JP2006338283A - Positioning controller - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a positioning controller capable of positioning a control target without producing a table of a velocity instruction. <P>SOLUTION: This positioning controller has: position detectors 104<SB>x</SB>, 104<SB>y</SB>, 104<SB>z</SB>detecting a present position when stopping the control target to a target position; a velocity instruction arithmetic means 16 calculating the velocity instruction from a relative distance between the present position and the target position; and velocity control units 17, 18, 19 controlling a velocity of the control target on the basis of the velocity instruction and an actual velocity in the present position of the control target. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a positioning control device, and more particularly to an electric motor positioning control device whose control object is an electric motor.

  As a conventional positioning control device, a positioning control device 39 shown in FIG. 6 is known. This conventional positioning control device controls an electric motor (not shown) by a feedback loop control system. The configuration of the control device 39 will be described.

  As shown in FIG. 6, the control device 39 that controls the electric motor that drives the cutter includes a subtractor 105, a position controller 101, a subtractor 106, a speed controller 102, and a subtractor 107. The control target 22 includes an electric motor and a mechanical load.

The subtractor 105 receives the position command signal X ^* from the position command setter 100 and the actual position signal X of the motor detected by the position detector 104 such as a resolver or encoder in the position feedback loop, and receives the position command signal. The actual position signal X is subtracted from X ^*, and the position deviation ε _p obtained from the calculation result is output to the position controller 101.

Position controller 101 receives the position deviation epsilon _p, and outputs a speed command signal V ^* so that the position deviation epsilon _p is zero to the subtractor 106, controls the position of the controlled object 22 by a position feedback loop.

The subtractor 106 obtains the speed command V ^* and the actual speed V (corresponding to the cutter moving speed) of the cutter base calculated from the rotational speed of the motor detected by the speed detector 103 such as an encoder in the speed feedback loop. Then, the actual speed V is subtracted from the speed command V ^*, and the speed deviation ε _v obtained from the calculation result is output to the speed controller 102.

Speed controller 102 receives the speed deviation epsilon _v, speed error epsilon _v outputs a current command value I ^* to be zero to the subtractor 107.

Subtractor 107, a current command value I ^*, and inputs the actual motor current value I by the current sensor disposed to the windings of the motor in a current feedback loop (not shown), from the current command value I ^* The motor actual current value I is subtracted, and the current deviation ε _I obtained from the calculation result is added to the control object 22. The electric motor that is the control target 22 is current-controlled so that the current deviation ε _I becomes zero. Eventually, when the actual speed signal V of the cutter table coincides with the speed command signal V ^* , the current value applied to the electric motor becomes zero and the generated torque of the motor becomes zero, resulting in no acceleration. That is, the motor speed is controlled at a constant speed to a certain target value.

On the other hand, when the maximum speed can be accelerated by the moving distance to the target position and the acceleration and deceleration rates of the control device, that is, when the speed pattern is trapezoidal or not, for example, it is divided into the case of a triangle, and the control device It is known to perform positioning control by creating a table of speed command values V ^* for each scan.

  However, in the conventional control apparatus, since the processing time for the calculation of creating the speed command table becomes long, the speed command table must be created in advance. As a result, for example, there may be a problem that the target position cannot be changed and positioned while the control target is moving. In addition, since each speed command table must be prepared for each positioning step, there is a possibility that a problem arises that a large amount of positioning patterns cannot be obtained due to the limitation of the memory capacity of the arithmetic unit.

  An object of the present invention is to provide a positioning control device capable of positioning a control target without creating a speed command table.

  In order to achieve the above object, the present invention provides a positioning control device for positioning a control object on a plane or space, a position detection means for detecting a current position when the control object is stopped at a target position, a current position, A speed command calculating unit that calculates a speed command from a relative distance to the target position, and a speed control unit that controls the speed of the control target based on the speed command and the actual speed at the current position of the control target.

