Machines are used in many industrial applications. One type of machine is a robot that includes a mechanical arm, e.g. a robotic arm, that positions a payload. There is a never-ending desire to improve the operation and positioning accuracy of robots.
The present implementation is directed to a vibration reduction assembly for reducing a magnitude of a vibration being transferred from a first component (e.g. a robot assembly) to a second component (e.g. a payload). The vibration reduction assembly can include (i) a first vibration reduction system that reduces vibration along a first axis that is oriented parallel with gravity; and (ii) a second vibration reduction system that reduces vibration along a second axis that is crossing (e.g. orthogonal) to the first axis. In one design, the first vibration reduction system and the second vibration reduction system are arranged between the first component and the second component.
As an overview, the vibration reduction assembly is uniquely designed to reduce the level of vibration being transferred from the first component to the second component. As a result thereof, the second component can be positioned in space with improved accuracy while isolating the second component from unwanted vibration and position errors. This, for example, allows for the stable, and very accurate positioning of the second component, and the manufacturing, measurement, processing, and/or assembly of devices with improved precision. The vibration reduction assembly makes possible the ability to perform high-precision operations such as, but not limited to optical non-contact operations like precise measurement, laser ablation, laser welding, or 3-D Printing on the end of an industrial robot assembly.
The first vibration reduction system can have low stiffness compliance to counteract static force of gravity from the second component. For example, the first vibration reduction system can have a lower stiffness compliance than the second vibration reduction system along the gravity direction. Further, the second vibration reduction system can have low-stiffness in non-gravity directions without having to address static gravity force. Moreover, the second vibration reduction system can inhibit vibration along a third axis that is orthogonal to the first axis and the second axis. For example, the second vibration reduction system can have a lower stiffness compliance than the first vibration reduction system along the non-gravity direction.
Stated in another fashion, (i) the first vibration reduction system has a lower stiffness compliance than the second vibration reduction system along the first axis; and/or (ii) the second vibration reduction system has a lower stiffness compliance than the first vibration reduction system along the second axis.
The first vibration reduction system can include one or more of a spring, a bellows, a pneumatic chamber, a fluid guide and piston. The first vibration reduction system can be directed through a center of gravity of the second component.
The vibration reduction assembly can include a control system that actively controls a force produced by the first vibration reduction system and/or the second vibration reduction system. Additionally, or alternatively, the vibration reduction assembly can include an actuation system that positions the second component. The actuation system can connect the second component to the first component. Moreover, the actuation system can act in parallel with at least one of the first vibration reduction system and the second vibration reduction system.
In one implementation, the second vibration reduction system includes a plurality of spaced apart flexures. In another implementation, the second vibration reduction system includes a plurality of spaced apart fluid bearings. For example, the second vibration reduction system can include at least three spaced apart fluid bearings that guide motion along a plane that is perpendicular to the first axis.
Additionally, or alternatively, the vibration reduction assembly can include a coupling assembly which connects the first vibration reduction system to the first component. In this design, the coupling assembly can rotate so that the first vibration reduction system is aligned with gravity.
Additionally, or alternatively, the vibration reduction assembly can include a component mover assembly which selectively moves the second component relative to the second vibration reduction system. This allows for the tip and tilting of the payload.
In another implementation, the present design is direct to a machine that includes the vibration reduction assembly, a first component, and a second component. The machine can include a sensor assembly that provides feedback, and a control system that actively controls the vibration reduction assembly to inhibit vibration in the first component from being transferred to the second component. As non-exclusive examples, the sensor assembly can provide feedback regarding (i) the position, velocity, orientation, acceleration, etcetera of the second component; and/or (ii) the position, velocity, orientation, acceleration, etcetera of the first component; and/or (iii) other inertial guiding objects.
The first component can include one or more of a multiple degree of freedom robotic arm, a vehicle, and an aerial vehicle. As a non-exclusive examples, the second component can include one or more of an optical assembly, a laser, an optical measurement device, and an optical processing unit.
In still another implementation, a machine for positioning a payload includes a robot assembly; and a vibration reduction assembly that isolates vibration in the robot assembly from being transferred to the payload, the vibration reduction assembly including (i) a first vibration reduction system that inhibits vibration along a first axis that is oriented parallel with gravity; and (ii) a second vibration reduction system that inhibits vibration along a second axis that is orthogonal to the first axis; wherein the first vibration reduction system and the second vibration reduction system are connected in series between the first component and the second component.
The machine can include a vibration reduction assembly controller and at least one sensor, and wherein the sensor outputs a signal of vibration of the second component and the vibration reduction assembly controller controls the actuation system and/or the vibration reducers based upon the signal from the sensor.
Additionally, or alternatively, the vibration reduction assembly controller can utilize a feedforward signal to control the actuation system and/or the vibration reducers. As non-exclusive examples, the feedforward signal can include a trajectory of robot arm and/or the payload so that the vibration reduction system can reduce the vibration of the payload.
In still another implementation, the vibration reduction assembly includes a vibration reduction system that reduces vibration along a first axis that is oriented parallel with gravity, and along a second axis that is crossing to the first axis. In this design, the vibration reduction system connects the first component to the second component.
In one implementation, the vibration reduction system includes a fluid bellows. The fluid bellows can be maintained at a vacuum or the fluid bellows can be maintained at a bellows pressure that is greater than atmospheric pressure.
The novel features of this embodiment, as well as the embodiment itself, both as to its structure and its operation, will be best understood from the accompanying drawings, taken in conjunction with the accompanying description, in which similar reference characters refer to similar parts, and in which:
The term “vibration” as used herein shall mean and include steady-state vibration, short term disturbances, random disturbances, transient disturbances, repeatable disturbances, and any unwanted motion. As non-exclusive examples, the vibration can arise from vibrations in the support 18 (e.g. the floor), the components of the machine 10, acoustic noise, and/or the surrounding environment.
