JPH09204217A - Device, method for servo control, and device and method for robot control using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To generate an acceleration/deceleration curve, whose shape is specified by the critical performance of a controlled system, and to unify the algorithm of that generation. SOLUTION: At a servo controller 1, a peak velocity attaining time (Tp ) value deciding means 4 receives a command value issued by a commanding means 2 and decides the time Tp required for the velocity to reach the peak velocity from this value through the acceleration/deceleration curve. Then, an α value deciding means 5 decides the value of a parameter (α) for time base elongation/contraction as the function of non-dimensional quantity defined by dividing the value of Tp with its reference value and sends it to an acceleration/deceleration pattern generating means 3. The shape of acceleration/deceleration curve is specified by a critical characteristic line common for the respective driving axles of the controlled system, the peak velocity attaining time related to the reference function of this acceleration/ deceleration curve, and is defined as the reference value of parameter (α) for time base elongation/contraction, and the acceleration/deceleration curve is generated and sent to the controlled system by performing the elongating/controlling operation of time base direction to the reference function based on the α value and performing a magnifying operation to the reference function value based on the command value from the commanding means 2.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a servo control which never exceeds the characteristic limit of a controlled object and generates an acceleration / deceleration pattern according to a unified algorithm for each drive axis which constitutes the controlled object. The present invention relates to an apparatus, a servo control method, a robot control apparatus, and a robot control method.

[0002]

2. Description of the Related Art Generally, control is performed such that acceleration control is performed for a speed or angular velocity to be controlled and then deceleration control is performed, or deceleration control is performed after constant speed control for a predetermined period after acceleration control. When performing, it is necessary to control the shape of the acceleration / deceleration curve (or the acceleration / deceleration command curve).

A frequently used acceleration / deceleration curve is, for example, a triangular acceleration / deceleration curve.

In FIG. 53, the horizontal axis represents time t, and the vertical axis represents velocity Ω = θ ⁽¹⁾ (the subscript “(n)” (n is a natural number) at the upper right of the position function θ is This means an n-th derivative with respect to time t, and this abbreviation will be used hereafter.), Which shows an example of the shape of a triangular acceleration / deceleration curve, and t = T
_The acceleration / deceleration curve a at which the speed reaches the peak value at the time of _P is 0
In the range of ≤t≤T _P , the linear acceleration part b is inclined to the upper right, and in the range of T _P <t≤2 · T _P , the linear deceleration part c is inclined to the lower right.

When the operation according to such a triangular acceleration / deceleration curve is expressed on the diagram together with the acceleration-speed characteristic or the torque-angular speed characteristic of the controlled object, the operating point is on the side of the quadrangle. A trajectory that moves along is drawn.

For example, when the control target is specified as a system including the motor and its drive circuit (hereinafter referred to as "motor system"), θ may be considered as the phase angle of the motor.
As shown in, the horizontal axis represents the torque T and the vertical axis represents the rotation speed N.
On the TN diagram (in the figure, only the first quadrant is shown).
At the time of acceleration, the operating point P moves in the direction indicated by the arrow on the side of the quadrangle d where T = T _a and N = N _a (the inclination of the acceleration part b of the acceleration / deceleration curve a is constant and constant). And the inclination of the deceleration part c is negative and constant.)

In this TN diagram, the lines corresponding to the three sides of the pentagon, which is one size larger than the quadrangle d, excluding the T axis and the N axis, indicate the limit TN line e of the motor system to be controlled. However, if the operating point P exceeds the limit T-N line e and sticks out of the outside, the performance and quality of the motor system can no longer be guaranteed.

[0008]

By the way, the above-mentioned triangular acceleration / deceleration curve a is easy and convenient for controlling the acceleration constant, but it is difficult to fully utilize the performance of the controlled object. There is a problem.

That is, in the TN diagram shown in FIG. 54, the portions f, f sandwiched between the limit TN line e and the quadrangle d.
(Indicated by diagonal lines in the figure) cannot be effectively used for control, so it is difficult to speed up the control operation, and
Since a large current value is consumed to realize high speed, a large motor with high output is required, which causes an increase in cost.

Then, at t = T _P , the acceleration is obviously discontinuous, so that a shock may be applied to the controlled object and the performance and the like may be adversely affected.

Therefore, by adopting an acceleration / deceleration curve having another shape, for example, an S-shaped accelerating portion or decelerating portion or one characterized by the shape of a sine function, the continuity of acceleration can be obtained. Guarantee or shaded parts f, f above
However, it was difficult to systematize and unify the algorithms for the generation of these acceleration / deceleration curves. It was necessary to separately prepare each drive shaft.

It is an object of the present invention to generate an acceleration / deceleration curve whose shape is defined by the limit performance of a controlled object and to unify the generation algorithm.

[0013]

In order to solve the above-mentioned problems, the present invention has the constitutions shown in (1) to (3) below.

(1) After specifying (by an experiment or the like) a limit characteristic line relating to characteristics of acceleration (or force or torque) with respect to speed (or speed, angular velocity or rotation speed) of each drive shaft to be controlled. One limit characteristic line that does not deviate from each limit characteristic line is determined by inscribed approximation to these limit characteristic lines, and acceleration (or force or torque) and velocity (or speed, angular velocity) are determined on this limit characteristic line. Alternatively, the shape of the acceleration / deceleration curve, the reference function thereof, and the peak speed arrival time related to the reference function are specified under the condition that the operating point defined by the rotational speed is included. That is, the acceleration / deceleration pattern generating means for holding the reference function and its peak speed arrival time is provided, and the operation according to the acceleration / deceleration curve generated by this is never deviated from the limit characteristic line common to each drive shaft to be controlled. The outer frame of control is specified in.

(2) The relationship between the designated value of the servo control variable and the peak speed arrival time is defined, and the value of the peak speed arrival time corresponding to the command value is obtained, and the peak speed arrival time according to the reference function is calculated. Determine the value of the time-axis scaling parameter defined as a function of the dimensionless quantity defined by dividing by. Therefore, command means for issuing a specified value of the servo control variable, peak speed arrival time value determining means for obtaining the peak speed arrival time corresponding to the command value, and time axis for determining the value of the time axis expansion / contraction parameter An expansion / contraction parameter value determining means is provided.

(3) The acceleration / deceleration curve is obtained by performing the expansion / contraction operation in the time axis direction on the reference function based on the time axis expansion / contraction parameter value and the scaling operation on the reference function value based on the command value of the servo control variable. Is generated and sent as a control signal to the controlled object. That is,
The acceleration / deceleration pattern generation means prepared in (1) generates an acceleration / deceleration curve by performing a scaling operation on the function value or a time axis expansion / contraction operation on the reference function.

Therefore, according to the present invention, the shape of the acceleration / deceleration curve corresponding to the common limit characteristic line for each drive axis to be controlled, that is, the reference function is defined, and the scaling operation of the function value with this as the upper limit is performed. Since the acceleration / deceleration curve is generated by the time axis expansion / contraction operation, it is possible to generate an acceleration / deceleration curve in which the motion of each drive shaft does not exceed the respective limit performance according to a unified algorithm.

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The servo control device and servo control method of the present invention will be described below.

Before describing the apparatus and method according to the present invention, the basic configuration and functions thereof will be described.

In the control according to the present invention, it is necessary to understand the following two basic matters.

A) The shape of the acceleration / deceleration curve is determined depending on the limit performance of the controlled object. In other words, the controlled object is always constrained to be used within the range of its limit performance, and therefore the shape of the acceleration / deceleration curve cannot be freely selected. Also,
If the shape of the acceleration / deceleration curve depends on the ability and experience of the designer, thinking and error are forced each time, and the design becomes inefficient.

Therefore, it is necessary to clarify how the shape of the acceleration / deceleration curve is defined based on the limit performance of the controlled object.

B) The acceleration / deceleration curve is generated by performing some kind of scaling operation on the reference function of the shape.

Even if the shape of the acceleration / deceleration curve is defined by the above a), it is troublesome that the generation algorithm is different for each acceleration / deceleration curve. This is because, in the case of a robot that is composed of a large number of arms and its drive system, the algorithm for generating the acceleration / deceleration curve when controlling each arm requires as many arms as the extreme example. Therefore, it is necessary for the control device of the arm drive system to be provided with a means for generating an acceleration / deceleration curve for each algorithm, which is complicated and uneconomical.

Therefore, whatever the shape of the acceleration / deceleration curve obtained in a) is, only the reference function of the shape of the acceleration / deceleration curve is prepared and scaled in order to unify the generated algorithms. (Variation and expansion / contraction of time axis)
It is necessary to handle the acceleration / deceleration curve freely by performing an operation.

In the following, description will be given while always keeping the above two matters in mind.

First, the controlled object in the present invention is required to have its limit performance characterized by acceleration (or force, torque, etc.)-Speed (or speed, angular velocity, rotational speed, etc.) characteristics. That is, as long as there is no limit constraint on the performance of the controlled object, the performance of the controlled object will not be exceeded regardless of the shape of the acceleration / deceleration curve used.
Since it is not possible to specify a criterion for determining the value of the shape of the acceleration / deceleration curve, it is excluded from the control targets according to the present invention. Therefore, as long as this condition is met, the controlled object according to the present invention may have any configuration,
A system including various actuators and driving circuits thereof is included in the controlled object.

Next, the acceleration (or force, torque, etc.)-Speed (or speed, angular velocity, rotation speed, etc.) characteristic that defines the limit performance of the controlled object is the position or angle with time, such as acceleration or torque. Taking the second derivative or the amount containing it on one axis,
When the first-order derivative of a position or angle with time, such as velocity or angular velocity, or a quantity including this is expressed on the other axis with respect to the relationship between them, the limit performance of the controlled object is specified on the diagram. A curve (characterized by a limit line. That is, the performance and quality of the controlled object in the curve and in the curve and the internal region surrounded by the two axes (in many cases, the area is represented by energy and power). However, the performance and quality of the controlled object cannot be guaranteed when the user goes into the external area.

For example, if the control target is specified to the motor system, the characteristics as shown in FIG. 1 can be exemplified.

FIG. 1 shows a torque-speed (rotational speed) characteristic of an AC (alternating current) motor system (only the first quadrant is shown). The horizontal axis represents the torque T and the vertical axis represents the speed N. This shows several examples of the limit TN line and the rated TN line.

In the example shown in FIG. 1A, the rated TN line g
1 is composed of a line segment of N = Nm, a line segment of T = T1 (rated torque), and a line segment descending to the right connecting both line segments, and a limit TN line g2 is a line of N = Nm. It is composed of a minute and a line segment that continuously slopes downward to the right and intersects the T axis at T = T2 (instantaneous maximum torque).

In the example shown in FIG. 1B, the rating T-
The N line h1 has the same shape as the rated T-N line g1, but the limit T-N line h2 is a line segment of N = Nm, and a line segment that slopes to the lower right and intersects the T axis at T = T2. , And a line segment that connects the two line segments to the lower right.

In the example shown in FIG. 1 (c), the rating T
The −N line i1 has the same shape as the rated TN line g1, and the limit TN line i2 is a line segment of N = Nm, a line segment of T = T2, and a right-downward line connecting both line segments. It is composed of line segments and.

The limit T-N line and the rated T-N line composed of a plurality of line segments as described above are expressions for convenience to make the characteristics of the motor system easy to understand, and the actual limit T The −N line and the rated TN line are generally curved lines having a complicated shape.

Since the motor system has been taken up as a control target, the effective values of mechanical power (power) and electric power (power consumption) of the motor will be described.

FIG. 2 simply shows an approximate equivalent circuit of the servomotor, which is a variable voltage source Vc indicating a control voltage.
With respect to cm, resistance (resistance value is “ _RM ”) and electromotive force (motor torque constant is “K _t ”, and motor angular velocity is “Ω”, then −K _t · Ω. ) Is connected in series with the voltage source shown in FIG.

For simplification of description, a triangular acceleration / deceleration curve as shown in FIG. 53 (the peak speed arrival time is "T _P ", the speed peak value is "Ω _p ", The area enclosed between the deceleration curve and the time axis, that is, the total movement (rotation) amount of the motor is “Δθ”. However, the result obtained here will be generalized later. Be careful.

Table 1 below shows symbols and meanings of various physical quantities used in a tabular form.

[0039]

[Table 1]

First, when the motor is operating, the motor resistance R _M
It is consumed when the power to be thermally and _"I P", which is as the following equation by.

[0041]

[Equation 1]

[0042] Thus, the effective value in the period 2 · T _{P "I}
P _RMS ", this becomes as shown in the following equation.

[0043]

[Equation 2]

Note that " _I P _RMS " is determined only by the current I _M , that is, the acceleration, and is not related to the total movement amount Δθ of the motor.

Next, the mechanical power supplied from the power supply to the mechanical part through the motor during the operation of the motor is set to " _K P
(T) ”and the effective value in the period 2 · T _P is“ _K P _RMS ”, this becomes the following formula.

[0046]

(Equation 3)

In the case of a triangular acceleration / deceleration curve, _K P
(T) is proportional to the time t as shown in the following equation [Equation 4],
Substituting the equation 4 into the equation 3 above to obtain the effective value _K P _RMS , the total movement amount Δθ of the motor can be obtained as shown in the following equation 5.
It is a function of the peak velocity Ω _p in proportion to the square of.