  Further preferably, the speed command calculation means inputs a control object moving speed, inputs a ramp function unit that outputs a ramp-like control object moving speed having a speed gradient with respect to time, and a ramp-like control object moving speed, and performs control. Limit circuit that limits ramp-like control object movement speed and outputs restricted ramp-like control object movement speed with maximum value of target movement speed as upper limit, restricted ramp-like control object movement speed, current position, It has a speed command calculation circuit that inputs a target position and a deceleration rate and outputs a speed command component of each axis of the speed command.

  Further preferably, the control object is a cutter driven by an electric motor.

  As described above, according to the present invention, the object to be controlled can be positioned without creating a speed command table. Further, positioning can be performed even if the target position is changed while the control target is moving.

  The best mode for carrying out the present invention will be described below with reference to the drawings.

  FIG. 1 shows a diagram in which an electric motor positioning control device according to the present invention is applied to a three-axis machining device (cutter). FIG. 1A shows a plan view of a triaxial machining apparatus. FIG. 1B shows a side view of the three-axis machining apparatus in FIG.

FIG. 2 is a diagram showing a current position and a target position when the electric motor positioning control device according to the present invention performs positioning control. The X axis, the Y axis, and the Z axis indicate orthogonal coordinate axes, and the position coordinates A (X _A , Y _A , Z _A ) in space indicate the current position (point A), and the position coordinates B (X _B , Y _B , Z _B ) indicates the target position (point B), and the arrow indicates the positive direction of the directed straight line from the current position to the target position.

  FIG. 3 is a diagram showing an example of a speed pattern of the cutter moving speed in the electric motor positioning control device according to the present invention. The horizontal axis indicates the elapsed time t, and the vertical axis indicates the cutter moving speed V.

  FIG. 4 is a control block diagram showing the electric motor positioning control device according to the present invention. In FIG. 4, the same components as those in FIG. 6 are denoted by the same reference numerals.

As shown in FIG. 1, 3-axis machining apparatus 1, X-axis table 2, X-axis feed means 3, X-axis driving electric motor 22 _x, X-axis position detector 104 _x, Y-axis table 6, Y-axis feed means 7, Y-axis drive motor 22 _y , Y-axis position detector 104 _y , Z-axis table 10, Z-axis feed means 11, Z-axis drive motor 22 _z , Z-axis position detector 104 _z , cutter head 14, motor A positioning control device 15 is provided. It is assumed that the controlled objects 22 each include a driving motor and a load.

  The X-axis table 2 is guided by an X-axis guide (not shown) so that it can reciprocate in the X-axis direction, and the Y-axis table 6 and the Z-axis table 10 are mounted.

The X-axis feed means 3 linearly rotates the X-axis drive motor 22 _x so that the X-axis table 2 can be reciprocated on the X-axis guide, for example, by rotationally driving a feed screw combined with a nut. It is a mechanical element that converts to motion.

The X-axis drive motor 22 _x is a drive source for reciprocating the X-axis table 2 in the X-axis direction.

The X-axis position detector 104 _x is a detector that detects the amount of movement of the X-axis table 2 in the X-axis direction, and detects the position by time-integrating the speed of the X-axis speed detector (not shown).

  The Y-axis table 6 is guided by a Y-axis guide (not shown) so as to be able to reciprocate in the Y-axis direction, is disposed on the X table 2, and is configured to mount the Z-axis table 10.

  The Y-axis feed means 7 is a mechanical element that converts the rotational motion of the Y-axis drive motor 8 into a linear motion so that the Y-axis table 6 can be moved, similarly to the X-axis feed means 3.

The Y-axis drive motor 22 _y is a drive source for reciprocating the Y-axis table 6 in the Y-axis direction.

The Y-axis position detector 104 _y is a detector that detects the amount of movement of the Y-axis table 6 in the Y-axis direction, and detects the position by time-integrating the speed of a Y-axis speed detector (not shown).

  The Z-axis table 10 is guided by a Z-axis guide (not shown) and disposed on the Y-axis table 6 so that the Z-axis table 10 can reciprocate in the Z-axis direction.

