JPH02189601A - Driving controller - Google Patents

Abstract

PURPOSE:To evade the generation of an accident such as collision with an obstacle by providing the controller with a means for controlling the speed of a driven body in a decelerating direction at the time of deciding the posibility of speed control even under the generation of an abnormal state. CONSTITUTION:The controller is provided with a means F for detecting the generation of an abnormal state, a means for deciding whether speed control can be possible or not even under the generation of the detected abnormal state and the means G for controlling the speed of the driven body A in the decelerating direction at the time of deciding the possibility of speed control. The possibility of speed control is decided by the deciding means, the speed control is executed without immediately stopping the control as usually to evade the generation of an accident such as collision with an obstacle.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a drive control device, and more particularly, to a device for controlling the speed of a driven body when an abnormality occurs in the control system of the driven body. be.

[Prior Art] In a conventional control system for a driven object, if an abnormality occurs while the driven object is moving at a speed greater than zero, the control system immediately sends a signal to the drive means (for example, a servo amplifier) of the driven object. The drive energy is cut off regardless of the type of abnormality.

A time chart of control of this conventional system is shown in FIG. That is, the driven body starts moving at time 0, and if an abnormality is detected at time t while moving at an arbitrary speed υ1 greater than zero, the energy supplied to the drive means is reduced to avoid the danger. It is something to block.

FIG. 6 shows an example of a control procedure flowchart of the conventional system. This is done in step 3 after starting the control.
The control is continued until the occurrence of an abnormality is detected in the loop from step S20 to step S21, and when the occurrence of an abnormality is detected, the driving energy to the driving means is cut off in step S22, and the operation of the driven body is stopped. be.

[Problem to be solved by the invention] However, in the above conventional example, the following (i) (ii)
There were problems like.

(i); System operation rate decreases. Regardless of the type or state of the abnormality that has occurred, control is interrupted by cutting off the drive energy to the driven object, so the operation of the driven object stops after the abnormality occurs. Therefore, the availability of this system decreases.

(ii): An unexpected failure occurs. That is, in FIG. 5, if an abnormality occurs at time t, even if the drive energy to the driven body is cut off at this point, the driven body will continue to follow the solid line curve C4 until its inertial energy is completely consumed. While drawing a gentle velocity trajectory as shown, the position X is reached at time t6.
Stop at 4.

By the way, originally, if no abnormality had occurred, the speed would be decelerated while tracing the speed trajectory shown by the broken line C5 in FIG.
If there is an obstacle at position X3 between the stop position x2 during speed control and the stop position X4 when no control occurs when the abnormality occurs, the abnormality will occur. If this occurs, it may collide with this and be damaged, resulting in a non-reproducible failure.

Therefore, the present invention focuses on the fact that not all abnormalities result in loss of speed control, and even if an abnormal state occurs, speed control is performed without immediately cutting off drive energy. The purpose is to propose a drive control device that performs deceleration control as much as possible.

[Means and operations for achieving the object] The structure of the drive control device of the present invention for achieving the above object includes a means for detecting the occurrence of an abnormal state, and a means for detecting the occurrence of an abnormal state, and a speed control device even under the occurrence of the detected abnormal state. means for determining whether control is possible;
The present invention is characterized by comprising means for controlling the speed of the driven body in a deceleration direction when it is determined that speed control is possible.

Therefore, as long as the determining means determines that speed control is possible, speed control is performed without immediately controlling the stop as in the conventional case.

[Examples] Examples of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 is a block diagram showing one embodiment of the present invention, and shows the principle of operation in the embodiment.

In the figure, A is a driven body, B is a drive means such as a motor that drives the driven body A, C is a supply means for supplying drive energy such as electric power to drive the drive means B, and D is a drive means B. This is a detection means for detecting the speed of the vehicle. Further, E is a detection means for detecting the position of the drive means B, and is, for example, an encoder provided on the shaft of the drive means B. F is a detection means for detecting these abnormalities, and G is connected to the abnormality detection means F by giving a command to the drive means B based on information from the speed detection means and position detection means E while monitoring the state of the abnormality detection means F. This is a control means that performs positioning control or speed control of the driven body A.

Next, a preferred embodiment of the present invention is shown in FIG.

