JPS6361307A - Optimum adjustable-speed device - Google Patents

Abstract

PURPOSE:To realize an optimum control by obtaining an adjustable-speed pattern based on the point sequence of a time and a speed as a spline interpolation curve and executing the adjustable-speed with this. CONSTITUTION:Several points on an optimum adjustable-speed curve to be realized by an optimum adjustable-speed device such as an NC device are inputted to a point sequence input means 1 and interpolation curves St and Sv are obtained from these point sequences and stored into a spline interpolation curve table 2. The point sequence comes to be a speed V at a time T. Next, when acceleration is to be realized which is the figure similar to the adjustable-speed curve and comes to be a speed Vi at a time Ti, the interpolation curve Sv of a prescribed time is obtained by an interpolation curve counting means 3 while the spline interpolation curve table 2 is referred to. Vi/V is multiplied to the curve Sv and the speed of a sampling time point is counted. By the speed, the moving quantity of the sampling period is counted and this is inputted to a servo system as an adjustable-speed command (position command).

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention provides means for interpolating a series of points along a smooth curved trajectory in response to a speed command given in steps in an automatic machine such as an NC device. The present invention relates to an optimum acceleration/deceleration device having the following characteristics.

[Conventional technology]

When a speed command is given to an automatic machine such as an NG machine tool or an industrial robot, the command is usually input to its controller as a step function.

That is, when a speed command is input as a step function as shown in FIG. 3, in order to avoid undesirable transient phenomena such as overshoot of the actual speed, conventionally,
Acceleration/deceleration has been achieved by changing the speed linearly as shown in FIG. 4, by changing the speed exponentially as shown in FIG. 5, or by a combination of these.

In this case, the parameters to be input are the slope of the straight line in the case of FIG. 4, and the time constant in the case of FIG.

However, in such linear acceleration/deceleration or exponential acceleration/deceleration, the slope and time constant of the straight line differ for each machine or load, so it is not possible to perform arbitrary acceleration/deceleration depending on each machine or load.

[Problem that the invention seeks to solve]

In this way, in the past, acceleration/deceleration has been uniquely realized by mathematical functions of the y=f(x) type, such as linear acceleration/deceleration or exponential acceleration/deceleration, but as R tangents become more complex, such Rather than a unique acceleration/deceleration, arbitrary speed and acceleration control that is optimal for the given a factor is required.

The present invention was made based on such a request, and an object of the present invention is to enable arbitrary speed and acceleration control based on an acceleration/deceleration pattern that is optimal for the mechanical system in use.

Means for Solving Problem C] To achieve this objective, the optimal acceleration/deceleration device of the present invention has the following features:
A means for inputting multiple point sequences of time and speed, a preset spline interpolation curve table that smoothly connects these point sequences, and acceleration/deceleration relative to the commanded speed by referring to the spline interpolation curve table. The present invention is characterized by comprising an interpolation curve calculation means for determining an interpolation curve of a signal.

[Effect]

In the target control system, the speed at a certain time is
As exemplified in Table 1, when input as a point sequence of [time, velocity], find a spline interpolation curve that smoothly connects these point sequences, that is, continuously connects both the -th order differential coefficient and the second order derivative coefficient. (See Figure 2).

Table 1 The input point sequence is Pa(To, Vo)+'P+(T
+, V+) ・・・”・・P, (T,,V,)・−・
Assuming that P, (T, ,,V,), the interpolation curve S of P7.1 to the interval is as follows.

ta(ql= ((Tll-1+T□+)/2 T1
1) q”+ (Tm++ Tn-+)/2・Q”Tm
v, (Ql = ((Va-++Sil-+)/2
Vsl Q"+(v, -+ V+++-+)/2・Q
”Vatll, ++1l11= ((T@+T□2)
/2− T□+l (q 1)”+(T□z T−
)/2・(q~1)”Tn,+us,+(q)=((
Va+V**z)/2-V=,+l (q-1)"+(
ν, t V-)/2・(q-1) +VM.

S ta(Q) TaatII(QI (+A+ 'A
cos tc q)+ts-+(Ql(%-'Acos
rtq) S v+a[ql ”' v, (Ql ('A
” 'A cos πq)+v,-+(Ql(%-'
Acosttq) (0≦q≦1.1≦m≦n-2) At this time, the time is at equal intervals, that is, T, -↑, -1=
If the input is T, , -T, then t, (Ql
becomes a straight line. Therefore, by substituting the above numerical value q into the interpolation curves St, S, the velocity at any point can be determined.

〔Example〕

The present invention will be specifically described below based on the embodiment shown in FIG. First, manually input several points on the optimum acceleration/deceleration curve to be achieved into the point sequence input means 1, and from these point sequences, the above-mentioned St,
Sv is determined and stored in the spline interpolation curve table 2. This point sequence has a velocity V at time T.

Next, if it is desired to realize an acceleration that is similar to this acceleration/deceleration curve and becomes V at time T1, it can be realized as follows.

In other words, the software samples Δ every time,
Since it is sufficient to calculate the speed from nΔt to (n+1)Δt, the interpolation curve calculation means 3 shown in FIG.
Sv when t=nΔtXT, /T is determined with reference to spline interpolation curve table 1 (Table 1). This s
Sw·V, /V, which is obtained by multiplying v by V, /V, is the speed of the sampling period sought. In this way, it is sufficient to calculate the speeds at all the sampler points, calculate the movement amount of the sampling period based on the speeds, and manually input it to the servo system as an acceleration/deceleration command, that is, a position command.

〔Effect of the invention〕

As explained above, in the present invention, the optimum acceleration/deceleration pattern for a mechanical system is determined as a spline interpolation curve based on a sequence of time and velocity points, and acceleration/deceleration is performed based on this. . As a result, the operator can manually set arbitrary speeds and acceleration/deceleration patterns to the a welding yarn, and therefore, it is possible to realize optimal control according to the individual machine and load situation.

[Brief explanation of drawings]

The first part is a block diagram showing an embodiment of the present invention, Figure 2 is a waveform diagram of a speed command interpolated according to the present invention, Figure 3 is a waveform diagram of a speed command that changes in steps, and Figure 4 is a waveform diagram of a speed command that changes in steps. FIG. 5 is a waveform diagram of a speed command when linear interpolation is performed, and FIG. 5 is a waveform diagram of a speed command when interpolation is performed using an exponential function.

Claims (1)

[Claims] 1. Input means for multiple point sequences of time and speed, a preset spline interpolation curve table that smoothly connects these point sequences, and a method for inputting the commanded speed by referring to the spline interpolation curve table. An optimal acceleration/deceleration device comprising: interpolation curve calculation means for determining an interpolation curve of acceleration/deceleration signals.