Application # 2007/0205910. WIRELESS MOTION CONTROL SYSTEM

United States Patent Application	*20070205910*
Kind Code	A1
Guite; John E. ; et al.	September 6, 2007

WIRELESS MOTION CONTROL SYSTEM

Abstract

Disclosed is a system and method for wireless motion control. The system generally includes a centralized motion coordinator device and one or more motion stick devices that communicate with each other wirelessly. The centralized motion coordinator controls operation of the one or more motion stick devices by wirelessly transmitting basic commands to the one or more motion stick devices. In response, the motion stick devices process the received commands and generate trajectory information based, at least in part, on the commands received from the centralized motion coordinator device. The trajectory information is used to control operation of a motor for advancement of an actuator assembly associated with the one or more motion stick devices along a predetermined axis.

Inventors:	Guite; John E.; (Petaluma, CA) ; Kelley; Jeffrey M.; (Woodacre, CA) ; Calahan; Mark C.; (Sebastopol, CA) ; Walewander; John L.; (Novato, CA) ; Danek; Steven W.; (Petaluma, CA) ; Barnes; Andrew D.; (Santa Rose, CA) ; Rathkey; John H.; (Petaluma, CA)
Correspondence Address:	DON W. BULSON (PARKER HANNIFIN);RENNER, OTTO, BOISSELLE & SKLAR, LLP 1621 EUCLID AVENUE / 19TH FLOOR CLEVELAND OH 44115 US
Assignee:	Parker-Hannifin Corporation Cleveland OH
Serial No.:	675240
Series Code:	11
Filed:	February 15, 2007

Current U.S. Class:	340/825.69; 318/16; 340/3.43; 340/825.72
Class at Publication:	340/825.69; 340/825.72; 318/16; 340/3.43
International Class:	G08C 19/00 20060101 G08C019/00

Claims

1. A wireless motion control system comprising:a centralized motion coordinator device having a first microprocessor and a first wireless transceiver;a motion stick device controlled by the centralized motion coordinator for controlled movement of an actuator assembly secured to a portion of the motion stick device, wherein the motion stick device includes:a second wireless transceiver for communicating with the centralized motion coordinator;a second microprocessor coupled to the second wireless transceiver for processing commands received from the centralized coordinator and encoding signals for transmission to the centralized motion coordinator; anda trajectory generator coupled to the second microprocessor, wherein the trajectory generator decodes commands received from the centralized motion coordinator and generates trajectory information for use by power electronics circuitry to control operation of a motor to move the actuator assembly along a predetermined axis.

2. The system according to claim 1 further including an encoder coupled to the motor to determine a position of the actuator assembly.

3. The system according to claim 2, wherein the encoder is a contactless sensor that measures at least one physical property associated with the actuator assembly.

4. The system according to claim 3, wherein the encoder detects a magnetic field to determine the position of the assembly.

5. The system of claim 2 further including fault detection circuitry coupled to the second microprocessor to compare the position of the assembly and the command information to determine if the command was performed successfully.

6. The system of claim 2 further including fault detection circuitry coupled to the second microprocessor to compare the position of the assembly and the command information to determine if the command was performed unsuccessfully.

7. The system according to claim 1, wherein the motor is a stepper motor.

8. The system according to claim 1, wherein the motor is a servo-motor.

9. The system according to claim 1 further including at least two motion stick devices coupled to the centralized motion coordinator.

10. A method for wireless control of an actuator assembly, the method comprising:wirelessly receiving a control signal from a centralized motion coordinator device at one or more motion stick devices, wherein each motion stick device includes a wireless transceiver;generating trajectory information based at least in part on the control signal to control operation of a motor to move an actuator assembly along a predetermined axis;detecting successful and/or unsuccessful completion of the operation by an encoder that measures at least one physical property associated with the motor; andtransmitting a confirmation command to the centralized motion coordinator device.

11. The method of claim 10, wherein the centralized motion coordinator transmits a motion command to at least one of the motion stick devices.

12. The method of 10, wherein the motion stick processes and decodes the motion command to generate trajectory data.

13. The method of claim 10, wherein the encoder is a contact less sensor that measures at least one physical property associated with the assembly.

14. The method of claim 13, wherein the encoder detects a magnetic field to determine the position of the assembly.

15. The method of claim 10, wherein the centralized motion coordinator simultaneously controls a plurality of motion stick devices through a wireless interface.