  The Z-axis feed means 11 is a mechanical element that converts the rotary motion of the Z-axis drive motor into a linear motion so that the Z-axis table 10 can be moved, like the Y-axis feed means 7.

The Z-axis drive motor 22 _z is a drive source for reciprocating the Z-axis table 10 in the Z-axis direction.

The Z-axis position detector 104 _z is a detector that detects the amount of movement of the Z-axis table 10 in the Z-axis direction, and detects the position by time-integrating the speed of a Y-axis speed detector (not shown).

  The cutter head 14 is configured to hold a cutter (processing tool) disposed on the Z-axis table 10.

As shown in FIG. 4, the motor positioning control device 15 includes a subtractor 106 _x , a speed controller 102 _x , and a subtractor 107 _x for the speed command calculation means 16 provided for the X, Y, and Z axes and the X axis. Similarly, a subtractor 106 _y , a speed controller 102 _y , a subtractor 107 _y for the Y axis, and a subtractor 106 _z , a speed controller 102 _z , and a subtractor 107 _z for the Z axis. Prepare.

The speed command calculating means 16 inputs the cutter moving speed V, the current position coordinates, the target position coordinates, and the deceleration rate δ, and outputs a speed command in each coordinate axis direction obtained from the calculation result to the subtractor 106 _x . With respect to the X axis, the subtractor 106 _x includes an X-axis velocity command V _x ^*, enter the actual speed V _x by the speed detector 103 subtracts the actual velocity V _x from the X-axis velocity command V _x ^* The X-axis speed deviation ε _vx obtained from the calculation result is output to the speed controller 102 _x .

The speed controller 102 _x receives the X-axis speed deviation ε _vx , multiplies the X-axis speed deviation ε _vx by the X-axis speed gain constant, and obtains an X-axis torque command, that is, an X-axis current command I _x obtained from the calculation result. ^* Is output to the subtractor 107 _x .

The subtractor 107 _x receives the X-axis current command I _x ^* and the actual current I _x from a current sensor (not shown) disposed in the winding of the X-axis drive motor 22 _x , and is obtained from the calculation result. The X-axis current deviation ε _Ix is added to the X-axis control target 22 _x . Since the Y axis and the Z axis are the same as the X axis, description thereof is omitted.

  FIG. 5 is a control block diagram showing the speed command calculating means 16 in the electric motor positioning control apparatus according to the present invention.

  As shown in FIG. 5, the speed command calculation means 16 includes a ramp function unit 25, a limit circuit 26, and a speed component calculation circuit 27.

Ramp function device 25 inputs the cutter moving speed of the moving speed of the cutter, and outputs the ramp-shaped cutter moving speed V _R to the limit circuit 26.

Limiting circuit 26 receives the ramp-shaped cutter moving speed V _R, the maximum value V _max of the cutter moving speed obtained by the formula 2 shown below as upper limit, to limit the ramp-like cutter moving speed V _R, restricted The ramp-shaped cutter moving speed V _L is output to the speed component calculation circuit 27.

The speed component calculation circuit 27 includes a limited ramp-shaped cutter moving speed V _L , a current position, that is, position coordinates A (X _A , Y _A , Z _A ), and a target position, that is, position coordinates B (X _B , Y _B , and Z _B), enter the deceleration rate [delta], the speed command V ^* of the velocity component V _x of the respective axes ^*, V _y ^*, calculates the V _z ^*, respectively subtractor 106 _x, 106 _y, 106 _z Output to.

Subtractor 106 _x includes an X-axis velocity command V _x ^*, enter the actual speed V _x by the speed detector 103 _x, and subtracting the actual velocity V _x from the X-axis velocity command V _x ^*, obtained by the calculation result The X-axis speed deviation ε _vx is output to the speed controller 102 _x .

  As a result, the driving motor, that is, the control target can be positioned without creating a speed command table.

  Next, the operation of the motor positioning control device will be described.

