JP4809390B2 - Origin calibration method in parallel mechanism and calibration jig for origin calibration - Google Patents

Description

  The present invention relates to an origin calibration method in a parallel mechanism used as an industrial robot, for example, and a calibration jig for origin calibration. The present invention is applied to a rotary parallel mechanism in which an operation head is supported by a plurality of pairs of arm units, among parallel mechanisms.

  The basic structure of this type of parallel mechanism is known, for example, from Patent Document 1. There, a parallel mechanism with a base, three servo motors arranged evenly on the lower surface of the base, three arm units driven by the servo motors, and an operation head supported by the three arm units, etc. Is configured. A drive shaft that transmits rotational power while expanding and contracting between the base and the operation head is added as necessary. On the lower surface side of the operation head, a hand for capturing a processing target is provided, and the base frame is disposed above the operation space of the operation head.

  Each arm unit is composed of a drive arm that is swiveled up and down by a servo motor and a rod that transmits the swivel motion of the drive arm to the operation head. The rod is connected to the drive arm and the operation head by a ball joint. It is. By changing the drive direction and drive amount of each drive arm, the operation head can be freely displaced in a predetermined three-dimensional space. The drive shaft is composed of a drive tube and a passive tube that are connected in a telescopic manner, and upper and lower ends of the drive shaft are connected to an output shaft of the motor and an operation shaft incorporated in the operation head via a cardan joint. This type of parallel mechanism can also be seen in US Pat.

JP 2001-277164 A (paragraph number 0010, FIG. 2) JP 2005-528993 A (paragraph number 0019, FIG. 1)

  The parallel mechanism of the present invention corrects the error accumulated in the operation head by performing the return to origin operation when a predetermined usage time has elapsed, after maintenance, or when the position information of the drive arm is lost. Specifically, a reference pin provided on each drive arm is brought into contact with an origin pin provided outside the normal operation range of the drive arm, and the origin is redefined from the encoder signal of the drive motor in that state.

  However, the positional accuracy of the reference pins and the origin pins is not absolute, and it is inevitable that the positions of both pins vary slightly for each parallel mechanism that has been assembled. Similar variations are also seen when overhauling individual parallel mechanisms. If there is variation in the origin position of the drive arm in this manner, the theoretical position and orientation of the operating head and the actual position and orientation of the operating head will deviate, making it impossible to operate the operating head properly. In particular, in the rotary parallel mechanism, the rotational movement of the drive motor is amplified by the drive arm and the rod and transmitted to the operation head, so that the position and posture of the operation head are likely to deviate greatly.

  An object of the present invention is to provide a parallel mechanism origin calibration method for calibrating a deviation between a theoretical origin position and an actual origin position, and a calibration jig for origin calibration. An object of the present invention is to provide a parallel mechanism origin calibration method and a calibration jig for origin calibration, which can strictly and easily perform the origin calibration work of the parallel mechanism.

  The parallel mechanism origin calibration method of the present invention includes a plurality of drive motors arranged on a base, a drive arm and a rod driven by the drive motor, a single operation head supported by the rod, and a base. A parallel mechanism having a drive shaft that transmits the rotational power of the provided motor to the operation shaft provided in the operation head is applied. In the origin calibration method, a calibration jig is disposed between a base and the operation head, the operation head is positioned at a temporary reference position by the calibration jig, and is detected by the position detector of the drive motor in the positioning state. Detected by the first process of transferring the next position signal to the control circuit, the second process of performing the home position return operation on one of the drive arms after removing the calibration jig, and the position detector of the drive motor that has returned to the home position The secondary position signal is transferred to the control circuit, the actual operating angle of the drive arm is calculated from the difference between the primary position signal and the secondary position signal, and the calculation result is compared with the theoretical value to determine the temporary reference position. A third process of specifying the correction value of the drive arm in the origin return state when true, and a fourth process of calibrating the origin of the drive arm by reflecting the correction value specified in the third process on the control circuit; Including and remaining drive The second step performs a fourth process for over-time, to calibrate the position of the origin of all the drive arm.

