Positioning apparatus mounted with vibration isolators and robot
09765846 · 2017-09-19
Assignee
Inventors
Cpc classification
F16M11/04
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
F16M7/00
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
F16G11/103
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
F16M11/18
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
F16M11/12
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
F16M2200/04
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
F16F15/02
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
International classification
F16F15/02
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
F16G11/10
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
F16M11/22
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
F16M11/18
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
F16M11/04
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
F16M11/12
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
Abstract
A positioning apparatus mounted with at least one linear axis or axis of rotation and a robot on a base and mounted with vibration isolators and the robot includes vibration isolators that are capable of seating and suspending the base and a controller that controls suspension and seating of the vibration isolators in accordance with an operating condition of the robot.
Claims
1. A positioning apparatus mounted with at least one linear axis or axis of rotation and a robot on a base, the positioning apparatus comprising: vibration isolators configured to seat and suspend the base; and a level adjustment device provided between the base and the vibration isolators, wherein during a series of operations of the robot that are delimited by at least one program, each operation in the series of operations sets an instruction speed of the operation of the robot, the level adjustment device is configured to control suspension and seating of the vibration isolators with respect to the base in accordance with a result of comparison between the highest instruction speed in the series of operations of the robot and a predetermined speed, the vibration isolators are configured to effect a state of the suspension or the seating before the program is executed, and maintain the state during the execution of the program, the level adjustment device is further configured to control the vibration isolators to be seated when the robot is operated at the highest instruction speed to replace a work or a tool on a machine tool or a measurement apparatus, and the level adjustment device is further configured to control the vibration isolators to be suspended when machining or measurement operated by the robot at a speed less than the highest instruction speed is started.
2. The positioning apparatus according to claim 1, wherein the vibration isolators have a structure that is suspended with pneumatic pressure or electromagnetic force.
3. The positioning apparatus according to claim 1, wherein the level adjustment device is configured to control the suspension or the seating of the vibration isolators in accordance with control signals outputted at timing specified in the at least one program.
4. The positioning apparatus according to claim 1, further comprising: at least one set of joint members configured to uniquely determine a position and a posture of the base when the vibration isolators are seated.
5. The positioning apparatus according to claim 1, wherein a control instruction for the vibration isolators is integrated into a first program for a machine tool or a measurement apparatus, a second program for the robot, or both the first and second programs.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
(1) The above-mentioned and other objects and features of this invention will become apparent from the following description of the embodiment with reference to the accompanying drawings, in which:
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DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
(14) Hereinbelow, the same or similar components in embodiments will be described with use of the same reference characters. An outline of the embodiments will be described below. In an air damper, a magnetic damper, or the like, suspension/seating of the damper can be effected at discretion with ON/OFF of air or ON/OFF of an electromagnet. Shaking due to operations of a robot can be minimized by seating of vibration isolators in advance, when the robot is operated at high speed, and by suspension of the vibration isolators in advance, when the robot is stationary or operates at low speed. The robot operates at high speed when a tool, a work, or the like is replaced and then machining, measurement, and the like are not carried out. Therefore, influence of floor vibrations that may occur with the seating of the vibration isolators does not appear. During the machining, the measurement, or the like that requires high positioning accuracy, the suspended vibration isolators isolate the floor vibrations and the operation of the robot is stopped or the robot is operated at low speed. Consequently, influence of the shaking caused by the robot, the vibrations, and the like can be reduced.
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(16) A work 18 is attached to a spindle 16 on X axis with a vacuum chuck 17 therebetween, a tool 19 is attached to a tool post 20 on Z axis, and machining is carried out by rotation of the two axes of X and Z and of the spindle. In order that precision machining may be carried out, the base 11 is supported by four vibration isolators 10 so that a structure which isolates the base 11 from the floor vibrations is provided. A robot 21 is mounted on the base 11 for automatic replacement of the work 18 and a hand 22 capable of gripping the work 18 is attached to the robot 21.
(17) In chucking of the work 18 by the vacuum chuck 17, a degree of freedom for attachment exists in directions parallel to a chuck face and thus the attachment needs to be carried out at an exact position such that center of rotation of the spindle 16 coincides with center of the work 18. Though the center of the work 18 can be aligned automatically to some degree with the center of the spindle with use of a three-jaw chuck in place of the vacuum chuck 17, the vacuum chuck is used in machining with high accuracy in order to avoid deformation of the work 18 tightened with three jaws.
