JP3064038B2 - Positioning control system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a positioning control system for positioning a plurality of independent devices to be positioned by sequentially connecting the devices to a positioning controller. The present invention relates to a positioning control system with improved data transmission at the time of connection.

[0002]

2. Description of the Related Art Factory automation (FA)
Is a transfer line system such as an automobile production line. In this transfer line system, a plurality of types of processing machines, welding machines, and the like are arranged along a moving line (transfer line), and desired processing is performed on a workpiece moving on the transfer line. As the tonsfer line, there are those using a belt conveyor or a traveling cart.

FIG. 8 is a diagram showing a schematic configuration of a transfer line system using a traveling vehicle. The transfer line 10 is formed in a loop shape, and a plurality of traveling vehicles move clockwise on the line. This figure shows a state in which six traveling vehicles 6a to 6f move. Around the transfer line 10, there are a work station 20, a work removal station 30, a positioning control station 40, a work installation station 50, and the like. The traveling vehicles 6a to 6f are transfer lines 10
Move clockwise up and stop at the corresponding location for each station. The traveling carriages 6a to 6f have holding means 7a to 7f for holding the work. The holding means 7a to 7f include a holding head for directly holding the work, and a head positioning means for positioning the holding head at a predetermined position according to the shape of the work.

[0004] The work station 20 controls the transfer machine to perform desired processing (such as drilling and welding) on the workpieces on the holding means 7d to 7f. The work removal station 30 transfers the finished work to the traveling carriage 6c.
And transfer it to another processing station (such as an assembly station or a painting station). The positioning control station 40 drives and controls the head positioning means of the holding means 7b to control the positioning of the holding head at a predetermined position according to the shape of the work set at the next work setting station. Work setting station 50
Is attached to the holding means 7a positioned at the work station 20.
The work to be processed is set up. As described above, since the positioning control station 40 controls the positioning of the holding heads of the holding units 7a to 7f in accordance with the shape of the work, the holding units 7a to 7f work the work stations while sequentially holding the works having different shapes. 20.

FIG. 9 shows the positioning control station 4 shown in FIG.
It is a figure which shows the outline of the connection relationship between 0 and the holding means 7b on the traveling vehicle 6b. The connection means (connectors) 9, 9b are detachable from each other, and electrically connect the positioning control station 40 and the holding means 7b. The connecting means 9 is provided on the positioning station 40 side, and the connecting means 9b is provided on the traveling carriage 6b side. The traveling vehicles 6a to 6f are provided with connection means 9a to 9f, respectively.

[0006] The positioning of the holding head in the positioning control station 40 is performed by a servo control system. This servo control system detects a movement amount of an actuator such as a servomotor, that is, a position, controls a drive current of the servomotor in accordance with a deviation between the detected position and a command position, and determines a rotation position of the servomotor by a PTP (Point to Point).
(Point) control.

The positioning control station 40 includes a host controller 1, positioning control means 2, brake control means 3X, 3Y, 3Z, and current control units 4X, 4Y, 4Z.
And the position sensor conversion means 5X, 5Y, 5Z.
The holding means 7b is composed of a holding head and a head positioning means, but the holding head is omitted in this drawing, and servo motors 6X, 6Y, 6 which are main parts of the head positioning means are omitted.
Z, brake means 7X, 7Y, 7Z and rotational position sensors 8X, 8Y, 8Z. Head positioning means is 3
It is a shaft configuration.

The host controller 1 includes brake means 7X,
A brake release signal for releasing the braking operation of 7Y, 7Z is output to brake control means 3X, 3Y, 3Z, and a position command signal for positioning a holding head (not shown) at a target position is controlled. Output to means 2.

The brake control means 3X, 3Y, 3Z respond to the input of the brake release signal to control the brake means 7X, 7Y,
A brake release voltage of about 24 [V] is applied to 7Z to release the braking operation of the brake means 7X, 7Y, 7Z. The brake means 7X, 7Y, 7Z are constituted by electromagnetic brakes which are off-ready (brake-on when voltage is applied and brake is off when voltage is applied).

The positioning control means 2 comprises a host controller 1
To input a position command signal from the controller and to position the holding head at a position corresponding to the signal, current control units 4X, 4Y, 4
A torque signal (current command signal) is output to Z. The current control units 4X, 4Y, 4Z receive the torque signal from the positioning control means 2 and supply a driving current according to the torque signal to the connection means 9, 9b.
Are supplied to the servo motors 6X, 6Y, 6Z via the.
The servo motors 6X, 6Y and 6Z drive a plurality of control axes for positioning the holding head at a desired position by a rotational driving force.

Each of the servomotors 6X, 6Y, 6Z has a rotational position sensor 8X, 8Y,
8Z is provided. These rotation position sensors 8X, 8Y, 8Z
Is not a position sensor that generates an incremental pulse like a pulse encoder or the like, but an absolute type position sensor that absolutely detects a rotational position and outputs an absolute position signal. Because the connecting means 9 and the connecting means 9b are separated on the transfer line 10 other than the positioning control station 40, the connecting means 9, 9
This is because the rotational positions of the servo motors 6X, 6Y, 6Z must be able to be detected immediately at the time point b is connected.

The position sensor conversion means 5X, 5Y, 5Z
Position signals from the rotational position sensors 8X, 8Y, 8Z are input, converted into position data indicating the rotational positions (current positions of the holding heads) of the servomotors 6X, 6Y, 6Z and output to the positioning control means 2. Positioning control station 40
Controls the rotational positions of the servo motors 6X, 6Y, 6Z constituting the holding means 7a to 7f on the traveling carriages 6a to 6f, and controls the positioning of the holding head at a target position.

[0013]

The conventional positioning control station 40 moves with the connecting means 9 when the traveling vehicles 6a to 6f sequentially move on the transfer line 10 and reach the positioning station 40. Trolley 6
The connecting means 9a to 9f on the sides a to 6f are connected, the holding heads of the holding means 7a to 7f are positioned, and after the positioning is completed, the connection between them is released.

