measuring means, accurate distance measurement cannot be performed under environmental conditions where smoke has entered. In environmental conditions where smoke is trapped, the distance can be measured using an active ultrasonic sonar, but the measurable distance is short and the measurement accuracy is also reduced.

  The present invention flexibly controls movement according to the surrounding environmental conditions, and moves at high speed when the environmental conditions are good, and moves at low speed when the environmental conditions are bad to avoid collision with an obstacle. It is an object to provide a robot movement control method and a mobile robot.

  A first invention is a method for measuring a distance to an obstacle and surrounding environmental conditions, and controlling a moving speed of the robot according to the measurement result, each having a predetermined measurement range and a set speed corresponding to each. Measure using multiple distance measuring means, evaluate the measurement results in order from the distance measuring means with the longest measuring range, adopt the measuring distance of the distance measuring means that the surrounding environmental conditions satisfy the predetermined condition, The moving speed is controlled to a set speed associated with the adopted distance measuring means.

A second invention is a mobile robot comprising a distance measuring means, a robot control means, and a moving speed control means, each having a predetermined measurement range and a set speed corresponding to each other, and a distance from an obstacle A plurality of distance measuring means for measuring and sending to the robot control means, the robot control means evaluates the received measurement results in order from the distance measuring means with the longest measurement range, and the surrounding environmental conditions are predetermined conditions. The distance measured by the distance measuring means satisfying the above is adopted, the corresponding set speed is sent to the moving speed control means, and the moving speed control means controls the moving speed of the robot to the received set speed.

  The third invention is the mobile robot according to the second invention, wherein the distance required to stop the robot when the stop speed is instructed to the moving speed control means is set to the distance measuring means. If the difference between the distance from the obstacle received by the robot control means and the distance required to stop the robot is less than a predetermined value, the stop instruction is given to the movement speed control means. It is characterized by sending.

  A fourth invention is the mobile robot according to the third invention, further comprising a traveling direction control means for controlling the traveling direction by changing the rudder angle, and each distance measuring means further determines the azimuth of the obstacle. The robot control means further obtains each trajectory when the robot travels while changing the rudder angle, and the obstacle at the position obtained from the trajectory and the received distance and azimuth. If there is no interference, a traveling direction control means is sent to the traveling direction control means, and if there is interference, a traveling direction control means is sent to the traveling speed control means to stop, and the traveling direction control means follows the received traveling instruction. The traveling direction is controlled.

  5th invention is a mobile robot as described in 4th invention, Comprising: When each distance measurement means detects a several obstruction further, it calculates | requires the distance and azimuth | direction angle with each obstruction, and robot control The robot control means further determines the interference between all detected obstacles and the trajectory when the robot travels at a predetermined rudder angle. A travel instruction is sent, and if the entire trajectory of the robot interferes with any obstacle, a stop instruction is sent to the moving speed control means.

  A sixth invention is the mobile robot according to the fifth invention, wherein the robot control means further predicts the movement trajectory of the obstacle from the change of the measurement distance received from the distance measurement means, and detects all obstacles detected. It is characterized in that the interference between the robot and the robot is determined.

  According to the present invention, the robot autonomously controls the moving speed and moving direction according to the surrounding environmental conditions, and moves at high speed when the surrounding environmental conditions are good, and moving speed when the surrounding environmental conditions are bad. It is possible to avoid collisions with obstacles.

  FIG. 1 shows an outline of obstacle detection according to the present invention, and FIG. 2 shows an example of environmental conditions around a robot to which the present invention is applied.

  In FIG. 1, the robot 1 has an obstacle detection range 31 of d1 meters. However, the distance measurement means 21 whose measurement reliability depends on the surrounding environmental conditions and an obstacle detection range 32 of d2 meters (d2 <d1). However, the distance measuring means 22 is provided with the distance measuring means 22 whose measurement reliability is less likely to be influenced by the surrounding environmental conditions as compared with the distance measuring means 21, and measures the distance to the obstacle 3.

  As the distance measuring means 21, for example, a camera with a distance measuring function, that is, a vision obstacle sensor is used. As shown in FIG. 2A, the vision obstacle sensor has a large amount of information to be input when the surroundings are bright and can measure a relatively wide range with high accuracy, but does not emit light itself. As shown in (B), the accuracy of distance measurement, that is, the reliability decreases when the surroundings become dark or in the case of backlight.

  On the other hand, as the distance measuring unit 22, for example, an ultrasonic obstacle sensor is used. The ultrasonic obstacle sensor has a short obstacle detection range compared to the vision obstacle sensor, but measures the distance by reflection of the ultrasonic wave emitted by itself, so even in the case of dark surroundings, dark field, or backlight Ranging is possible.