A number of Figures include an orientation system that illustrates an X axis, a Y axis that is orthogonal to the X axis, and a Z axis that is orthogonal to the X and Y axes. In this example, the Z axis is oriented parallel with gravity and can alternatively be referred to as the “gravity axis” or “gravity direction”. Further, the X and Y axes can be referred to as “non-gravity axes” or “non-gravity directions”. It should be noted that any of these axes can also be referred to as the first, second, and/or third axes. Further, movement along or about a single axis can be referred to as a one degree of freedom, and movement along and about the X, Y and Z axes can be referred to as six degrees of freedom. It should be noted that one or more of the axes can be referred to as crossing the other axes. For example, the second axis can cross the first axis at an orthogonal angle or at an angle other than orthogonal.
A plurality of different implementations are disclosed herein. As an overview, in each implementation, the vibration reduction assembly 24 is uniquely designed to reduce and at least partly inhibit vibration in the assembly 14 and/or the support 18 from being transferred to the payload 12. As a result thereof, the payload 12 can be positioned in space with improved accuracy while at least partly isolating the payload 12 from unwanted vibration and position errors of the robot assembly 14. This, for example, allows for the stable, and very accurate positioning of the payload 12, and the manufacturing, measurement, processing, and/or assembly of components with improved precision.
The vibration reduction assembly 24 makes possible the ability to perform high-precision operations (such as, but not limited to optical non-contact operations like precise measurement, laser ablation, laser welding, or 3-D Printing) on the end of an industrial robot assembly 14. Typically, a robot assembly 14 with a large range of motion and significant payload 12 capability has significant vibrations at its end that prohibit any precise operations without the end “docking” into some physically stabilizing piece of tooling. This docking is undesired for many reasons in many situations.
The size, shape and design of the payload 12 can be varied to achieve the task the machine 10 is designed to perform. For example, the payload 12 can be an optical instrument that is designed to interact with a target workpiece. As non-exclusive examples, the payload 12 can be a device for performing a desired task such as welding, three dimensional printing, cutting, measuring, soldering, manufacturing, depositing material, ablating material, gripping, spinning, placement, or fastening. For example, the payload 12 can be an optical instrument, such as a laser, and the desired task can be (i) precisely cutting one or more grooves (not shown) in one or more components (not shown); (ii) welding one or more components; and/or (iii) soldering one or more components. Alternatively, for example, the payload 12 can include a gripper (e.g. a robotic hand).
The term “payload” 12 can also be referred to as a “second component” or “object”.
In the non-exclusive example illustrated in
As provided above, the assembly 14 is supported by the support 18. As non-exclusive examples, the support 18 can be a floor, a wall, or other fixed surface in a factory, inside a building, or outside. Alternatively, the support 18 can be a movable structure, such as a movable robot, a vehicle, or an aerial vehicle such as an automated guided vehicle or aerial drone.
The assembly 14 moves and positions the payload 12. The design of the assembly 14 can be varied to suit the movement requirements of the payload 12. In the non-exclusive implementation of
The robotic arm 16 can include one or more rigid links 16C, one or more joints 16D, and one or more link actuators 16E. The links 16C are connected by joints 16D that allow for either rotational motion or translational movement, and the link actuators 16E are controlled to rotationally and/or translationally move the links 16C. It should be noted that (i) any of the links 16C can be referred to as a first, second, third, fourth, etc. link; (ii) any of the joints 16D can be referred to as a first, second, third, fourth, etc. joint; and (iii) any of the link actuators 16E can be referred to as a first, second, third, fourth, etc. link actuator. For example, each link actuator 16E can include one or more linear actuators and/or one or more rotational actuators.
The links 16C of the assembly 14 can be considered a kinematic chain, and the control system 22 can precisely control the link actuators 16E to precisely position the payload 12 with one or more degrees of freedom. In the non-exclusive implementation of
In one implementation, the attachment end 16B of the robot 16 can include a mount 26 that provides a rigid structure for attaching the vibration reduction assembly 24. In the non-exclusive implementation of
It should be noted that the robot assembly 14, one or more links 16C, one or more joints 16D and/or the mount 26 can be referred to generically as a “first component” or “movable part”.
In the non-exclusive implementation of
It should be noted that the industrial assembly 14 can be subjected to some amount of vibration disturbance from the support 18. Because of the mechanical dynamics of the robotic assembly 14, some of those vibrations are transmitted to the mount 26. Additionally, the robotic assembly 14 itself may add additional vibration modes. Still further, disturbance forces from air currents (i.e., wind), acoustic noise, and cables or hoses may act on the payload 12. As discussed below, the vibration reduction assembly 24 reduces the magnitude of this vibration that is being transmitted to the object 12 and counteracts the effects of these disturbances.
The sensor assembly 20 senses the position, velocity, and/or acceleration of the payload 12 and/or the position, velocity, and/or acceleration of one or more components of the vibration reduction assembly 24, and provides feedback that is used by the control system 22 to control the link actuators 16E of the robot 16 and the vibration reduction assembly 24. The design of the sensor assembly 20 can be varied to provide the desired feedback to control the link actuators 16E and the vibration reduction assembly 24. For example, if the robot 16 positions the payload 12 with six degrees of freedom, it is desirable for the sensor assembly 20 to provide feedback regarding all six degrees of freedom. In the non-exclusive example of
As non-exclusive examples, the sensor assembly 20 can include one or more cameras that function at one or more wavelengths, interferometers, photodetectors, or non-optical measurement devices such as accelerometers, ultrasonic, eddy current, or capacitive sensors. As non-exclusive examples, the sensor assembly 20 can be provided on a rigid third structure 32E.
The control system 22 controls the components of the machine 10. For example, the control system 22 can control (i) the payload 12; (ii) the robot assembly 14; (iii) the sensor assembly 20; and (iv) the vibration reduction assembly 24. The control system 22 can be a centralized or distributed system.
The control system 22 may include, for example, a CPU (Central Processing Unit) 22A, and electronic memory 22B. The control system 22 functions as a device that controls the operation of the machine 10 by the CPU executing the computer program. The control system 22 may not be disposed inside the machine 10, and may be arranged as a server or the like outside the machine 10, for example. In this case, the control system 22 and the machine 10 may be connected via a communication line such as a wired communications line (cable communications), a wireless communications line, or a network. Furthermore, each processing and function included in the program may be executed by program software that can be executed by a computer, or processing of each part may be executed by hardware such as a predetermined gate array (FPGA), ASIC or program software, and a partial hardware module that realizes a part of hardware elements may be implemented in a mixed form.
