JPH0335986A - Operation of articulated robot - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method of operating each arm in an articulated robot.

(Conventional wave #I) and a base arm pivoted by mutually parallel axes.

It consists of a distal arm pivotally supported at the distal end of the base arm and a working tool provided at the distal end of the distal arm, and a rotary actuator is connected to each axis, and by controlling this, the working tool can be positioned within an arbitrary plane. Articulated robots that have made this possible are known.

This is because the tip arm of this robot has a range of turning angles that are symmetrical with respect to the base arm.

For a particular work tool position, two types of arm postures will occur as shown in FIG.

In the past, there were cases in which the rotation angle of the base arm and tip arm of an articulated robot was taught using rectangular coordinates by selecting one of two types of arm postures without comparing which one to take.・ (Problem M to be solved by the invention) Since there is a difference in travel time depending on which of the two arm postures is selected, in order to improve the productivity of an articulated robot, the one with the shorter travel time should be selected. However, such consideration has not been taken into account in the past.

(Means for Solving the Problems) The present invention aims to move a working tool of a robot to a specified position in as short a time as possible, and has a plurality of arms that are pivotally supported by mutually parallel shafts and connected to each other, and the tip of the tip arm. In an articulated robot consisting of a work tool installed on the tip arm and a rotary actuator connected to each axis, when the work tool installed on the tip arm moves to a specified position, each of the multiple arm postures that occur The present invention is characterized in that the time required for arm rotation is compared and calculated, and the arm posture that minimizes the working tool movement time is selected.

(Example) An example of the present invention will be described based on the drawings shown below. In FIG. 2, the column 1 is provided with a first servo motor 2 and a reduction gear 4i3 connected to the servo motor 2. A base portion 4a of a base arm 4 is coupled to an output shaft 3a of a reducer 3, and at a tip end 4b of the base arm 4, a second servo motor 5 and a reducer 6 connected thereto convert the output shaft 6a into the output. It is provided parallel to the axis 3a. A base 7a of a tip arm 7 is connected to the output shaft 6a, and a sliding shaft 8 that moves by an axis parallel to the output shaft 6a and a tip of the sliding shaft are connected to the tip 7b of the tip arm 7. A working tool 9 is provided.

By the way, if the speed ratios of reducer 3 and reducer 6 are respectively V and V, then base arm 4 and tip arm 7 are
The turning angular velocity of the robot is from point PL to P.
The turning angles of the base arm 4 and the tip arm 7 when moving to 2 are θ8. Assuming θ2, the time required for turning is T
The normal robot is F T P (Point to Po
1 nt) control is performed, so the movement of the faster rotation axis is delayed according to the operation time of the slower rotation axis, so the robot operation time is (T
□, T2), whichever is longer.

On the other hand, as shown in Fig. 1, two types of postures, first and second, occur at a certain point P2.When the power tool moves from Pl to P2, the turning time in the case of the first posture is (T,, T□), the turning time in the second attitude (
rt' = T3'), then the attitude that provides the longest turning time that does not include time T is selected.

This will be further explained in detail with reference to FIG.

■ In the case of the horizontal multi-joint manipulator shown in Figure 1, given the position of the tip, the positions that the manipulator can take are the solid line part (P, [θ1.θ, ]) and the broken line part (P , [θ1.θ, ]).

If the attitude of the solid line part is given in advance, the attitude of the broken line part can be determined as θ,=-θ, (1). (2) ■ The amount the robot moves from point t (θ,, θyo) to point a (θ1.θ,) is S l-43 = θ, -〇, (3) S 2 o4 = θ, - 02(4) S: Can be expressed by the amount of movement.

Here, this horizontal multi-joint manipulator is 1 as shown in the figure below.
Assuming that the object moves along a trapezoidal speed curve, the relationship between the amount of movement and the end time of movement is expressed by the following equation (see FIG. 4).

5=(2-τend-Tacc-Tdsc)
ax/2 (5) From the above formula, the movement end time is.

ft (S, VmaxtTacc+Tdec)
(6) ■ Here, if each joint of the manipulator starts and arrives at the same time, what is the end time of the movement?

Tend=Max(ft (SlTVmax1. Ta
cc,, Tend,).

ft (S,, V+*ax2.Tacc,, Tde
c, )) (7).

(2) Calculate the end time of movement from point PL (θ0.θ) to point a (θ1.θ4) using equation (7).

Tend,=Max(ft(S,→3.V+++a
x, TaccL, Tdec,).

ft (S, , , Vmax, , Taccl, T
dec, ) ) ■ Similarly, calculate the end time of movement to p, (θ6.θ, ) obtained using equations (1) and (2).

Tend,=Max(ft(S,,, Vmax,,
Taccl, Tdec,).

ft (S, ,, Vmax2.Tacc2
．． Tacc2) ) ■ Compare the two movement end times and adopt the one with the shorter movement end time.

Furthermore, if a direct drive motor is used in the drive unit of the present invention, there is no play in the drive system, and there is no error between the right and left positions of the arm at the same coordinate position (as shown in the figure), so more effects can be obtained. .

Further, in this embodiment, a robot having two joints has been described, but the present invention can also be applied to a robot having two or more joints.

(Effects) According to the present invention, an articulated robot includes a plurality of arms that are pivotally supported by mutually parallel axes and are connected to each other, and a working tool provided at the tip of the tip arm, and a rotary actuator is connected to each of the axes. When the work tool installed on the tip arm moves to a specified position, the time required for each arm rotation among the multiple sliding arm positions is compared and calculated, and the arm position that minimizes the work tool movement time is calculated. , the work tool of the articulated robot can be moved to the specified position in the shortest time using the orthogonal coordinate system, and the productivity of the articulated robot can be improved.

[Brief explanation of drawings]

Fig. 1 is an explanatory diagram of the principle of the present invention, Fig. 2 is a front sectional view of the 2rjI1-section robot used in the present invention, Fig. 3 is a detailed explanatory diagram of the method of the present invention, and Fig. 4 is the amount of movement of the horizontal multi-joint manipulator. It is a figure showing the relationship between and movement end time. 1...Strut 2.5...Servo motor 4...Base arm 7...Tip arm 9...Work tool P,...Movement start point P...Movement end point

Claims (1)

[Claims] An articulated robot that is supported by axes parallel to each other and is composed of a plurality of connected arms and a working tool provided at the tip of the tip arm, and has a rotary actuator connected to each of the axes. When a tool moves to a designated position, the time required for each arm rotation among a plurality of arm postures that occur is compared and calculated, and the arm posture that minimizes the working tool movement time is selected. How the robot works.