  It is assumed that the initial speed when the robot 1 stops at d1 meters from the start of the movement stop operation is V1 meters / second, and the initial speed when it stops at d2 meters is V2 meters / second.

  In FIG. 3, the distance measuring means is selected according to the change in the surrounding environmental conditions, and moved at a moving speed according to the selected distance measuring means, and stops when an obstacle is detected in the obstacle detection range. The processing flow of the operation principle of the present invention is shown. In step S31, the robot 1 confirms that the surrounding environmental conditions, in this case, the brightness is equal to or higher than a predetermined value and is not backlit, and determines whether the distance measurement by the distance measuring means 21 is reliable. If it is determined that the distance measurement by the distance measurement means 21 is reliable, the process proceeds to step S32, the distance measurement means 21 is employed as the distance measurement means, the movement speed is set to V1 meter / second, and the process proceeds to step S33. . In step S33, it is determined whether there is an obstacle 3 in the obstacle detection range 31, and if there is no obstacle 3, the movement is continued as it is. If the obstacle 3 is detected, the process proceeds to step S34 to enter a stop operation.

  If it is determined in step S31 that the distance measurement by the distance measurement means 21 is not reliable, the process proceeds to step S35, the distance measurement means 22 is adopted as the distance measurement means, the movement speed is set to V2 meters / second, and the movement is performed. Proceed to step S36. In step S36, it is determined whether or not there is an obstacle 3 in the obstacle detection range 32. If there is no obstacle 3, the movement is continued as it is. If the obstacle 3 is detected, the process proceeds to step S34 to enter a stop operation.

  This makes it possible to select a moving speed according to the surrounding environmental conditions, move at an optimum speed, and safely stop even if an obstacle is detected when moving at a high speed.

  FIG. 4 shows the first embodiment provided with a vision obstacle sensor 23 having an obstacle detection range 33 of d3 meters and an ultrasonic obstacle sensor 24 having an obstacle detection range 34 of d4 meters as distance measuring means. Show.

  In the robot 1 according to the first embodiment, the initial speed when stopping at d3 meters from the start of the movement stop operation is V3 meters / second, and the initial speed when stopping at d4 meters is V4 meters / second. The case where the maximum speed Vr meter / second as the moving ability of V4 <Vr <V3 will be described in comparison with V3 and V4. Here, it is assumed that the distance required for the stop when the stop operation is started at the initial speed Vr meter / second is dr meter.

  The processing flow of Example 1 is shown in FIG. In step S51, the robot 1 confirms, for example, that the ambient brightness is equal to or greater than a predetermined value and is not backlit, and determines whether the distance measurement by the vision obstacle sensor 23 is reliable. If it is determined that the distance measurement by the vision obstacle sensor 23 is reliable, the process proceeds to step S52, the vision obstacle sensor 23 is adopted as the distance measuring means, the movement speed is set to Vr meter / second, and the movement is performed. Proceed to In step S53, it is determined whether there is an obstacle 3 within the distance dr meter. If there is no obstacle 3, the movement is continued as it is. If the obstacle 3 is detected, the process proceeds to step S54 and a stop operation is started.

  If it is determined in step S51 that the distance measurement by the vision obstacle sensor 23 is unreliable, the process proceeds to step S55, where the ultrasonic obstacle sensor 24 is employed as a distance measuring means, and the moving speed is set to V4 meters / second. Move to step S56. In step S56, it is determined whether or not there is an obstacle 3 in the obstacle detection range 34. If there is no obstacle 3, the movement is continued as it is. If the obstacle 3 is detected, the process proceeds to step S54 and a stop operation is started.

  Depending on the environmental conditions, it is also possible to use laser distance measuring means, infrared distance measuring means, or the like.

  In addition to the robot 1 shown in the first embodiment, the robot 11 shown in the second embodiment shown in FIG. 6 further includes a traveling direction control unit that controls the steering angles to -θ2, -θ1, 0, θ1, and θ2 (θ1 <θ2). Prepare. The trajectory of the right end of the robot 11 when the rudder angle is 0 is indicated by a broken line 41, the trajectory of the right end of the robot 11 when the rudder angle is -θ1 is indicated by a broken line 42, and the obstacle 3 is set with a rudder angle of -θ1. The avoidance result is indicated by the robot 11 ′. The vision obstacle sensor 25 detects the distance do with the obstacle 3 and the direction θo of the obstacle. Although not shown, the ultrasonic obstacle sensor 26 also detects the distance do with the obstacle 3 and the direction θo of the obstacle, like the vision obstacle sensor 25.