In the figure, 1 is a motor as a driving means, 2 is a feed screw which is also rotationally driven by the motor 1, 3 is a head as a driven body that is screwed into the feed screw 2, and 4 is a speed detection and position of the motor l. An encoder attached to the shaft serves as a detection means, a temperature sensor 5 detects an overheating state of the motor 1 as an abnormality detection means, a disconnection sensor 6 detects a disconnection of the signal line of the encoder 4 as an abnormality detection means,
Reference numeral 7 denotes a power source as a means for supplying energy to the motor 1. 8 is a control device that controls the drive of the motor 1, and includes a central processing unit (CPU) and a main memory device (ROM, R
It is composed of a microcomputer, etc. equipped with a computer (AM), etc. Further, reference numeral 9 denotes an obstacle installed within the movable range of the head 3. Xo, X+, X2
, X4 is the position on the feed screw 2, and X is the position of the left end of the obstacle 9. Under normal conditions, the head 3 is controlled by the control device 8 to move within the maximum range of x0←x2. That is, within this range, a predetermined trajectory plan toward the target position is established and positioning control is performed. As an example of trajectory planning, for example, maximum velocity v1. , and uniformly accelerated motion φv from zero velocity.

8, this is the so-called "trapezoidal velocity control" in which the velocity is uniformly decelerated to zero during uniform velocity motion.

The control means of an embodiment of the present invention having the above configuration will be explained based on the time chart shown in FIG. 3 and the flow chart shown in FIG. 4.

First, in the system shown in FIG. 2, consider closed-loop control (control in which the motion accurately follows the command by giving the motion command while constantly comparing the motion command and the actual motion). Here, before starting the system, the control device 8 is set to determine the operation to be performed when an abnormality occurs in the system. For convenience, the right end x2 of the head 3 is used as a positional reference for its movement, and a reciprocating start command between the positions x0 and x2 of the screw 2 is sent to the control device 8 at time to to start the system.

Assume that a certain period of time has passed and the motor 1 becomes overheated at time t1. Then, the temperature sensor 5 transmits the abnormality to the control device 8. By the way, in this heated state, problems such as damage and deterioration will not occur in the system even if control is continued for a short period of time. Therefore, in this embodiment, the control device 8 does not cut off the power supply 9, but instead shifts the motor 1 to deceleration control. Here, control is performed according to the following operational judgment set before the system is started.

■Continue double deceleration control and stop the system when the speed reaches zero. Or, (2): Perform deceleration control, and when the specified speed (=V,) is reached, continue the "trapezoidal speed control" operation with the speed vO (<V+) as the maximum speed, and continue to monitor for abnormalities. Furthermore,■
In addition to what is listed in , ■, actions deemed necessary shall be made.

With such control, the velocity trajectory of the head 3 traces the curve CI shown in FIG. 3, so that it never comes into contact with the obstacle 9.

Further, if the signal line of the encoder 4 is disconnected at time t1 during the reciprocating movement described above, this detection is performed by the sensor 6. In this type of abnormality, closed loop control as described above is impossible, so speed control is performed by oven loop control (setting the operation command to an appropriate value regardless of the actual operation). That is, the motor 1 is forcibly decelerated by oven loop speed control, and after the speed command becomes zero, the power supply 7 is immediately shut off at time tc. In this way, the velocity trajectory of the head 3 draws a curve like the broken line C2 or C3 in FIG. The distance can be greatly reduced, and the possibility that the head 3 will come into contact with the obstacle 9 is greatly reduced.

Control procedures for these abnormalities will be explained according to the flowchart in FIG. First, in step S1, an operation judgment during closed loop control is input, and in step S2, control is performed to start activation. An abnormality is monitored in step S3, and the loop from step 82 to step S3 is repeated as long as there is no abnormality.

Upon detection of the occurrence of an abnormality, the process moves to step S4, where it is determined whether the closed loop control is still possible due to the abnormality. If possible, proceed to step S5. Here, deceleration control is performed using closed loop control. In the next step S6, it is determined whether or not to continue the control by determining the conditions in step S1, and if the control is to be continued, the process advances to step S2. Thus,
If the abnormality is a controllable abnormality, the maximum speed ■ in the range of Xo←x2. Performs trapezoidal speed control. In step 6,
If it is determined that the control is not to be continued, step S7
to immediately cut off the energy and terminate the control. If it is determined in step 6 that control is possible, according to this control,
A reciprocating movement is performed in the range x0→X2 with Vo as the maximum speed. Since the maximum speed is reduced, if the abnormal condition is a rise in temperature, it can be fully expected that the temperature will fall due to this speed reduction.