In connection means 9, 9a to 9f,
The number of signal lines required to transmit the brake release voltage from the brake control means 3X to the brake means 7X is two, and the number of signal lines required to transmit the drive current from the current control unit 4X to the servo motor 6X is two. The number is four. Therefore, a total of 18 signal lines are required between the connecting means 9, 9a to 9f to transmit the brake release voltage and the driving current to the holding means. On the other hand, since the signal output from the rotational position sensor 8X is a digital position signal (16-bit configuration) indicating an absolute position, about 16 signal lines are required. Therefore, the connection means 9, 9a-
A total of about 48 position signal lines are required between 9f.

In general, the mechanical life of a detachable connector (the limit at which the initial performance can be stably maintained) is about 1,000 times in the number of times of attachment and detachment. As a result, the contact state becomes unstable, the contact resistance increases, and the reliability of signals transmitted between the connectors decreases.

Accordingly, the brake control means 3 is connected between the connection means 9, 9a to 9f which are frequently attached and detached each time the positioning control is performed.
X, 3Y, 3Z brake release voltages, current control units 4X,
4Y, 4Z drive current and rotational position sensors 8X, 8Y,
Transmission of an 8Z position signal or the like causes an error in positioning accuracy. In particular, the servo control system includes the rotational position sensor 8
Since the positioning control is performed based on the position signals of X, 8Y, and 8Z, for example, when an error occurs in the position signal, the rotation speeds of the servo motors 6X, 6Y, and 6Z rapidly increase or reversely rotate. Runaway.

That is, the position signal is more susceptible to the contact state than the brake release voltage and the drive current, and the reliability is significantly reduced. This is because the connection means 9, 9a to 9f
Has more signal lines for the position signal than the signal lines for transmitting the brake release voltage and the drive current, the drive current voltage value is several hundred volts, and the brake voltage voltage value is several tens of volts. This is because the voltage value of the position signal is as small as 5 to 12 volts.

SUMMARY OF THE INVENTION The present invention has been made in view of the above points, and when positioning control is performed between a device to be positioned and a positioning control device via a connecting means, a position signal connected by the connecting means is used. An object of the present invention is to provide a positioning control system in which an error does not occur.

[0019]

SUMMARY OF THE INVENTION A positioning control system according to the present invention comprises a control axis which is controlled to be positioned at a desired position by a driving means, and a position detecting means which detects a position signal indicating a current position of the control axis. A plurality of moving bodies that move along a predetermined path, and are provided independently of each other, and the position signal from the position detecting means and the position signal from the upper controller are provided. A driving current is supplied to the driving unit based on a position command signal, and the positioning control unit controls the positioning of the control axis at a desired position. The positioning control unit includes at least one of the plurality of moving bodies. A first connection unit for electrically connecting temporarily, supplying the position signal to the positioning control unit, and supplying the drive current to the drive unit And the number of signal lines in the first connection portion is smaller than the total number of signal lines of the position signal output from the position detection means in the positioning means. And a signal line converting means for adapting the position signal output from the position detecting means in the positioned means to a signal line in the first connecting part.

[0020]

The moving body moves along a predetermined route such as a transfer line. The moving body has a positioning means including a control axis which is controlled to be positioned at a desired position by a driving means, and a position detecting means which detects a position signal indicating the current position of the control axis. Therefore, by appropriately controlling the driving current of the driving means, the positioning means is positioned at a predetermined position. The control of the drive current is performed by a positioning control means provided independently of the moving body.

The positioning control means supplies a driving current to the driving means based on the position signal from the position detecting means and the position command signal from the host controller, and controls the positioning of the control axis to a desired position. Since the moving body and the positioning control means are independently separated from each other, they must be electrically connected to each other in order to supply a driving current to the driving means for positioning.

The connection means electrically connects the positioning control means to at least one of the plurality of moving bodies. The first connection of the connection means supplies a position signal to the positioning control means, and the second connection supplies a drive current to the drive means. In the connecting means, the number of signal lines in the connecting means for supplying the position signal to the positioning control means is smaller than the number of signal lines of the position signal output from the position detecting means. The smaller the number of signal lines in the connection means, the less the influence of the contact state of the connection means, and the more reliable the transmitted position signal is.

However, the number of signal lines of the position signal output from the position detecting means is different from the number of signal lines in the first connection portion. Therefore, the signal line converting means adapts the position signal output from the position detecting means in the positioned means to the signal lines in the first connection part, and eliminates the difference in the number of signal lines.
Thus, even if the number of signal lines in the connection means is smaller than the number of signal lines of the position signal output from the position detection means, the position signal can be accurately supplied to the positioning control means.

[0024]

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings. FIG. 1 is a diagram showing a positioning control system according to one embodiment of the present invention. In the present embodiment, a description will be given assuming that the configurations of the holding units 7a to 7f on the traveling vehicles 6a to 6f are all the same. Therefore, FIG. 1 shows only the connection relationship between the positioning control station 40 of FIG. 8 and the holding means 7b on the traveling carriage 6b, and the other holding means 7a, 7
The connection relationship with c to 7f is omitted.

The connection means (connectors) 9, 9b are detachable from each other, and electrically connect the positioning control station 40 and the holding means 7b. The connection means 9b is constituted by a spring wire contact having a durability of 500,000 times or more of attachment and detachment times. The spring wire contacts form a number of contact points with the plug by a number of spring wires arranged on the circumference of the plug. Since this spring wire forms a contact point and also serves as an insert guide, it can withstand much more attachment and detachment than a general slit socket type connector, and maintains a stable contact pressure and contact state for a long time. to continue.

The positioning control station 40 comprises a host controller 1, positioning control means 2, brake control means 3, current control section 4, position sensor conversion means 5, and current / voltage switching means 12. The holding means 7b is composed of a holding head and a holding head positioning means. However, in this drawing, the structure of the holding head is omitted, and servo motors 6X, 6Y, 6Z which are main parts of the head positioning means are omitted.
And brake means 7X, 7Y, 7Z and rotational position sensors 8X, 8Y, 8Z.

