JPH02205495A - Articulated robot - Google Patents

Abstract

PURPOSE:To eliminate the artificial work of an obstruction information input, to simplify a sensing device and to simplify an evasion procedure, by setting a passing impossible zone whenever a robot movable part is brought into contact with an obstruction and re-deciding the route so as to avoid the zone. CONSTITUTION:A robot is rotated with joints 3, 4 as the axis by an actuator, the hand 5 of the arm 2 terminal holds and transfers the body to be transferred and the movable part surface is covered by a contact sensor. The start attitude and target attitude of the robot are given by the coordinates data with one point of the joint angle space inside, i.e., (n) pieces of the positions of actuators as the element, the actuator is changed with the straight line connecting the start and target attitudes as the route and stopped when the contact sensor is operated or reaches the target attitude. At the contact stoppage time the positional data of the actuator is read, the coordinates are stored as contact attitude, returned to start attitude by reversing, (n) dimensional space is recognized as a quasi-contact space with the coordinate of the contact attitude as the center and the actuator is varied by finding the curve connecting the start attitude and target attitude without passing through any quasi-contact space.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Field of Industrial Application The present invention relates to a path determination method for determining an obstacle avoidance path during the operation of an articulated robot.

(Example) Conventional technology When conventional articulated robots move their hands while avoiding obstacles, they either have to input accurate information about the obstacles from the outside, or after they have completely recognized them using a visual sensor, etc. ,
I was searching for a route to avoid obstacles. Such an articulated robot is shown, for example, in Japanese Patent Laid-Open No. 53-43369. For this reason, there are disadvantages in that complicated operations such as input operations and complicated sensing devices such as visual recognition devices are required.

c) Problems to be solved by the invention The present invention has been made in view of the above points.
This aims to eliminate the manual work of inputting obstacle information, prevent the sensing device from becoming more complex, and simplify the processing procedure for searching for an obstacle avoidance route.

2) Means for Solving the Problems The present invention includes a means for moving a robot arm along a predetermined path, a contact sensor provided on the movable part of the robot, and a means for solving the problem when detected by the contact sensor. It has a setting means for setting a vicinity of a point as an impassable area, and a route determining means for re-determining a route to travel from a start point to an end point while ignoring the impassable area.

E) Each time the vehicle comes into contact with an active obstacle, an impassable area is set and the route is redetermined to avoid the impassable area.
Route determination is made with a simple configuration.

f) Embodiment Figure 2 shows an example of the articulated robot of the present invention, (1)
(2) is an arm, which is rotated around joints (3) and (4) by respective actuators (not shown). (5)
indicates a hand at the tip of arm (2), which grasps and transports the object to be transported. These arms (1) (2), hands (
The surface of the movable part such as 5) is covered with a contact sensor. (
6) indicates a control unit that controls the actuators to drive the robot, and also receives signals from the contact sensor. Such a robot has a work space as shown in FIG.

FIG. 1 is a flowchart for explaining the operation of the articulated robot of the present invention, and shows a generalized version of the articulated robot shown in FIG. 2 with n degrees of freedom.

The n-dimensional space centered around the position of each actuator is called the robot's joint angle space, and the two-dimensional joint angle space is shown in FIG.

Assuming that the robot's starting posture and target posture are each given by coordinate data whose elements are one point in the joint angle space, that is, the positions of n actuators, and no information about obstacles is given, then Explain the operation.

Initially, the robot is in the starting posture, and if the target posture is given, first find a straight line connecting the starting posture and the target posture in the joint angle space, and set the trajectory of that straight line as the trajectory or path along which the actuator should change. (STEP a),
The actuators of the robot are actually allowed to change along the route, and the hand (5) is moved as shown in FIG. In this state, when a part of the robot comes into contact with an obstacle and the contact sensor operates or the robot reaches the target posture, the robot's operation is stopped (STEP b). If the target posture is reached, the valve is activated. The route that has been taken is definitely an obstacle avoidance route (STEP c, d).

If the vehicle stops due to contact with an obstacle, first
Read the position data of the @ actuator and store its coordinates in the joint angle space as the contact posture. If you have already memorized other coordinates, also memorize them (
STEPe), and then return the robot to the starting posture by reversing the path (STEP f). An n-dimensional space with a certain size around the memorized coordinates of the contact posture cannot be used as a path. Recognized as a single-touch space. If the number of contacts is multiple times and multiple contact postures are memorized, for each point,
A single contact space of the same size is determined (STEP g).

When defining a single contact space, the size of the space is maximum when the number of memorized contact postures is one, and as the number of contact postures increases, the size of the space becomes smaller, and when the number of contact postures is infinite. The size of the space is set to be 0 at some times, that is, the size of the single contact space is set to decrease monotonically as the number of contact postures increases. This creates a learning effect in which the user starts searching for an obstacle avoidance route, tries to largely avoid the obstacle at first, and each time the obstacle avoidance fails, the recognition of the obstacle information becomes more precise. can be obtained effectively.

After finding the single contact space for all the memorized contact postures, as shown in Fig. 6, the starting posture (S) and target posture (G) are created in the joint angle space without passing through any single contact space. Obtain a curve connecting the , and use that trajectory as a new route (STEP
h), change the actuator according to the newly obtained path and repeat from step b).

Note that in 5TEP h, if a curve connecting the starting attitude and the target attitude cannot be obtained, the size of the single contact space is reduced until a curve is obtained.

G) Effects of the Invention As described above, the articulated robot of the present invention sets an impassable area every time the robot movable part comes into contact with an obstacle, and re-determines the route to avoid the impassable area. As a result, route determination can be performed with a simple configuration in terms of hardware and software, and overall cost reduction can be expected.

[Brief explanation of the drawing]

FIG. 1 is a flowchart showing the operation of the articulated robot of the present invention;
Fig. 2 is a side view of the articulated robot of the present invention, Figs. 3 and 5 are explanatory diagrams of the state of the working space of the articulated robot, and Fig. 4
FIG. 6 is a state explanatory diagram of a joint angle space of an articulated robot. (1) (2)... Arm, (3) (4>... Joint,
(5)...hand, (6)...control unit.

Claims (1)

[Claims] 1) In an articulated robot that moves an arm from a predetermined starting point to an end point, there is a means for moving the robot arm according to a predetermined path, a contact sensor provided on the movable part of the robot, and a means for moving the robot arm along a predetermined path, and a When a point is detected, a setting means for setting the vicinity of the point as an impassable area, and a route determining means for re-determining a route to travel from the starting point to the ending point while avoiding the impassable area. Articulated robot.