[0048]

(Equation 4)

[0049]

(Equation 5)

FIG. 3 shows the peak velocity Ω _p and the peak velocity arrival time T _P when the triangular acceleration / deceleration curve is continuously used.
FIG. 4 is a t-Ω diagram showing the state of one cycle when the value is changed. FIG. 4 shows the locus of the operating point corresponding to each acceleration / deceleration curve and the effective value of the mechanical power and the effective value of the electrical power. It is shown.

In FIG. 3, the acceleration / deceleration curve j _i (i = 1 to 4) has the respective peak velocity arrival times T _Pi (i = 1).
To 4) and the peak speed is Ω _pi (i = 1 to 4).

The horizontal axis of FIG. 4 is K _t · I _M, and
The vertical axis forming the quadrant is the speed Ω, and the vertical axis forming the fourth quadrant is R _M · I _M / K _t , and the acceleration / deceleration curve j
The effective value of the mechanical power corresponding to _i (i = 1 to 4) is “ _K P _RMSi ” (i = 1 to 4).

As shown in the figure, the effective value _I P _RMS of the electric power consumed by the resistor R _M is constant regardless of the acceleration / deceleration curve, and is equal to the area of the shaded portion. In addition, the effective value of mechanical power _K P _RMSi (i = 1 to 4)
Corresponds to the area of each quadrangle, as can be seen from the fact that the operating point moves on the side of the quadrangle as shown by the arrow, and differs for each operation.

Since the ability of the controlled object depends on its temperature, the algorithm for generating the acceleration / deceleration curve is _I P _RMS
It is preferable to include the value in the evaluation value for control.

When the controlled object is operated continuously,
The values of _I P _RMS and _K P _RMS are determined as described above, but it can be shown that the relationship between the total movement amount Δθ and the peak speed arrival time T _P is defined from the condition that these are always constant. it can.

That is, when _I P _RMS is controlled to be constant,
The following expression [expression 6] is obtained from expression [expression 2], and T _P is 2 of Δθ.
A relationship that is proportional to the 1st power is derived.

[0057]

(Equation 6)

That is, when Δθ is taken on the horizontal axis and T _P is taken on the vertical axis as shown in FIG. 5, if the relationship between the two is defined as shown by the parabola pr connecting points A and B, The temperature of the controlled object can be kept constant even when the continuous operation of the controlled object is performed at any Δθ. The point A in FIG. 5 is the minimum value T _{PMI of} T _P determined by the limit of the frequency characteristics of the controlled object.
A point corresponding to _N, and a point B indicates a point corresponding to the maximum value of the peak velocity Ω _p .

In the case of controlling _K P _RMS constant, the relational expression that T _P is proportional to the third power of Δθ is derived, and in the case of controlling _I P _RMS + _K P _RMS constant, Is Δθ of 2
Since the fourth-order equation of T _P including the power is derived, the Δθ-T _P characteristic can be defined based on these, as in the case of FIG.

Next, regarding b), the scaling operation for the reference function and the expression of the acceleration / deceleration pattern obtained by the scaling operation will be described.

The "acceleration / deceleration pattern" referred to here is
The state quantity (that is, the velocity and the angular velocity) directly described by the acceleration / deceleration curve is, of course, a broad concept including the time derivative of the state amount, the integral amount, and the like.

The acceleration / deceleration curve relating to the controlled object needs to be generated according to a unified algorithm regardless of its shape.

Therefore, by imposing as few constraints as possible on the shape of the acceleration / deceleration curve, a unified expression of the acceleration / deceleration curve including the conventional acceleration / deceleration curve having a triangular shape or a sine wave shape is given. .

This new acceleration / deceleration pattern is characterized by the introduction of a reference function for determining the shape of the acceleration / deceleration curve and the scaling operation for the reference function.
Hereinafter, this will be referred to as a “scalable pattern”.

The standard function of the scalable pattern is called a "normalization function", which will be referred to as "θ _N (τ / T)". However, “τ” represents a time axis parameter, T represents a time constant of the control system, and is a constant necessary for making dimensionless to τ / T.

The position function related to the scalable pattern is ".THETA. (T)" (where t is real time), and the time axis expansion / contraction parameter is defined by the relationship "t = .alpha..tau.". Introduce “α”.

The amount of movement related to Θ (t) (that is, Θ ⁽¹⁾
Total amount of movement obtained by integrating (t) over the entire movement time. ) Is defined as “Δθ”, and the first-order time derivative of the normalization function θ _N θ _N ⁽¹⁾
Is referred to as "normalized speed", and the time until the peak value is reached, that is, the peak speed arrival time related to the normalized speed θ _N ⁽¹⁾ is defined as " _TPn ". Further, if the peak velocity arrival time for velocity, which is the first-order time derivative of the position function Θ (t), is “T _P ”, then T _P has a lower limit value (this is referred to as “T _PMIN ”) and an upper limit. Since there is a value (denoted as “T _PMAX ”), T _Pn can be chosen to be some value within the range T _PMIN ≦ T _P ≦ T _PMAX .

The definitions of the above various quantities are summarized in Table 2 below.

[0069]

[Table 2]

FIG. 6 is a graph showing the normalized speed θ _N ⁽¹⁾ , where the horizontal axis is “τ” and the vertical axis is “θ _N (τ /
T) ”, and“ T _all ”indicates the total travel time. The normalized speed θ _N ⁽¹⁾ is 0 ≦ τ ≦ T _Pnu (= T
_Pn ), the acceleration part and T _{P nu ≤τ≤T all} -T _Pnd
Constant speed portion during the period (hereinafter, referred to as "T _c "),
T _{al l} serves and a speed reduction unit in the period -T _Pnd ≦ τ ≦ T _all, the area of the area surrounded by these parts and tau shaft, i.e. constant integral value has the property that is equal to 1. In other words, “normalization” in the normalization function θ _N means θ _N
It means that the total movement amount related to is always adjusted to 1. Since the standardized speed θ _N ⁽¹⁾ does not always include the constant speed part (that is, the period T _c = 0), the standardized speed θ _N ^{(1) is set} to the acceleration part and the deceleration part in this case. It is possible to add the constant velocity part to the acceleration part and the constant velocity part after the scaling operation only when T _c ≠ 0.

The relational expression showing the property of the normalization function θ _N is shown below.

[0072]

(Equation 7)

[0073]

(Equation 8)

[0074]

[Equation 9]

[0075]

(Equation 10)

The expression [7] means the existence of the peak speed value of the standardized speed, and the expression [10] implicitly assumes that the deceleration portion does not include a vibration component. Generally, it is necessary to satisfy “θ _N (∞ / T) = 1” even when the component is included.

Next, for convenience of explanation, an assumption is made for the standardization function θ _N to the extent that generality is not impaired.

The first is that the acceleration time is considered in consideration of the fact that the limit characteristic line that determines the performance of the controlled object has symmetry between the portion belonging to the first quadrant and the portion belonging to the second quadrant on the characteristic diagram. T _Pnu is set equal to the deceleration time T _Pnd , and the second is to set T _Pn to the minimum value T _PMIN of T _P , and when these are expressed by a mathematical expression, the following expression is obtained. .

[0079]

[Equation 11]

[0080]

(Equation 12)

It should be noted that these assumptions are for convenience only, and the assumptions are intended to give concreteness to the explanation by reducing the arbitrariness of the setting of T _Pn and the shape of the acceleration / deceleration curve as much as possible. Be careful not to pass too much.

Specific examples of the standardizing function θ _N include the following functions.

I) In the case of a triangular acceleration / deceleration curve.

[0084]

(Equation 13)

Ii) In the case of an acceleration / deceleration curve obtained when the position command is given to the third-order filter as a ramp signal.

In controlling the servo system to be controlled, a system corresponding to the actual servo system is simulated by software processing and prepared in the control device (such a servo system will be described below. By introducing a "virtual servo system") and using it as a calculation means, it can be used for generation of acceleration / deceleration curves and calculation of various estimated quantities. For example, in the control circuit of the motor system,
A circuit part directly related to motor control and a part related to dynamic compensation for stabilizing control are provided in the servo system, but a virtual motor system (hereinafter, referred to as a virtual motor system having a filter configuration corresponding to these is provided. "Virtual motor system") is prepared as an internal model by software processing in the control device, the output when a command is given to the virtual motor system is used as it is for the control signal to the actual servo system. be able to.

For example, the virtual servo system is configured as a third-order low-pass filter, and the output when the position command of the ramp signal as shown in FIG. 7 (this is referred to as “Δθ _REF ”) is input is used. By doing so, it becomes unnecessary to explicitly perform the calculation related to the normalization function. That is, in general, the response characteristic of the servo system is not always expressed by an analytical expression, and therefore it is useful from a practical point of view to introduce a virtual servo system that imitates the actual servo system.

In the case of the third-order filter, the function expression can be easily obtained, and the following expression is obtained.

[0089]

[Equation 14]

In the above equation, "T _i " (i = 1, 2, 3)
Is the time constant of the servo loop, " _Tf " is the break time of the ramp signal (see FIG. 7), and "exp ()" is an exponential function. Further, in deriving the above equation, the inverse Laplace transform may be performed on the output obtained from the product of the Laplace expression of the ramp signal and the loop transfer function of the filter, but the process is directly related to the gist of the present invention. Since it does not exist, the explanation is omitted.

Iii) In the case of an acceleration / deceleration curve having a shape including a sine function.

[0092]

(Equation 15)

Now, when the normalization function θ _N is defined as described above, the scalable pattern can be defined as the following equation based on this.

[0094]

(Equation 16)

First, the position function Θ (t) is obtained by multiplying the normalizing function θ _N by Δθ and multiplying the time axis τ and the time constant T by α, as shown in the following equation.

[0096]

[Equation 17]

The velocity function Θ ⁽¹⁾ (t) is obtained by multiplying Δθ by 1 / α and multiplying it by the normalized velocity θ _N ⁽¹⁾ as shown in the following equation.

[0098]

(Equation 18)

The acceleration function Θ ⁽²⁾ (t) is obtained by dividing Δθ by the square of α as shown in the following equation, and the acceleration function θ _N ⁽²⁾ (hereinafter referred to as “normalized acceleration”). .).

[0100]

[Equation 19]

From these equations, it becomes clear that the function related to the scalable pattern can be obtained by independently performing the expansion / contraction operation in the time axis direction for the normalization function etc. and the scaling operation for the function value itself.

FIG. 8 is a diagram for explaining the scaling operation with respect to the standardized speed with τ on the horizontal axis and the speed Ω on the vertical axis. FIG. 8A shows the normalized speed with Δθ = 2. The operation of doubling the value of θ _N ⁽¹⁾ is shown in FIG.
FIG. 8B shows an operation in which α = 2 and the normalized speed θ _N ⁽¹⁾ is doubled in the time axis direction. FIG. 8C shows the operation in FIG. 8A and the operation in FIG. 8B. It shows an operation that is a combination of operations.

As described above, if the standardized speed (or standardized function) is given in advance, it is independent in the vertical axis direction (variation direction of the function value) or in the horizontal axis (time axis) direction. By adopting the rule of performing expansion / contraction operation (scaling), the normalized function θ _N or the normalized speed θ _N ⁽¹⁾
The acceleration / deceleration pattern can be freely controlled regardless of the shape of the. In other words, all the acceleration / deceleration patterns generated by such a method are included in the scalable pattern.

It should be noted that a specific example of the scalable pattern can be easily obtained by substituting the expressions of the standardization functions shown in [Equation 13] to [Equation 15] into [Equation 16] to [Equation 18]. Since the generation algorithm does not depend on the specific shape of the acceleration / deceleration curve with respect to the concept of the scalable pattern, the description thereof will be omitted.

As described above, it becomes clear that the position, velocity, and acceleration related to the scalable pattern can be derived based on the normalization function. More generally, the physical quantities relating to the motion of the controlled object are _N ), the amount of change (total amount of movement Δθ), and the time axis expansion / contraction parameter (α).

For example, in the case of the effective current value related to the controlled object, in the control such that the effective value _I P _RMS of electric power is kept constant when the controlled object is specified to the motor system (see FIG. 5). ), It is possible to discuss the magnitude of _I P _RMS by the effective current value of the motor, and the effective current value is often more convenient when referring to the specifications of the motor.

Therefore, the effective current value of the motor is set to " _IRMS ".
Then, this can be defined by the following formula [Formula 20], and by using the formula [Formula 19] and the relation of “t = α · τ”, the following formula [Formula 21] can be obtained.

[0108]

(Equation 20)

[0109]

(Equation 21)

In the equation [21], the effective current value of the motor when the motion control is performed according to the scalable pattern is
It shows that it can be calculated from the effective value of the normalized acceleration (θ _RMS ⁽²⁾ ), Δθ and α.

In the above description, when calculating the value of the standardization function, the amount of calculation is not considered and the value to be calculated is obtained immediately. However, when the shape of the standardization function is complicated. Since it is expected that the calculation of the function value will take time, in such a case, it is practical to prepare a data table relating to the standardization function in advance and to make a database of the function value.

From the above description, it is clear that the item b), that is, the introduction of the scalable pattern can realize the unification of the acceleration / deceleration pattern generation algorithms, but Since the description of the relationship between the limit performance and the shape of the acceleration / deceleration curve remains, this point will be described in detail below.