The head positioning means is a servo motor 6
X is X axis, servo motor 6Y is Y axis, servo motor 6Z
Is a positioning means having a three-axis configuration with Z as the Z axis. In the present embodiment, the case where the holding unit has a three-axis configuration will be described. However, even if the holding unit has another one-axis or two-axis configuration, or these control axes (one-axis, two-axis or three-axis It is needless to say that it may have a plurality of

The present embodiment is different from the conventional one in that the position signals output from the rotational position sensors 8X, 8Y, 8Z are switched by the sensor signal switching means 11 and selectively input to the position sensor conversion means 5. The configuration is such that the brake release voltage of the brake control means 3 and the drive current of the current control unit 4 are switched by the current / voltage switching means 12, respectively, and the servo motors 6X, 6Y,
6Z and the brake means 7X, 7Y, 7Z.

That is, in the present embodiment, the number of signal lines in the connecting means 9 and 9b for supplying the position signals output from the rotational position sensors 8X, 8Y and 8Z to the positioning control means 2 is determined by the rotational position sensors 8X and 8X. It is configured to be smaller than the total number of signal lines of the position signals output from 8Y and 8Z, and the components of the positioning station 40 are simplified as compared with the conventional one. In the present embodiment, the number of signal lines of the position signals output from the rotation position sensors 8X, 8Y, 8Z is 30 (10 × 3) in total, but the connection for supplying the position signals to the positioning control means 2 is provided. The number of signal lines in the means 9 and 9b is one third of the number, ie, ten. However, the number of signal lines for control of the sensor signal switching means 11 increases, but this is not a problem in view of the total decrease.

The reason why the number of signal lines of the position signals output from the rotational position sensors 8X, 8Y, 8Z is ten is that the rotational position sensors 8X, 8Y, 8Z are disclosed in, for example, Japanese Patent Application Laid-Open No. 57-7040.
This is because an inductive phase shift type position sensor as disclosed in JP-A-6-106 or JP-A-58-106691 is used. The configuration of this phase shift type position sensor will be described later.

The host controller 1 includes brake means 7X,
A brake release signal for releasing the braking operation of 7Y, 7Z is output to the brake control means 3, and a position command signal for positioning the servomotors 6X, 6Y, 6Z (holding heads) at target positions is controlled. Output to means 2. At this time, the host controller 1 controls the brake means 7X, 7Y, 7Z and the servomotors 6X, 6Y,
The axis switching signal is output to the sensor signal switching means 11 and the current / voltage switching means 12 according to which axis in 6Z is to be positioned.

The current / voltage switching means 12 is connected to the brake control means 3 and the current control section 4, and applies a brake release voltage to each of the brake means 7X, 7Y, 7Z according to an axis switching signal from the host controller 1. The drive current is switched and connected to the servomotors 6X, 6Y, and 6Z, respectively.
Further, the sensor signal switching means 11 includes the position sensors 8X, 8
Y, 8Z, and switches the position signals from the position sensors 8X, 8Y, 8Z to the position sensor conversion means 5 according to the axis switching signal from the host controller 1, and connects them. Therefore, the brake means 7X, 7Y, 7Z, the servo motors 6X, 6
Y, 6Z and a set of position sensors 8X, 8Y, 8Z constitute a brake control unit 3, a current control unit 4, and a positioning control unit 2.
To form independent servo control loops.

The sensor signal switching means 11 and the current / voltage switching means 12 include the position sensors 8X, 8Y, 8Z, the brake means 7X, 7Y, 7Z, and the servomotors 6X, 6Y, 6
Z, a switching element provided corresponding to each of Z, and one set of position sensors, by selectively conducting only the switching elements corresponding to the brake means and the servomotor, one set of position sensors, It is configured to selectively connect only the brake means and the servomotor.

The brake control means 3 applies a brake release voltage of approximately 24 [V] to the brake means 7X, 7Y, 7Z selected by the host control 1 via the current / voltage switching means 12 in response to the input of the brake release signal. The braking operation of the braking means 7X, 7Y, 7Z is released. The brake means 7X, 7Y, 7Z are constituted by electromagnetic brakes which are off-ready (brake-on when voltage is applied and brake is off when voltage is applied). Therefore,
The brake means 7X, 7Y, 7Z maintain the braking operation in a normal state where no brake release voltage is applied, and release the braking operation by applying a brake release voltage of 24 [V]. .

The positioning control means 2 comprises a host controller 1
, And outputs a torque signal (current command signal) corresponding to the position command data F0 to the current control unit 4 to control the positioning of the servomotors 6X, 6Y, and 6Z (holding heads) at target positions. The current control unit 4 is a positioning control unit 2
And a driving current corresponding to the torque signal is supplied to any of the servomotors 6X, 6Y, 6Z via the current-voltage switching means 12 and the connection means 9, 9b.

The servo motors 6X, 6Y and 6Z drive a plurality of control axes for controlling the positioning of the holding head at a desired position by a rotational driving force. Servo motor 6X, 6
Y and 6Z are, for example, synchronous AC servomotors. Servo motors 6X, 6Y, 6Z have position sensors 8X, 8Y, 8 for absolutely detecting their current positions.
Z is combined. These position sensors 8X, 8Y, 8Z
It is composed of an inductive phase shift type position sensor.

The position sensor conversion means 5 converts the position signals P1X, P1Y, P1 from the position sensors 8X, 8Y, 8Z.
One of Z is input via the sensor signal switching means 11, converted into digital position data P 2, and output to the positioning control means 2. The position data P2 is digital data indicating the rotational positions (current positions of the holding heads) of the servo motors 6X, 6Y, 6Z. Also, position signals P1X, P1 output from the position sensors 8X, 8Y, 8Z.
Since Y and P1Z absolutely indicate the rotational positions of the servo motors 6X, 6Y and 6Z, the connection control means 9 and the connection means 9b are connected, so that the positioning control means 2 controls the servo motors 6X, 6Y and 6Z. Absolute rotation position data can be immediately recognized, and positioning control can be executed.

The positioning control station 40 includes servo motors 6X, 6Y, 6Z constituting the holding means 7a to 7f.
Are sequentially switched to control the rotational position, and control the positioning of the holding head to the target position. The positioning control station 40 performs such a series of operations on the traveling carriage 6a that sequentially moves on the transfer line 10.
６6f.