16. The method of claim 10 further including the motion stick device transmitting a status signal associated with a physical property of a wireless link established between the motion stick device and the to the centralized motion coordinator device.

17. An automated manufacturing system comprising:a centralized motion coordinator device having a first microprocessor and a first wireless transceiver for automated control of a plurality of motion stick devices, wherein the plurality of motion stick devices are controlled by the centralized motion coordinator to perform a controlled movement of an assembly secured to a portion of the motion stick device for performing one or more manufacturing tasks, wherein each of the motion stick devices includes:a second wireless transceiver for communicating with the centralized motion coordinator;a second microprocessor coupled to the second wireless transceiver for processing commands received from the centralized coordinator and encoding signals for transmission to the centralized motion coordinator; anda trajectory generator coupled to the second microprocessor, wherein the trajectory generator decodes commands received from the centralized motion coordinator and generates trajectory information for use by power electronics circuitry to control operation of a motor to move the assembly along a predetermined axis to manufacture an article.

18. The automated manufacturing system according to claim 17 further including an encoder coupled to the motor to determine a position of the assembly.

19. The automated manufacturing system according to claim 18, wherein the encoder is a contactless sensor that measures at least one physical property associated with the assembly.

20. The automated manufacturing system according to claim 19, wherein the encoder detects a magnetic field to determine the position of the assembly.

21. The automated manufacturing system of claim 18 further including fault detection circuitry coupled to the second microprocessor to compare the position of the assembly and the command information to determine if the command was performed successfully and/or unsuccessfully.

22. The automated manufacturing system according to claim 17, wherein the motor is a stepper motor.

23. The automated manufacturing system according to claim 17, wherein the motor is a servo-motor.

24. The automated manufacturing system of claim 17, wherein the motion stick transmits a confirmation signal to the centralized motion coordinator when the motion command received from the centralized motion is successfully performed.

25. The automated manufacturing system of claim 24, wherein the motion stick also transmits a status signal associated with a physical property of a wireless link established between the motion stick device and the to the centralized motion coordinator device.

26. The automated manufacturing system of claim 17, wherein the manufacturing tasks include at least one from the group of manufacturing a device, shipping the device, and/or packaging the device.

Description

RELATED APPLICATION DATA

[0001]This application claims the benefit of U.S. Provisional Application No. 60/775,767, filed Feb. 15, 2006, which is incorporated by reference.

BACKGROUND OF THE INVENTION

[0002]The present invention relates generally to a system and method for wireless motion control and, more particularly, to a system and method for wireless control of general motion machinery.

[0003]In automation markets, a continuing frustration of machine builders is the cost and complexity of wiring machines and automation components. This frustration is enhanced when the application is a multi-axis application. For example, a conventional four-axis motion control system may consist of nineteen or more cables, which allow for power, control and feedback signals. Such cabling requirements tends to make such wired electromechanical systems difficult to upgrade, require significant facility space and are generally more costly than a wireless motion control system.

[0004]A common requirement for controlling and monitoring electromechanical systems is to provide motion commands and determine and/or measure the position of one or more moving elements. Controlling the position associated with moving elements is generally straightforward when a direct electrical or mechanical connection is incorporated between the moving element and the sensor that detects the movement of the moving element. A primary reason for the straightforward nature of the wired motion control system is that unlimited bandwidth allows trajectory data, feedback signals and control information to be transmitted as needed from the controlling device to the device being controlled and vice versa.

[0005]However, due to bandwidth limitations it is generally much more difficult to control motion when using wireless devices. This is especially true when a closed-loop feedback mechanism is desired. One drawback with conventional wireless motion control is difficulty in controlling the wireless system in real-time. Another drawback is the limited bandwidth available over the wireless medium. The lack of bandwidth is significantly enhanced when multiple axes of motion control are desired. These drawbacks combine to limit coordinated wireless motion control. In addition, traditional wireless network components are relatively expensive, which generally eliminates the cost savings of cable reduction. There are also safety concerns inherent with wireless networks. One safety concern is a loss of control of network components if one or more of the components of the wireless network were unable to properly communicate with each other. Another safety concern is securing the wireless network from being compromised.