The programming and the hardware for the control system 22 can be varied to achieve the desired task that the machine 10 will be performing. The control system 22 can be divided as two or more systems. For example, one control system can be used to control the vibration reduction assembly 24, and the other can be used for the robotic assembly 14.
The control system 22 can include a vibration reduction assembly controller that uses the sensor outputs of the sensor assembly 20 (e.g. a signal of vibration of the second component) and the vibration reduction assembly controller can control the actuation system and/or the vibration reducers based upon the signal from the sensor assembly 20. Additionally, or alternatively, the vibration reduction assembly controller can utilize a feedforward signal to control the actuation system and/or the vibration reducers. As non-exclusive examples, the feedforward signal can include a trajectory of robot arm and/or the payload so that the vibration reduction system can reduce the vibration of the payload.
The vibration reduction assembly 24 connects the payload (second component) 12 to the robot (first component) 16, and extends between the payload 12 and the mount 26. Further, the vibration reduction assembly 24 reduces (inhibits) vibration in the robot 16 (e.g. in the mount 26, links 16C, joints 16D, and link actuators 16E) and the support 18 from being transferred to the payload 12. The vibration reduction assembly 24 also counteracts disturbance forces that act on the payload 12. As a result thereof, the robotic assembly 14 can, together with the vibration reduction assembly 24, more accurately position the payload 12 relative to the target surface 28.
It should be noted that the design of the vibration reduction assembly 24 can be adjusted to suit any sized or shaped payload 12. Further, the design of the vibration reduction assembly 24 can be varied to suit the movement requirements of the payload 12. In alternative implementations, (i) if the robotic assembly 14 is designed to position the payload 12 with one degree of freedom, the vibration reduction assembly 24 can be designed to inhibit vibration of the payload 12 in at least one degree of freedom; (ii) if the robot assembly 14 is designed to position the payload 12 with two degrees of freedom, the vibration reduction assembly 24 can be designed to inhibit vibration of the payload 12 in at least two degrees of freedom; (iii) if the robot assembly 14 is designed to position the payload 12 with three degrees of freedom, the vibration reduction assembly 24 can be designed to inhibit vibration of the payload 12 in at least three degrees of freedom; (iv) if the robot assembly 14 is designed to position the payload 12 with four degrees of freedom, the vibration reduction assembly 24 can be designed to inhibit vibration of the payload 12 in at least four degrees of freedom; (v) if the robot assembly 14 is designed to position the payload 12 with five degrees of freedom, the vibration reduction assembly 24 can be designed to inhibit vibration of the payload 12 in at least five degrees of freedom; or (vi) if the robot assembly 14 is designed to position the payload 12 with six degrees of freedom, the vibration reduction assembly 24 can be designed to inhibit vibration of the payload 12 in six degrees of freedom. It should be noted that the robot assembly 14 and the vibration reduction assembly 24 can be designed so that the degrees of movement of the robot assembly 14 are different from the degrees of reduction of the vibration reduction assembly 24. As a non-exclusive example, the robot assembly 14 can be designed to have one degree of movement, and the vibration reduction assembly 24 can be designed to have reduction in more than one (e.g. two, three, four, five, or six) degrees of freedom. As yet another example, the robot assembly 14 can be designed to have six degrees of movement, and the vibration reduction assembly 24 can be designed to have reduction in less than six (e.g. five, four, three, two, or one) degrees of freedom.
A number of different implementations of the vibration reduction assembly 24 are disclosed herein. In certain implementations, the vibration reduction assembly 24 is uniquely designed with a first vibration reduction system 30 and a second vibration reduction system 32 that are arranged (connected) in series to connect the payload 12 to the assembly 14. The first vibration reduction system 30 reduces vibration in the assembly 14 and/or the support 18 along the Z axis (and about the Z axis) from being transferred to the payload 12, while the second vibration reduction system 32 reduces vibration in the assembly 14 and/or the support 18 along the X axis and/or along the Y axis from being transferred to the payload 12. Stated in another fashion, the first vibration reduction system 30 reduces vibration in the assembly 14 and/or the support 18 along the gravity direction from being transferred to the payload 12, while the second vibration reduction system 32 reduces vibration in the non-gravity directions.
With this design, the problem of providing a high-performance vibration reduction assembly 24 for an industrial robot assembly 14 (or other device) performing a precision operation is solved by (i) the first vibration reduction system 30 that is oriented with gravity, and that has a low-stiffness compliance to counteract the static force of gravity, and (ii) the second vibration reduction system 32 that has additional low-stiffness elements in the non-gravity directions that do not have to address the static gravity force. Stated in another fashion, the first vibration reduction system 30 inhibits vibration along the Z axis (oriented parallel with gravity); and the second vibration reduction system inhibits vibration along the X axis and/or along the Y axis. Because the first vibration reduction system 30 addresses the vibration along the Z axis, this can simplify the design of each of the reduction systems 30, 32.
As alternative, non-exclusive examples, low stiffness shall mean less than 1, 2, 5, 10, 20, 30, 50 or 100 Newton/millimeters. Stated in another fashion, as alternative, non-exclusive examples, low stiffness shall mean that the payload 12 will have a natural frequency of less than 1, 2, 5, or 10 hertz.
It should be noted that the first vibration reduction system 30 and the second vibration reduction system 32 are illustrated in a simplified fashion (in cut-away) in
The design of the first vibration reduction system 30 can be varied to achieve the desired vibration reduction of the payload 12 along the Z axis. In the non-exclusive implementation in
For example, the first vibration reduction system 30 can be a fluid (e.g. air) spring, piston, or bellows. In
Further, in
Additionally, the first vibration reduction system 30 can include one or more piston seals 30G (only one is shown) that seal the piston disc 30E to the first frame 30A and/or the piston shaft 30F to the first frame 30A. For example, the piston seal 30G can be a low friction seal such as a rolling diaphragm or an air bearing to isolate the piston disc 30E vibrations along the Z axis (and possibly also about the Z axis (θz)) from vibrations present in the mount 26.