In addition to the signal lines shown in FIG. 1, for example, a bogie identification signal line for specifying the traveling bogies 6a to 6f and the connecting means 9, 9b are surely fitted between the connecting means 9, 9b. There are a mating identification signal line for recognizing whether or not they are matched, a power line for supplying power to the sensor signal switching means 11, and the like, but these are omitted for convenience of explanation.

Next, the detailed configurations of the positioning control means 2 and the current control section 4 will be described with reference to FIG. The host controller 1 is connected to the position controller 21 and controls the servo motors 6X. The position command data F0 indicating the target positions of 6Y and 6Z is output to the position control unit 21. The host controller 1 is connected to the serial communication interface 23 and outputs various data D1.

The positioning control means 2 includes a position control unit 21 and
Speed control unit 22 and serial communication interface 23
And a speed calculation unit 24. Position control unit 21
Is connected to the host controller 1 and the position sensor conversion means 5, and the position command data F0 indicating the target position of the servo motors 6X, 6Y, 6Z and the servo motors 6X, 6Y,
Position data P2 indicating the current position of 6Z is input.

The position control unit 21 is connected to the speed control unit 22 and calculates a deviation between the position command data F0 and the position data P2, and obtains a speed command signal F1 according to the position deviation.
Is output to the speed control unit 22. Position sensor conversion means 5
Outputs the position data P2 and outputs the position sensors 8X,
The phase signal P3 for controlling the switching position of the field of the servo motors 6X, 6Y, 6Z is generated from the position signals P1X, P1Y, P1Z of 8Y, 8Z and output to the serial communication interface 23.

The speed control unit 22 is connected to the position control unit 21, the speed calculation unit 24, and the serial communication interface 23, and indicates the speed command signal F1 from the position control unit 21 and the current speed of the servomotors 6X, 6Y, 6Z. The speed signal F2 is input. The speed signal F2 is obtained by converting the position data P2 of the position sensor converting means 5 by the speed calculating unit 24. The speed calculation unit 24 is a position sensor conversion unit 5
Is input, and the rotational speeds of the servo motors 6X, 6Y, 6Z are calculated by digital calculation based on the amount of change in the position data P2 per a predetermined unit time.

The speed control unit 22 is connected to the serial communication interface 23, finds the difference between the speed command signal F1 and the speed signal F2, and determines the torque signals (currents) of the servo motors 6X, 6Y, 6Z according to the speed difference. Command signal)
T1 is output to the serial communication interface 23.

The serial communication interface 23 is connected to the host controller 1, the speed control unit 22, and the position sensor conversion means 5, and receives various data D1, torque signal T1, and phase signal P3 from the host controller 1 via a communication line. The data is transmitted to the serial communication interface 41 of the current control unit 4. Serial communication interface 23
And the serial communication interface 41 are connected by a bidirectional communication line. Various data D1 from the host controller 1 and data D1 generated in the current control unit 4 are provided.
2 is exchanged between the host controller 1 and the current controller 4.

The current control section 4 comprises a serial communication interface 41 and a current amplifier 42. The serial communication interface 41 is connected to the serial communication interface 23 of the positioning control means 2 and the current amplifier 42, receives the torque signal T1 and the phase signal P3 from the serial communication interface 23, and outputs the torque signal (current command signal) T2 and the phase signal P2. The signal P4 is output to the current amplifier 42 as a signal P4, and various data D2 such as a status signal indicating a control state in the current amplifier 42 is transmitted to the serial communication interface 23.

The current amplifier 42 is connected to the serial communication interface 41 and the current / voltage switching means 12, receives the torque signal T2 and the phase signal P4, generates a three-phase PWM signal based on the input, and drives the power transistor. Then, the drive current is supplied to each phase (U-phase, V-phase, W-phase) of the servomotors 6X, 6Y, 6Z via the current-voltage switching means 12.
Phase). At this time, the current detection isolator CT
As a result, the current feedback signal T3 of the U-phase and V-phase current values is fed back to the current amplifier 42. The current amplifier 42 includes a torque signal (current command signal) T2 for each phase.
The driving current obtained by amplifying the deviation between the current feedback signal T3 and the current feedback signal T3 of each phase is supplied to the servomotors 6X, 6Y, 6Z via the current-voltage switching means 12.

The serial communication interface 41
And the current amplifier 42 are connected by a data line.
Various data can be exchanged between the two. The current amplifier 42 has a function of detecting control states such as overload, power supply voltage drop, overcurrent, overvoltage, and overheating of the servomotor, and a servo status signal indicating these control states, It has a memory for storing various data such as an ID code indicating the rating and a motor rating code indicating the rating of the servomotor to be controlled.

The data stored in the memory in the current amplifier 42 is transmitted as necessary to the host controller 1 via the data line and the serial communication interfaces 41 and 23 as the data D2. The motor rating code is stored as a table in the memory. Therefore, by selecting a table number corresponding to the rating of the servo motor connected via the communication line, the current amplifier 42 can control servo motors having different ratings. As a result, even when the servo motor is replaced, the current control unit can be changed to a control system corresponding to the servo motor simply by changing the table number.

That is, the servo motors 6X, 6Y, 6Z
If all the ratings are the same, only the switching control may be performed while the table number indicating the rating of the servomotor is kept constant. If the servo motors 6X, 6Y, and 6Z have different ratings, a table number indicating the rating of the servo motor is transmitted via a communication line before controlling the servo motor. The section 4 can control the servomotors having different capacities by sequentially switching them.

Next, the operation of this embodiment will be described. First,
When the connecting means 9 on the positioning station 10 side and the connecting means 9b on the traveling trolley 6b are connected to form a servo control system as shown in FIG. 1, at this point, the host controller 1 controls the servo motors 6X and 6Y. , 6Z is transmitted to the serial communication interface 41 of the current control unit 4 via the serial communication interface 23. The serial communication interface 41 transmits the transmitted table number data to the current amplifier 42. Thereby, the current amplifier 42
Specifies the ratings of the servo motors 6X, 6Y, 6Z, and functions as a current control unit corresponding to the ratings of the servo motors 6X, 6Y, 6Z. At this time, the servo motor 6X,
6Y and 6Z may have different ratings.