As shown in FIG. 2, when positioning from point A to point B in orthogonal coordinates (X, Y, Z), the distance L to the target position is:
L = √ ((X _B −X _A ) ² + (Y _B −Y _A ) ² + (Z _B −Z _A ) ² ) (1)
It becomes.

First, from the state where point A is moving at a constant speed, it is assumed that the point begins to decelerate at a constant deceleration rate δ (section S _d shown in FIG. 3), and generation of a speed command when stopping at the target position B is performed. A method will be described. The maximum value V _max of the cutter moving speed that does not pass through the target position B point separated from the point A by the distance L is
V _max = √ (2δL) (2)
It becomes.

On the other hand, the direction cosine of the straight line AB is
COSα = (X _B −X _A ) / √ ((X _B −X _A ) ² + (Y _B −Y _A ) ² + (Z _B −Z _A ) ² )
(3)
COSβ = (Y _B −Y _A ) / √ ((X _B −X _A ) ² + (Y _B −Y _A ) ² + (Z _B −Z _A ) ² )
(4)
COSγ = (Z _B −Z _A ) / √ ((X _B −X _A ) ² + (Y _B −Y _A ) ² + (Z _B −Z _A ) ² )
(5)
It becomes.

  Here, α, β, and γ indicate angles formed by the directed straight line AB and the positive directions of the X, Y, and Z axes, respectively.

Therefore, the velocity components V _x , V _y , V _z in the coordinate axis direction are
V _x = V _max COS α = V _max × (X _B -X _A ) / L (6)
_{V y = V max COSβ = V} max × (Y B -Y A) / L (7)
V _z = V _max COSγ = V _max × (Z _B -Z _A ) / L (8)
It becomes. Here, V _x , V _y, and V _z indicate speed components of the speed V in the X-axis, Y-axis, and Z-axis directions, respectively.

Therefore, if the current position A (X _A , Y _A , Z _A ) can be detected, the speed command in each coordinate axis direction at the time of deceleration can be obtained by Expression 6 to Expression 8. Here, as a display of the speed command, an asterisk (*) is added instead of the speed components V _x , V _y , and V _z to make V _x ^* , V _y ^* , and V _z ^* .

  Next, a method for generating a speed command when the cutter moving speed accelerates from zero and is steady will be described.

The speed command at the time of acceleration of the cutter moving speed V (section S _a shown in FIG. 3) is obtained by inputting the cutter moving speed V to the ramp function unit 25 having a desired slope, thereby making the ramp-shaped cutter moving speed as a speed command. V _R is output to the limit circuit 26.

Further, with respect to the speed command at the normal time of the cutter moving speed V (section S _f shown in FIG. 3), the ramp-shaped cutter moving speed V _R is inputted to the limit circuit 26 to obtain the maximum of the cutter moving speed obtained by Expression 2. The value V _max is set as the upper limit, the ramp-shaped cutter moving speed V _R is limited, and the limited ramp-shaped cutter moving speed V _L as a speed command is output to the speed component calculation circuit 27.

On the other hand, the limited ramp-shaped cutter moving speed V _L generated as described above, the current position, that is, position coordinates A (X _A , Y _A , Z _A ), and the target position, that is, position coordinates B (X _B , Y _B , Z _B ) and the deceleration rate δ are input to the speed component calculation circuit 27, the speed components V _x ^* , V _y ^* , V _z ^* of each axis of the speed command V ^* are obtained by Expressions 1 to 8. Calculate and output to each of the subtractors 106 _x , 106 _y , 106 _z .

Furthermore, for example, the position and speed control for the X-axis, entering actual speed V _x by the speed command V _x ^* and the speed detector 103 _x to a subtractor 106 _x, the actual speed V _x from the speed command V _x ^* The speed deviation ε _vx obtained by the subtraction is output to the speed controller 102 _x . When the speed deviation ε _vx is input to the speed controller 102 _x , the speed deviation ε _vx is multiplied by a speed gain constant, and a torque command obtained as a result of the operation, that is, a current command I _x ^* is output to the subtractor 107 _x . When the current command I _x ^* and the actual current value I _x by a current sensor (not shown) disposed in the motor winding are input to the subtractor 107 _x , the actual current value I _x is obtained from the current command I _x ^*. The current deviation ε _Ix obtained from the calculation result is added to the control target 22 _x . Thereby, the speed and position of the electric motor are controlled so that the current deviation ε _Ix becomes zero, and the electric motor can be controlled to the target speed and the target position. As a result, the driving motor, that is, the control target can be positioned without creating a conventional speed command table.

