JPH01177983A - Automatic acceleration and deceleration control method of movable body - Google Patents

Abstract

PURPOSE:To accelerate and decelerate a movable body without shocks and make the speed of the movable body into zero just when the body reaches an objective set position for stopping the movable body exactly at the position by travelling the movable body in correspondence with the acceleration and deceleration curves set beforehand. CONSTITUTION:In travelling a movable body (the jointed section of a crane, for example) from the present stopping position to an objective set position, the movable body is travelled in correspondence with the acceleration curve 21 set beforehand at the time of accelerating the movable body until it reaches a fixed speed 22 or a reducing area from the present stopping position, and then in correspondence with the speed reduction curve 23 set beforehand so that the speed may become zero (0) exactly at the objective setting position for the movable body. By using this method, the movable body can be stopped without shocks at the objective setting position.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an automatic acceleration/deceleration control method for a moving body such as a joint included in a crane, for example.

[Conventional technology]

Conventionally, in construction cranes, when the joint axis reaches near the target teaching point, the brake is applied suddenly or in stages, or the speed is reduced in one step to prevent the joint from moving. A method of applying the brakes has been adopted.

[Problem that the invention seeks to solve]

In the conventional construction crane, when the joint reaches near the target teaching point, the brake is applied suddenly or in stages, or the speed is reduced in one step, and finally the brake is applied. Therefore, it is not necessary to have a large impact on the suspended load and the crane body, and it is not sufficient to make a positive NK stop at the target teaching point (regeneration ability).

SUMMARY OF THE INVENTION An object of the present invention is to provide an automatic acceleration/deceleration control method for a moving body that can perform acceleration/deceleration with almost no impact and whose speed reaches exactly zero upon reaching a target point.

[Means for solving problems]

The present invention provides a movable body that is movable from a current stop position to a target teaching point, and when accelerating the movable body, the acceleration curve follows a preset acceleration curve until the movable body reaches a constant speed from the current stop position or enters a deceleration region. Accordingly, this is an automatic acceleration/deceleration control method for a moving body in which the moving body is moved according to a deceleration curve set in advance so that the velocity of the moving body becomes exactly zero at the target teaching point of the moving body.

[Effect]

According to the present invention, by performing acceleration/deceleration according to a preset acceleration/deceleration curve, acceleration/deceleration can be performed with almost no impact, and the speed becomes exactly zero when the target point is reached.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings.

Although this embodiment describes the case where linear acceleration/deceleration is performed, the present invention is not limited to this and any other method may be used.

FIG. 1 is a block diagram for explaining the outline of the joints of a mobile object, such as a crane, which is the object of the present invention. That is, the angle or length signal of the joint shaft 11 obtained from the potentiometer 12 connected to the joint shaft 11 is
By passing the analog signal through the A/D converter 13, which converts the analog signal into a digital signal, the analog value is converted into a digital value. ) The input is input to the arithmetic unit 14, which will be described later, and after arithmetic processing there, the digital value is converted to an analog value through the D/A converter 15, which converts the digital value to an analog value, and input to the Chibo device 16, where it is finally converted into an analog value. Move the axis.

FIG. 2 is a graph (velocity curve) showing the relationship between time and moving speed when the distance deviation between the current position of the joint axis 11 in FIG. ff1 and the target point is large.

In the figure, 21 indicates a linear acceleration section that accelerates at a constant acceleration, 22 indicates a constant speed section that moves at a constant speed, and 23 indicates a linear deceleration section that decelerates at a constant deceleration.

Figure 3 shows a speed curve when the distance deviation between the current position (start point) of the joint axis 11 in Figure 1 and the target point is small. The relationship is shown in terms of angles (travel distance). 31 indicates the movement angle (travel distance) of the linear acceleration portion corresponding to 21 in Fig. 2, which is a downward convex quadratic curve, and 32 is the second
The constant speed portion corresponding to 22 in the figure is a linear straight line), and the linear deceleration portion 33 corresponding to 23 in FIG. 2 is an upwardly convex quadratic curve.