The limit performance of the controlled object is defined by the limit characteristic line in the acceleration-speed characteristic diagram or the like as described above, and it is easily understood that this serves as a design guideline for the acceleration / deceleration pattern. This is because the motion of the controlled object corresponds to the operating point or the locus of the operating point on the characteristic diagram in a one-to-one manner, and the acceleration / deceleration is such that the operating point deviates from the guaranteed operating range bounded by the limit characteristic line. This is because the generation of the pattern is not permitted or dangerous in terms of control.

Therefore, in the following, first, the behavior of the operating point corresponding to the motion according to the scalable pattern on the characteristic diagram will be described.

FIG. 9A shows an operating point Q (θ _N on the normalized acceleration (θ _N ⁽²⁾ )-normalized velocity (θ _N ⁽¹⁾ ) diagram for the normalizing function of the scalable pattern. ⁽²⁾ , θ _N
⁽¹⁾ ) about the trajectory M, where the horizontal axis is the standardized acceleration and the vertical axis is the standardized speed. For comparison, temporal changes in the standardized speed and the standardized acceleration are shown in FIGS. 9B and 9C, and the subscript "" attached to the physical quantity in these figures is shown. "P" means the peak value of each amount.

In the locus M shown in FIG. 9A, the portion M1 shown in the first quadrant of the figure corresponds to the acceleration portion in the acceleration / deceleration curve, and the portion M2 shown in the second quadrant of the figure shows the acceleration / deceleration curve. It corresponds to the deceleration part, and the operating point Q is the locus M.
Move up in the direction indicated by the arrow.

Here, it should be noted that θ _N ⁽²⁾ is θ _N
^This means that it is a monovalent function for ⁽¹⁾ . For example, as shown in FIG. 10A, there are a plurality of acceleration values corresponding to one value of θ _N ⁽¹⁾ , or as shown in FIG. 10B, a locus including a loop is not drawn. That is.

When the acceleration / deceleration curve relating to the normalization function includes the constant velocity part, the operating point Q is (0, θ _NP) during this period.
⁽¹⁾ ).

If the behavior of the trajectory related to the normalization function is clarified, the behavior of the scalable pattern obtained by performing the scaling operation on it is also clarified. At that time, the scaling operation is performed on the characteristic diagram. Figure 1 shows how it affects the trajectory of the normalization function.
1 will be described.

In FIG. 11, the horizontal axis represents the acceleration (Θ ⁽²⁾ (t)) and the vertical axis represents the velocity (Θ ⁽¹⁾ (t)).
FIG. 10 shows the locus of (Θ ⁽²⁾ , Θ ⁽¹⁾ ) and also shows the locus M related to the normalization function shown in FIG. 9.
It should be noted that, for simplification of description, only loci belonging to the first quadrant are shown in the figure.

As described with reference to FIG. 9, in the scaling operation related to the scalable pattern, the scaling operation of the function value itself and the expansion / contraction operation in the time axis direction are independent of each other.

FIG. 11A is for explaining the scaling operation (scaling by Δθ) of the function value itself, and as can be seen from the formulas [18] and [19], Θ
^{Since (2)} and Θ ^{( 1)} are proportional to Δθ, when the time axis expansion / contraction parameter is fixed to α = 1, this operation shows the trajectory M related to the normalization function as it is for both axes. It is nothing but to obtain a trajectory Ma similar to the trajectory M by multiplying by Δθ.

FIG. 11B is for explaining the expansion / contraction operation (magnification by α) in the time axis direction. If Δθ = 1 in the formulas [18] and [19], As shown in the formula [Equation 22], the speed is 1 / α of the standardized speed, and the acceleration is the standardized acceleration α.
Since it is converted to a value obtained by dividing by a square of, the operation is performed with respect to the locus M related to the normalization function as shown in the figure, where α is 1 / square for the acceleration axis and α is for the velocity axis.
It is nothing but to obtain the locus Mb by reducing the number by one.

[0124]

(Equation 22)

In the figure, 0 ≦ α ≦ 1 is set for the sake of easy understanding, but this is T _Pn = T _PMAX in consideration of the arbitrariness of the selection of the peak velocity arrival time T _Pn related to the normalization function. Corresponds to the case you choose.

FIG. 11C shows the operation of FIG. 11A and FIG.
1 shows a locus Ma * b obtained from a locus M relating to a normalization function by combining with the operation 1 (b), and shows a general behavior of an operating point U relating to a scalable pattern. .

As described above, also with respect to the locus of the operating point U related to the scalable pattern, the locus M of the operating point P related to the standardizing function has an important role, and both are closely related through the scaling operation. It becomes clear.

Next, with respect to the standardizing function and the function relating to the scalable pattern, the physical meaning of the area surrounded by the loci of the operating points will be described.

As described with reference to FIG. 4, when the motor shaft is rotated at a constant speed while a constant torque load is applied to the motor, the effective value of the mechanical power is the torque-speed characteristic diagram. It is represented by the area of a quadrangle region surrounded by the locus drawn by the operating point and the acceleration axis and the velocity axis in the following, but in the following, the area within the locus drawn by the operating point will be examined when performing acceleration / deceleration motion .

In FIG. 12, the horizontal axis represents θ _N ⁽²⁾ and Θ ^(2), and the vertical axis represents θ ⁽¹⁾ and Θ ^(1). * b is shown together.

First, regarding the normalization function θ _N , FIG.
If the area in the locus M in the θ _N ⁽²⁾ −θ _N ⁽¹⁾ characteristic diagram of (indicated by the slanting line descending to the left in the figure) is “s”, the following formula is obtained.

[0132]

(Equation 23)

Therefore, the effective current value of the controlled object when operating according to the acceleration / deceleration curve related to the standardization function is “i _RMS ”.
Then, this can be obtained by the following equation.

[0134]

(Equation 24)

That is, it can be seen that the effective current value i _RMS is proportional to the square root of the area s in the locus M.

Further, the same calculation as described above can be performed for the locus associated with the scalable pattern.
The area within the locus Ma * b (shown by the slanting line in the lower right of the figure ^{) in} the Θ ^{(2) −} Θ ^{( 1)} characteristic diagram of is as “S”, and the effective current value related to the controlled object is as “ _IRMS ”. Then, S becomes like the following formula.

[0137]

(Equation 25)

[Equation 20], [Equation 21], [Equation 2]
4] and [Equation 25], the effective current values I _RMS and i _RMS
The following relationship is found between and.

[0139]

(Equation 26)

That is, if the effective current value i _RMS related to the normalization function, and therefore θ _RMS ⁽²⁾ is known, the effective current value I _RMS during actual operation can be known (that is, the squared value of I _RMS can be obtained). It can be known from the squared value of i _RMS .).

Based on the relationship between the function related to the scalable pattern and the normalization function as described above, various physical quantities related to the property of the acceleration / deceleration curve are set to the normalization function regardless of the shape of the acceleration / deceleration curve. It can be reduced to such an amount.

Based on the above results, a method of generating a scalable pattern in consideration of the limit characteristic of the controlled object will be described.

FIG. 13A shows the acceleration function Θ on the horizontal axis.
⁽²⁾ Taking (t) and taking the velocity function Θ ⁽¹⁾ (t) on the vertical axis, the locus Mt of the operating point U (Θ ⁽²⁾ , Θ ⁽¹⁾ ) relating to the motion of the controlled object is shown. In the figure, “Θ _P ⁽²⁾ ” indicates the peak value of acceleration, and “Θ _P ⁽¹⁾ ” indicates the peak value of velocity. These include information on T _P and Δθ. ing. Now, the question is how to determine the shape of the acceleration / deceleration curve when the controlled object is moved along the locus Mt. For the sake of simplification of description, it is assumed that the acceleration / deceleration curve does not include a constant velocity portion, and the locus Mt is in the first quadrant and the second quadrant of the Θ ⁽²⁾ -Θ ⁽¹⁾ diagram. The portion having the symmetry, that is, the portion of the trajectory Mt belonging to the first quadrant is represented by Θ
^{(1) When} it is folded back about the axis, it can be overlapped with the part of the trajectory Mt belonging to the second quadrant. Even if such an assumption is made, the generality of the following discussion will not be impaired.

Since the velocity function Θ ⁽¹⁾ (t) is a function of the acceleration function Θ ⁽²⁾ (t), the locus Mt in the figure can be expressed by the following equation.

[0145]

[Equation 27]

"Θ _F ⁽¹⁾ " in the above equation is a functional.

If the above equation is written in a more understandable form, the following equation is obtained.

[0148]

[Equation 28]

The above equation is obviously a differential equation, and by solving it, a solution like the following equation can be obtained.

[0150]

(Equation 29)

The integration constant (constant in C or Ω (t)) in the above equation is determined by considering initial conditions and boundary conditions (related to Δθ, T _P, etc.). For example, from the initial condition Ω (t = 0) = 0, C = 0, and finally, the solution shown in the following equation is obtained, and when this is conceptually illustrated in FIG.
(B).

[0152]

[Equation 30]

From the above discussion, it is clear that the locus Mt defines the shape of the acceleration / deceleration curve.
We will supplement that understanding by presenting some concrete examples.

FIG. 14 is a Θ ⁽²⁾ -Θ ⁽¹⁾ diagram showing an example of a characteristic line showing the limit performance of the controlled object (see the limit TN line i2 in FIG. 1C). , The limit characteristic line L is Θ ⁽¹⁾ =
Θ _MAX ⁽¹⁾ line segment Lb, Θ ⁽²⁾ = Θ _MAX ⁽²⁾ line segment La,
These line segments are connected at points A and B, and include a line segment Lab inclined downward to the right. That is, the point A is the line segment L
It is the connection point between a and the line segment Lab, and its coordinate value is (Θ _MAX
⁽²⁾ , Θ _ap ⁽¹⁾ ), and the time when the operating point passes through this point A is t = T _a . Further, the point B is a line segment Lab and a line segment Lb.
And the coordinate value is (Θ ⁽²⁾ _b , Θ ⁽¹⁾ _MAX ).
And the time when the operating point passes through this point B is t = T _b .

The line segment Lab has its slope (this is "-T _m "
And ) Or the intercept on the Θ ⁽¹⁾ axis (this is referred to as “Θ _c ⁽¹⁾ ”) is determined by giving the coordinate values of points A and B, so the limit characteristic line L is expressed by the following equation. be able to.

[0156]

(Equation 31)

The above equation corresponds to the equation [27], and the following equation is obtained from the integration operation of the first equation in the equation [31].

[0158]

(Equation 32)

Further, the solution of the differential equation utilizing the Laplace transform can be used for the second equation in the equation [31], and the following equation is obtained after the transformation.

[0160]

[Equation 33]

The Laplace expression of each quantity is specified by adding (s) to the function using the parameter s (which is irrelevant to the area s described above).

From the equation [32], Θ ⁽¹⁾ (s) can be obtained by the following equation.

[0163]

(Equation 34)

By applying the inverse Laplace transform to the above equation, Θ ⁽¹⁾ (t) is obtained as the following equation.

[0165]

(Equation 35)

This formula corresponds to the above [Formula 29], and by imposing the initial condition of the following formula [Formula 36], as a result, [Formula 37] is obtained as a solution corresponding to the formula [30].
You can get the formula.

[0167]

[Equation 36]

[0168]

(37)

Next, assuming that the time for the speed Θ ⁽¹⁾ to reach its maximum value Θ _MAX ⁽¹⁾ is “T _PMAX ”, in equation (37), t =
By substituting T _PMAX , the following formula [Formula 38] is obtained, and from this, T _PMAX is obtained as shown in the formula [Formula 39].

[0170]

(38)

[0171]

[Equation 39]

Summarizing the results so far, the speed function is expressed by the following equation.

[0173]

(Equation 40)

Therefore, to obtain the position function from this,
The following expression [expression 41] is obtained by integrating the first expression of the expression [40] (however, the integration constant is set to zero from the initial condition), and the second expression of the expression [40] is integrated. (However, the integration constant is set as “C”.) By the following expression [Formula 42] is obtained.

[0175]

[Equation 41]

[0176]

(Equation 42)

In the determination of the integration constant C, the following equation [Equation 4
3], the boundary condition at t = T _a may be used.

[0178]

[Equation 43]

By summarizing the above results, the formula [44] is obtained for the velocity and the formula [45] is obtained for the position, which is shown in FIG.

[0180]

[Equation 44]

[0181]

[Equation 45]

In this example, since it is assumed that the locus L has symmetry in the first quadrant and the second quadrant, the acceleration part and the deceleration part of the acceleration / deceleration curve have symmetrical shapes. Of course, if the assumption is not satisfied, the solution for the speed reducer can be obtained by the same procedure as described above. It is also easy to generalize the above discussion to the case where the acceleration / deceleration curve includes the constant velocity part (since the operating point of the constant velocity part is only at the Θ ⁽¹⁾ axis).

FIG. 16 is a Θ ⁽²⁾ -Θ ^{( 1)} diagram showing another example of the characteristic line showing the limit performance of the controlled object, and the limit characteristic line L'is a straight line inclined downward to the right. It consists of line segments only. That is, in the limit characteristic line L shown in FIG. 14, a point A (Θ _MAX ⁽²⁾ , 0) is set and a point B (0, Θ _MAX ⁽¹⁾ ) is set.
Is the limit characteristic line L '.