  The position and speed control for the X axis has been described above, but the same applies to the Y axis and the Z axis.

  In the above description, the present invention is applied to the case where the controlled object is a rotary electric motor. However, the present invention can also be applied to the case of a linear electric motor instead of the rotary electric motor. Further, the present invention can be applied to, for example, a hydraulic actuator or a pneumatic actuator instead of an electric actuator such as an electric motor.

  Furthermore, the present invention can be applied to the case where the control axes are three axes, but the present invention can also be applied to the case of two axes.

  Moreover, although this invention was applied to the processing apparatus, it is applicable to the target object which needs positioning without being restricted by the processing apparatus.

  Furthermore, although the present invention has been applied to a trapezoidal velocity pattern, it can also be applied to a triangular shape.

The figure which applied the electric motor positioning control apparatus which concerns on this invention to the triaxial processing apparatus is shown. It is a figure which shows the present position and target position when the electric motor positioning control apparatus which concerns on this invention performs positioning control. It is a figure which shows an example of the deceleration rate of the cutter moving speed in the electric motor positioning control apparatus which concerns on this invention. It is a control block diagram which shows the electric motor positioning control apparatus which concerns on this invention. It is a figure which shows the speed command calculating means in the electric motor positioning control apparatus which concerns on this invention. It is a control block diagram which shows the electric motor positioning control apparatus of a prior art.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 XYZ processing apparatus 2 X-axis table 3 X-axis feed means 6 Y-axis table 7 Y-axis feed means 10 Z-axis table 11 Z-axis feed means 14 Cutter head 15 Electric motor positioning control device 16 CPU calculation unit (speed command calculation means)
17 X-axis motor speed control unit 18 Y-axis motor speed control unit 19 Z-axis motor speed control unit 22 _x X-axis drive motor (X-axis control target)
22 _y Y-axis drive motor (Y-axis control target)
22 _z Z-axis drive motor (for Z-axis control)
25 Ramp Function Unit 26 Limit Circuit 27 Speed Component Calculation Circuit 39 Conventional Motor Positioning Control Device 100 Position Command Setter 101 Position Controller 102 Speed Controller 103 Speed Detector 104 Position Detector 104 _x X-axis Position Detector 104 _y Y Axis position detector 104 _z Z-axis position detector 105 Subtractor 106 Subtractor 107 Subtractor X _A X-axis actual position signal Y _A Y-axis actual position signal Z _A Z-axis actual position signal V ^* _x X-axis speed command signal V ^* _y Y-axis speed command signal V ^* _z Z-axis speed command signal

Claims (3)

In a positioning control device for positioning a control object on a plane or space,
Position detecting means for detecting a current position when the control object is stopped at a target position;
Speed command calculating means for calculating a speed command from a relative distance between the current position and the target position;
Speed control means for speed-controlling the control object based on the speed command and the actual speed at the current position of the control object;
A positioning control device comprising: The speed command calculating means includes
A ramp function unit that inputs a controlled object moving speed and outputs a ramp-like controlled object moving speed having a speed gradient with respect to time;
A limit circuit that inputs a ramp-shaped control target moving speed, sets the maximum value of the control target moving speed as an upper limit, limits the ramp-shaped control target moving speed, and outputs a limited ramp-shaped control target moving speed;
And a speed command calculation circuit for inputting a speed command component for each axis of the speed command by inputting a limited ramp-like control target moving speed, a current position, a target position, and a deceleration rate. Item 4. The positioning control device according to Item 1.   The positioning control device according to claim 1, wherein the control target is a cutter driven by an electric motor.

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