In this embodiment, since all the structures of the holding means on the traveling trolley are described as being the same, the above-described processing is repeated even if the holding means changes in order as the traveling trolley moves. No need. However, if the configuration of the holding means is different for each traveling vehicle, the above-described processing is required. That is, when the ratings of the servo motors 6X, 6Y, 6Z constituting the holding means are changed in accordance with the movement of the traveling vehicle, the servo motors 6X, 6Y, 6Z function as current control units corresponding to the ratings of the servo motors. The table number data D1 is transmitted to the current control unit 4. Thereby, even if the traveling carriages having different holding means are mixed and traveled on the transfer line 10, the positioning station 40 simply goes through the above-described processing,
There is an effect that positioning control can be easily performed.

Next, the host controller 1 outputs an axis switching signal to the sensor signal switching means 11 and the current / voltage switching means 12 to control the axes (servo motors 6X, 6Y,
6Z). In this embodiment, first, the host controller 1 selects the servo motor 6X. The host controller 1 outputs position command data F0 indicating the target position of the servo motor 6X to the position control unit 21. The position control unit 21 outputs a speed command signal F1 based on the position command data F0 and the position data P2 to the speed control unit 22. The speed control unit 22 includes a speed command signal F1 and a speed signal F
2 is output to the serial communication interface 23.

Transmission is performed between the serial communication interface 23 and the serial communication interface 41,
From the serial communication interface 41 to the current amplifier 42
, A torque signal T2 and a phase signal P4 are output. The current amplifier 42 controls the drive current of the servo motor 6X based on the torque signal T2, the current feedback signal T3, and the phase signal P4. The output P1 of the position sensor 8X coupled to the servomotor 6X is
Is converted into position data P2, and is fed back to the position control unit 21 of the positioning control means 2. The servo control system repeats the above operation for the servo motors 6Y and 6Z, and positions the rotation position, that is, the holding head at a predetermined position.

In the course of this control, if abnormalities such as overload, power supply voltage drop, overcurrent, overvoltage and overheating occur, data of status signals indicating these control states are sent from the current amplifier 42 to the serial communication interface 41. Sent. The data of the status signal is transmitted to the host controller 1 via the serial communication interface 23. The host controller 1 receives the status signal data and performs processing according to the type of the status signal.

Next, the configuration of the rotational position sensors 8X, 8Y, 8Z used in this embodiment will be described. FIG. 3 is a diagram showing an absolute type position sensor including an inductive type phase shift type position sensor which is an example of a rotational position sensor used in the present embodiment. The details of this position sensor are described in JP-A-57-70406 or JP-A-58-70406.
Since it is publicly known in Japanese Patent Application Laid-Open No. 1066691, it will be briefly described here.

The rotational position sensor includes a stator 71a in which a plurality of poles A to D are provided at predetermined intervals (for example, 90 degrees) in a circumferential direction, and a stator 7a surrounded by the poles A to D.
And a rotor 71b inserted into the space 1a. The rotor 71b is made of a shape and a material that changes the reluctance of each of the poles A to D according to the rotation angle, and is, for example, an eccentric cylindrical shape. Primary coils 1A to 1D and secondary coils 2A to 2D are wound around the respective poles A to D of the stator 71a. A first pair of two poles A and C, which are radially opposed, and a second pair of poles B and D are coiled so as to operate differentially, and It is configured to cause a reluctance change.

The primary coils 1A and 1C wound on the first pair of poles A and C are excited by the sine signal sinωt and the primary coil 1 wound on the second pair of poles B and D.
B and 1C are excited by the cosine signal cosωt. As a result, the combined output signal Y is obtained from the secondary coils 2A to 2D. This synthesized output signal Y is a primary AC signal (primary coil excitation signal) sinω which is a reference signal.
t or cosωt, the rotation angle θ of the rotor 71b
Y = s phase-shifted by an electrical phase angle corresponding to
in (ωt−θ).

Therefore, when the above-described inductive phase shift type position sensor is used, the primary AC signal sinω
It is necessary to include a reference signal generator that generates t or cosωt, and a phase difference detector that measures the electrical phase shift θ of the combined output signal Y and calculates the position data of the rotor. The reference signal generator and the phase difference detector are provided in the position sensor converter 5.

FIG. 4 is a diagram showing an example of the position sensor conversion means 5. In FIG. 4, the position sensor conversion means includes a reference signal generator for generating reference AC signals sinωt and cosωt, and a phase difference (a phase shift amount) between a mutual induction voltage of the secondary coils 2A to 2D and the reference AC signal sinωt. And a phase difference detecting unit for detecting Dθ.

The reference signal generator comprises a clock oscillator 72, a synchronous counter 73, ROMs 74a and 74b, D / A converters 75a and 75b, and amplifiers 76a and 76b. The phase difference detector comprises an amplifier 77, a zero cross circuit 78 and a latch circuit. Consists of 79. The clock oscillator 72 generates a high-speed and accurate clock signal, and other circuits operate based on the clock signal. The synchronous counter 73 counts the clock signal of the clock oscillator 72, and outputs the count value as an address signal to the ROM 74a and the latch circuit 79 of the phase difference detector.

The ROMs 74a and 74b store amplitude data corresponding to the reference AC signal.
Generates the amplitude data of the reference AC signal in accordance with the address signal (count value) from the CPU. ROM 74a is cosωt
And the ROM 74b stores the amplitude data of sinωt. Accordingly, the ROMs 74a and 74b receive the same address signal from the synchronous counter 73, and thereby the two types of reference AC signals sinωt and cos
ωt is output. Note that even if the ROM with the same amplitude data is read out using address signals having different phases, the same
Different reference AC signals can be obtained.