Additionally, the first vibration reduction system 30 can include a pressure sensor 30H (illustrated as a box) which senses the pressure of the fluid 30D in the fluid chamber 30C. Moreover, the first vibration reduction system 30 can include a chamber adjuster 34 (illustrated as a box) that can selectively adjust and actively control the pressure in the fluid chamber 30C.
With this design, the pressure sensor 30H can provide feedback regarding the pressure to the control system 22, and the control system 22 can actively control the chamber adjuster 34 to actively adjust and control the pressure in the chamber 30C. This active control of the pressure of the pneumatic fluid 30D in the chamber 30C also actively controls the force produced the first vibration reduction system 30. The chamber adjuster 34 can include one or more electronic regulators, servo valves, pumps and reservoirs to add and remove pneumatic fluid to the chamber 30C under the control of the control system 22 to control of the pressure.
With this design, an external disturbance along the Z axis transferred to the mount 26 will cause the mount 26 to move. The movement of the mount 26 will cause the pressure in the chamber 30C to change (fluctuate). The pressure sensor 30H can detect these changes, and the feedback is used to control the chamber adjuster 30H to control the pressure in the chamber 30C to reduce the vibration along the Z axis from being transmitted to the second vibration reduction system 32 and the payload 12. In this design, the first vibration reduction system 30 is an actively controlled low stiffness support system. Alternatively, the first vibration reduction system 30 can be a passive system without the chamber adjuster 34 that actively controls the pressure.
Further, the chamber adjuster 34 can adjust (increase) the pressure in the chamber 30C prior to large movements along the Z axis with the robotic arm 16 to better track movement.
The second vibration reduction system 32 reduces vibration from the mount 26 (and the first vibration reduction system 30) along the X axis and/or along the Y axis from being transferred to the payload 12. In the non-exclusive implementation of
In the non-exclusive implementation of
Alternatively, for example, the second vibration reduction system 32 can be designed with more or fewer components than are illustrated in
It should be noted that in the implementation illustrated in
Additionally, in it should be noted that the vibration reduction assembly 24 and payload 12 can function as a module that can be added to the robot assembly or another processing machine.
In the implementation of
In one non-exclusive implementation, the payload mover assembly 236 can move and position the payload 212 (e.g. about a controlled rotational axis (pivot joint)) relative to the second vibration reduction system 232 about the X axis (“θx”) and/or about the Y axis (“θy”). With this design, for example, if the payload 212 is a laser or a portion thereof, the payload mover assembly 236 can point the laser. For example, the payload 212 can include at least a part of an optical system or an optical element (e.g., a light source), for example, for outputting a laser beam. In certain embodiments, the laser light source can be located around a proximal base 16A of the robotic arm 16 or at other locations, and can be linked to the payload 212 (end effector) by an optical fiber or other light guide/wave guide. Alternatively, the payload mover assembly 236 can be designed to move the payload 212 with more than two (e.g., additionally about the Z axis) or fewer than two degrees of freedom. Stated in another fashion, the payload mover assembly 236 can be designed to move and position the payload with one, three, four, five, or six degrees of freedom. In another example, the payload mover assembly 236 can be designed to move the payload 212 about the X, Y and Z axes. Still alternatively, the payload mover assembly 236 can be designed to move the payload 212 along the X, Y and Z axes and about the X, Y and Z axes.
It should be noted that the knowledge and control of the payload center of gravity 212A may be critical to the rotational vibration reduction performance, and the positioning performance.
In the implementation of
The design of the actuator system 338 can be varied. For example, the actuator system 338 can include one or more actively controlled actuators. In the simplified illustration of
In this design, (i) the Z actuator(s) 340 generate a controllable force along the Z axis on the payload 312; (ii) the X actuator(s) 342 generate a controllable force along the X axis on the payload 312; and (iii) the Y actuator(s) 344 generate a controllable force along the Y axis on the payload 312. Further, one or more of the actuators 340, 342, 344 can be controlled to adjust and control the position of the payload 312 about the X, Y and/or Z axis relative to the target surface 328.
The design of each actuator 340, 342, 344 can be varied. As non-exclusive examples, one or more of the actuators 340, 342, 344 can be a voice coil actuator, a linear actuator, rotational actuator, variable reluctance actuator or another type of actuator.
In one non-exclusive implementation, (i) each of the Z actuators 340 includes a first Z component 340A that is secured to the first frame 330A and a second Z component 340B that is secured to the first structure 332A; (ii) each of the X actuators 342 includes a first X component 342A that is secured to the first structure 332A and a second X component 342B that is secured to the third structure 332E; and (iii) each of the Y actuators 344 includes a first Y component 344A that is secured to the first structure 332A and a second Y component 344B that is secured to the third structure 332E. For example, for each actuator 340, 342, 344, one of the components 340A, 340B, 342A, 342B, 344A, 344B can include one or more magnet arrays, and the other of the components 340A, 340B, 342A, 342B, 344A, 344B can include one or more conductor arrays.
With this design the Z actuator(s) 340 act in parallel with the first vibration reduction system 330, and the X and Y actuator(s) 342, 344 act in parallel with the second vibration reduction system 332.
Additionally, the sensor assembly 320 can include one or more sensors (not shown) which measures one or more of the relative position, orientation, velocity, acceleration, etcetera of the respective components 340A, 340B, 342A, 342B, 344A, 344B of each actuator 340, 342, 344. With this design, the sensor assembly 320 can generate feedback regarding the relative position, in addition to the feedback regarding the position of the payload 12. This feedback can be used by the control system 322 to actively control (direct electrical current) to the actuators 340, 342, 344 to individually and actively adjust the force generated by each actuator 340, 342, 344. This active control of the force by each actuator 340, 342, 344 can be used to rapidly maintain the position of the payload 312 under the control of the control system 322.
In this design, the actuator system 338 actively generates one or more controllable forces on the payload 312 to further isolate the payload 312 from external disturbances. The control system 322 can actively control the actuator system 338 using feedback from the sensor assembly 320 to counteract external disturbances and the internal disturbances. The actuator system 332 provides reduction of higher bandwidth disturbances.