Figure 4 shows the current position (starting point) of joint axis 1 in Figure 1.
This is a diagram showing the relationship between time and speed when the deviation from the point to the target point is small and the speed is decelerated before reaching a constant speed. ! This figure shows the change in speed when the amount of movement of the acceleration/deceleration portion shown in 2.23 is smaller than the amount of movement. 41 is the speed of the acceleration control section, and 42 is the speed of the deceleration control section.

FIG. 5 shows a mechanical model of the joint section, consisting of a position detector 91 mounted on the machine body, a hydraulic cylinder 92 and frames 93,94.

FIG. 6 is a control block diagram showing the internal part of the cheapo device fl16 and its relationship with the hydraulic cylinder that is the actuator, focusing on the mechanical part.

Control calculation device 105 for performing digital control calculation; Servo amplifier 104 for generating analog control calculation and final electrical output signal. It is comprised of a solenoid valve 103 that controls the amount of oil to the joint hydraulic cylinder 102, a position detector 101 corresponding to 91 and 92 in FIG. 5, and the hydraulic cylinder 102. In FIG. 6, dashed lines indicate hydraulic lines, broken lines indicate mechanical connections, and solid lines indicate electrical signal lines.

FIG. 7 is a flowchart of arithmetic operations performed in the arithmetic unit 14 (FIG. 2), for example, within a central processing unit (CPU).

The flowchart in Figure 7 shows 1 time per operation sampling time.
After the start, check whether FL (acceleration/deceleration start flag) is ON in step 51. If not, set PL=ON, and step 5
Perform initial settings from 3 to 56. In other words, d! (deviation)
= L2 (target point) - LL (start point),! (amount of movement)
=0°V(velocity)=o1MOL)E(mode)=0.

Ll and L2 are given as teaching data, and the acceleration a
, upper limit speed vmax and calculation sampling time dt
is stored in memory as an arithmetic constant in advance.

In this case, 1M0DB (mode) = 0 corresponds to the linear acceleration part 21 in Fig. 2, and step MODE (mode) =
1 also corresponds to the constant rate part of 22, Nl, pDB
(Mode)=2 also corresponds to the linear acceleration portion of 23. When MODE = 0 (57 → 60 → 6
For route 1), in step 6, add the value obtained by multiplying a (acceleration) by di (calculation sampling time) to V (current speed).

If the current speed had not exceeded Vmax (constant speed indicated by 22 in Figure 2)! Add the value obtained by multiplying (current position) by vKdt (route 61→62→65).

If V is equal to or exceeds v max in step 62, then in step 63 V is set to Vmax, MODE is set to 1, and constant speed movement starts from the next calculation cycle (62→63→6
4 route). In this case, the same goes for Stetsu f65! niV
Add the value obtained by multiplying by di and proceed to step 66, ! is d
Check if it is greater than i/2. If it is large, it means that the deviation (d) has advanced by half the amount during acceleration, and from this point onwards, the deceleration will begin, so MODE-J is selected.

This is the acceleration/deceleration pattern shown in FIG. 4 without a constant speed portion.

After this, step 72! Check whether the value exceeds di. If processing is performed with MOD E = 1! does not exceed di), and substitute z/di for R (movement rate). When MODE is 1, the route is 51 → 57 → 6o → 68 → 69 → 7 degrees and V is v ma
Move at a constant speed as x. Then, in step 71, when the remaining amount of movement to the target point becomes equal to or smaller than the pear that moves during deceleration, in step 72, MOL)E=J is set, and the movement is decelerated from the first calculation cycle (route 71→72) ). The determination formula in step 71 is obtained as follows.

It is assumed that acceleration (a) and deceleration are equal. In Figure 2, t (deceleration time) = vmax/a.

The amount of advance during deceleration is t, and the area of the triangle is vm.
ax * t 1/2. Therefore Ymax * t
1/2 = “/max”/(2*a), and the formula for determining 1 is di-! ≦V*V/(2*a). When MODE is 2, the route is 51 → 57 → 60 → 68 → 13 M
This is a deceleration operation that is the opposite of the operation when ODE is O. That is, in step 73, V multiplied by 9alCdt is subtracted and the current speed is determined.