(18) Mounting of the robot 21 on the base 11 has a merit in cost in that the robot 21 may be reduced in size all the more because the robot 21 is allowed to have smaller reach for the replacement of the work 18, in comparison with installation of the robot 21 on the floor. Such mounting has another merit in that installation area for a whole system may be reduced all the more because the robot 21 occupies no area on the floor. Furthermore, the vibration isolators 10 often lack reproducibility of position, posture, and the like. Installation of the robot 21 on the base 11, however, ensures that relative coordinates between the robot 21 and the work 18 are uniquely determined upon accurate positioning control over the axes, irrespective of the positions, postures, and the like of the vibration isolators 10. On condition that the vacuum chuck 17 is used, the attachment and detachment of the work with high reproducibility of position is important because exact coincidence between the center of the work 18 and the center of the spindle 16 is required.
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(20) In case where the disturbance exceeds thrusts of motors that carry out the position control over the axes, the axes fall into an alarm condition based on excessive error or the like. Conventionally, this has been a major reason why the robot 21 cannot be installed on the vibration isolators 10.
(21) The high-speed operation of the robot 21 in such an automated machining system with use of the robot 21 is required in order to shorten cycle time. The robot 21, however, does not always operate at high speed. The high-speed operation of the robot 21 leads to shortening of the cycle time in a step of the automatic replacement of the work 18 and the robot does not have to operate at high speed during machining. On the other hand, the suspension of the vibration isolators is not required during the automatic replacement of the work but required only during the machining. In this regard, as illustrated in
(22) Though
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(24) For control of the suspension or the seating of the vibration isolators, as with description for
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(28) The level adjustment device 52 is informed of a vertical position of the piston 40 through a reference plate 53 and the position of the piston 40 is automatically adjusted to a reference position by increase by the level adjustment device 52 in amount of air to be supplied into the first chamber 45, when the position of the piston 40 is below the reference, and by decrease in amount of air inflow and increase in amount of air to be discharged from a level adjustment discharge pipe 51, when the position of the piston 40 is above the reference.
(29) On condition that control is carried out by the level adjustment device 52 so that the position of the piston 40 strictly keeps the reference position, however, frequent fluctuation in the amount of air supplied into or discharged from the first chamber 45 causes shaky upward and downward movement of the piston 40 and such movement itself turns into vibrations.
(30) Therefore, the level adjustment device 52 is commonly operated with a dead zone with a certain range provided for deviation of the piston 40 from the reference position. Thus stable suspension is attained in a state in which the level adjustment device 52 provides a flow rate balanced with a flow rate that is discharged from the first chamber 45 through a throttle valve 47 under a condition that there is no major fluctuation in load on the piston 40. The level adjustment device 52 has a role of maintaining the same amount of suspension even if a payload on the base 11 (see
(31) The dead zone described above for the level adjustment device 52 is a cause of lack of the position reproducibility in the suspended vibration isolators that has been described with reference to
(32) In common applications of air dampers, the air dampers are not used with switching between the suspension and the seating and a device that carries out the switching between the suspension and the seating by electric signals is not required. In applications in accordance with the embodiment, however, the control to the suspension or the seating by the external signals is carried out with mounting of the solenoid valve 49.
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(35) Though the magnetic damper can be configured with use of repulsive forces between permanent magnets as a principle, it is easier to use the coil (electromagnet) 63 of
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(37) The speed of the robot 21 in operation is not fixed and thus real-time switching of the suspension/seating of the air dampers based on determination of only comparison in the speed of the robot 21 leads to frequent switching of the suspension/seating. In the air dampers, operating speed of the piston 40 is restricted as described with reference to
(38) Therefore, maximum value of instruction speed in one program is taken notice of and comparison between the maximum value and the threshold of the instruction speed is carried out before the execution of the program. Such processing causes automatic determination of the suspension/seating of the vibration isolators before the execution of the program and maintenance of the determined state during the execution of the program and thus prevents the frequent switching of the suspension/seating.