The D / A converters 75a and 75b are provided in the ROM 7
The digital amplitude data from 4a and 74b are converted into analog signals and output to amplifiers 76a and 76b. Amplifiers 76a and 76b amplify the analog signal from the D / A converter and convert it to reference AC signals sinωt and cos
ωt is applied to each of the primary coils 1A, 1C and 1B to 1D. Assuming that the frequency division number of the synchronous counter 73 is M, the M count value is the maximum phase angle 2 of the reference AC signal.
It corresponds to π radians (360 degrees). That is, one count value of the synchronous counter 73 indicates a phase angle of 2π / M radian.

The amplifier 77 amplifies the combined value of the secondary voltages induced in the secondary coils 2A to 2D, and
8 is output. The zero cross circuit 78 is a rotation position sensor 3
The zero cross point from the negative voltage to the positive voltage is detected based on the mutual induction voltage (secondary voltage) induced in the secondary coils 2 </ b> A to 2 </ b> D of 7 and 41, and a detection signal is output to the latch circuit 79.

The latch circuit 79 latches the count value of the synchronous counter started with the rising clock signal of the reference AC signal at the time when the detection signal of the zero cross circuit 78 is output (zero cross point). Therefore, the value latched by the latch circuit 79 is exactly the phase difference (phase shift amount) Dθ between the reference AC signal and the mutual induction voltage (synthetic secondary output).

That is, the composite output signal Y = sin (ωt−θ) of the secondary coils 2A to 2D is supplied to the zero-cross detecting means 78. The zero-cross detecting means 78 outputs a pulse L in synchronization with the timing when the electric phase angle of the composite output signal Y is zero. The pulse L is used as a latch pulse of the latch circuit 79. Therefore, the latch circuit 79 latches the count value of the synchronous counter 73 in response to the rise of the pulse L. A period in which the count value of the synchronization counter 73 makes one cycle is synchronized with one cycle of the sine wave signal sinωt. Then, the reference AC signal sinω
phase difference θ between t and the synthesized output signal Y = sin (ωt−θ)
Is latched. Therefore, the latched value is output as digital position data Dθ. Note that the latch pulse L can be appropriately used as a timing pulse. Also, the latch circuit 79
The value indicating the absolute position within one rotation of the servo motor among the values latched by the controller is output as digital phase data P6 and is used for field switching position control.

Since the combined output signal of the phase shift type position sensor as shown in FIGS. 3 and 4 outputs an absolute rotational position as a phase difference signal, it has a feature that it is hardly affected by noise. Therefore, as in the present embodiment, the sensor signal switching means 1 is switched from the rotational position sensors 8X, 8Y, 8Z.
1 and the position sensor converting means 5 via the connecting means 9 and 9b.
However, even if the combined output signal is directly fed back, the influence of noise or the like is not affected, so that it cannot be avoided. However,
The combined output signal may be fed back using a communication line such as a serial communication interface (this will be described later).

Although FIGS. 3 and 4 show a case where the range of one rotation is absolutely detected, a plurality of such absolute sensors may be combined to detect the absolute position over multiple rotations. In FIG. 1, the rotation position sensors 8X, 8Y, and 8Z output 1
Zero signal lines are output because the rotational position sensors 8X, 8Y, and 8Z are multi-rotation sensors and output two types of combined output signals.

FIG. 5 is a diagram showing another embodiment of the present invention. 5, the same components as those in FIG. 1 are denoted by the same reference numerals, and the description thereof will be omitted. The difference between the embodiment of FIG. 5 and that of FIG. 1 is that the sensor signal switching means 11 and the current / voltage switching means 12 of FIG. 1 are united and provided as the axis switching means 13 on the holding means 7b side. It is a point.

With the configuration as in the present embodiment, the number of signal lines in the connection means 9 and 9b is reduced to about one third as compared with the conventional one in FIG. However, shaft switching means 1
3 must be provided in all of the holding means 7a to 7f of the traveling vehicles 6a to 6f, so that there is a disadvantage that the overall cost increases. In particular, since the switching means for the drive current output from the current control unit 4 is more expensive than the other means for switching the brake release voltage and the position signal, the switching means is used as the holding means 7a.
Since it is useless to provide every 7 f, only the drive current switching means may be provided on the positioning station 40 side.

FIG. 6 is a diagram showing still another embodiment of the present invention. 6, the same components as those in FIG. 1 are denoted by the same reference numerals, and the description thereof will be omitted. 6 is different from the embodiment of FIG. 1 in that the position sensor converting means 5 of FIG. 1 is provided as a position sensor converting means 5b on the holding means 7b side, and the digital position output from the position sensor converting means 5b. Data to parallel-serial conversion means 14
b, the data is transferred to the positioning station 40 side. The positioning station 40 converts the serial data into parallel position data by the serial-parallel conversion means 14, and then converts the serial data into parallel position data.
Is output to the

With the configuration as in the present embodiment, the number of signal lines in the connection means 9 and 9b is reduced to about one third or less as compared with the conventional one in FIG. It is greatly reduced as compared with the case of 5. For example, when the position sensor conversion unit 5b outputs position data of a 16-bit configuration,
Sixteen signal lines are connected to the parallel-serial converter 14b from the position sensor converter 15b. Since the parallel-serial converter 14b converts the 16-bit position data into at least two signal lines and outputs the converted signal, the number of signal lines can be greatly reduced. In addition, parallel-
The serial conversion means 14b and the serial-parallel conversion means 14 may be constituted by the serial communication interface shown in FIG. 2 and both may be connected by a serial communication line.

FIG. 7 is a view showing still another embodiment of the present invention, in which three-axis positioning devices are used as traveling vehicles 6a to 6f.
3 shows a configuration of a positioning control system provided at four corners. 7, the same components as those in FIG. 1 are denoted by the same reference numerals, and the description thereof will be omitted. In the present embodiment, the current control units 41 to 44 are connected in a multipoint manner by a serial communication line, and the drive axes (X axis, Y axis or Z axis) of the positioning devices 61 to 64 are simultaneously controlled. .