  The calibration jig is composed of a rod-shaped jig main body, and a base side connection body and a head side connection body connected to the jig main body. Therefore, in the first process, after removing the motor, the drive shaft, and the operation shaft, both ends of the calibration jig are attached to the mounting seat of the motor provided on the base and the mounting seat provided on the operation head. The operation head is positioned and held at the temporary reference position by the calibration jig.

  In the parallel mechanism in which the base-side reference surface and the head-side reference surface are formed on the opposing surfaces of the base and the operation head, both ends of the calibration jig are connected between the base-side reference surface and the head-side reference surface in the first process. The operation head can be positioned and held at the temporary reference position by the calibration jig.

  In the second process, the reference pin provided on the drive arm is brought into contact with the origin pin provided on the motor bracket, and the drive arm is operated to return to the origin.

  A calibration jig for calibrating the origin in the present invention includes a plurality of drive motors arranged on a base, a drive arm and a rod driven and operated by the drive motor, a single operation head supported by the rod, A parallel mechanism having a drive shaft that transmits rotational power of a motor provided on a base to an operation shaft provided on an operation head is applied. The calibration jig is composed of a rod-shaped body having a base side joint portion positioned at a base side reference position provided on the base and a head side joint portion positioned at a head side reference position provided on the operation head. . Accordingly, the operation head is positioned at the temporary reference position in the three-dimensional space in a state where the base side joint and the head side joint of the calibration jig are fixed to the base side reference position and the head side reference position.

  The calibration jig includes a rod-shaped jig main body, and a base-side coupling body and a head-side coupling body that are detachably coupled to the jig main body. Each of the base side connection body and the head side connection body is integrally provided with a fitting portion and a flat portion. The operating head is positioned at the temporary reference position by the fitting portion and the flat portion formed on the base side connection body and the fitting portion and the flat portion formed on the head side connection body.

  When the base-side reference surface and the head-side reference surface are formed on the opposing surfaces of the base and the operating head, the base is positioned on the base-side reference surface at both ends of the calibration jig formed in a rod shape. The side joint portion and the head side joint portion positioned on the head side reference surface can be provided integrally.

  In the origin calibration method of the present invention, the operating head is positioned at the temporary reference position by the calibration jig, and the position information of the driving arm at that time is transferred to the control circuit as a primary position signal. Thereafter, the calibration jig is removed and one of the drive arms is operated to return to the origin, and the position information of the drive arm when the reference pin of the drive arm comes into contact with the origin pin is received as a secondary position signal by the control circuit. hand over. Further, the correction value of the drive arm resulting from the variation in the position of the origin pin is specified from both position signals and reflected in the control circuit to calibrate the origin of the drive arm. Therefore, according to the origin calibration method of the present invention, by calibrating each drive arm according to the previous procedure, the theoretical origin position and the actual origin position can be matched, and thus the operation head can always be accurately and accurately set. It will be possible to operate. Since the deviation of the driving arm is specified from the primary position signal and the secondary position signal detected by the position detector of the driving motor and the deviation is reflected in the control circuit, the origin calibration is performed. It can be done strictly and easily.

  After removing the motor, drive shaft, and operation shaft, calibrate the origin by attaching both ends of the calibration jig to the motor mounting seat on the base and the mounting seat on the operation head. A calibration jig can be attached to position the operating head at the temporary reference position. Therefore, it is not necessary to separately provide a reference surface that is used only for the origin calibration, and the labor for processing the base and the operation head can be reduced correspondingly, thereby contributing to cost reduction.