[0006]Thus a need exists for a reliable and relatively inexpensive wireless motion control system that overcomes the deficiencies set forth above.

SUMMARY OF THE INVENTION

[0007]Aspects of the present invention relate to a system and method for wireless motion control. The system generally includes a centralized motion coordinator device and one or more motion stick devices. The centralized motion coordinator controls operation of the one or more motion stick devices by wirelessly transmitting commands to one or more motion stick devices. The motion stick devices receive the command and generate trajectory data based on the received command. The motion stick devices independently determine successful and/or unsuccessful completion of a task and transmit an appropriate signal to the centralized motion coordinator device.

[0008]Another aspect of the present invention relates to a wireless motion control system comprising: a centralized motion coordinator device having a first microprocessor and a first wireless transceiver; a motion stick device controlled by the centralized motion coordinator for controlled movement of an actuator assembly secured to a portion of the motion stick device, wherein the motion stick device includes: a second wireless transceiver for communicating with the centralized motion coordinator; a second microprocessor coupled to the second wireless transceiver for processing commands received from the centralized coordinator and encoding signals for transmission to the centralized motion coordinator; and a trajectory generator coupled to the second microprocessor, wherein the trajectory generator decodes commands received from the centralized motion coordinator and generates trajectory information for use by power electronics circuitry to control operation of a motor to move the actuator assembly along a predetermined axis.

[0009]Another aspect of the invention relates to a method for wireless control of an actuator assembly, the method comprising: wirelessly receiving a control signal from a centralized motion coordinator device at one or more motion stick devices, wherein each motion stick device includes a wireless transceiver; generating trajectory information based at least in part on the control signal to control operation of a motor to move an actuator assembly along a predetermined axis; detecting successful and/or unsuccessful completion of the operation by an encoder that measures at least one physical property associated with the actuator assembly; and transmitting a confirmation command to the centralized motion coordinator device.

[0010]Another aspect of the system relates to an automated manufacturing system comprising: a centralized motion coordinator device having a first microprocessor and a first wireless transceiver for automated control of a plurality of motion stick devices, wherein the plurality of motion stick devices are controlled by the centralized motion coordinator to perform a controlled movement of an assembly secured to a portion of the motion stick device for performing one or more manufacturing tasks, wherein each of the motion stick devices includes: a second wireless transceiver for communicating with the centralized motion coordinator; a second microprocessor coupled to the second wireless transceiver for processing commands received from the centralized coordinator and encoding signals for transmission to the centralized motion coordinator; and a trajectory generator coupled to the second microprocessor, wherein the trajectory generator decodes commands received from the centralized motion coordinator and generates trajectory information for use by power electronics circuitry to control operation of a motor to move the assembly along a predetermined axis to manufacture an article.

[0011]To the accomplishment of the foregoing and related ends, the invention, then, comprises the features hereinafter fully described and particularly pointed out in the claims. The following description and the annexed drawings set forth in detail certain illustrative embodiments of the invention. These embodiments are indicative, however, of but a few of the various ways in which the principles of the invention may be employed. Other objects, advantages and novel features of the invention will become apparent from the following detailed description of the invention when considered in conjunction with the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0012]FIG. 1 is a wireless motion control system in accordance with aspects of the present invention.

[0013]FIG. 2 is a perspective view of an exemplary centralized wireless motion coordinator in accordance with aspects of the present invention.

[0014]FIG. 3 is a schematic block diagram of the exemplary centralized motion coordinator in accordance with aspects of the present invention.

[0015]FIG. 4 is a perspective view of a portion of an exemplary motion stick in accordance with aspects of the present invention.

[0016]FIGS. 5A-5B are perspective view of a portion of an exemplary motion stick in accordance with aspects of the present invention.

[0017]FIG. 5C is a side layout view of the portion of the exemplary motion stick illustrated in FIGS. 5A-5B.

[0018]FIG. 6 is a schematic block diagram of the exemplary motion stick device in accordance with aspects of the present invention.

[0019]FIG. 7 is a side layout view of an actuator portion of the exemplary motion stick device in accordance with aspects of the present invention.

[0020]FIG. 8 is an exemplary method in accordance with aspects of the present invention.

DETAILED DESCRIPTION

[0021]In the detailed description that follows, corresponding components have been given the same reference numerals, regardless of whether they are shown in different embodiments of the present invention. To illustrate the present invention in a clear and concise manner, the drawings may not necessarily be to scale.