In this embodiment, the current control units 41 to 44 have the same configuration as the current control unit 3 in FIG. 2, and the respective serial communication interfaces 41 are connected in a multipoint manner. The host controller 1 includes a brake control unit 31
To 34 simultaneously output a brake release signal. The XYZ axis switching unit 121 determines the brake release voltage of the brake control unit 31 and the drive current of the current control unit 41 by using the positioning device 61.
To the X1 axis, the Y1 axis, and the Z1 axis. The XYZ axis switching means 121 similarly performs switching control on the brake control means 32-34 and the current control units 42-44.

The positioning device 61 includes servo motors 6X1, 6Y1, 6Z1, brake devices 7X1, 7Y1, 7Z1 and position sensors 8X1, 8 like the holding means 7b in FIG.
Y1, 8Z1. However, these components are not shown in the drawings. Positioning devices 62 to 64
Is configured similarly to the positioning device 61. And
X-axis position sensors 8X1 of the respective positioning devices 61 to 64
The position signals of 8X2, 8X3, 8X4 are input to the position sensor parallel-to-serial conversion means 15X, and the Y-axis position sensors 8Y1,
The position signals of 8Y2, 8Y3, and 8Y4 are input to the position sensor parallel-to-serial conversion means 15Y, and the Z-axis position sensors 8Z1,
The position signals of 8Z2, 8Z3, and 8Z4 are input to the position sensor parallel-to-serial conversion unit 15Z.

Position sensor parallel-to-serial conversion means 15X, 15
Y, 15Z are the sensor signal switching means 11, the position sensor conversion means 5b and the parallel-serial conversion means 14 of FIG.
b is integrally formed. However, these components are not shown in the drawings. The sensor signal switching unit of the position sensor / parallel-serial conversion unit 15X receives the position signals from the position sensors 8X1, 8X2, 8X3, and 8X4, and outputs any of the position signals according to an axis switching signal (not shown) from the host controller 1. One of them is selectively output to the position sensor conversion means.

The position sensor conversion means includes a position sensor 8X
The position signals from 1, 8X2, 8X3, 8X4 are converted into digital position data and output to the parallel-serial conversion means. The parallel-serial conversion means converts the parallel position data into serial data, and connects the connection means 9, 9.
The signal is output to the XYZ-axis switching means 122 on the positioning station 10 side via b. Position sensor parallel-to-serial conversion means 1
5Y and 15Z also the Y axis and Z of the positioning devices 61 to 64
Similar processing is performed on the position signal of the axis position sensor.

The XYZ axis switching means 122 selectively switches the serial position data from the position sensor parallel-to-serial conversion means 15X, 15Y, 15Z in response to the axis switching signal from the host controller 1, and performs serial-parallel conversion means 1.
41. The serial-parallel conversion means 141 converts the serial position data from the XYZ axis switching means 122 into parallel data and outputs it to the positioning control means 2.

In the present embodiment, the X of the positioning devices 61 to 64
Positioning control is performed on the axis, and then positioning control is performed in the order of the Y axis and the Z axis, and the positioning control of the entire holding means on the traveling carriage is performed. Therefore, it takes some time until the positioning of the entire holding means is completed. Therefore, when the positioning time is longer than the work time in each work station 20, a plurality of positioning stations 40 are provided, and the traveling vehicles enter the work station in parallel, and the positioning control is performed in parallel. Good.
The position sensor parallel-to-serial conversion means 15X, 15Y, 1
The 5Z parallel-serial conversion means and serial-parallel conversion means 141 may be constituted by the serial communication interface shown in FIG. 2 and both may be connected by a serial communication line.

In FIG. 1, the brake release voltage of the brake control means 3 and the drive current of the current control section 4 are switched by the current / voltage switching means 12 so that the brake means 7X, 7Y, 7
Although the description has been given of the case where the power is supplied to Z and the servo motors 6X, 6Y, 6Z, the brake control means 3 and the current control unit 4 may be provided for each control axis as shown in FIG.

Further, in this embodiment, the case where the holding means is constituted by three control axes (servo motors 6X, 6Y, 6Z) has been described, but such three control axes are mounted on the traveling vehicles 6a to 6f. When a plurality of positioning devices are provided, for example, at the four corners of the traveling vehicles 6a to 6f, the positioning control system of FIG. 1 may be configured for each positioning device.

The parallel-serial conversion means 14,
14b may be omitted and the position data of the position sensor conversion means 5b may be directly output to the positioning control means 2 via the connection means 9 and 9b. In the embodiment of FIG. 6, a case has been described in which the position signals of the position sensors 8X, 8Y, 8Z are switched by the sensor signal switching means 11 and supplied to the position sensor conversion means 5b. .

That is, each position sensor 8X, 8
For Y and 8Z, a position sensor conversion unit 5b, a parallel-serial conversion unit 14b, and a serial-parallel conversion unit 14 are separately provided.
4 may be switched by the sensor signal switching means and input to the positioning control means 2. Also, for each position sensor 8X, 8Y, 8Z,
The position sensor conversion means 5b and the parallel-serial conversion means 14b are separately provided, and the parallel-serial conversion means 1
The position data from 4b may be transferred to the positioning station 40 via the connection means 9 and 9b, and the position data may be switched by the sensor signal switching means and input to the serial-parallel conversion means 14.

The position sensors 8X, 8Y,
8Z, the position sensor conversion means 5b and the parallel
The serial conversion means 14b is separately provided, and the position data from the parallel-serial conversion means 14b is switched by the sensor signal switching means and inputted to the serial-parallel conversion means 14 of the positioning station 40 via the connection means 9 and 9b. It may be. Further, for each of the position sensors 8X, 8Y, 8Z, the position sensor converting means 5b
May be separately provided, and the position data from the position sensor conversion means 5b may be switched by the sensor signal switching means and input to the parallel-serial conversion means 14b.

The serial communication system employed in the present embodiment is constituted by simple hardware which is inexpensive in cost and adopts a new communication system capable of transmitting and receiving data at high speed. For details on this serial communication method,
Since this is described in Japanese Patent Application No. 2-49640 previously filed by the present applicant, the description thereof is omitted.