  In the parallel mechanism in which the base-side reference surface and the head-side reference surface are formed on the opposing surfaces of the base and the operation head, just hold both ends of the calibration jig between the base-side reference surface and the head-side reference surface. The operation head can be positioned and held at the temporary reference position. Therefore, the operation for positioning the operation head at the temporary reference position using the calibration jig can be quickly and easily performed. When the calibration jig is joined to the base side reference surface and the head side reference surface, the motor output shaft or the operation shaft provided on the operation head and the calibration jig do not interfere mechanically. The origin calibration work can be easily performed with less effort. For example, as shown in FIG. 7, the operation head can be positioned at the temporary reference position by holding the calibration jig between the base and the operation head while the motor and the operation shaft are mounted.

  When the reference pin provided on the drive arm is brought into contact with the origin pin provided on the motor bracket to perform origin return, the primary position signal and origin return are performed using the position signal detected by the drive motor position detector. The secondary position signal can be obtained. Therefore, compared with the case where the primary position signal and the secondary position signal are detected by separately provided sensors, the correction value of the drive arm is specified more strictly without any instrumental error, and the origin calibration is appropriately performed. be able to.

  The calibration jig for calibrating the origin in the present invention is composed of a rod-shaped body having a base side joint and a head side joint. In addition, the primary side of the drive arm, which is indispensable for calibrating the origin by sandwiching both the base side and head side joints between the base side reference position and the head side reference position and positioning the operating head at the temporary reference position. Pass the position signal to the control circuit. At the time of origin calibration, it is possible to know how much the drive arm has been displaced from the temporary reference position, and correct the theoretical origin position and actual origin position from the secondary position signal and the primary position signal obtained at that time. By specifying the value and reflecting this in the control circuit, the origin of the drive arm can be accurately calibrated. Further, since the calibration jig is composed of the rod-shaped body having the base side joint and the head side joint, the entire structure of the calibration jig can be simplified, and the calibration jig can be provided at a lower cost.

  According to the calibration jig composed of the rod-shaped jig main body, the base-side connection body and the head-side connection body that are detachably connected to the jig main body, the connection and separation of the jig main body from both connection bodies Can be done easily. Specifically, by simply inserting and engaging the connecting shafts provided at both ends of the jig main body to the bosses of the connecting body, the jig main body and each connecting body can be easily integrated, and the operation head is moved to the temporary reference position. Can be positioned quickly. Furthermore, after the operation head is positioned at the temporary reference position by the calibration jig, the jig main body can be quickly separated from each coupling body to perform the return to origin operation.

  If the base-side reference surface and the head-side reference surface are formed on the opposing surfaces of the base and the operation head, the operation head is positioned and held at the temporary reference position only by holding both ends of the calibration jig between the two reference surfaces. be able to. In this case, the calibration jig can be configured as a single part by integrally providing the base side joint and the head side joint at both ends of the jig main body formed in a rod shape. Compared with the calibration jig to be performed, the structure of the calibration jig can be simplified and the cost can be reduced. Furthermore, it is possible to simplify the series of origin calibration operations as a whole by omitting the trouble of attaching the calibration jig to the base and the operation head.

(Example) FIGS. 1-6 shows the Example which applied the parallel mechanism based on this invention to the conveyance robot. As shown in FIG. 2, the parallel mechanism is configured with a high-rigidity base 1 installed in a state straddling a table or a conveyor as a base. Specifically, as shown in FIGS. 2 and 3, a base 2 fixed to the upper wall of the gantry 1, three drive motors 3 disposed on the lower surface of the base 2, and 3 driven by the drive motor 3. Each arm unit 4, an operation head 5 supported by each arm unit 4, a drive shaft 6 disposed in the center portion, and the like. The base 2 is located above the operation space of the operation head 5, and a motor 7 that rotationally drives the drive shaft 6 is provided on the upper surface thereof.