Therefore, the condition shown in the following equation [Equation 46] is
By substituting into the equations [44] and [45], the solutions shown in the equations [47] and [48] can be obtained without resolving the differential equations.

[0185]

[Equation 46]

[0186]

[Equation 47]

[0187]

[Equation 48]

FIG. 17 is a Θ ^{(2 )} -Θ ⁽¹⁾ diagram showing still another example of the characteristic line showing the limit performance of the controlled object, and the limit characteristic line L ″ is Θ ⁽²⁾ = θ. Line segment of _MAX ⁽²⁾ and Θ ⁽¹⁾
= Theta consists of a segment of _{MA X} ^(1), a trace corresponding to the triangular acceleration and deceleration curve, as described in FIG. 4, Equation 49]
It is expressed by an equation.

[0189]

[Equation 49]

Therefore, if this is solved, the solutions shown in [Equation 50] and [Equation 51] can be obtained, but the intermediate calculation is omitted because it is not important (the acceleration / deceleration curve and T- This will supplement the description of the correspondence with the loci on the N-diagram.)

[0191]

[Equation 50]

[0192]

(Equation 51)

From the above, it is understood that the shape of the acceleration / deceleration curve is defined by the characteristic line (that is, the locus) that defines the performance of the controlled object.

Therefore, with respect to the motion of the controlled object, since it is not permitted or dangerous to exceed the limit performance of the controlled object, the acceleration / deceleration curve is defined by the limit performance characteristic line of the controlled object, that is, If the standardization function related to the scalable pattern is specified from the limit performance characteristic line of the control target, it is possible to control so that the operating point or locus corresponding to the acceleration / deceleration pattern is always located within the range of the limit performance characteristic line. it can.

That is, for the controlled object, T _PMAX (maximum peak velocity arrival time) and Δθ _MAX (= Θ (T _PMAX )) always exist, and these are bounded as shown in the equation [39]. Since it is uniquely determined by the condition, the acceleration / deceleration pattern corresponding to the operation when the controlled object is drawn to the limit of its capability may be used as the reference of the scalable pattern.

Specifically, the position function related to such an acceleration / deceleration pattern is defined as "Θ _MAX (t)", and the normalization function θ _N related to the scalable pattern is defined as the following equation.

[0197]

[Equation 52]

Therefore, if T _P for Δθ (≦ Δθ _MAX ) is determined, the time axis expansion / contraction parameter α is determined as shown in the following equation [Equation 53], and a function related to the scalable pattern, for example, the position function Θ ( t) is determined as shown in the following expression [Equation 54].

[0199]

(Equation 53)

[0200]

(Equation 54)

Now, recall the arbitrariness of the selection of the peak velocity arrival time T _Pn related to the normalization function.

FIG. 18 shows a scalable pattern in which the limit performance of the controlled object is taken into consideration. The change of the acceleration / deceleration curve and the corresponding Θ ⁽²⁾ −Θ ⁽¹⁾
It is a conceptual illustration of a correspondence relationship between a change in the locus of the operating point on the diagram.

The acceleration / deceleration curve AL shown in the figure corresponds to the limit characteristic line L of the controlled object, and the acceleration / deceleration curve al has a certain Δθ (<
_Acceleration / deceleration curves for Δθ _MAX ) and T _P (<ΔT _PMAX ), that is, obtained by performing a scaling operation on the normalization function of [Equation 52],
The characteristic line corresponding to this is l. In the drawing, the correspondence between each part of the acceleration / deceleration curve and each part of the characteristic line is indicated by the symbols.

Therefore, it is concluded that the acceleration / deceleration curve generated as the scalable pattern does not deviate from the range defined by the limit characteristic line L of the controlled object for the corresponding operating point.

[0205] Incidentally, as can be seen from the number 44] where the acceleration and deceleration curve t = 0, T _a, or no longer be guaranteed continuity of acceleration in T _{PMA X,} or the control target limit characteristic line shape It is necessary to take some measures to deal with the case where is not as simple as the above example, and the following two methods will be described.

The first is the "low-pass filter method",
For example, as shown in FIG. 19, the acceleration / deceleration curve corresponding to the equation [44] is passed through a low-pass filter LPF having a predetermined cutoff frequency, and its output (in FIG.
_o ⁽¹⁾ (t) ”, and the peak velocity arrival time is“ T
_P ′ ”and the maximum speed is“ Θ _MAX ⁽¹⁾ ′ ”. ) Is given to the controlled object as a control signal. That is, since a point in the acceleration / deceleration curve having a problem of continuity of acceleration or a portion near the connection point corresponds to a portion including a high frequency component, the low-pass filter LPF facilitates the connection of the components of the acceleration / deceleration curve. can do. By this, Θ ⁽²⁾ corresponding to the output of the low pass filter LPF
The locus Lo on the −Θ ⁽¹⁾ diagram is located inside the limit characteristic line L as shown by the broken line in FIG. Note that the filter configuration can be generally an n-th (n is a natural number) low-pass filter, and its order and frequency characteristics (pole arrangement) can be determined so as to match the frequency characteristics of the control target. . For example, when the virtual servo system as described above is built in the control device, the servo parameters and time constants related to the virtual servo system are fixed according to the parameters and time constants related to the actual servo system. Thus, the virtual servo system can be used for the low-pass filter, and in this case, control can be performed so that T _P ′ ≧ T _PMIN .

Further, the second is the "inscribed method", which is shown in FIG.
As shown in FIG. 1, when the limit characteristic line L of the controlled object is a complicated curve, it is approximated by a polygon (a side of a polygon) LL inscribed in the curve, as shown by a chain double-dashed line. Is the way to do it. That is, if the function Θ _F ^{(1) of the} equation [27] is simple, the differential equation can be solved by the above procedure, but if the function is complicated, some approximation is required. . Therefore, the accuracy of the approximation can be improved by increasing the n value of the n-sided polygon inscribed in the limit characteristic line L as an approximate function of the target function.

If there is no corner in the limit characteristic line L, a smooth acceleration / deceleration curve can be obtained, the low-pass filter method is unnecessary, and the shape of the limit characteristic line L is simple. For example, even if it is a curve, it is sufficient if it can be expressed easily by an analytical expression. Since these methods are complementary, there is no practical problem due to the combination of these methods. An acceleration / deceleration curve can be obtained. That is, when the limit characteristic line L is complicated, the inscribed method is required to obtain the approximate expression, and the low-pass filter method is required to smoothly connect the approximate characteristic lines.

From the above discussion, however, the shape of the acceleration / deceleration curve is determined by the matters of the above a) and b), that is, the limit performance of the controlled object. It is clarified that it is generated by a unified algorithm that performs a scaling operation on the digitized function, and based on these, the basic configuration of the servo control device according to the present invention is understood.

FIG. 22 shows the basic structure of the servo control device. The servo control device 1 includes a command means 2, an acceleration / deceleration pattern generation means 3, a T _P (peak speed arrival time) value determination means 4, α ( The time axis expansion / contraction parameter) value determining means 5 and the low-pass filter 6 are included.

That is, the signal (position command or the like) issued by the command means 2 is used as the acceleration / deceleration pattern generation means 3 and the T _P value determination means 4.
Sent to

The T _P value determining means 4 defines the relationship between the position command Δθ and the T _P value, and T _P value corresponding to the Δ _P
The value is determined, and this value is sent to the α value determining means 5 in the subsequent stage.

[0213] For example, as shown in FIG. 23 (a), taking the [Delta] [theta] on the horizontal axis, taking the T _P on the vertical axis, points corresponding respectively to the lower limit and the upper limit of the T _P value MIN ([Delta] [theta] _MIN,
T _PMIN ) and the point MAX (Δθ _MAX , T _PMAX ) are determined as points unique to the controlled object.

Therefore, for example, considering a characteristic in which a point MIN and a point MIN are connected by a straight line as shown in the figure, 0 is obtained.
In the range of ≦ Δθ ≦ Δθ _MIN , T _P = T _PMIN , Δθ _MIN ≦ Δ
In the range of θ ≦ Δθ _MAX , the T _P value (where T _PMIN ≦ T _P ≦ T _PMAX ) according to the inclination of the straight line is obtained, and in the range of Δθ ≧ Δθ _MAX , T _P = T _PMAX is obtained.

The shape of the line connecting the point MIN and the point MAX depends on what is used as the evaluation function. For example, as shown in FIG. 5, when the effective value _I P _RMS of electric power is targeted for evaluation and control is performed to keep it constant, as shown in the formula [6], T _P is proportional to the square root of Δθ. At that time, the acceleration / deceleration curve has been described as having a triangular shape, but if the effective value _I P _RMS is associated with the effective current value, the effective current value becomes constant.
When the effective current value I _RMS is made constant in the formula [26] and the effective current value i _RMS is determined by the normalization function, a general result that α = T _P / T _Pn is proportional to the square root of Δθ Leads to.

If FIG. 23 (a) is generalized to the case where the acceleration / deceleration curve includes a constant velocity portion, it becomes as shown in FIG. 23 (b). That is, FIG. 23B shows Δθ on the horizontal axis and T _all (= 2 · T _P + T _c ) on the vertical axis, and the characteristics are as shown by the solid line, and 0 ≦ Δθ ≦ In the range of Δθ _MIN , T _all = 2 · T _PMIN , and in the range of Δθ _MIN ≦ Δθ ≦ Δθ _MAX , the T _all value (however, 2 · T
_{In the range of PMIN} ≦ T _all ≦ 2 · T _PMAX ), Δθ ≧ Δθ _MAX , the T _P value according to the straight line having the slope of 1 / Θ _MAX ⁽¹⁾ is determined. Note that for the slope value 1 / Θ _MAX ⁽¹⁾ , the amount of movement of the constant velocity part of the acceleration / deceleration curve is Θ _MAX ⁽¹⁾ · T _c .

In FIG. 23 (b), when the dynamic range of the controlled object is large, the point MIN and the point MAX approach each other as shown by the one-dot chain line in FIG. Is 2 as shown by the chain double-dashed line
Two points coincide (that is, T _P is constant until this point is reached, but beyond this, the T _P value becomes the maximum speed Θ _MAX ^(
It depends on ¹⁾ . ) It will be.

In this way, the T _P value determining means 4 sets Δ
When the T _P value corresponding to θ is determined, the α value determining means 5 determines the value of the time axis expansion / contraction parameter α based on this. However, as can be seen from “α = T _P / T _Pn ”, the division is performed only once. In addition, [Equation 52],
As shown in the formula [53], the standardizing function determined by the limit characteristic line is set to "T _Pn = T _PMAX ", but the selection of T _Pn is generally arbitrary.

Acceleration / deceleration pattern generation means 3 is command means 2
The acceleration / deceleration pattern is generated based on the command signal from the .alpha. As described with reference to FIG. 8, the operation here is nothing but a scaling operation with Δθ or α with respect to the normalization function. That is, the acceleration / deceleration pattern generation means 3 has a standardization function corresponding to the limit performance of the controlled object (see [Equation 52], [Equation 54], etc.).
The scaling operation can generate a scalable pattern, and the motion according to the pattern never deviates from the limit performance of the controlled object.

When the low-pass filter method is used, the output of the acceleration / deceleration pattern generating means 3 is sent to the servo system 7 to be controlled after passing through the low-pass filter 6, but depending on the case, it is 1 in FIG. As shown by the dotted line,
It is sent to the servo system 7 as it is. The “servo system” here means a wide system including a servo circuit and the like in addition to a drive source and / or a drive mechanism to be controlled. Further, in FIG. 22, the portion excluding the servo system 7 is a portion that can be realized by software processing in the control device.

The basic procedure of the servo control method is summarized in FIG.

First, in step S1, the limit performance of the controlled object is specified. For example, in the case of a motor, the limit T-N line as shown in FIG. 1 is specified from the specifications provided by the manufacturer, but in some cases, an experiment or theoretical calculation for determining the limit performance of the controlled object. Can be specified from.

In the next step S2, the shape of the acceleration / deceleration curve is determined based on the limit characteristic line of the controlled object. That is,
As shown in [Equation 27] to [Equation 30], this is nothing but solving the differential equation corresponding to the limit characteristic line. As a result, the normalization function related to the scalable pattern is determined from the limit performance characteristic line of the controlled object.

Then, in step S3, the Δθ-T _P characteristic is defined. As a result, T corresponding to the command value Δθ
The values of _P and α can be determined (see FIG. 23).

In the next step S4, a scalingable pattern is generated by performing a scaling operation on Δθ and α for the standardization function. That is, step S
In the acceleration / deceleration pattern obtained by the scaling operation (see FIG. 8) for the standardization function determined in 2, the locus of the operating point that moves on the characteristic diagram accordingly is limited by the limit performance characteristic line of the control target. It will always be located within the range without departing from it. It should be noted that, although it is a stumbling block, with respect to the scaling law for α, the time dimension such as T _P is the α multiplication rule, the velocity dimension is the α times multiplication rule, and the acceleration and current dimensions are the square of α. Obey the 1x rule of.

Then, in step S5, the control signal related to the acceleration / deceleration pattern is sent to the controlled object as it is or through the low-pass filter 6.

In the actual control operation of the servo control device 1, steps S1 and S2 and part of step S3 are already determined at the design stage.
It should be noted that the motion control of the controlled object is performed by repeating steps S3 to S5 according to the command from the command means 2.