(39) Strictly, maximization in the instruction speed for the robot 21 does not always cause maximization in the reaction exerted on the base 11 and the maximization in the reaction depends on posture, setting of acceleration and deceleration, and the like of the robot 21. A speed, however, is often specified for each operation on a program for the robot 21 and it is therefore easy to automatically detect the maximum speed from the program. The speed of the robot 21 is sometimes specified for each axis but it is preferable to specify the speed at a position of the hand 22 (in tool coordinate system).
(40) Hereinbelow, the flow chart of
(41) [Step sa01] A program A for the attachment of a work to the vacuum chuck by the robot is chosen.
(42) [Step sa02] Whether the maximum speed in the program A exceeds the threshold or not is determined and the flow transfers to step sa03 if the maximum speed exceeds the threshold (YES) or transfers to step sa04 if the maximum speed does not exceed the threshold (NO).
[Step sa03] Control signals for the seating of the air dampers are outputted.
[Step sa04] Control signals for the suspension of the air dampers are outputted.
[Step sa05] The program A is executed.
[Step sa06] Whether execution of the program A has been completed or not is determined and the flow transfers to step sa07 if the program A has been completed (YES) or completion is waited if the program A has not been completed (NO).
[Step sa07] Control signals for the suspension of the air dampers are outputted.
[Step sa08] A machining program a for the precision lathe is executed.
[Step sa09] Whether execution of the program a has been completed or not is determined and the flow transfers to step sa10 if the program a has been completed (YES) or completion is waited if the program a has not been completed (NO).
[Step sa10] A program B for the detachment of the work from the vacuum chuck by the robot is chosen.
[Step sa11] Whether the maximum speed in the program B exceeds the threshold or not is determined and the flow transfers to step sa12 if the maximum speed exceeds the threshold (YES) or transfers to step sa13 if the maximum speed does not exceed the threshold (NO).
[Step sa12] The control signals for the seating of the air dampers are outputted.
[Step sa13] The control signals for the suspension of the air dampers are outputted.
[Step sa14] The program B is executed.
[Step sa15] Whether the program B has been completed or not is determined and processing is ended if the program B has been completed (YES) or the processing is ended upon the completion if the program B has not been completed (NO).
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(44) In the flow chart of
(45) Among programs in the flow chart of
(46) Though the switching to the suspension or the seating of the vibration isolators 10 is carried out based on the speed of the robot 21 in description referring to
(47) An operation of washing out the chips in the machine is carried out by the robot 21 in the roughing because a large quantity of chips are produced in the roughing and then the high-speed operation of the robot 21 can be attained because the vibration isolators are seated.
(48) Hereinbelow, the flow chart of
(49) [Step sb01] The program C for the attachment of a work to the vacuum chuck by the robot is executed.
(50) [Step sb02] An instruction for the seating of the air dampers in the program C is executed.
(51) [Step sb03] The air dampers are seated.
(52) [Step sb04] Whether the program C has been completed or not is determined and the flow transfers to step sb05 if the program C has been completed (YES) or completion is waited if the program C has not been completed (NO).
(53) [Step sb05] The roughing program b for the precision lathe is executed.
(54) [Step sb06] The program D for the washing in the machine by the robot is executed.
(55) [Step sb07] Whether execution of the program b has been completed or not is determined and the flow transfers to step sb08 if the program b has been completed (YES) or completion is waited if the program b has not been completed (NO).
(56) [Step sb08] Execution of the program D is ended.
(57) [Step sb09] The finishing program c for the precision lathe is executed.
(58) [Step sb10] An instruction for the suspension of the air dampers in the program c is executed.
(59) [Step sb11] The air dampers are suspended.
(60) [Step sb12] The program E for a grip on next work by the robot is executed.
(61) [Step sb13] Whether the program c has been completed or not is determined and the flow transfers to step sb14 if the program c has been completed (YES) or completion is waited if the program c has not been completed (NO).
(62) [Step sb14] The program F that causes the robot to detach a work from the vacuum chuck and to replace the work with the next work is executed.
(63) [Step sb15] An instruction for the seating of the air dampers in the program F is executed.
(64) [Step sb16] The air dampers are seated.
(65) [Step sb17] Whether execution of the program C has been completed or not is determined and processing is ended if the program C has been completed (YES) or the processing is ended upon the completion if the program C has not been completed (NO).
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