  Three motor brackets 8 are provided at equal intervals on the lower surface of the base 2, and the drive motor 3 is assembled to these motor brackets 8. The drive motor 3 integrally includes a servo motor and a speed reducer, and outputs reciprocating turning power decelerated by the speed reducer. As shown in FIG. 3, the three drive motors 3 are arranged on the base 2 with their central axes constituting each side of an equilateral triangle, and the figure center of the equilateral triangle is the axis center of the drive shaft 6. Matched to the position. The motor 7 is a servo motor having the same structure as that of the drive motor 3, and a flange at the lower end of the speed reducer portion is fastened with a bolt 10 to a mounting seat 9 provided on the upper surface of the base 2 (see FIG. 4). In a state in which the motor 7 is fastened to the mounting seat 9, the boss portion provided on the flange at the lower end of the speed reducer portion is fitted and engaged with the output shaft opening 60 continuing to the mounting seat 9. As a result, the motor 7 is positioned in all directions with respect to the base 2, and the output shaft 11 projects from the lower surface of the base 2. The mounting seat 9 also serves as a base side reference surface (base side reference position).

  In FIG. 2, the arm unit 4 includes a drive arm 12 that is swiveled up and down by the drive motor 3 and a rod 13 that transmits the swiveling operation of the drive arm 12 to the operation head 5. An arm boss 14 is fixed to the base end of the drive arm 12, and this arm boss 14 is fixed to the output shaft of the drive motor 3. As shown in FIG. 3, the rod 13 includes a pair of link rods 15 arranged in parallel and a spring unit 16 provided near the upper and lower ends of the link rods 15 to draw and urge both link rods 15. It is.

  The upper and lower ends of the rod 13 are connected to the drive arm 12 and the operation head 5 by ball joints 17 respectively. As described above, according to the arm unit 4 connected via the ball joint 17, the drive arm 12 can be freely reciprocated up and down by the drive motor 3 to freely move the operation head 5 in a predetermined three-dimensional space. Can be displaced. Of the space in which the operating head 5 can be displaced three-dimensionally, an operating range having a diameter of 1040 mm and a height of 200 mm on the reference plane is the working area of the operating head 5. A line connecting the ball centers of the opposing ball joints 17 is parallel to the central axis of the drive motor 3.

  The operation head 5 is composed of a triangular plate-like block, and an operation shaft 20 that inherits the rotational power of the drive shaft 6 is rotatably supported at the center thereof. As shown in FIG. 4, the operation shaft 20 is rotatably supported by a cross roller bearing 21 and is fastened and fixed by a nut 22 provided with the cross roller bearing 21 interposed therebetween. In order to prevent and hold the operating shaft 20, a mounting seat 23 is formed on the periphery of the opening of the bearing hole 57, and the outer ring of the bearing 21 is pressed and fixed by a holding ring 24 fastened to the mounting seat 23 with a bolt. Using a flange 25 provided at the lower end of the operation shaft 20, a capturing structure such as a suction tool or a hand is attached. The mounting seat 23 also serves as a head side reference surface (head side reference position).

  The drive shaft 6 is transmitted while expanding and contracting the rotational power of the motor 7. In order to reduce the frictional resistance during expansion and contraction transmission and to smoothly follow the high-speed movement of the operation head 5, the drive shaft 6 is composed of a ball spline shaft and a universal joint 27 connected to the upper and lower ends of the ball spline shaft. To do. As shown in FIG. 2, the ball spline shaft is composed of an upper half drive spline shaft 28 and a lower half passive spline shaft 29. In order to easily perform maintenance and replacement of the drive shaft 6, the input end and the output end of the drive shaft 6 are attached to and detached from the output shaft 11 of the motor 7 and the previous operation shaft 20 via friction fasteners 31 and 32, respectively. It is connected as possible.

  As shown in FIG. 4, the friction fastener 31 connected to the output shaft 11 of the motor 7 operates to reduce the diameter of the joint main body 33 having a connection hole that fits outside the output shaft 11 and the peripheral wall of the joint main body 33. Hexagon socket head cap bolt 34 is used. A slit 35 is formed in a part of the peripheral wall of the joint body 33, and the previous bolt 34 is screwed in a state orthogonal to the slit 35. The joint body 33 is connected and fixed to a joint body on the drive side of the universal joint 27. When the hexagon socket head cap bolt 34 is loosened, the connection state between the output shaft 11 of the motor 7 and the universal joint 27 can be released.