Further, in generating the scalable pattern in step S4, it is necessary to prepare various amounts including the standardizing function as a database in advance. For example, taking the acceleration / deceleration patterns shown in [Equation 44] and [Equation 45] as examples, the standardization function has a shape as shown in the upper part of FIG. 15, and T _aMAX , T _PMAX or T
_PMAX - _TaMAX , θ _NP ⁽¹⁾ (peak value of normalized speed) is required. Further, the calculation of the current effective value I _RMS is, theta _NRMS
⁽²⁾ (This is T _{PMIN in} the fourth equation of [Equation 21].
_Replaced by _PMAX . ), The moment of inertia J, the torque coefficient K _t, etc., are required. The expression of the normalized function (Equation 45] where reference.) Various amounts of contained (theta _c and T _m, etc.) is required of course. The acceleration / deceleration pattern generation means 3 in the servo control device 1 holds data relating to these amounts.

A reference shape for the limit characteristic line is prepared in advance, and a scaling factor in the horizontal axis direction (this is referred to as “T_rate”) and a scaling factor in the vertical axis direction (this) are prepared with respect to the reference shape. Is referred to as "S_rate".), It is convenient because the shape of the limit characteristic line can be freely expanded or contracted by specifying these scaling factors. In the example shown in FIG. 14, the shape of the limit characteristic line L can be specified by four parameters indicating the position coordinates of the points A and B, but the reference shape of the limit characteristic line is determined in advance (that is, the points A and B). By designating a set of scaling factors (T_rate, S_rate), the reference shape can be expanded or contracted in the horizontal axis direction or the vertical axis direction by different scaling factors. For example, (T_r
If ate = 0.7 and S_rate = 0.5), the limit characteristic line shrinks by 70% in the horizontal axis direction and shrinks by 50% in the vertical axis direction. Therefore, if a structure in which these scaling factors can be instructed to the apparatus by an appropriate teaching means is used, the number of parameters is reduced and the usability is improved.

Based on the basic matters and the configuration explained above, the explanation of the present article will be started.

As described above, the scalable pattern is controlled by a combination of the scaling operation relating to the movement amount Δθ and the scaling operation using the time axis expansion / contraction parameter α value. However, the time axis operation as shown in FIG. There is room for consideration as to whether it is appropriate.

[0232] For example, when the limit characteristic line is given as in the example shown in FIG. 14, the amount required when generating the variable scaling pattern ^{_{(Θ MAX (2), Θ}} aMAX (1)),
(Θ _{PMA X} ⁽²⁾ , Θ _MAX ⁽¹⁾ ), Δθ _MAX , and T _PMAX (note that the other two quantities are calculated from the former four quantities).

Now, a scaling parameter introduced by dividing Δθ by Δθ _MAX (this is referred to as “α ′”).
When the movement amount Δθ is changed while keeping the peak speed arrival time at T _PMAX , (where Δθ ≤ Δθ _MAX
And α ′ = Δθ / Δθ _MAX (≦ 1). ), FIG. 2
As shown in 5, the Θ ⁽¹⁾ axis and Θ ^{(2) with} respect to the limit characteristic line L
By performing both α times expansion and contraction operations on the shaft, 1
A characteristic line L'as shown by a dashed line is obtained.

However, such a characteristic line has a considerable margin for the operation control of the controlled object. For example, the control target when identified to the pulse motor of the constant current drive, in order to independently flow a certain amount of current to rotation and stopping of the motor, or the calorific value of the motor is substantially constant theta ⁽²⁾ on the axis It is preferable that the operating point of is closer to Θ _MAX ⁽²⁾ .

Therefore, in order to control the operation of the controlled object faster, this is √ for the expansion / contraction operation in the time axis direction.
If the operation is performed by shortening by α ′ times, as shown in FIG. 18, the expansion / contraction operation by α times in the time axis direction is performed by multiplying α squared for the Θ ⁽²⁾ axis and for the Θ ⁽¹⁾ axis. Note that the characteristic line L'shown by the alternate long and short dash line shows that an expansion and contraction action of α times is generated.
With respect to Θ ⁽²⁾ axis, ² of 1 / √α '
The multiplication and the Θ ⁽¹⁾ axis are expanded by 1 / √α ′ times, and as a result, the characteristic line L ″ shown by the broken line in FIG. 25 is obtained.

That is, the above-mentioned scaling operations can be summarized as follows.

(A) Expansion / contraction related to the movement amount Δθ (ratio α ′)
Is to multiply the velocity axis (Θ ⁽¹⁾ ) and the acceleration axis (Θ ⁽²⁾ ) by α '.

(B) Expansion / contraction on the time axis (ratio √α ') means that the velocity axis (Θ ⁽¹⁾ ) is multiplied by 1 / √α' and the acceleration axis (Θ
⁽²⁾ ) is multiplied by 1 / α '.

Therefore, the combining operation of (A) and (B) is
It is nothing but the multiplication of the velocity axis by α '/ (√α') = √α 'and the acceleration axis by α' / (√α ') ² = 1.

As described above, the expansion / contraction operation of 1 / √α 'on the time axis is performed by the normalizing function θ _{N of the} scalable pattern.
Since it is equivalent to changing the variable t / T in (t) to t / ((√α ′) · T), the functional expression of the scalable pattern in the case of the limit characteristic line L is expressed by ] And [Equation 56] (the normalization function is
= 1. ). Hereafter, α ′ will be simply referred to as α without distinguishing it.

[0241]

[Equation 55]

[0242]

[Equation 56]

The quantities in the above equation are as shown in the following equation. Further, the equations [55] to [58] are modified by subscripting "MAX" as necessary for various quantities in the equations [44] and [45]. There is no essential difference in content.

[0244]

[Equation 57]

[0245]

[Equation 58]

By shortening by √α times in the time axis direction as described above, it means that the peak velocity arrival time T _P follows the conversion rule shown in the following equation.

[0247]

[Equation 59]

A graph of the contents of the above equation is shown in FIG.
A [Delta] [theta]-T _P diagram shown in (a), Δθ-T of an extension of its longitudinal axis on the total movement time T _all is shown in FIG. 26 (b)
_{It is an all} figure. It is clear from the equation [56] that the graph curve shown in the range of 0 ≦ Δθ ≦ Δθ _MAX is parabolic.

In the definition of the equation [12], α = T _P / T
_{Although PMAX} is used, as can be seen from [Equation 56], α is proportional to the square of T _P / T _PMAX in the above case, and the result is that α is generally T _P / T _PMAX Means to be determined by a function.

Although the above description has been made for the case where the controlled object has only one drive shaft, it is easy to extend the above discussion to the controlled object including a plurality of drive shafts. This is because when the α value and Δθ related to each drive shaft are distinguished by attaching the identification numbers i (= 1, 2, ... M), for example, a common α for each drive shaft (
_{CM N} ". ) Is determined as shown in the following equation.

[0251]

[Equation 60]

However, note that the above equation introduces an implicit assumption about Δθ _MAX .

That is, the limit characteristic lines are different for each drive axis, and Δθ _MAX is also independent for each drive axis, and this cannot be shared as in the formula [60]. Is.

Therefore, when the motion of the controlled object is performed by a plurality of drive shafts, a limit characteristic line which is the greatest common divisor for each drive shaft is required. When such a limit characteristic line is selected, For the first time, one Δθ _MAX is determined, and it becomes possible to select the α value as in the formula [60]. This is because if the limit characteristic lines for each drive axis are different, and if a scalable pattern is generated based on the limit characteristic line for a certain drive axis, the safety of movement of other drive axes will be improved. This is because it may not be guaranteed.

Therefore, description will be made below regarding the selection of the limiting characteristic line which should be the greatest common divisor for a plurality of drive shafts.

FIGS. 27 to 35 exemplify the mutual relations when the controlled object has two drive shafts and the limiting characteristic lines thereof have the shapes as shown in FIG. .

FIG. 27 shows a limit characteristic line L relating to one drive shaft.
1 is located inside the limit characteristic line L2 related to the other drive shaft, and FIG. 28 shows Θ related to one limit characteristic line L1.
_{When 1MAX} ^{(2 )} and Θ _2MAX ⁽²⁾ related to the other limit characteristic line L2 are compared, Θ _1MAX ⁽²⁾ <Θ _{2MA X} ^(2), and Θ _1MAX related to one limit characteristic line L1. ⁽¹⁾ and the other limit characteristic line L
2 is compared with Θ _2MAX ⁽¹⁾ , Θ _1MAX ⁽¹⁾ > Θ
_{It is set to 2MAX} ^(1), and the sloped portion L1a of the limit characteristic line L1
b is a horizontal part L2 parallel to the Θ ⁽²⁾ axis of the limit characteristic line L2
An example of intersecting with b is shown.

Further, in FIG. 29, Θ _1MAX ⁽²⁾ <Θ _2MAX ⁽²⁾ and Θ _1MAX ⁽¹⁾ <Θ _2MAX ^{(1) are set,} and the inclined portion L2ab of the limit characteristic line L2 is the inclined portion of the limit characteristic line L1. L1ab and Θ
⁽²⁾ An example is shown in which the horizontal portion L1b parallel to the axis is crossed.

In FIG. 30, Θ _1MAX ⁽²⁾ <Θ _2MAX ⁽²⁾ and Θ
_1MAX ⁽¹⁾ <Θ _2MAX ⁽¹⁾ and the slope L of the limit characteristic line L2
An example is shown in which 2ab intersects the horizontal portion L1b of the limit characteristic line L1 and the vertical portion L1a parallel to the Θ ⁽¹⁾ axis.

In FIG. 31, Θ _1MAX ⁽²⁾ <Θ _2MAX ⁽²⁾ and Θ
_1MAX ⁽¹⁾ > Θ _2MAX ⁽¹⁾ and the slope L of the limit characteristic line L2
2ab and an inclined portion L1ab of the limit characteristic line L1 intersect, and in FIG. 32, Θ _1MAX ⁽²⁾ <Θ _2MAX ⁽²⁾ and Θ _2MAX ⁽²⁾
_1MAX ⁽¹⁾ <Θ _2MAX ⁽¹⁾ and the slope L of the limit characteristic line L2
2ab is a slanted portion L1ab and a vertical portion L of the limit characteristic line L1.
An example of crossing with 1a is shown.

In FIG. 33, Θ _1MAX ⁽²⁾ <Θ _2MAX ⁽²⁾ and Θ
_1MAX ⁽¹⁾ > Θ _2MAX ⁽¹⁾ and the vertical portion L of the limit characteristic line L1
1a and the horizontal portion L2b of the limit characteristic line L2 are crossed, and in FIG. 34, Θ _1MAX ⁽²⁾ <Θ _2MAX ⁽²⁾ and Θ _1MAX.
⁽¹⁾ > θ _2MAX ^(1), and the vertical portion L1a of the limit characteristic line L1
Shows an example of intersecting the inclined portion L2ab of the limit characteristic line L2.

Then, in FIG. 35, Θ _1MAX ⁽²⁾ > Θ _2MAX ⁽²⁾
And Θ _1MAX ⁽¹⁾ <Θ _2MAX ⁽¹⁾ , the inclined portion L2ab of the limit characteristic line L2 intersects the inclined portion L1ab and the horizontal portion L1b of the limit characteristic line L1, and the vertical portion L2 of the limit characteristic line L2.
It shows an example in which a crosses the inclined portion L1ab of the limit characteristic line L1.

Although not shown in the figure, in addition to this, when the relationship between L1 and L2 is exchanged, or Θ _1MAX ⁽²⁾ = Θ _2MAX
⁽²⁾ and / or the case where Θ _1MAX ⁽¹⁾ = Θ _2MAX ⁽¹⁾ , etc. can be mentioned. Moreover, a triangular shape as shown in FIG. 16 or a triangular shape as shown in FIG. It is obvious that a large number of combinations can be considered by including even the ones, and there are several dozens of cases with only two limit characteristic lines. Therefore, when the number of limit characteristic lines increases, the number of combinations further expands. Raising is easily understood. In the present invention, an algorithm that is valid in any case for such a combination of limit characteristic lines is adopted. That is, a common limit characteristic line (hereinafter, referred to as "common limit characteristic line") by "inscribed approximation" for a plurality of limit characteristic lines.
An algorithm for uniquely defining the above is provided, and a scalable pattern defined by a common limit characteristic line is generated to control the operation of a plurality of drive axes constituting the controlled object.

When the contents of the "inscribed approximation" here are qualitatively shown by taking the case of FIGS. 27 to 35 as an example, the characteristic line indicated by the bold line in these figures indicates the common limit characteristic line. ing. That is, in FIG. 27, the limit characteristic line L1 located inside is the common limit characteristic line, and in FIG. 28, the common limit characteristic line is a part of the horizontal portion L2b of the limit characteristic line L2, the limit characteristic line. It is composed of a part of the inclined portion L1ab of L1 and the vertical portion L1a.

In the case of FIG. 29, the intersection between the horizontal portion L1b of the limit characteristic line L1 and the inclined portion L2ab of the limit characteristic line L2 is C.
Then, the common limit characteristic line is constituted by a part of the horizontal portion L1b of the limit characteristic line L1 and the vertical portion L1a, and a line segment connecting the upper end points A1 and C of the limit characteristic line L1. In this case, the common limit characteristic line is composed of a part of the horizontal portion L1b or the vertical portion L1a of the limit characteristic line L1 and a part of the inclined portion L2ab of the limit characteristic line L2.