The servomotor is not limited to a synchronous servomotor, but may be an induction AC servomotor. In that case, there is no need to generate the phase signal P6. Also, A
It goes without saying that the present invention is not limited to the C servomotor, but may be another type such as a DC servomotor. Further, the position sensor is not limited to the inductive phase shift type sensor, and may output an absolute position data using an optical absolute encoder, an incremental encoder, or another type of sensor. Further, the communication line is not limited to the electric cable, but may be an optical cable.

Various positioning control systems can be configured by appropriately combining the above embodiments. For example, by combining FIG. 1 and FIG. 7, the XYZ axis switching means 122 of FIG.
The positioning control system provided on the side can be configured. Also,
By combining FIG. 5 and FIG. 7, XY of FIG.
A positioning control system in which the Z-axis switching units 121 and 122 are provided on the holding unit 7b side can be configured. In the embodiment shown in FIG. 2, the speed control loop is formed during the positioning control to control the rotation speed of the servomotor. However, the upper limit of the rotation speed may be clamped to perform the positioning control only by the position control loop.

[0088]

According to the present invention, when positioning control is performed between the device to be positioned and the positioning control device via the connecting means, errors are less likely to occur in the position signals connected by the connecting means, and There is an effect that control can be performed with high accuracy.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of a positioning control system according to an embodiment of the present invention, showing a connection relationship between a positioning control station in FIG. 8 and holding means on a traveling vehicle.

FIG. 2 is a diagram illustrating a detailed configuration of a positioning control unit and a current control unit in FIG. 1;

FIG. 3 is a diagram showing an absolute type position sensor including an inductive type phase shift type position sensor which is an example of a rotational position sensor used in the present embodiment.

FIG. 4 is a diagram illustrating an example of a position sensor conversion unit in FIG. 2;

FIG. 5 is a diagram showing another embodiment of the present invention.

FIG. 6 is a diagram showing still another embodiment of the present invention.

FIG. 7 is a view showing still another embodiment of the present invention;
3 shows a configuration of a positioning control system in a case where positioning devices having a three-axis configuration are provided at four corners of a traveling vehicle.

FIG. 8 is a diagram showing a schematic configuration of a transfer line system using a traveling vehicle.

9 is a view showing a conventional technique, and is a view schematically showing a connection relation between a positioning control station in FIG. 8 and a holding means on a traveling vehicle.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Upper controller, 2 ... Positioning control means, 3 ... Brake control means, 4 ... Current control part, 5, 5b ... Position sensor conversion means, 6a-6f ... Traveling trolley, 6X, 6Y, 6Z
... servo motors, 7a to 7f ... holding means, 7X, 7Y,
7Z: brake means, 8X, 8Y, 8Z: rotational position sensor, 9, 9a to 9f: connecting means, 10: transfer line, 11: sensor signal switching means, 12: current / voltage switching means, 121, 122: XYZ axis switching Means, 13 ... Axis switching means, 14, 141 ... Cyril-parallel conversion means, 14b ... Parallel-serial conversion means, 15X, 1
5Y, 15Z: Position sensor parallel-to-serial conversion means, 21: Position control unit, 22: Speed control unit, 23, 41: Serial communication interface, 24: Speed calculation unit, 42: Current amplifier, 61 to 64: Positioning device, 71a: Stator ,
71b: rotor, 72: clock oscillator, 73: synchronous counter, 74a, 74b: ROM, 75a, 75b: D
/ A converters, 76a, 76b, 77: amplifier, 78: zero cross circuit, 79: latch circuit

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ identification code FI G05B 19/414 G05B 19/414 R (58) Investigated field (Int.Cl. ⁷ , DB name) G05B 19/418 B23P 21 / 00 307 B23Q 15/00 G05B 19/414 B23Q 41/02

Claims (7)

(57) [Claims] 1. A control system comprising: at least one positioning means including a control axis which is controlled to be positioned at a desired position by a driving means; and a position detection means which detects a position signal indicating a current position of the control axis. A plurality of moving bodies that move along the path of, and are provided independently of the moving bodies, and are driven by the driving means based on the position signal from the position detection means and a position command signal from a host controller. A current supply, and a positioning control means for controlling the positioning of the control axis to a desired position; and electrically connecting the positioning control means to at least one of the plurality of moving bodies, A first connection unit for supplying the position signal to the positioning control unit; and a second connection unit for supplying the drive current to the drive unit. The number of signal lines to be connected is smaller than the total number of signal lines of the position signal output from the position detecting means in the positioned means, and the output from the position detecting means in the positioned means. Signal line conversion means for adapting the position signal to be applied to a signal line in the first connection section. 2. The method according to claim 1, wherein the moving body has at least two positioning means, and the signal line converting means has a position signal switching means for switching and outputting a position signal from the position detecting means of the positioning means. The positioning control system according to claim 1, wherein the first connection unit of the connection unit supplies the position signal switched by the position signal switching unit to the positioning control unit. 3. The connection section of the connection section, wherein the signal line conversion section has a position signal conversion section for converting a position signal from the position detection section of the positioning section into a serial signal and outputting the serial signal. 2. The positioning control system according to claim 1, wherein said controller supplies a serial signal from said position signal converting means to said positioning control means. 4. The moving body has at least two positioning means, the positioning control means has current switching means for switching and outputting the driving current, and the second connecting part of the connection means has The positioning control system according to claim 1, wherein the driving current switched by the current switching unit is supplied to the driving unit. 5. The moving body has at least two positioning means, and brake means for driving a brake on the control axis and releasing a braking operation by applying a brake release voltage, wherein the positioning control means comprises: A voltage switching means for switching and outputting a brake release voltage, wherein a second connection part of the connection means supplies the brake release voltage switched by the voltage switching means to the brake means. Item 2. The positioning control system according to Item 1. 6. The positioning control system according to claim 1, wherein said moving body has at least two positioning means and current switching means for switching and outputting said driving current. 7. The moving body switches at least two of the positioning means, a brake on the control axis, and a brake means for releasing a brake operation by applying a brake release voltage, and switching and outputting the brake release voltage. Voltage switching means, wherein the positioning control means has brake control means for outputting the brake release voltage, and a second connection part of the connection means switches the brake release voltage of the brake control means to the voltage. The positioning control system according to claim 1, wherein the position is supplied to a means.