  As shown in FIG. 4, the friction fastener 32 connected to the operation shaft 20 is a commercially available friction lock fastener (trade name: Mechalock). The friction fastener 32 includes an inner ring that fits inside and outside through a tapered surface, an outer ring 37, a nut 38 that pulls the inner ring, and the like. By fitting the upper end of the shaft portion of the operation shaft 20 into the connecting hole of the inner ring and further screwing the nut 38 with the outer ring 37 fitted into the joint on the passive side of the universal joint 27, the operation shaft 20 and the universal joint are connected. 27 can be fastened and fixed simultaneously. On the contrary, when the nut 38 is loosened, the connection state between the operation shaft 20 and the universal joint 27 can be released.

  In order to perform the origin return of each drive arm 12, the reference pin 40 is fixed to the peripheral surface of the arm boss 14 so that the pin axis is orthogonal to the rotation axis of the drive motor 3 (see FIG. 5). Further, a round shaft-shaped origin pin 41 that receives the reference pin 40 is fixed to the side end surface of the motor bracket 8. Note that the origin pin 41 and the reference pin 40 are installed at positions where they do not come into contact with each other in the normal operation range. In this way, by arranging the origin pin 41 in a state intersecting with the trajectory of the reference pin 40, when the drive arm 12 is returned to the origin position, the reference pin 40 is received by the origin pin 41, and the drive arm 12. The origin position of can be specified.

  The positional accuracy of the reference pin 40 and the origin pin 41 is not absolute, and it is inevitable that the positions of the pins 40 and 41 vary slightly for each parallel mechanism that has been assembled. Similar variations also occur when individual parallel mechanisms are overhauled. In order to correct such variation in the origin position, the calibration is performed using the calibration jig 45.

  1 and 6, a calibration jig 45 includes a rod-shaped jig main body 46, a base side connection body (base side joint portion) 47 detachably connected to the jig main body 46, and a head side connection body ( Head side joint portion) 48. The jig main body 46 is made of a steel bar that is long in the vertical direction, and connection shaft portions 49 and 50 that are detachably fitted to the base side connection body 47 and the head side connection body 48 are formed at both the upper and lower ends thereof. The vertical dimension between the base ends of the upper and lower connecting shaft portions 49 and 50 and the concentricity are strictly defined.

  The base-side connecting body 47 includes a boss 52, a fitting shaft portion (fitting portion) 68 provided on the top of the boss 52, and a flange 53 that is formed to protrude from the upper end of the fitting shaft portion 68. The lower end surface (flat portion) 69 of the boss 52, the lower surface (flat portion) 70 of the flange 53, and the peripheral surface of the fitting shaft portion 68 are each finished, so that the lower surface of the flange 53 extends from the lower end surface of the boss 52. And the concentricity between the boss 52 and the fitting shaft portion 68 are strictly defined. The lower end surface (flat portion) 69 of the boss 52 and the lower surface (flat portion) 70 of the flange 53 and the inner surface of the fitting hole portion between the peripheral surface of the fitting shaft portion 68 and the connecting shaft portion 49 are finished. Thus, the height dimension from the lower end surface 69 of the boss 52 to the lower surface 70 of the flange 53 and the concentricity between the fitting shaft portion 68 and the fitting hole portion are strictly defined.