[0022]The present invention relates to a system and method for wireless motion control. The system generally includes a centralized motion coordinator device and one or more motion stick devices. The centralized motion coordinator controls operation of the one or more motion stick devices. The centralized motion coordinator and the one or more motion stick devices communicate with each other through a wireless communication link.

[0023]In general, the centralized motion coordinator device wirelessly transmits basic movement commands to the one or more motion stick devices. The one or more motion stick devices process the received commands and generate trajectory information based, at least in part, on the commands received from the centralized motion coordinator device. The trajectory information is used to control operation of a motor for advancement of an assembly associated with the one or more motion stick devices along a predetermined axis. A motion stick device generally includes an encoder to monitor one or more physical parameters (e.g., position, velocity, acceleration, etc.) associated with the motion stick and fault detection circuitry. After a move command is received and completed, the motion stick device will generally transmit a proper confirmation to the centralized motion coordinator device. By eliminating the transmission of trajectory information between the centralized motion coordinator device and the one or motion stick devices, a low bandwidth, low cost wireless protocol may be used to implement wireless motion control.

[0024]Referring to FIG. 1, an exemplary wireless motion control system 10 is illustrated. The motion control system 10 includes a centralized motion coordinator device 12 and one or more motion stick devices 14A-14D. As shown in FIG. 1, the centralized motion coordinator device 12 and the one or more of the motion stick devices 14A-14D communicate through wireless communication links 16A-16D, via wireless transceivers provided in each device.

[0025]The wireless motion control system 10 may be used in any motion control application. Exemplary motion control applications include: medical diagnostic machinery requiring automation of sample handling, microtiter plate stacking, etc.; manufacture of devices (e.g., medical devices) requiring automation of device assembly, handling and/or packaging; manufacture and testing of semiconductor wafers requiring automation of wafer handling, wafer cleaning and etch and wafer die bonding, etc. While aspects of the present invention may be used in any application that utilizes a motion control system, aspects of the present invention are particularly advantageous for motion control applications having multiple axes due to the cost and space savings associated with cable reduction and the ease of adding additional motion control components to existing systems.

[0026]Referring to FIG. 2, a perspective view of an exemplary centralized motion coordinator device 12 is shown. The centralized motion coordinator device 12 includes a housing 20, a wireless transceiver 22 and one or more communication ports. As shown in FIG. 2, the communication ports may include a CANopen port 24, a USB port 26, an Ethernet port 28, etc. One of ordinary skill in the art will appreciate that the centralized motion coordinator device 12 may have any desired communication port, which may depend on the application and/or devices in which the centralized motion coordinator device 12 is to communicate.

[0027]Referring to FIG. 3, a schematic block diagram of the centralized motion coordinator device 12 is illustrated. The centralized motion coordinator device 12 includes a primary control circuit 50 that is configured to carry out overall control of the functions and operations of the centralized motion coordinator device 12. The control circuit 50 may include one or more processing devices 52, such as a CPU, microcontroller or microprocessor. The processing device 52 executes code stored in a memory (not shown) within the control circuit 50 and/or in a separate memory, such as memory 54, in order to carry out operation of the centralized motion coordinator device 12. The processing device 52 is generally operative to perform all of the functionality disclosed herein. In one embodiment, two processing devices are used to implement aspects of the present invention. One processor may be used to control general operation of the centralized motion coordinator 12 and another processor may be used to control operation of the wireless transceiver 22.

[0028]The memory 54 may be, for example, a buffer, a flash memory, a hard drive, a removable media, a volatile memory and/or a non-volatile memory. In addition, the processing device 52 processes and/or executes code to carry out various functions of the centralized motion coordinator device 12. The memory 54 may include one or more application programs and/or modules 56 to carry out any desirable software and/or hardware operation associated with the centralized motion coordinator device 12 and/or devices controlled by the centralized motion coordinator device 12.

