KR100221490B1 - Method for controlling velocity of robot - Google Patents

Abstract

The present invention relates to a robot acceleration / deceleration control method. In general, the performance of the robot, such as the reliability and durability of the high-precision robot, depends on how smoothly the motor in the robot accelerates and decelerates. According to the present invention, the starting torque is designed to drive the motor by the S-curve to reduce the force on the motor, Therefore, the effect of the present invention is that the torque of the motor is distributed in a continuous curve so that the robot movement is smooth, and the noise and vibration problems occurring during operation are significantly reduced.

Description

How to control acceleration / deceleration of robot

1 is a schematic system configuration diagram of the present invention.

2 is a relationship between the speed command and the torque of the present invention.

3 is a relationship diagram for continuously obtaining the torque of the present invention.

4a and b are detailed views of the speed command of the present invention;

5 is a flow chart of operation according to the present invention.

6 is a relationship diagram according to the prior art.

* Explanation of symbols for main parts of the drawings

10: main control 11: timer

20: position control unit 30: servo driver

40: motor

The present invention relates to a method for controlling the acceleration / deceleration of a robot. More specifically, the acceleration / deceleration control of a robot, which improves the function and reliability of the robot by improving a continuous curve of the speed command during acceleration and deceleration of the driving motor. It is a way.

In general, the performance of a robot, such as the reliability and durability of a high-precision robot, depends on how smoothly it accelerates and decelerates the motor associated with the robot. However, the conventional technology is to implement a smooth acceleration and deceleration, such as the "S" curve, but in practice it was not applied to the problem in the calculation time, and the linear acceleration, deceleration method as shown in FIG. It was. In this case, if the speed command is generated as shown in (a), the robot needs to have a step-shaped torque like the moment the motor first moves (b). There is a lot to come up. In addition, an overshoot phenomenon occurs at the constant velocity entry (a) and the deceleration stop (b) after acceleration, resulting in a long position reproducing time.

Accordingly, the present invention is conceived in view of the above-described problems, and the robot is designed to reduce the positional reproduction time by designing the starting torque of the motor to be a continuous curved torque. The purpose is to provide a deceleration control method.

Hereinafter, with reference to the accompanying drawings will be described in detail the technical method and effect for achieving the object of the present invention.

The main control unit 10 and the position control unit 20 having a 32-bit high-performance micro-processor are connected. The main control unit 10 is connected with a timer 11, and the main control unit 10 has a predetermined time unit. When the main controller 10 receives a signal, it sends a speed command to the position controller 20. In addition, a plurality of servo drivers 30 are connected to the position controller 20 to drive the motor 40.

Referring to the operation and effect of the present invention configured as described above in detail.

Table S [max] for the rate of change of acceleration and deceleration is made in the manner as shown in FIG. S [max] consists of 2 times or more of the section to be decelerated, because the reason is to maintain the first designed torque type even if the deceleration section changes.

S [max] can be obtained from the following equation.

In addition, the acceleration ratio according to the actual acceleration section can be obtained by the following equation.

act _ acc: actual acceleration section

acc [i] (i = 1 ~ act _ acc): acceleration rate

mod (x, y): remainder of x divided by y

init: Initial selection position of acceleration / deceleration change rate table S [max]

add: Next selected position of acceleration / deceleration change rate table S [max]

If the speed command that can be sent to the position controller of FIG. 1 during the acc [i] obtained as a result of Expression 2 and ΔT in FIGS. 4A and 4B is V_CMD [m],

A speed command in the form of FIGS. 4A and 4B can be obtained by the following third equation.

m: Timer generating part up to the target position

V _ CMD: Maximum speed command to send to position controller when timer 11 of FIG. 1 occurs

Sum _ Vi: Sum of products of V-CMD and acc [k] selected in the acceleration / deceleration change table

Vi obtained as a result of the fifth equation corresponds to Vi in FIGS. 4a and b.

Equations 3 and 5 require a lot of calculations to find a speed command, so we restructured as follows.

That is, the third equation is divided into acceleration, constant velocity, and deceleration as follows.

i) if i is less than act _ acc (for acceleration)

(V _i-1 = 0 if i-1 <0)

ii) if i is greater than m (deceleration)

iii) act _ acc ≤ i ≤ m (for constant velocity)

Vi is obtained by substituting the results of the above formulas 6, 7, 8 and 5 into formula 5.

(See Figure 4a)

If m is less than i (if no constant velocity occurs), Sum _ Vi which passes through equations 6 and 7 is found and substituted into equation 5 to obtain Vi. (See also drawing 4b)

Referring to the operation flow of the present invention based on the above equation as follows.

As shown in FIG. 5, if each command is designated and loop variable (i) is smaller than deceleration period (act _ acc), that is, acceleration is detected, equation (6) is used. Loop variable (i) If is greater than the acceleration / deceleration section, it is again detected whether the loop variable (i) is greater than the number of speed command sections (m), that is, whether it is deceleration, and if it is deceleration, the seventh equation is used and the loop variable (i If is smaller than the speed command interval (m) is performed by the fifth equation and transmitted to the position controller 20. At this time, the loop variable (i) detects whether the speed command section + is smaller than the deceleration section (m + act _ acc), that is, if the speed is not constant, the robot operation of the step is terminated. It adds 1 to the variable and returns to the initial state so that the next step can be performed repeatedly.

As described above, the present invention designes a starting torque of a curved shape to reduce the load on the motor, and since the torque of the motor is distributed in a continuous curve, the robot operates smoothly, excluding the problems caused by noise and vibration, It is an invention to reduce the position reproduction time by reducing the overshoot during the entry and deceleration stop.

Claims (3)

When the main control unit 10 having a micro-processor and a position control unit 20 and the timer 11 connected to the main control unit 10 sends a signal in units of a predetermined time, the main control unit 10 receives a signal. While the speed command is sent to the position controller 20 every time, the position controller 20 drives the motor 40 through a plurality of servo drivers 30, so that the loop variable i is If it is smaller than the deceleration section (act _ acc), the variable (Sum _ Vi) will be driven using the formula (Sum _ Vi) + speed command (CMD _ V [i]) × acceleration / deceleration data [i]. The robot acceleration / deceleration control method characterized by the above-mentioned. A variable sum (Sum _ Vi) is a variable (Sum _ Vi) -speed command (CMD _ V [i]) × acc [when the loop variable i is larger than the speed command interval number m. m-i], the acceleration and deceleration control method of the robot, characterized in that the drive to drive. 2. The variable Sum_Vi is set to V _i-1 when the loop variable i is less than or equal to the speed command interval m and is greater than or equal to the deceleration period act_acc. The robot's acceleration and deceleration control method characterized in that the driving is performed by substituting the equation.