  Here, when the speed is Vr meters / second, the robot can safely change the traveling direction even if the steering angle is set to -θ1 or θ1, but the robot falls over if the steering angle is set to -θ2 or θ2. In addition, when the speed is V4 meters / second, the traveling direction can be changed safely even if the steering angle is set to -θ2 or θ2.

  It is assumed that the robot decelerates from a speed Vr meter / second Vr to a speed V4 meter / second within a distance (d3-d4) meters.

  7 and 8 show a processing flow of the second embodiment.

  In the processing flow 1 of the second embodiment illustrated in FIG. 7, in step S <b> 71, the robot 11 determines whether the distance measurement by the vision obstacle sensor 23 is reliable. If it is determined that the distance measurement by the vision obstacle sensor 23 is reliable, the process proceeds to step S72, the vision obstacle sensor 23 is adopted as the distance measuring means, the movement speed is set to Vr meters / second, and the movement is performed, step S73. Proceed to

  If it is determined in step S71 that the distance measurement by the vision obstacle sensor 23 is not reliable, the process proceeds to FIG.

  In step S73, it is determined whether or not there is an obstacle 3 within a distance d3 meters. If there is no obstacle 3, the movement is continued as it is. If obstacle 3 is detected, the process proceeds to step S74 and the azimuth angle θ0 of the obstacle 3 is detected. To get. In step S75, it is determined whether or not the trajectory when traveling straight on the basis of the azimuth angle θ0 of the obstacle 3 interferes with the obstacle 3, that is, collides. For example, as shown in FIG. 6, the collision determination is performed by considering the width of the robot 11 on the azimuth angle θ 0 side where the obstacle 3 is detected, in this case, the right end, and the trajectory of the right end of the robot 11 when traveling straight is the obstacle 3. What is necessary is just to determine whether it interferes.

  When it determines with not colliding at step S75, it returns to step S73, and when it determines with colliding, it progresses to step S76 and sets a steering angle to-(theta) 1. Here, the steering angle −θ1 is steered opposite to the detected azimuth angle θ0 so as to avoid the obstacle 3.

  In step S77, a trajectory when moving at the steering angle −θ1 is obtained, a collision determination between the trajectory and the obstacle 3 is performed. If it is determined that no collision occurs, the process proceeds to step S81, and if it is determined that a collision occurs, step S78 is performed. , The moving speed is reduced to V4 meters / second, and the steering angle is set to -θ2. In step S79, a trajectory when moving at the steering angle −θ2 is obtained, and a collision determination between the trajectory and the obstacle 3 is performed. If it is determined that there is no collision, the process proceeds to step S82, and if it is determined that there is a collision, step S80 is performed. Proceed to, and stop operation starts.

  In step S81, it is determined whether or not the obstacle 3 has been avoided. If the avoidance has not been completed, the movement is continued. If the avoidance has been completed, the process proceeds to step S83, where the steering angle is 0 and the movement speed is Vr meters / second. Set and return to step S71. The process in step S82 is similar to the process in step S81.

  If it is determined in step S71 that the distance measurement by the vision obstacle sensor 23 is not reliable, the process proceeds to B in the process flow 2 of the second embodiment in FIG. 8, and the ultrasonic obstacle sensor 24 is employed as a distance measurement unit in step S84. Then, the moving speed is set to V4 meters / second, and the process proceeds to step S85.

  In step S85, it is determined whether or not there is an obstacle 3 within a distance d4 meters. If there is no obstacle 3, the movement is continued as it is. If the obstacle 3 is detected, the process proceeds to step S86 and the azimuth angle θ0 of the obstacle 3 is detected. To get. In step S87, it is determined whether or not the trajectory when traveling straight on the basis of the azimuth angle θ0 of the obstacle 3 interferes with the obstacle 3, that is, collides.

  When it determines with not colliding at step S87, it returns to step S85, and when it determines with colliding, it progresses to step S88 and sets a steering angle to-(theta) 1.

  In step S89, a trajectory when moving at the steering angle −θ1 is obtained, and a collision determination between the trajectory and the obstacle 3 is performed. If it is determined that no collision occurs, the process proceeds to step S93. Then, the steering angle is set to -θ2. In step S91, a trajectory when moving at the steering angle −θ2 is obtained, a collision determination between the trajectory and the obstacle 3 is performed. If it is determined that no collision occurs, the process proceeds to step S94, and if a collision is determined, step S92 is determined. Proceed to, and start the stop operation.

  In step S93, it is determined whether or not the obstacle 3 has been avoided. If the avoidance is not completed, the movement is continued as it is. If the avoidance is completed, the process proceeds to step S95, the steering angle is set to 0, and the process returns to step S84. . The process in step S94 is similar to the process in step S93.