In step 6, it is determined whether or not to continue such control, for example, when the detected temperature has further increased.

A case will be described in which it is determined in step S4 that closed loop control is impossible due to the abnormality. In this case, the control shifts to oven loop control in step S8, and after this control is performed until the commanded speed becomes zero, the drive energy is promptly cut off in step S7 to end the control.

Although this embodiment has been described with reference to a simplified feeding mechanism, it goes without saying that the present invention can be applied to robots, machine tools, and other similar devices that control the movement of a driven body using an NC or the like.

As explained in the previous section, the deceleration control of the driven body is possible even with open-loop control, so it can be controlled even in a system that is not equipped with the speed detection means and position detection means E shown in Fig. 1. is possible. Therefore, driving means B in the same figure
For example, by using a stepping motor that has good followability for oven loop control, it is possible to achieve deceleration that is not significantly inferior when compared to a system equipped with speed detection means and position detection means E. Control is possible.

[Effects of the Invention] As is clear from the above description, the present invention, which is a control device for driving a driven body, includes a means for detecting the occurrence of an abnormal state, and a means for detecting the occurrence of an abnormal state. The present invention is characterized by comprising means for determining whether the speed of the driven body is controllable, and means for controlling the speed of the driven body in a direction of deceleration when it is determined that the speed of the driven body is controllable.

Therefore, as long as speed control is possible, the control is not immediately stopped as in the conventional case, and situations such as collision with an obstacle can be avoided.

According to the second aspect of the invention, "speed controllable" is defined as being capable of executing closed loop control to the target speed.

According to the third aspect of the invention, the means for controlling the speed in the deceleration direction includes a closed loop speed control means and a speed limit means,
When an abnormal state in which speed control is possible is detected, closed loop speed control is continued so as not to exceed the maximum speed specified by the speed limit means, so the operating rate is maintained, and the above speed control is maintained for low speed operation. The possibility of recovery from an abnormal state increases.

According to the fourth aspect of the invention, the means for controlling the speed in the deceleration direction further includes an interloop speed control means, and when an abnormal condition in which speed control is not possible is detected, the interloop speed control means reduces the speed to zero. Since the speed is reduced, even if the abnormal condition is serious, the worst-case scenario such as a collision can be avoided.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the configuration of the principle of an embodiment of the present invention. FIG. 2 is a block diagram showing the configuration of an embodiment of the present invention. FIG. 3 is an operation of a driven body in the embodiment of the present invention. FIG. 4 is a flow chart showing an example of the control means; FIG. 5 is a time chart showing the operation of the conventional system; and FIG. 6 is a flow chart showing the control procedure. In the figure, A: Driven body, B: Drive means, C: Drive energy supply means, D: Speed detection means, E: Position detection means, F: Abnormality detection means. , G... Control means, 1... Motor, 2... Screw shaft, 3... Head, 4... Encoder, 5... Temperature sensor, 6...
... Disconnection sensor, 7... Power supply, 8... Control device, 9
...It's an obstacle.

Claims (4)

[Claims] (1) In a control device for driving a driven object, means for detecting the occurrence of an abnormal condition, means for determining whether speed control is possible even under the occurrence of the detected abnormal condition, and speed control. A drive control device comprising means for controlling the speed of a driven body in a direction of deceleration when it is determined that it is possible. (2) The first aspect of claim 1, characterized in that "speed controllable" is defined as being capable of executing closed-loop control to the target speed.
The drive control device described in . (3) The means for controlling in the deceleration direction includes a closed-loop speed control means and a speed limit means, and when an abnormal condition in which speed control is possible is detected, the means for controlling in the deceleration direction is configured to prevent the speed from exceeding the maximum speed specified by the speed limit means. 3. The drive control device according to claim 2, wherein the drive control device continues closed-loop speed control. (4) The means for controlling in the deceleration direction further includes an open-loop speed control means, and when an abnormal condition in which the speed cannot be controlled is detected, the open-loop speed control means decelerates the speed to zero. A drive control device according to claim 3.