As a result thereof, an external disturbance transferred to the mount 326 will cause the mount 326 to move. Simultaneously, the force by the actuator system 338 can be actively adjusted to maintain the desired position of the payload 312. With this design, the plurality of higher bandwidth actuators 340, 342, 344 can be controlled to improve force control performance.
Thus, to provide a high precision stable operation of the payload 312, the vibration reduction assembly 324 allows the robot assembly 314 to position the payload 312 in space while isolating it from unwanted vibration and position errors of the robot assembly 314, and while counteracting external disturbances on the payload 312.
Additionally, when it is desired to move the payload 312 with the robot assembly 314, the actuator system 338 can be controlled to apply feed-forward forces to the payload 312 that provide a desired acceleration profile on the payload 312. This permits the payload 312 to track the motion of robot assembly 314 in a controlled way rather than just bounce on the end of the robot 316. Additionally, the pressure in the first vibration reduction system 330 may be actively controlled to provide vertical accelerations or to compensate for changes in the mass of payload 312.
In one implementation, when it is desired to move the payload 312, the actuator system 338 can be controlled by the control system 322 to move and position the payload 312, while the link actuators 316E can be controlled by the control system 322 so that the robot assembly 314 follows this movement to maintain the available stroke of each of the actuators 340, 342, 344.
In the implementation of
The vibration reduction assembly 424 includes the first vibration reduction system 430, the second vibration reduction system 432, the payload mover assembly 436, and the actuator system 438 that are similar to the corresponding components described above. However, in the implementation of
It should be noted that in the designs provided herein, the first vibration reduction system 430 is connected to the first component 414 and the second vibration reduction system 432 is connected to the second component 412. With this design, it is relatively easy to design the assembly so that the second vibration reduction system 430 is aligned with the center of gravity of the payload. However, the orientation of these components can be reversed with the first vibration reduction system 430 connected to the second component 412 and the second vibration reduction system 432 is connected to the first component 414. This reversed configuration is possible with any of the designs disclosed herein.
Further, the coupling assembly 448 allows the first frame 430A to pivot relative to the mount 426 so that the first vibration reduction system 430 is maintained aligned with gravity (e.g. along the Z axis) as the orientation of mount 426 is changed. In the implementations of
The design of the coupling assembly 448 can be varied. For example, the coupling assembly 448 can define a ball and socket joint and can includes (i) a socket component 448A that is secured to the mount 426; (ii) a ball component 448B that is positioned in the socket component 448A; and (iii) a shaft 448C that cantilevers away from the ball component 448B. In this design, the distal end of the shaft 448C is secured to the first vibration reduction system 430. However, other designs of the coupling assembly 448 are possible.
Additionally, the coupling assembly 448 may include a coupling actuator assembly 450 that is controlled by the control system 422. The design of the coupling actuator assembly 450 can be varied. For example, the coupling actuator assembly 450 can include one or more actively controlled actuators. In the simplified, non-exclusive illustration of
Further, with this design, the coupling actuator assembly 450 can control the position of the shaft 448C during accelerations and movement robotic assembly.
As non-exclusive examples, the coupling actuator assembly 450 can include one or more spherical actuators, voice coil actuators, linear actuators, and/or damper elements. For example, the ball and socket joint can be filled with a hydraulic fluid that dampens motion of shaft 448C relative to the mount 426.
Additionally, the sensor assembly 420 can include a sensor (not shown) which measures the relative position, orientation, velocity and/or acceleration of mount 426 and the shaft 448C. With this design, the sensor assembly 420 can generate feedback regarding the relative position, orientation, velocity and/or acceleration, in addition to the feedback regarding the position, orientation, velocity and/or acceleration of the payload 412. This feedback can be used by the control system 422 to actively control (direct electrical current) to the coupling actuator assembly 450. This active control of the force can be used to rapidly maintain the position of the payload 412 under the control of the control system 422.
In this design, when it is desired to move the payload 412 with the robot assembly 414, the coupling actuator assembly 450 can be controlled to apply feed-forward forces to permit the payload 412 to track the motion of robot assembly 414 in a controlled way rather than just bounce on the end of the robot assembly 414. Stated in another fashion, the coupling actuator assembly 450 allows the payload 412 to be held “on station” to the robot assembly 414 while being decoupled from the vibration from the robot assembly 414.
In the implementation of
It should be noted that the vibration reduction assembly 524 can be added to an existing, robotic arm (not shown) to add more degrees of freedom and/or increased precision on the placement of the payload 512.
In
In this design, the vibration reduction assembly 624 includes the coupling assembly 648 (only a portion is shown), the first vibration reduction system 630, the second vibration reduction system 632, and the payload mover assembly 636. However, the vibration reduction assembly 624 can be designed to have fewer components than illustrated in
In this implementation, only the distal end of the shaft 648C of the payload coupling assembly 648 is illustrated in
The first vibration reduction system 630 provides vibration reduction of the payload 612 along the Z axis. More specifically, (i) the first vibration reduction system 630 supports the mass of the payload 612 and the second vibration reduction system 632, (ii) the first vibration reduction system 630 at least partly isolates the payload 612 and the second vibration reduction system 632 from high frequency external disturbances along the Z axis, and (iii) the force from the first vibration reduction system 630 can act through the center of gravity of the payload 612.
In
The upper frame 630A is an inverted “U” shaped bracket that is secured to the distal end of the shaft 648C of the payload coupling assembly 648. The upper frame 630A includes an upper, frame cross beam 630F and two, spaced apart beam sides 630G that cantilever downward from the upper frame cross beam 630F. In this design, the first side frame 630B is attached to a distal end of one of the beam sides 630G, and the second side frame 630C is attached to a distal end of the other of the beam sides 630G. The rigid first side frame 630B supports the first Z isolator 630D, and the rigid second side frame 630C supports the second Z isolator 630E.
The design of each of the Z isolators 630D, 630E can be varied to achieve the desires vertical Z axis reduction. For example, each of the Z isolators 630D, 630E can be a low stiffness support that extends between the first vibration reduction system 630 and the second vibration reduction system 632. In one non-exclusive implementation, each Z isolators 630D, 630E is a cylindrical shaped fluid (e.g. air) bearing and piston that provides a low stiffness, low friction connection between the first vibration reduction system 630 and the second vibration reduction system 632. Each cylindrical fluid bearing and piston 630D, 630E is very stiff along the X and Y axes, and about the X and Y axes, and extremely low friction along and about the Z axis. Typically ground-based disturbance vibrations are the most significant along the Z axis, and therefore Z axis reduction can be critical. The cylindrical fluid bearings 630D, 630E work well with heavy payloads and their large gravity loads.