  As a result, it is possible to select the moving speed and moving direction according to the surrounding environmental conditions and to avoid or stop the obstacle safely even if the obstacle is detected when moving at high speed. Become.

  In the embodiment, the case where two distance measuring means are used has been described, but it is also possible to use three or more distance measuring means.

  In the embodiment, the case where there is one obstacle has been described. However, each distance measuring unit is further provided with a function of detecting a plurality of obstacles, and when a plurality of obstacles are detected, The distance and the azimuth are obtained and sent to the robot control means. The robot control means further moves the direction control means when all detected obstacles do not interfere with the trajectory when traveling at a predetermined steering angle, that is, when they do not collide. If the entire trajectory interferes with any obstacle, a stop instruction is sent to the moving speed control means so that it is possible to cope with a case where there are a plurality of obstacles.

  In the embodiment, the case where the obstacle is stationary has been described. Further, the movement trajectory of the obstacle is predicted from the change in the measurement result received from the distance measuring means, and whether the robot and the obstacle interfere with each other. By determining, it is possible to deal with a case where an obstacle is moving.

Overview of obstacle detection according to the present invention Example of environmental conditions around a robot to which the present invention is applied Processing flow of the principle of operation of the present invention Example 1 Processing flow of Example 1 Example 2 Processing flow 1 of Example 2 Processing flow 2 of Example 2 Conventional Example 1 Conventional example 2

Explanation of symbols

1, 11, 11 ′ Robot 3 Obstacle 21 Distance measuring means 1
22 Distance measuring means 2
23, 25 Vision obstacle sensor 24, 26 Ultrasonic obstacle sensor 31, 32, 33, 34, 35 Obstacle detection range 41, 42 Trajectory

Claims (6)

A method for measuring the distance to an obstacle and the surrounding environmental conditions and controlling the movement speed of the robot according to the measurement result,
Measure using a plurality of distance measuring means each having a predetermined measurement range and a set speed,
Evaluate the measurement results in order from the distance measurement means with the longest measurement range, and adopt the measurement distance of the distance measurement means that the surrounding environmental conditions satisfy the predetermined condition,
A robot moving speed control method, wherein the moving speed of the robot is controlled to a set speed associated with the adopted distance measuring means. A mobile robot comprising distance measuring means, robot control means, and movement speed control means,
A plurality of distance measuring means each having a predetermined measurement range and a set speed corresponding to each other, and measuring the distance to the obstacle and sending it to the robot control means,
The robot control means evaluates the received measurement results in order from the distance measurement means having the longest measurement range, adopts the measurement distance of the distance measurement means in which the surrounding environmental conditions satisfy a predetermined condition, and sets the corresponding set speed. Sent to the moving speed control means,
The moving speed control means controls the moving speed of the robot to the received set speed. The mobile robot according to claim 2,
The set speed associated with each distance measuring means is set to be equal to or less than the maximum speed at which the distance required for stopping the robot is within the distance measurement range of the distance measuring means when the moving speed control means is instructed to stop.
A mobile robot characterized by sending a stop instruction to the moving speed control means when the difference between the distance from the obstacle received by the robot control means and the distance required to stop the robot is equal to or less than a predetermined value. The mobile robot according to claim 3,
Furthermore, it has a traveling direction control means for controlling the traveling direction by changing the rudder angle,
Each distance measuring means further determines the azimuth of the obstacle and sends it to the robot control means,
The robot control means further obtains each trajectory when the robot travels while changing the rudder angle, performs interference determination between the trajectory and the obstacle at the position obtained from the received distance and azimuth, and does not interfere In this case, the traveling direction control means sends a traveling instruction at the steering angle, and when it interferes, the traveling speed control means sends a stop instruction, and the traveling direction control means controls the traveling direction according to the received traveling instruction. A mobile robot. The mobile robot according to claim 4,
Further, when each of the distance measuring means detects a plurality of obstacles, the distance to each obstacle and the azimuth are obtained and sent to the robot control means.
The robot control means further performs an interference determination between all detected obstacles and the trajectory when the robot travels at a predetermined rudder angle, and if there is no interference, sends a travel instruction at the rudder angle to the travel direction control means. A mobile robot characterized by sending a stop instruction to the moving speed control means when the entire trajectory of the robot interferes with any obstacle.   6. The mobile robot according to claim 5, wherein the robot control means further predicts the movement trajectory of the obstacle from the change in the measurement distance received from the distance measurement means, and determines the interference between all the detected obstacles and the robot. A mobile robot characterized by performing.

Images