In the case of FIG. 31, the common limit characteristic line is the vertical portion L1a of the limit characteristic line L1 and the horizontal portion L of the limit characteristic line L2.
2b, and the upper end point A1 of the vertical portion L1a and the horizontal portion L2
32 is a line segment connecting the right end point B2 of b and the vertical portion L1a of the limit characteristic line L1 and the limit characteristic line L in the case of FIG.
When the intersection with the two inclined portions L2ab is D, the common limit characteristic line is the entire horizontal portion L1b of the limit characteristic line L1 and a part of the vertical portion L1a, and the right end point B1 of the horizontal portion L1b of the limit characteristic line L1. And a line segment connecting the point D and the point D.

In the case of FIG. 33, the common limit characteristic line is the vertical portion L1a of the limit characteristic line L1 and the horizontal portion L of the limit characteristic line L2.
In the case of FIG. 34, the common limit characteristic line is composed of a part of the vertical portion L1a of the limit characteristic line L1, a horizontal portion L2b of the limit characteristic line L2, and a part of the inclined portion L2ab. It

In the case of FIG. 35, the intersection point between the horizontal portion L1b of the limit characteristic line L1 and the inclined portion L2ab of the limit characteristic line L2 is E.
And the intersection point of the inclined portion L1ab of the limit characteristic line L1 and the vertical portion L2a of the limit characteristic line L2 is F, the common limit characteristic line is a part of the horizontal portion L1b of the limit characteristic line L1,
Part of the vertical portion L2a of the limit characteristic line L2 and the line segment EF
It is composed of

Each of the common limit characteristic lines obtained as described above has a shape as shown in FIG.
Four parameters indicating the coordinates of point A and point B (Θ _MAX ⁽²⁾ ,
Θ _{ap MAX} ⁽¹⁾ ), (Θ _PMAX ⁽²⁾ , Θ _MAX ⁽¹⁾ ). Also, point A and point B are respectively Θ ⁽²⁾
If you move it along the axis or the Θ ⁽¹⁾ axis, you can get a triangular characteristic line, and if you match points A and B, you can get a square characteristic line. It is clear that these are included as special cases.

Identification numbers i (i = 1, 2, ...) For distinguishing the drive axes for the above four parameters are added to the right side (for example, Θ _iMAX ⁽²⁾ ), and The steps required for the processing related to tangent approximation are as follows.

(A) Maximum acceleration Θ related to the common limit characteristic line
Determination of _MAX ⁽²⁾ (b) Θ ⁽²⁾ = Θ _MAX ⁽²⁾ The intersection determined between the straight line and each limit characteristic line, and the calculation of the velocity at the intersection (c) Maximum related to the common limit characteristic line Determination of velocity Θ _MAX ⁽¹⁾ (d) Θ ⁽¹⁾ = intersection determined between the line of Θ _MAX ⁽¹⁾ and each limit characteristic line and calculation of acceleration at the intersection First, common to (a) The maximum acceleration Θ _MAX ⁽²⁾ related to the limit characteristic line is selected as shown in the following equation.

[0272]

[Equation 61]

That is, as shown in FIG. 36, the smallest value of Θ _MAX ⁽²⁾ is selected. Note that m in the above formula
in (X1, X2, ...) are variables X1, X2, ...
It is a function that chooses the smallest one.

Further, in (b), the intersection point determined between the straight line of Θ ⁽²⁾ = Θ _MAX ⁽²⁾ and each limit characteristic line irrespective of which limit characteristic line Θ _MAX ⁽²⁾ is selected from. And all the velocities at the intersections are calculated.

[0275] The term "intersection" used here means Θ ⁽²⁾ = Θ _MAX.
^In addition to the intersection of the straight line shown in ⁽²⁾ and the limit characteristic line, the intersection of the extension line of the constituent portion of the limit characteristic line is included.

[0276] For example, when the number of the limit characteristic line of the two, as shown in FIG. 37, theta by [Expression 58] where _MAX
^Two intersections P1 and P2 are determined between the limit characteristic line selected as ⁽²⁾ (referred to as "Lt") and the straight line indicated by Θ ⁽²⁾ = Θ _MAX ⁽²⁾ . That is, the point P1 is the upper end point of the vertical portion Lta of the limit characteristic line Lt, and the point P2 is a line obtained by extending the horizontal portion Ltb of the limit characteristic line Lt to the right and Θ ^(2).
= Θ _MAX It is the intersection with the straight line shown in ⁽²⁾ .

Further, such an intersection is an intersection of the other limit characteristic line (referred to as "Lh") or an extension line of its constituent portion and a straight line shown by Θ ⁽²⁾ = Θ _MAX ^(2). 38, for example, in the example shown in FIG. 38, two intersection points Q1,
One of the Q2, Q1 is the inclined portion Lha of the limit characteristic line Lh.
b and Θ ⁽²⁾ = Θ _MAX ⁽²⁾ obtained as an intersection of the straight lines, while Q2 is an extension of the horizontal portion Lhb of the limit characteristic line Lh and a straight line indicated by Θ ⁽²⁾ = Θ _MAX ⁽²⁾ It is obtained as the intersection with. Further, in the example shown in FIG. 39, two intersections Q1 and Q2
One of them Q1 is the horizontal portion Lhb and Θ of the limit characteristic line Lh.
⁽²⁾ = Θ _{MAX It} is obtained as an intersection with the straight line shown in ⁽²⁾ , while Q2 is the extension of the inclined portion Lhab of the limit characteristic line Lh and Θ ^(2
) = Θ _MAX ⁽²⁾ is obtained as an intersection with the straight line shown in FIG.
In the example shown in Fig. 1, one intersection Q1 is obtained as an intersection of the horizontal portion Lhb of the limit characteristic line Lh and the straight line shown by Θ ⁽²⁾ = Θ _MAX ⁽²⁾ . In this case, the intersection Q1 is the limit characteristic. Line L
It is also the intersection of the slope Lhab of h and the straight line indicated by Θ ⁽²⁾ = Θ _MAX ⁽²⁾ , so this is counted as two (that is, FIG. 3).
In the example of 9, it is considered that the points Q1 and Q2 match. ).

After all, four intersections are obtained in the case of two limit characteristic lines, and the velocity at each intersection is "Θ ⁽¹⁾ (Pj)" (j = 1,
2), "Θ ⁽¹⁾ (Qj)" (j = 1, 2),
For Θ _apMAX ^{(1 )} related to the common limit characteristic line, the smallest one among these is selected as shown in the following equation.

[0279]

(Equation 62)

Thus, the values of the two parameters (Θ _MAX ⁽²⁾ and Θ _apMAX ⁽¹⁾ ) related to the common limit characteristic line are determined.

As for the above (c), the maximum speed Θ _MAX ⁽¹⁾ related to the common limit characteristic line is expressed by the following equation and FIG.
The smallest one among the maximum velocities related to each limit characteristic line is selected.

[0282]

[Equation 63]

Then, in (d), Θ ⁽¹⁾ = Θ _MAX regardless of which limit characteristic line the Θ _MAX ⁽¹⁾ is selected from.
Find the intersection determined between the straight line in ⁽¹⁾ and each limit characteristic line,
All accelerations at the intersection are calculated.

Regarding the meaning of "intersection", the above (b)
Is the intersection of the straight line indicated by Θ ⁽¹⁾ = Θ _MAX ⁽¹⁾ and the extension line of the limiting characteristic line or its constituent parts. For example, when the number of limiting characteristic lines is two, As shown in FIG. 42, there are two intersections between the limit characteristic line Lt selected as Θ _MAX ⁽¹⁾ by the equation [60] and the straight line shown by Θ ⁽¹⁾ = Θ _MAX ^(1). R1 and R2 are determined. That is, the point R1 is the right end point of the horizontal portion Ltb of the limit characteristic line Lt, and the point R2.
Is a line obtained by extending the vertical Lta of the limit characteristic line Lt upward and
⁽¹⁾ = Θ _MAX It is the intersection with the straight line shown in ⁽¹⁾ .

[0285] Further, such an intersection is a characteristic of the other limit.
Line Lh and its extension and Θ ⁽¹⁾= Θ_MAX ⁽¹⁾Shown in
It can be obtained as an intersection with a straight line, for example, as shown in FIG.
In the example shown in, one of the two intersections S1 and S2 is S1.
Slope Lhab and Θ of the limit characteristic line Lh⁽¹⁾= Θ_MAX ⁽¹⁾To
Obtained as an intersection with the straight line shown, while S2 is the limit characteristic line
The extension of the vertical part Lha of Lh and Θ⁽¹⁾= Θ_MAX ⁽¹⁾Shown in
Obtained as the intersection with a straight line. In addition, in the example shown in FIG.
Is the limit characteristic of one of the two intersections S1 and S2.
Vertical part Lha and Θ of line Lh⁽¹⁾= Θ_MAX ⁽¹⁾And the straight line shown in
Of the limit characteristic line Lh.
Extending to the lower right of section Lhab and Θ⁽¹⁾= Θ_MAX ⁽¹⁾Shown in
45 is obtained as an intersection with the straight line, and in the example shown in FIG.
The two intersections S1 are the vertical portions Lha and Θ of the limit characteristic line Lh.⁽¹⁾
= Θ_MAX ⁽¹⁾This is obtained as the intersection with the straight line shown in
In this case, the intersection S1 is the slope Lha of the limit characteristic line Lh.
b and Θ⁽¹⁾= Θ_MAX ^{(1 )}Is also the intersection with the straight line shown in
Then, this is counted as two (that is, point S1 in the example of FIG. 43).
And the point S2 are regarded as coincident with each other. ).

As a result, four intersections are obtained in the case where there are two limit characteristic lines, and the acceleration at each intersection is “Θ ⁽²⁾ (Rj)” (j =
1, 2) and “Θ ⁽²⁾ (Sj)” (j = 1, 2), the smallest Θ _PMAX ⁽²⁾ of the common limit characteristic lines is as shown in the following equation. Select one.

[0287]

[Equation 64]

In this way, the values of the two parameters (Θ _PMAX ⁽²⁾ , Θ _MAX ⁽¹⁾ ) related to the common limit characteristic line are determined.

Then, the point A on the common limit characteristic line,
When the coordinates of B are determined, the expression by an equation such as [Equation 31] can be obtained, and it becomes apparent that the scalable pattern corresponding to the common limit characteristic line can be obtained according to the above discussion.

Further, it can be confirmed that the common limit characteristic line shown by the thick line can be obtained by directly applying the steps (a) to (d) to the examples shown in FIGS. 27 to 35.

In the above description, the number of limit characteristic lines is limited to two for ease of understanding, but in general, it can be easily expanded to the case where the number of limit characteristic lines is two or more. Is clear.

When determining the common limit characteristic line,
The shape of each limit characteristic line is specified as shown in FIG. 14, but this is for giving concreteness to the description, and generally, the shape of the limit characteristic line is a polygonal shape, or a more general shape. It can be expandedly applied to a case having a curved shape. For example, in the example shown in FIG. 46, the common limit characteristic line may be constructed from the lower curved portion (thick line in the figure) of the limit characteristic lines L1 and L2. If such a curved common limit characteristic line is difficult to handle, polygonal approximation may be used to use a characteristic line as shown by the one-dot chain line in FIG.

Further, in the above description, the common limit characteristic line is 3 for each limit characteristic line as shown in FIGS. 27 to 35.
Although it is assumed that it is obtained by edge inscribed approximation (that is, a line that passes through the innermost side of each limit characteristic line is selected and further approximated by three sides), this is merely for convenience of description, and n ( ≧ 3) Of course, it can be generalized to the side inscribed approximation (for example, if the four side inscribed approximation is adopted in the example of FIG. 29, the common limit characteristic line is a constituent part of the limit characteristic lines L1 and L2. Of which, it consists of choosing the lower part.)

However, if the common limit characteristic line is determined as described above, the motion of each drive shaft according to the scalable pattern generated corresponding to this does not deviate from the respective limit performance.

The functional expression of the scalable pattern related to the common limit characteristic line when the controlled object has two drive axes and the following conditions are imposed is as follows. 55] to [Equation 58].

Condition i) The shape of the limit characteristic line for each drive shaft is set as shown in FIG. 14, that is, the limit characteristic line for one drive shaft has four parameters (Θ _1MAX ⁽²⁾ , Θ
_{1apMA X} ⁽¹⁾ ), (Θ _1PMAX ⁽²⁾ , Θ _1MAX ⁽¹⁾ ), and the limit characteristic line related to the other drive axis is 4 parameters (Θ _2MAX
⁽²⁾ , Θ _2apMAX ⁽¹⁾ ), (Θ _2PMAX ⁽²⁾ , Θ _2MAX ⁽¹⁾ ).

Condition ii) Three-sided inscribed approximation is used to determine the common limit characteristic line. The common limit characteristic line is defined by the above (a) to (d) and has four parameters (Θ
_MAX ⁽²⁾ , Θ _apMAX ⁽¹⁾ ), (Θ _PMAX ⁽²⁾ , Θ _MAX ⁽¹⁾ ).