[0029]The centralized motion coordinator device 12 also includes a wireless transceiver 58 that enables the centralized motion coordinator device 12 to establish wireless connectivity with one or more motion stick devices 14. As discussed below, any wireless medium may be used in accordance with the present invention. Preferably, the transceiver 58 utilizes a radio frequency medium. Suitable wireless protocols include, for example, IEEE 802.11-compatible protocol and/or IEEE 802.15-compatible protocol (e.g., Zigbee). A suitable wireless communication standard for use in accordance with aspects of the present invention will generally meet the following design considerations: facilitate two-way wireless communication, have low cost and low power consumption. One of ordinary skill in the art will appreciate that other design considerations may enter the decision-making process when selecting a wireless medium depending on, for example, the nature of the application, the geographical size of the location, wireless interference, etc.

[0030]The transceiver 58 generally includes a radio frequency transmitter and receiver for transmitting and receiving signals via the antenna 60 as is conventional. The centralized motion coordinator device 12 generally utilizes the transceiver 58 and antenna 60 for two-way communication with one or more motion stick devices 14 over a wireless communication link. The transceiver 58 is coupled to the control circuit 50 so as to carry out overall operation of the centralized motion coordinator device 12.

[0031]The centralized motion coordinator device 12 further includes an I/O interface 64. The I/O interface 64 may be in any desired form. For example, the I/O interface 64 may take the form of one or more communication ports, such as for example, CANopen port 24, USB port 26 and Ethernet port 28. The I/O interface 64 may be used to couple the centralized motion coordinator device 12 to other devices. In one embodiment, the I/O interface 64 may be coupled to a personal computer in order to download application software from the personal computer to the memory 54 and/or application software 56. As one of ordinary skill in the art will readily appreciate, the application software 56 stored on the centralized motion coordinator device 12 may take a variety of forms, but is generally executable code that includes commands for transmission to and to control the one or more motion stick devices 14 in which the centralized motion coordinator device 12 is linked.

[0032]The centralized motion coordinator device 12 also generally includes a power supply unit (PSU) 66 within the centralized motion coordinator device 12 to allow the device to receive power from an external source. A non-rechargeable and/or rechargeable battery may also be used in accordance with aspects of the present invention.

[0033]In operation, the centralized motion coordinator device 12 generally transmits simple motion, input and output (I/O) and query commands to the one or more motion stick devices 14. The motion stick device 14 acknowledges the receipt of commands. The simple motion, I/O and query commands generally do not include trajectory data. As discussed in detail below, the commands are wirelessly transmitted to one or more motion stick devices 14. The motion stick devices, in turn, generate the trajectory data as needed to control operation of the motion stick devices 14. In addition, the centralized motion coordinator device 12 generally receives confirmation and status signals associated with and transmitted from one or more motion stick devices 14. A confirmation signal is generally transmitted once a motion stick device 14 has completed a requested operation. The confirmation signal signifies that the motion stick device 14 has completed the command and is ready for the next motion command. In general, the status signal indicates the health of the motion stick device and/or the health of the wireless link between the centralized motion coordinator device 12 and the one or more motion stick devices 14.

[0034]If no confirmation signal is received by the centralized motion coordinator device 12 after a command is transmitted to a motion stick device, generally no other motion commands will be sent to the particular motion stick device. In addition, if a motion stick device transmits a status signal indicating that the wireless link has been dropped and/or the health of the motion stick has been compromised, one or more predetermined events may take place. Such predetermined events include, for example, human intervention, resetting the motion stick device, re-establishing the wireless communication link, etc.

[0035]Referring to FIG. 4, an exemplary motion stick device 14 is illustrated. The motion stick 14 includes a housing 80 (e.g. housing 80A, 80B and 80C) that generally houses one or more components of the motion stick device 14. For example, housing 80A may house a wireless transceiver 82, a microprocessor 84, trajectory generator 86, an encoder 88, fault detection circuitry 90 and a controller 92. Housing 80B may house motor 94. Housing 80C may house an actuator assembly 96. The housings 80A, 80B and 80C may be unitary or included multiple subassemblies.

[0036]Referring to FIGS. 5A-5C and 6, the wireless transceiver 82 may be any type of wireless transceiver. Like the wireless transceiver 58 (discussed above) any wireless medium may be used in accordance with the present invention. Preferably, the transceiver 82 utilizes a radio frequency medium. Suitable wireless radio frequency protocols include, for example, IEEE 802.11-compatible formatives and/or IEEE 802.15-compatible formatives (e.g., Zigbee). The transceiver 82 generally includes a radio frequency transmitter and receiver for transmitting and receiving signals via an antenna 98 as is conventional. The motion stick 14 generally utilizes the transceiver 82 and antenna 98 for two-way communication with the centralized motion coordinator device 12 over a wireless network. The transceiver 82 is coupled to the control circuit 100 so as to carry out overall operation of the motion stick device 14.