  The head-side coupling body 48 includes a boss 54, a flange 55 that is formed near the lower end of the boss 54, and a fitting shaft portion (fitting portion) 56 provided on the lower surface of the flange 55. The upper end surface (flat portion) 72 of the boss 54 and the lower surface (flat portion) 73 of the flange 55 are finished, respectively, and the height dimension from the upper end surface of the boss 54 to the lower surface of the flange 55, and the fitting shaft portion. The concentricity of the fitting hole portion between 56 and the connecting shaft portion 50 is strictly defined. Further, the peripheral surface of the fitting shaft portion 56 and the inner surface of the fitting hole portion are also finished so that the fitting shaft portion 56 is fitted into the bearing hole 57 of the cross roller bearing 21 and the head side. The connecting body 48 can be positioned concentrically with the operation head 5. In short, in the base side coupling body 47 and the head side coupling body 48, the dimensions of the shaft and hole to be fitted, or the joint surface that defines the vertical dimension are controlled so as to be within a predetermined dimensional tolerance. Finished.

  The calibration operation of the origin position of the drive arm 12 is performed by loosening the bolts 34 and nuts 38 of the upper and lower friction fasteners 31 and 32 to remove the drive shaft 6, and the motor 7 and the operation shaft 20 from the base 2 and the operation head 5. This is done in the removed state. The calibration work is performed according to the following first to fourth processes using the mounting seat 9 as a base side reference surface and further using the mounting seat 23 as a head side reference surface.

  In the first process, the calibration jig 45 is disposed between the base 2 and the operation head 5, and the operation head 5 is positioned at the temporary reference position by the calibration jig 45. Specifically, as shown in FIG. 6, the flange 53 of the base-side coupling body 47 is joined to the mounting seat 9 of the motor 7 provided on the base 2 and fastened with bolts 59 using the fastening screw holes of the motor 7. Fix it. As a result, the fitting shaft portion 68 of the base side connecting body 47 is positioned in the X-axis and Y-axis directions at the output shaft opening 60, and is positioned in the Z-axis direction by the lower end surface 70 of the flange 53. Can be positioned in all directions. In this state, the boss 52 projects through the output shaft opening 60 to the lower surface side of the base 2. Further, the fitting shaft portion 56 of the head side connecting body 48 is fitted into the bearing hole 57, the flange 55 of the head side connecting body 48 is joined to the mounting seat 23 provided in the operation head 5, and then the fastening screw of the holding ring 24. Fasten and fix with bolts 61 using the holes. As a result, the fitting shaft portion 56 of the head-side coupling body 48 is positioned in the X-axis and Y-axis directions by the bearing holes 57, and is positioned in the Z-axis direction by the lower end surface 73 of the flange 55. Can be positioned in the azimuth direction.

  Next, the brake provided in the drive motor 3 is released, the operation head 5 is moved downward, and the upper connecting shaft portion 49 of the jig main body 46 is inserted into the inner surface of the boss 52 of the base side connecting body 47. Match. The operating head 5 is moved again, and the boss 54 of the head side connecting body 48 is externally engaged with the lower connecting shaft portion 50 of the jig main body 46. In this state, the operating head 5 is pressed upward to bring the jig main body 46 and the upper and lower connecting bodies 47 and 48 into close contact with each other, and the brake provided on the drive motor 3 is operated to move the operating head 5 to the temporary reference position (see FIG. (Position shown in 1). At this time, the center of the calibration jig 45 is on a vertical line passing through the center of the base 2, and the operation head 5 is supported in a horizontal posture. Further, as shown in FIG. 5, the drive arm 12 is at a position where the arm center axis is displaced upward by an angle θ1 from a horizontal line passing through the center of the drive motor 3. In this state, the primary position signal detected by the encoder (position detector) of the drive motor 3 is transferred to the control circuit 63.

  In the second process, the brake provided in the drive motor 3 is released, the drive arm 12 is moved downward, the vertical distance between the base 2 and the operation head 5 is increased, and the jig main body 46 is moved to the upper and lower connecting bodies 47 and 48. Remove from. In this state, the tip of one of the drive arms 12 is pivoted upward to bring the reference pin 40 into contact with the origin pin 41 and return to the origin position as shown in FIG. By the origin return operation, the drive arm 12 is displaced by an angle θ2 beyond the temporary reference position.