Condition iii) The scalable pattern is generated by expanding / contracting the time axis by 1 / √α times with respect to the normalizing function as described above. However, the time axis expansion / contraction parameter α is a velocity value in percentage. By introducing the parameter “P” (0 <P ≦ 100) for specifying “α
= (Δθ / Δθ _MAX ) · (100 / P) ² ”. When P = 100 (%) in this formula, “α = Δθ / Δθ _MAX ” in the formula [56], which means the designation when the fastest performance is desired in the controlled object, If it is desired to reduce the operation speed, the P value can be designated according to the degree.

The following table summarizes the definitions of various quantities.

[0300]

[Table 3]

The features of the algorithm relating to the determination of the common limit characteristic line described above are itemized and summarized as follows.

(I) When the controlled object is composed of a plurality of drive shafts, it is possible to speed up the motion of the drive shaft as a whole. (Ii) Any drive shaft deviates from its limit performance. (Iii) common limit characteristic lines can be determined according to a systematic procedure even if the number of limit characteristic lines is large (iv) easy extension to multi-sided inscribed approximation Is.

The device configuration using the common limit characteristic line is the same as that of the device shown in FIG. 22, and the difference is that the scalable pattern is generated based on the normalizing function corresponding to the common limit characteristic line. And that the controlled object has two or more drive shafts. With respect to the parameter P introduced to obtain a new degree of freedom for the time-axis expansion / contraction parameter α, if this is sent from the command means 2 to the α value determination means 5 as shown by the signal SP in FIG. good.

Therefore, as shown in FIG. 47, the flowchart relating to the control method is such that step Sa relating to determination of the common limit characteristic line is inserted between steps S1 and S2 in the flowchart of FIG. Instead of step S2, step S2 'for defining the shape of the acceleration / deceleration curve based on the common limit characteristic line is replaced. Note that the scaling operation in the moving amount and the time axis (see (A) and (B) above) is included in the scaling operation in step S4, and the Δθ-T _P characteristic and [number] shown in FIG. 56] The determination of the α value by the equation etc. is included in step S3. It should be noted that the use of the common limit characteristic line can exert an effect when applied when two or more of the plurality of drive shafts constituting the controlled object move, and thus one of the drive shafts can be used. It does not force the use of the common limit characteristic line even in the case of moving only. This is because, in this case, it suffices to generate a scalable pattern according to the limit characteristic line for one drive shaft and control the motion of the drive shaft.

Since it is clear from the command which drive axis of the plurality of drive axes that constitutes the controlled object moves, the drive axis that directly contributes to the motion of the controlled object,
In other words, the common limit characteristic line can be defined only for the driving shaft that moves. In other words, in this case, the drive axis that does not move is excluded when determining the common limit characteristic line. For example, when moving only a certain drive axis, that limit characteristic line is selected as the common limit characteristic line. To be done.

[0306]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An example in which the present invention is applied to a robot controller will be described below. FIG. 48 schematically shows a main part of the hardware configuration of the robot controller 10.

The robot controller 10 has a CPU (central processing unit) 11 as a core, and a storage unit 13 connected directly or indirectly to a bus 12 thereof.

The storage unit 13 stores, for example, a robot program related to the description of the operation procedure of the robot, a system program related to the description of the robot system (for example, description such as coordinate conversion for determining the operation of each axis of the robot). Will be remembered.

The servo units 14, 14, ... Are independent for each drive shaft (including the drive shaft of the arm and the mounting shaft of the tool) that constitutes the robot 15, and the robot is in accordance with the command issued from the CPU 11. It is provided to control actuators (motors, cylinders, etc.) that drive the shafts of 15.

The teaching pendant 16 relating to the operation instruction of the robot 15 is a T.P. P. (Abbreviation of teaching pendant) It is connected to the bus 12 via an interface 17.

In applying the present invention to the robot controller 10, the configuration of the servo controller 1 shown in FIG.
It is necessary to construct each drive axis of the robot 15. That is,
It can be considered that the servo system 7 shown in FIG. 22 corresponds to one of the drive axes of the robot 15, and the servo control means for controlling the robot is functionally the CPU 11, the storage unit 13, the servo unit 14, the teaching pendant 16, and the like. It is realized by combining. Since the limit characteristic lines of the drive axes that drive the arm and the tool of the robot 15 are different from each other, it is necessary to determine the common limit characteristic line as described above.

For example, exemplifying a case where the robot has a two-axis structure having two arms, and when the arm driving system complies with the above conditions i) to iii), the scalable pattern is It is expressed by the formulas [55] to [58].

In the following description, the generality of the description is lost even if it is assumed that the movement amount Δθ ₁ related to one arm is equal to or larger than the movement amount Δθ ₂ related to the other arm (Δθ ₁ ≧ Δθ ₂ ). Since it does not exist, this is adopted and PTP (Point
Taking the case of the To Point operation as an example, the motion control of the arm can be divided into the following two cases (here, P = 100 for convenience of explanation).

1) In the case of Δθ ₂ ≦ Δθ ₁ ≦ Δθ _MAX 2) Δθ ₂ ≦ Δθ _MAX ≦ Δθ ₁ or Δθ _MAX ≦ Δθ ₂ ≦ Δθ ₁
in the case of.

First, in the case of 1), as Δθ, the larger one of Δθ ₁ and Δθ ₂ is selected as shown in the following formula [Equation 65], and α is as shown in the following formula [Equation 66]. To α
Select the larger of ₁ and α ₂ (see Table 3 above for the meaning of the symbols).

[0316]

[Equation 65]

[0317]

[Equation 66]

Therefore, assuming that the position of the drive shaft of one arm is "Θ ₁ (t)" and the position of the drive shaft of the other arm is "Θ ₂ (t)", these are given by the following equations. These are the scalable patterns to be obtained, and when this is illustrated, the width in the time axis direction is √α · 2 as shown in FIG. 49.
・ T _{PMAX gives} a synchronized curve.

[0319]

[Equation 67]

When the robot is a two-axis orthogonal robot, the drive axes are in an orthogonal relationship, one drive axis is the X axis, and the position is set as X = Θ ₁ (t), and the other drive axis is driven. It is possible to set the position as Y = Θ ₂ (t) with the Y axis as the Y axis, and by taking the ratio of the two, the following expression can be obtained from the expression [67], and it can be seen that the PTP operation is a linear motion.

[0321]

[Equation 68]

[0322] Next, in the case of 2), a constant speed period (which, as shown in FIG. 50 for the drive shaft of the arm "T _BOX"
And ) Is obtained, and in this figure, the acceleration / deceleration curve am is a combination of the curve portion in the acceleration period and the curve portion in the deceleration period am1 (in this example, the length of the acceleration period and the length of the deceleration period Are equal to each other) and the straight line portion am2 in the constant speed period are added together. The area enclosed between the acceleration / deceleration curve am and the time axis is Δθ ₁ ,
The area enclosed between am1 and the time axis is Δθ _MAX , am
The area of the quadrangle in 2 is Δθ _1BOX (= Δθ ₁ −Δ
θ _MAX ).

In this case, Δθ and α are determined by the following equation.

[0324]

[Equation 69]

[0325]

[Equation 70]

Therefore, the position of the drive shaft of each arm Θ
₁ (t) and Θ ₂ (t) are obtained by the following equations, and when shown in FIG. 51, the acceleration / deceleration curve having the constant speed period of T _BOX and the acceleration period and the deceleration period of T _PMAX is obtained. can get.

[0327]

[Equation 71]

[0328]

[Equation 72]

In the above description, the value of the parameter P is 1
The value is fixed to 00, but if this is specified as an arbitrary value, it becomes as follows.

First, in the case of 1), the above [Equation 6]
The equation 6] may be generalized to include the term “100 / P” as shown in the following equation, and therefore α ≧ 1 may occur.

[0331]

[Equation 73]

In the case of 2), the above formula [70] is generalized to include the term “100 / P” as shown in the following formula [74], and the above formula [71] is also included. As for, by multiplying all the time constants in the formula by √α (= 100 / P), the following formula [Formula 75] is obtained.

[0333]

[Equation 74]

[0334]

[Equation 75]

FIG. 52 shows the position Θ of the drive shaft of each arm.
₁ (t), Θ ₂ (t), and the peak velocity is P
/ 100 times, and the T _P value and T _BOX value are 100 / P times. Therefore, for example, when P = 50%, the peak speed is halved and the travel time (tact time) is doubled, so that the meaning of the parameter P can be easily understood. There is. That is,
The peak speed is P / 100 by specifying the parameter P value.
Control that is doubled and unknown about travel time,
On the contrary, compared to the control in which the travel time is multiplied by 100 / P, but the peak speed is unknown, the control in which both the peak speed and the travel time are clear by specifying the parameter P value is better for the designator. It can be said that the design is more kind.

[0336]

As is apparent from the above description, according to the inventions of claims 1 and 2, the limit performance of each drive shaft that defines the motion performance of the controlled object is not deviated. By generating the acceleration / deceleration curve, the performance and quality of the controlled object can be guaranteed. Further, by generating an acceleration / deceleration curve corresponding to one limit characteristic line extracted by inscribed approximation with respect to each limit characteristic line relating to the performance of the drive shaft of the control target, it is possible to bring out the capability of the control target to that limit performance. At the same time, no matter what the shape of the limit characteristic line is, it is possible to generate the acceleration / deceleration curve obtained by the scaling operation of the function value with respect to the reference function of the acceleration / deceleration curve or the expansion / contraction operation in the time axis direction. It is possible to unify the algorithms for generating the deceleration curve.

According to the third aspect of the present invention, the connectivity of the acceleration / deceleration curve can be guaranteed by sending the output of the acceleration / deceleration pattern generating means to the controlled object via the low-pass filter.

According to the inventions of claims 4 and 5,
When determining the peak velocity arrival time corresponding to the displacement amount command value related to the servo control variable, the displacement amount command value and the displacement amount command value are included so that the square of the peak velocity arrival time is proportional to the displacement amount command value. By defining the relationship with the peak velocity arrival time, the intercept of the acceleration axis on the characteristic diagram can be made to match or approach the maximum value related to the limit characteristic line, enabling faster motion control of the controlled object. Next to
Further, when the constant current drive control of the controlled object is performed, its ability can be fully utilized.

According to the inventions of claims 6 and 7,
By determining the value of the parameter for time axis expansion and contraction by the value obtained by dividing the command value of the displacement amount related to the servo control variable by its reference value, and the value of the parameter introduced to freely specify the ratio, The shape of the acceleration / deceleration curve can be freely changed according to the control purpose. For example, by designating the parameter value, the height of the peak of the acceleration / deceleration curve and the width in the time axis direction can be controlled as desired.

According to the inventions of claims 8 and 9,
By maximizing the capacity of the servo system related to the robot arm and tool mounting part, the work speed is increased.
In addition, the robot operation can be stabilized without deviating from the limit performance characteristics of each servo system. Further, no matter what the structure of the robot is, it is possible to use a unified acceleration / deceleration curve generation algorithm for each servo system, so the designer has to make efforts to find the shape of the acceleration / deceleration curve for each robot control. Is released from.

[Brief description of drawings]

FIG. 1 is a schematic graph showing several examples of characteristic lines indicating a limit performance and a rated performance related to a motor system.

FIG. 2 is a diagram showing an example of an equivalent circuit of a servo motor.

FIG. 3 is a diagram showing several triangular acceleration / deceleration curves.

FIG. 4 is a diagram showing an effective value of mechanical power and an effective value of electrical power corresponding to the acceleration / deceleration curve of FIG.

FIG. 5 is a diagram showing Δθ-T _P characteristics in control in which the effective value of electric power is constant.

FIG. 6 is an explanatory diagram of a shape of normalized speed.

FIG. 7 is a graph showing a ramp signal.

FIG. 8 is an explanatory diagram of a scaling operation related to a normalized speed, where (a) performs only a scaling operation related to a function value, and (b) performs only a time-axis expansion operation with respect to the normalized speed. In the above case, (c) shows the case where the combined operation of (a) and (b) is performed.

FIG. 9 is a diagram for explaining a locus on a θ _N ⁽²⁾ −θ _N ⁽¹⁾ diagram related to a normalization function, and (a) is θ _N ⁽²⁾
-Θ _N ⁽¹⁾ diagram, (b) t-θ _N ⁽¹⁾ diagram, (c) t-
It is a θ _N ⁽²⁾ diagram.

FIG. 10 shows an example in which the functional relationship between θ _N ⁽²⁾ and θ _N ⁽¹⁾ is not univalent with respect to the trajectory on the θ _N ⁽²⁾ −θ _N ⁽¹⁾ diagram regarding the normalized function. It is a figure.

FIG. 11 is a diagram for explaining the relationship between the trajectory on the θ _N ⁽²⁾ −θ _N ⁽¹⁾ diagram regarding the normalization function and the scaling operation regarding the normalization speed, and (a) is a function value. When only the scaling operation related to is performed, (b) is a time axis extension operation with respect to the normalized speed, (c) is (a)
The respective cases where the operations of (1) and (b) are combined are shown.

[Figure 12] θ _N ⁽²⁾ relating to the normalized function - [theta] _N ⁽¹⁾ line and the area of the region surrounded by the trajectory in diagram, theta according to variable scaling pattern ^{(2) -Θ (1)} diagram It is a figure which also shows the area in the area | region enclosed by the above locus.

13A is a diagram for explaining a trajectory on a Θ ⁽²⁾ -Θ ⁽¹⁾ diagram relating to a controlled object, and FIG. 13B is an acceleration / deceleration defined by the trajectory of FIG. 13A. It is a graph figure for demonstrating a curve.