[0037]The trajectory generator 86 generally decodes motion commands received from the centralized motion coordinator 12. The decoded commands are then processed to generate trajectory information. Trajectory information includes any information that may be used to control the motor 94, which in turn controls movement of the actuator assembly 96 (also referred to herein as lead screw table). For example, trajectory information includes machine language commands, position data, velocity data, acceleration data, rate data, etc.

[0038]The trajectory information is processed by the control circuit 100 and received by the power electronics circuitry 92. The power electronics circuitry 92 may be any type of power electronics operable to receive trajectory information to control motor 94. For example, the power electronics 92 may be a collection of discrete field-effect transistors (FET) or an integrated power module (IPM) including combinations thereof. It will be appreciated by those skilled in the art that each motor 94 has specific control requirements, and that the specific configuration of the power electronics 92 is typically machine-dependent.

[0039]The motor 94 may be any desired motor that is operable to perform the functionality described herein. For example, the motor 94 may be a stepper motor, a servomechanism (servo) motor, a variable reluctance motor (VRM), a combination of stepper and servo motors, etc. The motor used in a particular wireless motion control system will generally vary based upon the application. For example, in the field of medical diagnostic machinery requiring automation of sample handling, microtiter plate stacking and other general motion needs, a stepper motor will likely be the design choice. When the application is medical devices requiring automation of medical device assembly, handling and packaging, a servo motor will likely be the design choice. When the application is machines for the manufacture and testing of semiconductor wafers requiring automation of wafer handling, wafer cleaning and etch, and wafer die bonding, the likely motor technology selected will be a combination of stepper and servo motors.

[0040]The encoder 88 is coupled to the motor 94 and the control circuit 100. The encoder 88 determines the position of the motor 94. The encoder 88 is typically a contactless sensor that measures at least one physical property associated with the motor 94. For example, the encoder may detect a magnetic field to determine the position of the motor 94. The encoder 88 outputs a signal based on the detected physical property (e.g., position of the motor 94). The signal output by the encoder 88 is generally communicated to the fault detection circuitry 90.

[0041]The fault detection circuitry 90 is coupled to the microprocessor 84 through the control circuit 100. The fault detection circuitry 90 performs any desired fault determination functions. For example, the fault detection circuitry 90 may compare the position of the motor 94 and the command information received from the centralized motion coordinator 12 to determine if the command was performed successfully. The fault detection circuitry 90 may be incorporated in the encoder 88 and/or power electronics circuitry 92 depending on the particular design implementation of the wireless control system.

[0042]If the command was performed successfully, a confirmation signal is generally transmitted from the wireless transceiver 82 of the motion stick device 14 to the wireless transceiver 58 of the centralized motion coordinator 12. If the command was not performed successfully, a variety of alternatives may occur. Such alternatives include, for example, immediate terminating operation of the motion stick device 14, transmitting an error signal to the centralized motion coordinator 12, transmitting a message to an operator that human intervention is needed, etc.

[0043]The output of the motor 94 may be rotary or linear and is controllable by the power electronics 92. The motor 94 may be coupled to an actuator assembly 96. The actuator 96 converts energy produced by the motor 94 into motion. The motion can be rotary, linear and/or non-linear depending on the actuator. For example, a linear actuator may utilize a motor that produces rotational motion and converts the rotational motion to linear motion by advancing the assembly along the threaded rod. Depending on the rotation of the motor, the assembly will extend or retract along the axis of the threaded rod.

[0044]Referring to FIGS. 4 and 7, an exemplary actuator assembly 96 is illustrated. The actuator assembly 96 generally has an extruded frame 120, and a pair of end covers 122 and 124 mounted on respective opposite longitudinal ends of the frame 120.

[0045]The following components are mounted on the frame 120: housings 80A, 80B and 80C, motor 94, a coupling 126 that connects the rotatable shaft of the motor 94 and a lead screw 128 coaxially to each other, a bearing block 130, and a table mechanism 132. A guide 134 for linearly guiding the table mechanism 132 as it is displaced by the lead screw 128 is mounted on the frame 120 and extends between the end covers 122 and 124. The guide 124 is fixed to the frame 120.