Then, in step 24, the current speed V is changed to the lowest pitch speed a
When the current speed becomes equal to or lower than *at, the value obtained by multiplying the current speed by BVCVKdt is added in step 76 as the minimum pitch speed.

The determination formula in step 74 is provided to prevent the following two problems.

(1) The calculation sampling time is a value with a fixed width, and since there are calculation errors, it is not always the case that when V = Q, j; di is achieved, and the target point may not be reached.

(2) For the same reason as above, there may be cases where the velocity becomes V = Q before reaching the target point and the vehicle accelerates in the opposite direction.

In step 771C, if j becomes greater than or equal to d7, R = 1 in step 79, ENDFL (end flag) = ON in step 80, and the route 51→57→58→59 is executed in the next sampling period. The acceleration/deceleration control ends.

Here, the movement rate RK will be explained. In general, cranes and other loading equipment have multiple axes and often move multiple axes simultaneously. Therefore, acceleration/deceleration control up to the target point must be performed simultaneously on multiple axes.

This multi-axis simultaneous acceleration/deceleration control can be realized using the above-mentioned acceleration/deceleration control method by simply adding the following functions.

(a) Find the deviation from the current position of each axis to the target point.

(b) Divide the deviation by each VmaX to find the required time.

(C) Using the axis with the maximum required time as a reference axis, data of the reference axis is substituted into a and v max, and acceleration/deceleration control for the reference axis is started.

(d) - LJ (starting point) + dA (deviation) *R for each axis per cycle (1 sampling time)
is calculated and output in the form of a position command.

The t,b movement rate R is a calculated value that enables multi-axis acceleration/deceleration control by single-axis acceleration/deceleration control, and is a value that indicates the degree of reaching the target point. This means that all axes have reached their target points.

From the explanation of the embodiments described above, if the calculation time is reduced (for example, 0.1 seconds or less), almost stepless multi-axis acceleration/deceleration control is possible, and it is also possible to accurately stop at the target point. It becomes possible.

〔Effect of the invention〕

According to the present invention described above, it is possible to provide an automatic acceleration/deceleration control method for a moving body that can perform acceleration/deceleration with almost no impact and whose speed reaches exactly zero when it reaches a target point.

[Brief explanation of the drawing]

Figure 1 is a diagram for explaining the outline of the joints of a moving object, such as a crane, which is the object of the present invention, and Figure 2 is a speed curve when the current position of the joint in Figure 1 has a large distance deviation from the target point. Figure 3 is a diagram showing the movement angle (traveling distance) curve based on Figure 2, Figure 4 is a diagram showing the case where the distance deviation from the current position of the joint in Figure 1 to the target point is small. Figure 5 is a block diagram showing an example of a mechanical model, Figure 6 is a block diagram from a mechanical system perspective,
FIG. 7 is a flowchart of calculations performed within the calculation device of FIG. 11... Joint axis targeted for bacteriostatic control, 12... Joint axis 1
13...N0 converter, 14... Arithmetic device, 15... D/A converter, 16... Servo device, 2... Speed of acceleration control part . 22...Speed of constant speed control part, 23...Speed of deceleration control part, 31...Movement-pupil of acceleration control part, 3
2... Movement amount of constant speed control part, 33... Movement amount of deceleration control part, 41... Speed of acceleration control part, 42
...Speed of the deceleration control part. Applicant's Representative Patent Attorney Takeshi Suzue Industry 1, District 2, Figure 4, Time, Figure 3, Field, 5th Ward, 6th Ward

Claims (1)

[Claims] In a movable body that is movable from a current stop position to a target teaching point, when the movable body is accelerated, the movable body is moved according to a preset acceleration curve until it reaches a constant speed from the current stop position or enters a deceleration region. An automatic acceleration/deceleration control method for a moving body, which moves the moving body according to a preset deceleration curve so that the velocity of the moving body becomes exactly zero at a target teaching point.