  In the third process, the secondary position signal detected by the encoder of the drive motor 3 in a state where the reference pin 40 is in contact with the origin pin 41 is transferred to the control circuit 63. The control circuit 63 calculates the actual operating angle of the drive arm 12 from the difference between the previous primary position signal and the secondary position signal, and compares the calculation result with the theoretical value to identify the temporary operation specified in the first process. The correction value from the theoretical value of the drive arm 12 in the origin return state when the reference position is true is specified.

  In the fourth process, the correction value specified in the third process is reflected in the control circuit 63 to calibrate the origin position of the drive arm 12. Specifically, either a correction value is manually input, a reset button of an input device (not shown) is turned on when the correction value is fixed, or it is automatically rewritten in the control device 63. The correction value can be reflected in the control circuit 63 by this method. Thus, by calibrating the origin position, the theoretical origin position and the actual origin position can be matched, and as a result, the operation head 5 can be appropriately displaced without error. For the remaining two drive arms 12, the origin positions of all the drive arms 12 are calibrated by repeating the second to fourth steps. When a series of calibration operations are completed, the upper and lower connecting bodies 47 and 48 are removed from the base 2 and the operation head 5, the motor 7 and the operation shaft 20 are assembled, and then the drive shaft 6 is assembled.

  In the above embodiment, the calibration jig 45 is attached using the mounting seat 9 as the base side reference surface and further using the mounting seat 23 as the head side reference surface. Therefore, it is necessary to divide the calibration jig 45 into three parts, that is, the jig main body 46 and the upper and lower connecting bodies 47 and 48, and to connect these three parts sequentially. However, when the head-side reference surface 65 is provided on the lower surface side of the base 2 as shown in FIG. 7, the calibration jig 45 can be configured as a single component. Specifically, the calibration jig 45 can be formed by fixing an upper flange (base side joint portion) 66 and a lower flange (head side joint portion) 67 above and below the cylindrical jig main body 46.

  The calibration jig 45 is disposed between the base 2 and the operation head 5 to position the operation head 5 at the temporary reference position. At this time, the motor 7 and the operation shaft 20 may be left in the mounted state. Therefore, the trouble for removing the motor 7 and the operation shaft 20 can be saved. Further, since the labor for sequentially connecting the jig main body 46 and the upper and lower flanges 66 and 67 can be saved, a series of origin calibration operations can be performed more quickly and easily.

  The vertical length of the calibration jig 45 in the above embodiment can be freely selected as long as it is within the operating range of the operation head 5. For example, when the operation head 5 is positioned at the temporary reference position by the calibration jig 45, the vertical length of the calibration jig 45 is such that the center axis of the drive arm 12 is positioned on a horizontal line passing through the center of the drive motor 3. Can be set.

  The calibration jig 45 need not be calibrated to a straight bar shape. For example, three rod-shaped bodies can be connected to the head-side coupling body so as to be foldable so that a tripod shape can be formed. In that case, the head side coupling body is fixed to the mounting seat 23 of the operation head 5, and the tips of the three arms that have been opened are brought into contact engagement with the reference surfaces provided at the three lower surfaces of the base 2. Thus, the operation head 5 can be positioned at the temporary reference position. The operation head 5 may be positioned at the temporary reference position by forming reference holes at three positions on the lower surface of the base 2 and inserting and engaging the tips of the three arms into the reference holes.

It is a partially broken front view of the parallel mechanism in the state where the calibration jig is mounted. It is a front view of a parallel mechanism. It is a top view of a parallel mechanism. It is a partially broken front view which shows the connection structure of a drive shaft. It is a front view of the state which returned the origin to the drive arm. It is sectional drawing of a calibration jig. It is sectional drawing which shows another Example of a calibration jig | tool.