[0046]The table mechanism 132 comprises a lead screw bushing (not shown) threaded over the lead screw 128 for converting rotary motion of the lead screw 128 into linear motion, a pair of tracks 136A and 136B for sliding movement on the guide 134. A plurality of bearings are generally disposed between mating surfaces of the tracks 136A and 136B and the guide 134 for reducing friction resistance between.

[0047]The table mechanism 132 may have connecting holes defined in its upper surface for fastening another member mounted thereon. In operation, the actuator 96 is generally used in a horizontal or vertical direction. The table mechanism of the actuator generally moves along a predetermined axis that is generally parallel to the lead screw 128. One of ordinary skill in the art will readily appreciate that the actuator assembly illustrated herein is exemplary in nature and is in no way intended to limit the scope of the claimed invention.

[0048]The motion stick 14 may also include an I/O interface 160, as shown in FIG. 6. The I/O interface 160 may be in any desired form. For example, the I/O interface 160 may take the form of discrete inputs and outputs 180 or one or more communication ports, such as for example, a serial port (not shown), a telecommunication port (not shown), Ethernet port (not shown). The I/O interface 160 may be used to couple the motion stick device 14 to other devices. In addition, the motion stick device 14 generally includes a power supply unit (PSU) 162 housed within the motion stick device 14 to allow the device to receive power from an external source.

[0049]An exemplary method 200 for wireless control of an actuator assembly in accordance with aspects of the present invention is illustrated in FIG. 8. At step 202, a control signal is wirelessly transmitted from a centralized motion coordinator 12. At step 204, the control signal is received at one or more motion stick devices 14, wherein each motion stick device 14 includes a wireless transceiver 82. At step 206, the one or more motion stick devices 14 acknowledge the receipt of the control signal. At step 208, the one or more motion stick devices generate trajectory information based at least in part on the control signal to control operation of a motor to move an actuator assembly 96 along a predetermined axis. At step 210, an encoder 88 detects successful and/or unsuccessful completion of the operation of the one or more motion stick devices 14. The encoder 88 measures at least one physical property associated with the motor 94. At step 212, a confirmation signal is transmitted by the one or more motion stick devices 14 to the centralized motion coordinator device upon successful completion of the command. In addition to a confirmation signal, the motion stick device 14 may also transmit an error message when the command is not performed successfully or when a problem is detected with the motion stick device. At step 214, the centralized motion coordinator 12 acknowledges the receipt of the confirmation message. In one embodiment, a status signal associated with a physical property of a wireless link established between the motion stick device and to the centralized motion coordinator device may be transmitted from the one or more motion stick devices 14 to the centralized motion coordinator 12.

[0050]As discussed above, the centralized motion coordinator device 12 wirelessly transmits basic movement commands to the one or more motion stick devices 14. The one or more motion stick devices 14 process the received commands and generate trajectory information based, at least in part, on the commands received from the centralized motion coordinator device 12. The trajectory information is used to control operation of a motor for advancement of an assembly associated with the one or more motion stick devices along a predetermined axis. By eliminating wireless network traffic associated with exchanging trajectory information between the motion stick devices and the centralized motion coordinator, many motion stick devices may be simultaneously controlled by a centralized motion coordinator. In addition, by eliminating the transmission of trajectory information between the centralized motion coordinator device and the one or motion stick devices, a low bandwidth, low cost wireless protocol may be used to implement wireless motion control.

[0051]Although the invention has been shown and described with respect to a certain preferred embodiment or embodiments, it is obvious that equivalent alterations and modifications will occur to others skilled in the art upon the reading and understanding of this specification and the annexed drawings. In particular regard to the various functions performed by the above described elements (components, assemblies, devices, compositions, etc.), the terms (including a reference to a "means") used to describe such elements are intended to correspond, unless otherwise indicated, to any element which performs the specified function of the described element (i.e., that is functionally equivalent), even though not structurally equivalent to the disclosed structure which performs the function in the herein illustrated exemplary embodiment or embodiments of the invention. In addition, while a particular feature of the invention may have been described above with respect to only one or more of several illustrated embodiments, such feature may be combined with one or more other features of the other embodiments, as may be desired and advantageous for any given or particular application.

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