It should be noted that the first side frame 630B is illustrated in cut-away, and can form a portion of the fluid chamber for the first Z isolator 630D, and the second side frame 630C can form a portion of the fluid chamber for the second Z isolator 630E.
Alternatively, one or more of the Z isolators 630D, 630E can include a spring, bellows, a rubber diaphragm, or some other Z restraint (linear guide, typical bearing).
In the non-exclusive implementation in
Additionally, the first vibration reduction system 630 can include one or more pressure sensor(s) (not shown) which sense the pressure of the fluid in Z isolators 630D, 630E. Moreover, the first vibration reduction system 630 can include a chamber adjuster (not shown) that can selectively adjust and actively control the pressure in each Z isolators 630D, 630E. In this design, the first vibration reduction system 630 is an actively controlled low stiffness support system. Alternatively, the first vibration reduction system 630 can be a passive system without the chamber adjuster that actively controls the pressure.
With the present design, a disturbance along the Z axis transferred to the first vibration reduction system 630 will cause the upper frame 630A and the side frames 630B, 630C to move. The Z isolators 630D, 630E will at least partly inhibit the disturbance along the Z axis from being transferred to the second vibration reduction system 632.
The second vibration reduction system 632 at least partly inhibits vibration along the X axis and/or along the Y axis from being transferred to the payload 612. In the non-exclusive implementation of
In the non-exclusive implementation of
The number and design of the first flexures 732F can vary. In the non-exclusive implementation of
In
The number and design of the second flexures 832G can vary. In the non-exclusive implementation of
The implementation of
It should be noted that in the design of
Additionally, if there is a large motion of the second structure 632C and the third structure 632E along either the X or Y axis, there will be some swinging action and motion of the second structure 632C along the Z axis that will be cancelled out at the third structure 632E because of the double pendulum design because each of the connector assemblies 632B, 632D will be bending.
Alternatively, for example, the second vibration reduction system 632 can be designed with more or fewer components than are illustrated in
For example, the payload mover assembly 636 can be controlled to rotate the payload 612 about one or more axes relative to the second vibration reduction system 632. In the non-exclusive implementation of
Additionally or alternatively, the coupling assembly 648 can be designed to include a coupling actuator assembly 450 (illustrated in
With the coordinated rotation of the payload 612 about the Z axis and about the X axis, the payload 612 can be tip/tilted as necessary. This can effectively replace a missing fifth and sixth axis of the industrial robot assembly (not shown in
Alternatively, or additionally, the robot assembly can be designed to rotate the vibration reduction systems 630, 632, and the payload 612 about the Z axis.
In
In
The first vibration reduction system 1230 provides vibration reduction of the payload 1212 along the Z axis. More specifically, (i) the first vibration reduction system 1230 supports the mass of the payload 1212 and the second vibration reduction system 1232, (ii) the first vibration reduction system 1230 isolates the payload 1212 and the second vibration reduction system 1232 from high frequency external disturbances along the Z axis, and (iii) the force from the first vibration reduction system 1230 can act through the center of gravity of the payload 1212.
In
Further, in
Additionally, the first vibration reduction system 1230 can include one or more pressure sensor(s) (not shown) which sense the pressure of the fluid in the Z isolators 1230D, 1230E. Moreover, the first vibration reduction system 1230 can include a chamber adjuster (not shown) that can selectively adjust and actively control the pressure in each Z isolators 1230D, 1230E. In this design, the first vibration reduction system 1230 is an actively controlled low stiffness support system. Alternatively, the first vibration reduction system 1230 can be a passive system without the chamber adjuster that actively controls the pressure.
The second vibration reduction system 1232 inhibits vibration along the X axis and/or along the Y axis from being transferred to the payload 1212, without having to contend with static gravity forces.
The outer first structure 1270 is generally rectangular “U” shaped and includes an outer rear frame 1270A, a first, outer side frame 1270B, and a second, outer side frame 1270C. In this implementation, the outer rear frame 1270A is a rigid beam that extends along the X axis, and outer side frames 1270B, 1270C are flat beam shaped, are spaced apart along the X axis, and cantilever from opposite sides of the outer rear frame 1270A along the Y axis.
The inner second structure 1272 is also somewhat rectangular “U” shaped and includes an inner rear frame 1272A, a first, inner side frame 1272B, and a second, inner side frame 1272C. In this implementation, the inner rear frame 1272A is a rigid beam that extends along the X axis, and inner side structures 1272B, 1272C are spaced apart along the X axis, and cantilever from opposite sides of the inner rear structure 1272A along the Y axis.
In
In
It should be noted that the second structure 1272 includes three spaced apart bearing surfaces 1272G that interact with the bearing connector assembly 1274 as discussed below.
The bearing connector assembly 1274 couples the second structure 1272 to the first structure 1270. The design of the bearing connector assembly 1274 can be varied. For example, the bearing connector assembly 1274 can include one or more bearings that allow for relative motion between the first structure 1270 and the second structure 1272 along the X and/or Y axes, while inhibiting relative motion along the Z axis. In the non-exclusive implementation of
With this design, the bearings 1274A, 1274B, 1274C provide three spaced apart areas of constrain between the structures 1270, 1272 in the same (horizontal) plane. As a result thereof, the bearings 1274A, 1274B, 1274C cooperate to allow for relative motion between the first structure 1270 and the second structure 1272 along the X and Y axes, while inhibiting relative motion along the Z axis.