FIG. 14 is a Θ ⁽²⁾ -Θ ⁽¹⁾ diagram showing an example of a characteristic line showing the limit performance of the controlled object.

15 is a diagram for explaining an acceleration / deceleration pattern defined by the characteristic line of FIG.

16 is a Θ ⁽²⁾ -Θ ⁽¹⁾ diagram showing a characteristic line different from that in FIG. 14;

FIG. 17 is a Θ ⁽²⁾ -Θ ⁽¹⁾ diagram showing yet another characteristic line.

FIG. 18 is a diagram for explaining a correspondence relationship between an acceleration / deceleration curve and a locus on a Θ ⁽²⁾ −Θ ⁽¹⁾ diagram.

FIG. 19 is an explanatory diagram of a low pass filter method.

FIG. 20 shows Θ ⁽²⁾ − when the low-pass filter method is used.
FIG. 3 is a schematic diagram for explaining a trajectory on a Θ ⁽¹⁾ diagram.

FIG. 21 is an explanatory diagram of an inscribed method.

FIG. 22 is a block diagram showing a basic configuration of a servo control device according to the present invention.

FIG. 23 (a) shows an example of a Δθ-T _P diagram,
(B) shows an example of a Δθ-T _all diagram.

FIG. 24 is a flow chart diagram showing a basic processing flow of a servo control method according to the present invention.

FIG. 25 is a graph of FIG.
This is for explaining the expansion / contraction operation in the time axis direction when the power is specified to be proportional to the movement amount Δθ.
This figure is a diagram for explaining the action of the expansion / contraction operation on the characteristic line.

26 (a) is a Δθ-T _P diagram, and FIG. 26 (b) is a Δθ-T.
_{It is an all} diagram.

FIG. 27 is for explaining the relationship between two limit characteristic lines with FIGS. 28 to 35, and shows an example in which one limit characteristic line is inside the other limit characteristic line.

FIG. 28 is a diagram showing an example in which a common limit characteristic line is composed of a part of two limit characteristic lines.

FIG. 29 is a diagram showing an example in which the common limit characteristic line includes a portion other than the constituent portions of the two limit characteristic lines.

FIG. 30 is a diagram showing another example in which the common limit characteristic line is composed of a part of two limit characteristic lines.

FIG. 31 is a diagram showing another example in which the common limit characteristic line includes a portion other than the constituent portions of the two limit characteristic lines.

FIG. 32 is a diagram showing another example in which the common limit characteristic line includes a portion other than the constituent portions of the two limit characteristic lines.

FIG. 33 is a diagram showing an example in which a common limit characteristic line has a rectangular shape.

FIG. 34 is a diagram showing another example in which the common limit characteristic line is composed of a part of two limit characteristic lines.

FIG. 35 is a diagram showing another example in which the common limit characteristic line includes a portion other than the constituent portions of the two limit characteristic lines.

FIG. 36 is a view for explaining a method of determining the common limit characteristic line, together with FIGS. 37 to 46, and is a diagram showing selection of the maximum acceleration.

37 is a view for explaining the intersection of the straight line shown in Θ = Θ _MAX ⁽²⁾ and the limit characteristic line and the calculation of the velocity at the intersection together with FIGS. 38 to 40. In this figure, the maximum acceleration is selected. It is a figure which shows the intersection about the made limit characteristic line.

FIG. 38 is a diagram showing intersections of limit characteristic lines for which maximum acceleration is not selected.

FIG. 39 is a diagram showing another example of intersections with respect to the limit characteristic line for which maximum acceleration is not selected.

FIG. 40 is a diagram showing a case where there is one intersection.

41 is a view for explaining a method of determining a common limit characteristic line with FIGS. 42 to 45, and this figure is a diagram showing selection of the maximum speed.

42 is a view for explaining the intersection of the straight line shown by Θ = Θ _MAX ⁽¹⁾ and the limit characteristic line and the calculation of the acceleration at the intersection with FIGS. 42 to 45. In this figure, the maximum speed is selected. It is a figure which shows the intersection about the made limit characteristic line.

FIG. 43 is a diagram showing intersections with respect to a limit characteristic line in which the maximum speed is not selected.

FIG. 44 is a diagram showing another example of intersections with respect to the limit characteristic line in which the maximum speed is not selected.

FIG. 45 is a diagram showing a case where there is one intersection.

FIG. 46 is a diagram for explaining determination of a common limit characteristic line when the limit characteristic line is curved.

FIG. 47 is a flow chart diagram for explaining a servo control method according to the present invention.

48 shows an application example of the present invention to a robot control device together with FIGS. 49 to 52, and this figure is a diagram showing an example of a hardware configuration of the robot control device.

FIG. 49 is a diagram showing an example of an acceleration / deceleration curve for a two-axis robot in combination with FIGS. 50 to 52, and this figure is a diagram showing an example of the shape of the acceleration / deceleration curve when there is no constant speed control.

FIG. 50 is a diagram showing a state in which an acceleration / deceleration curve including constant speed control is decomposed into a curved portion related to the acceleration / deceleration period and a linear portion related to the constant speed period.

FIG. 51 is a diagram showing an example of the shape of an acceleration / deceleration curve when constant speed control is included.

FIG. 52 shows that the peak speed related to the acceleration / deceleration curve is increased by P / 100 and the moving time is 1 by specifying the parameter P value.
It is a figure which shows the example of a shape at the time of controlling so that it may become 00 / P times.

FIG. 53 is a diagram showing a triangular acceleration / deceleration curve.

FIG. 54 is a diagram showing an example of TN characteristics.

[Explanation of symbols]

1 ... Servo control device, 2 ... Command means, 3 ... Acceleration / deceleration pattern generation means, 4 ... Peak speed arrival time value determination means, 5 ...
Time axis expansion / contraction parameter value determining means, 6 ... Low-pass filter, 7 ... Control target, 10 ... Robot control device, 15 ...
robot

Claims (9)

[Claims] 1. The limit of motion performance is defined by a limit characteristic line on a characteristic diagram of acceleration (or force or torque) with respect to speed (or speed, angular velocity or rotation speed), and each limit performance line is different. A servo control device for performing acceleration / deceleration control corresponding to the limit performance of a control target that is moved by a plurality of drive shafts having different shapes. Command means for issuing a command value for a servo control variable And the command value related to the servo control variable and the time required for the speed to reach the peak value on the acceleration / deceleration curve (hereinafter referred to as “peak speed arrival time”), and the command related to the servo control variable. A peak velocity arrival time value determining means for determining the value of the peak velocity arrival time from the value, and the peak velocity arrival time defined by dividing the peak velocity arrival time by its reference value. A time axis expansion / contraction parameter value determining means for determining the value of the time axis expansion / contraction parameter defined as a function of the dimension quantity, and one extracted by inscribed approximation to each limit characteristic line relating to the performance of the drive shaft to be controlled. The shape of the acceleration / deceleration curve is defined under the condition that the operating point defined by acceleration (or force or torque) and speed (or speed, angular velocity or rotation speed) is located on the limit characteristic line of The peak velocity arrival time related to the reference function of the curve is used as the reference value of the time axis extension / contraction parameter, and the extension / contraction operation in the time axis direction relative to the reference function based on the time axis extension / contraction parameter value and the reference function value based on the instruction value from the instruction means A servo control device comprising: an acceleration / deceleration pattern generation means for generating an acceleration / deceleration curve by a scaling operation with respect to and sending it to a controlled object. 2. The limit of motion performance is defined by a limit characteristic line on a characteristic diagram for acceleration (or force or torque) speed (or velocity, angular velocity or rotation speed), and each limit performance line is different. A servo control method for performing acceleration / deceleration control corresponding to the limit performance of a control target that is moved by a plurality of drive shafts having different shapes. Do not deviate from each limit characteristic line by inscribed approximation to these limit characteristic lines after specifying the limit characteristic lines related to the characteristics of speed (or force or torque) with respect to speed (or speed, angular velocity or rotation speed). One limit characteristic line is determined, and acceleration (or force or torque) is placed on this limit characteristic line.
And speed (or speed, angular velocity or number of revolutions) defines the shape of the acceleration / deceleration curve under the condition that the operating point is defined, and its reference function and the peak speed arrival time related to the reference function, Defined by defining the relationship between the specified value of the servo control variable and the peak speed arrival time, obtaining the value of the peak speed arrival time corresponding to the command value, and dividing this by the peak speed arrival time according to the above reference function. The value of the time axis expansion / contraction parameter specified as a function of the dimensionless amount is determined, and the expansion / contraction operation in the time axis direction for the reference function is performed based on the time axis expansion / contraction parameter value, and based on the command value of the servo control variable. The acceleration / deceleration curve is generated by performing a scaling operation on the reference function value and is sent as a control signal to the controlled object. Control method. 3. The servo control device according to claim 1, wherein a low-pass filter is provided between the acceleration / deceleration pattern generation means and the controlled object. 4. The servo speed controller according to claim 1, wherein the peak speed arrival time value determining means determines the peak speed arrival time when determining the peak speed arrival time corresponding to the command value of the displacement amount related to the servo control variable. The servo control device is characterized in that the relationship between the command value of the displacement amount and the peak speed arrival time is defined so that the square of the time is proportional to the command value of the displacement amount. 5. The servo control method according to claim 2, wherein when determining the peak velocity arrival time corresponding to the command value of the displacement amount related to the servo control variable, the square of the peak velocity arrival time is the command value of the displacement amount. The servo control method is characterized in that the relationship between the command value of the displacement amount and the peak speed arrival time is defined so as to include the characteristic of being proportional to. 6. The servo control device according to claim 4, which is introduced to freely specify a ratio of a command value of a displacement amount related to a servo control variable divided by its reference value. A means for inputting or setting the value of the parameter is provided, and the time axis expansion / contraction parameter value determining means divides the command value of the displacement amount related to the servo control variable by its reference value and the parameter of the above means. A servo control device characterized in that the value of the time axis expansion / contraction parameter is determined based on the value. 7. The servo control method according to claim 5, wherein the value of the time axis expansion / contraction parameter is a value obtained by dividing a command value of the displacement amount related to the servo control variable by its reference value, and the ratio thereof. A servo control method characterized in that it is determined according to the value of a parameter introduced for specifying. 8. The limit of motion performance is defined by a limit characteristic line on a characteristic diagram of acceleration (or force or torque) with respect to speed (or speed, angular velocity or rotation speed), and each limit performance line is different. A plurality of drive shafts having different shapes cause movement of a plurality of arms and / or tool mounting portions, and a robot configured by a plurality of servo systems including drive sources for these arms or tool mounting portions and their drive circuits. In the robot controller that controls the operation of, the servo control means for controlling each servo system uses the command means that issues a command value for the servo control variable, the command value related to the servo control variable, and the speed in the acceleration / deceleration curve. Define the relationship with the peak speed arrival time until the peak value is reached, and determine the peak speed arrival time value from the command value related to the servo control variable. Means for determining a peak velocity arrival time value, and a time axis extension / contraction for determining the value of the time axis extension / contraction parameter defined as a function of a dimensionless amount defined by dividing the peak velocity arrival time by its reference value. Parameter value determining means, and the acceleration (or force or torque) and speed (or speed, angular velocity) on one limit characteristic line extracted by inscribed approximation to each limit characteristic line related to the performance of the drive axis of the servo system. Alternatively, the shape of the acceleration / deceleration curve is defined under the condition that the operating point defined by (rotation speed) is located, and the peak speed arrival time according to the reference function of the acceleration / deceleration curve is set as the reference value of the time axis expansion / contraction parameter, Acceleration / deceleration music is performed by the expansion / contraction operation in the time axis direction for the reference function based on the parameter value for time axis expansion / contraction and the scaling operation for the reference function value based on the command value from the command means Robot controller being characterized in that a deceleration pattern generating means for delivering generated in the servo system with. 9. The limit of motion performance is defined by a limit characteristic line on a characteristic diagram of acceleration (or force or torque) with respect to speed (or speed, angular velocity or rotation speed), and each limit performance line is different. A plurality of drive shafts having different shapes cause movement of a plurality of arms and / or tool mounting portions, and a robot configured by a plurality of servo systems including drive sources for these arms or tool mounting portions and their drive circuits. In the robot control method related to the motion control, first, after specifying the limit characteristic lines relating to the characteristics of acceleration (or force or torque) with respect to speed (or speed, angular velocity or rotational speed) of each drive axis, One limit characteristic line that does not deviate from each limit characteristic line is determined by inscribed approximation to the characteristic line, and the acceleration ( Or force or torque)
And speed (or speed, angular velocity or number of revolutions) defines the shape of the acceleration / deceleration curve under the condition that the operating point is defined, and its reference function and the peak speed arrival time related to the reference function, Defined by defining the relationship between the specified value of the servo control variable and the peak speed arrival time, obtaining the value of the peak speed arrival time corresponding to the command value, and dividing this by the peak speed arrival time according to the above reference function. The value of the time axis expansion / contraction parameter specified as a function of the dimensionless amount is determined, and the expansion / contraction operation in the time axis direction for the reference function is performed based on the time axis expansion / contraction parameter value, and based on the command value of the servo control variable. By performing a scaling operation on the reference function value, an acceleration / deceleration curve is generated and sent as a control signal to each servo system. Tsu door control method.