Explanation of symbols

2 Base 3 Drive motor 5 Operation head 6 Drive shaft 7 Motor 12 Drive arm 13 Rod 20 Operation shaft 40 Reference pin 41 Origin pin 45 Calibration jig 46 Jig main body 47 Base side joint (base side coupling body)
48 Head side joint (head side connector)
63 Control circuit

Claims (7)

A plurality of drive motors arranged on the base, a drive arm and rod driven and operated by the drive motor, a single operation head supported by the rod, and rotational power of the motor provided on the base, A parallel mechanism origin calibration method having a drive shaft transmitted to an operation shaft provided in the operation head,
A calibration jig is disposed between the base and the operation head, the operation head is positioned at a temporary reference position by the calibration jig, and the primary detected by the position detector of the drive motor in the positioning state. A first process of passing the position signal to the control circuit;
After removing the calibration jig, a second step of performing an origin return operation on one of the drive arms;
The secondary position signal detected by the position detector of the drive motor at the time of return to origin is transferred to the control circuit, and the actual operating angle of the drive arm is calculated from the difference between the primary position signal and the secondary position signal. Further, a third process of comparing the calculation result with a theoretical value and specifying the correction value of the drive arm in the home return state when the temporary reference position is true;
A fourth step of calibrating the origin of the drive arm by reflecting the correction value specified in the third step on the control circuit,
A parallel mechanism origin calibration method in which the second process to the fourth process are performed on the remaining drive arms to calibrate the origin positions of all the drive arms. The calibration jig is composed of a rod-shaped jig main body, a base side connection body and a head side connection body connected to the jig main body,
In the first step, after removing the motor, the drive shaft, and the operation shaft, the calibration jig is attached to the mounting seat of the motor provided on the base and the mounting seat provided on the operation head. The parallel mechanism origin calibration method according to claim 1, wherein both ends are mounted and the operation head is positioned and held at a temporary reference position by the calibration jig. In a parallel mechanism in which a base side reference surface and a head side reference surface are formed on the opposing surfaces of the base and the operation head,
2. In the first step, both ends of the calibration jig are sandwiched between the base side reference surface and the head side reference surface, and the operation head is positioned and held at a temporary reference position by the calibration jig. The origin calibration method of the parallel mechanism.   4. The parallel mechanism origin calibration method according to claim 1, wherein in the second step, a reference pin provided on the drive arm is brought into contact with an origin pin provided on a motor bracket, and the drive arm is returned to the origin. A plurality of drive motors arranged on the base, a drive arm and rod driven and operated by the drive motor, a single operation head supported by the rod, and rotational power of the motor provided on the base, A calibration jig for calibrating the origin applied to a parallel mechanism having a drive shaft that is transmitted to an operation shaft provided in the operation head,
A rod-shaped body in which the calibration jig includes a base-side joint portion positioned at a base-side reference position provided on the base and a head-side joint portion positioned at a head-side reference position provided on the operation head. Consists of
A parallel mechanism for positioning the operating head at a temporary reference position in a three-dimensional space in a state where the base side joint and the head side joint of the calibration jig are fixed to the base side reference position and the head side reference position. Calibration jig for calibrating the origin. The calibration jig is composed of a rod-shaped jig main body, a base side connection body and a head side connection body that are detachably connected to the jig main body,
Each of the base side coupling body and the head side coupling body is integrally provided with a fitting portion and a flat portion,
The operation head can be positioned at the temporary reference position by the fitting portion and the flat portion formed on the base side connection body, and the fitting portion and the flat portion formed on the head side connection body. 5. A calibration jig for calibrating the origin in the parallel mechanism according to 5. The base side reference surface and the head side reference surface are formed on opposing surfaces of the base and the operation head,
A base-side joint portion positioned by the base-side reference surface and a head-side joint portion positioned by the head-side reference surface are integrally provided at both ends of the calibration jig formed in a rod shape. Item 6. A calibration jig for calibrating the origin in the parallel mechanism according to Item 5.

Images