The design of each bearing 1274A, 1274B, 1274C can be varied. In one non-exclusive implementation, each bearing 1274A, 1274B, 1274C includes a pair of opposed, preloaded fluid bearings that support the second structure 1272 relative to the first structure 1270 along the Z axis and allow for motion along the X axis and/or Y axis. More specifically, in this design, each bearing 1274A, 1274B, 1274C includes (i) an upper fluid bearing part 1276A that creates an upper (non-contact) fluid bearing between the structures 1270, 1272, and an upward force on one of the bearing surfaces 1272G along the Z axis that urges the second structure 1272 upward relative to the first structure 1270; and (ii) a lower fluid bearing part 1276B that creates a lower (non-contact) fluid bearing between the structures 1270, 1272, and a downward force on one of the bearing surfaces 1272G along the Z axis that urges the second structure 1272 downward relative to the first structure 1270. The upper and lower fluid bearings are opposite each other, and cooperate to maintain the second structure 1272 relative to the first structure 1270 along the Z axis and allow for motion along the X axis and/or Y axis. Stated in another fashion, (i) for the first bearing 1274A, the opposed forces are against one of the bearing surfaces 1272G, (ii) for the second bearing 1274B, the opposed forces are against another one of the bearing surfaces 1272G, and (iii) for the third bearing 1274C, the opposed forces are against yet another one of the bearing surfaces 1272G.
Alternatively, the bearing connector assembly 1274 can be designed to include more than three or fewer than three bearing 1274A, 1274B, 1274C. Still alternatively, the bearing connector assembly 1274 can be designed to inhibit motion along the Z axis and allow for relative motion along only one axis. Still alternatively, these bearing 1274A, 1274B, 1274C may be designed allow for compliance about the Z axis for reduction of vibration about the Z axis (θz). Alternatively or additionally, these bearing 1274A, 1274B, 1274C may be designed (i) to allow for compliance about the X axis for reduction of vibration about the X axis (θx), and/or (ii) to allow for compliance about the Y axis for reduction of vibration about the Y axis (θy).
It should be noted that the bearing connector assembly 1274 of
The optional payload mover assembly 1236 can be controlled to rotate the payload 1212 relative to the second structure 1272 about the X axis and/or the Y axis. As illustrated in
It should be noted that in this design, the rotational axis 1257 is positioned below the plane of motion provided by the bearings 1274A, 1274B, 1274C and is aligned with the forces generates by the Z isolators 1230D, 1230E. Because the rotational axis 1257 is below the plane of motion provided by the bearings 1274A, 1274B, 1274C, this allows for increased range of motion of a larger payload 1212 about the rotational axis 1257.
Alternatively, if the payload 1212 does not require movement about the X axis and the Y axis, the center of gravity of the payload 1212 can be at a non-rotation location 1280 illustrated with a circle in
It should be noted that two alternative mounting positions of the payload 1212 to the vibration reduction assembly 1224 are discussed herein. However, other locations of the payload 1212 are possible without major changes to the design of
The actuation system 1238 is controlled to hold the payload 1212 “on station” to track the machine 1210 while being decoupled from the vibration from the machine 1210. Further, the actuator system 1238 improves the performance of the vibration reduction, and can act in parallel with the vibration reduction system 1230, 1232 to isolate the payload 1212 from vibration.
Moreover, because of the near zero stiffness reduction of the fluid bearings described above, there is no natural “zero” position for the system to keep the components from gradually sliding away. In this design, the actuator system 1238 can be used to maintain the desired positions of the components of the vibration reduction assembly 1224, and the payload 1212 along the X, Y and Z axes and possibly about the X, Y and Z axes. In certain implementations, the stroke in the X and Y axes is mechanically limited. Thus, in certain designs, at the start of operation, the second structure 1272 can be positioned at the center of the stroke, which can be considered a “zero” position.
The design of the actuator system 1238 can be varied. For example, the actuator system 1238 can include one or more actively controlled actuators. In the implementation of
In this design, (i) the Z actuator(s) 1240A, 1240B are controlled to generate one or more controllable force(s) along the Z axis to cause relative movement between (or maintain the desired position between) the second vibration reduction system 1232 and the first vibration reduction system 1230; (ii) the X actuator(s) 1242A, 1242B are controlled to generate one or more controllable force(s) along the X axis to cause relative movement between (or maintain the desired position between) the second structure 1272 and the first structure 1270 along the X axis; and (iii) the Y actuator(s) 1244 are controlled to generate one or more controllable force(s) along the Y axis to cause relative movement between (or maintain the desired position between) the second structure 1272 and the first structure 1270 along the Y axis. Stated in a different fashion, (i) the Z actuator(s) 1240A, 1240B are controlled to precisely position the second vibration reduction system 1232 and the payload 1212 along the Z axis; (ii) the X actuator(s) 1242A, 1242B are controlled to precisely position the second structure 1272 and the payload 1212 along the X axis; and (iii) the Y actuator(s) 1244 are controlled to precisely position the second structure 1272 and the payload 1212 along the Y axis.
With this design the Z actuator(s) 1240A, 1240B act in parallel with the first vibration reduction system 1230, and the X and Y actuator(s) 1242A, 1242B, 1244 act in parallel with the second vibration reduction system 1232.
The design of each actuator 1240A, 1240B, 1242A, 1242B, 1244 can be varied. As non-exclusive examples, one or more of the actuators 1240A, 1240B, 1242A, 1242B, 1244 can be a voice coil actuator, a linear actuator, rotational actuator, variable reluctance actuator or another type of actuator.
It should be noted that one or more of the actuators 1240A, 1240B, 1242A, 1242B, 1244 can be controlled to position the payload 1212 about one or more of the axes. For example, one or more of the actuators 1240A, 1240B, 1242A, 1242B, 1244 can be controlled to position the payload 1212 about the X, Y, and Z axes.
Additionally, when it is desired to move the payload 1212 (e.g. with the robot assembly 314 illustrated in
In one, non-exclusive implementation, during initialization (e.g. startup) of the system, the sensor assembly (not shown in
It should be noted that the implementation illustrated in
The multiple designs provided herein allow the constant acceleration of gravity to be addressed by the first reduction system 1230, thus freeing the second reduction system 1232 from having to address changing gravity loads. Generally, the vibrational loads will be limited in magnitude and centered about a “zero” position, while the gravity load is generally much larger magnitude, non-centered, and can change with robot orientation. By not having to address a changing gravity load, horizontal isolator/actuators can likely be built much smaller and lighter with less cost and more effectiveness.
In the non-exclusive implementation of
In the implementation of
In the non-exclusive implementation of
In the non-exclusive implementation of
The vibration reduction system 1430 reduces vibration in the first frame 1484 from being transferred to the second frame 1486 (and the payload 12) along the X, Y, and Z axes, and about the X and Y axes. In the non-exclusive implementation of
In
As provided above, the chamber adjuster 1434 can selectively and actively control the pressure in the bellows chamber 1430B. Additionally, the vibration reduction system 1430 can include a pressure sensor 1430H (illustrated as a box) which senses the pressure of in the bellows chamber 1430B.
With this design, the pressure sensor 1430H can provide feedback regarding the pressure to the control system 22 (illustrated in
In the non-exclusive implementation of
For example, the chamber adjuster 1434 can selectively adjust the level of vacuum in the bellows chamber 1430B to selectively adjust the characteristics of the vibration reduction assembly 1424.
With the present design, an external disturbance transferred to the first frame 1484 will cause the first frame 1484 to move. The movement of the first frame 1484 along the X, Y and Z axes, and about the X and Y axes will cause the pressure in the bellows chamber 1430B to change (fluctuate). The pressure sensor 1430H can detect these changes, and the feedback is used to control the chamber adjuster 1434 to control the pressure in the bellows chamber 1430B to reduce the vibration being transmitted to the second frame 1486 and the payload 12. In this design, the vibration reduction system 1430 is actively controlled. Alternatively, the vibration reduction system 1430 can be a passive system without the chamber adjuster 1434 that actively controls the pressure.
The actuation system 1438 is controlled to hold the payload 12 “on station” to track the robot 16 while being decoupled from the vibration from the robot 16. Further, the actuator system 1438 can act in parallel with the vibration reduction system 1430 to isolate the payload 12 from vibration.
The design of the actuator system 1438 can be varied. For example, the actuator system 1438 can include one or more actively controlled actuators that extend between the first frame 1484 and the second frame 1486. In the implementation of
In the non-exclusive implementation of
In this design, (i) the Z actuator(s) 1440A, 1440B, 1440C, 1440D are controlled to generate one or more controllable force(s) along the Z axis, and about the X and Y axes to cause relative movement between (or maintain the desired position between) the frames 1484, 1486; (ii) the X actuator 1442 is controlled to generate one or more controllable force(s) along the X axis to cause relative movement between (or maintain the desired position between) the frames 1484, 1486; and (iii) the Y actuator 1244 is controlled to generate one or more controllable force(s) along the Y axis to cause relative movement between (or maintain the desired position between) the frames 1484, 1486.
With this design the actuator system 1438 act in parallel with the vibration reduction system 1430.
The design of each actuator 1440A, 1440B, 1440C, 1440D, 1442, 1444 can be varied. As non-exclusive examples, one or more of the actuators 1440A, 1440B, 1440C, 1440D, 1442, 1444 can be a voice coil actuator, a linear actuator, rotational actuator, variable reluctance actuator or another type of actuator.
It should be noted that one or more of the actuators 1440A, 1440B, 1440C, 1440D, 1442, 1444 can be controlled to position the payload 12 about one or more of the axes. For example, one or more of the actuators 1440A, 1440B, 1440C, 1440D, 1442, 1444 can be controlled to position the payload 12 along the X, Y and Z axes, and about the X and Y axes.
Additionally, when it is desired to move the payload 12 (e.g., with the robot assembly 16), the actuator system 1438 can be controlled to apply feed-forward forces to the payload 12 that provide a desired acceleration profile on the payload 12. This permits the payload 12 to track the motion of the robot assembly 16 in a controlled way rather than just bounce on the end of the robot 16. In one, non-exclusive implementation, when it is desired to move the payload 12, the actuator system 1438 can be controlled to move and position the payload 12, while the robot 16 is controlled to follow this movement to maintain the available stroke of each of the actuators 1440A, 1440B, 1440C, 1440D, 1442, 1444.
In one, non-exclusive implementation, a sensor assembly (not shown in
However, in the implementation of
More specifically, in
With the present design, the first frame 1584 is attached to and fixedly connected to the bellows bottom 1530Ab, and the second frame 1586 is attached to and fixedly connected to the bellows top 1530Aa.
Further, with the present design, the chamber adjuster 1534 again can selectively and actively control a bellows pressure in the bellows chamber 1530B with feedback from a pressure sensor 1530H (illustrated as a box in
In the non-exclusive implementation of
The vibration reduction assemblies 24, 224, 324, 524, 624, 1224, 1424, 1524 provided herein will allow for the positioning of the payload 12, 212, 312, 412, 512, 612, 1212 with improved accuracy, and will allow for greatly reduced robot settling times, because the payload 12, 212, 312, 412, 512, 612, 1212 is precisely positioned while the robot assembly 14, 214, 314, 414, 514 is still vibrationally settling. The designs provided herein may also permit “on the fly” applications where the robot assembly 14, 214, 314, 414, 514 never stops moving. This leads to greatly improved robot, drone, or other positioning system cycle times and capital utilization.
It should be noted the machine can be designed to include other types of vehicles, such as boats, trains or other devices. Further, it should be noted that the control systems 22, 222, 322, 422, and 522 in the present specification can be set up inside the machines 10, 210, 310, 410 and 510.
It is understood that although a number of different embodiments of the machine have been illustrated and described herein, one or more features of any one embodiment can be combined with one or more features of one or more of the other embodiments, provided that such combination satisfies the intent of the present disclosure.
Further, while a number of exemplary aspects and embodiments of the machine have been discussed above, those of skill in the art will recognize certain modifications, permutations, additions and sub-combinations thereof. It is therefore intended that the following appended claims and claims hereafter introduced are interpreted to include all such modifications, permutations, additions and sub-combinations as are within their true spirit and scope.
This application claims priority on U.S. Provisional Application No. 63/089,634 filed on Oct. 9, 2020, and entitled “VIBRATION REDUCTION ASSEMBLY WITH A GRAVITY ALIGNED REDUCTION SYSTEM”. As far as permitted the contents of U.S. Provisional Application No. 63/089,634 are incorporated in their entirety herein by reference.
Number | Date | Country | |
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63089634 | Oct 2020 | US |