United States Patent
`US 6,982,696 B1
`(10) Patent No.:
`(12)
`Shahoian
`(45) Date of Patent:
`Jan. 3, 2006
`
`
`US006982696B1
`
`(54) MOVING MAGNET ACTUATOR FOR
`PROVIDING HAPTIC FEEDBACK
`
`(75)
`
`Inventor: Erik J. Shahoian, San Ramon, CA
`(US)
`(73) Assignee: us Corporation, San Jose, CA
`(*) Notice:
`Subject to any disclaimer, the term of this
`patent is extended or adjusted under 35
`USS.C. 154(b) by 100 days.
`
`(21) Appl. No.: 09/608,130
`.
`Filed:
`
`(22)
`
`Jun. 30, 2000
`Related U.S. Application Data
`(60) Provisional application No. 60/142,155,filed on Jul.
`1, 1999.
`
`(51)
`
`Int. Cl.
`(2006.01)
`G09G 5/00
`(52) U.S. Ch oes 345/156; 345/168; 345/173;
`715/701; 715/702
`(58) Field of Classification Search ................ 345/156,
`345/157, 158, 159, 163, 167, 168, 173; 341/20;
`715/700, 701, 702
`See application file for complete search history.
`
`(56)
`
`References Cited
`
`U.S. PATENT DOCUMENTS
`2,972,140 A
`2/1961 Hirsch
`3,157,853 A
`11/1964 Hirsch
`3,220,121 A
`11/1965 Cutler
`3,497,668 A
`2/1970 Hirsch
`3,517,446 A
`6/1970 Corlyon etal.
`3,623,064 A
`11/1971 Kagan
`3,902,087 A
`9/1975 Hightower
`3,903,614 A
`9/1975 Diamondetal.
`3,911,416 A
`10/1975 Feder
`4,160,508 A
`7/1979 Salisbury, Jr.
`4,197,488 A
`4/1980 Kant
`4,236,325 A
`12/1980 Hall et al.
`
`4,262,549 A
`4,266,785 A *
`4,333,070 A
`4,464,117 A
`4,484,191 A
`4,513,235 A
`
`4/1981 Schwellenbach
`5/1981 Burrus occ 369/216
`6/1982 Barnes
`8/1984 Forest
`11/1984 Vavra
`4/1985 Acklam etal.
`(Continued)
`FOREIGN PATENT DOCUMENTS
`H2-185278
`7/1990
`
`Ip
`
`(Continued)
`
`OTHER PUBLICATIONS
`Baigrie, “Electric Control Loading—A Low Cost, High
`Performance Alternative,” Proceedings, pp. 247-254, Nov.
`6-8, 1990.
`,
`
`(Continued)
`Primary Examiner—Henry N. Tran
`Assistant Examiner—Jean Lesperance
`74) Attorney, Agent, or Firm—Kilpatrick Stockton LLP
`Y,
`AS
`P
`
`(57)
`
`ABSTRACT
`
`A moving magnet actuator for providing haptic feedback.
`The actuator includes a grounded core member, a coil is
`wrapped arounda central projection of the core member, and
`a magnethead positioned soas to provide a gap between the
`core member and the magnet head. The magnet head is
`moved in a degree of freedom based on an electromagnetic
`force caused by a current flowed throughthe coil. An elastic
`material, such as foam, is positioned in the gap between the
`magnet head and the core member, wherethe elastic material
`is compressed and sheared when the magnet head moves and
`substantially prevents movement of the magnet head past a
`range limit that is based on the compressibility and shear
`factor of the material. Flexible members can also be pro-
`vided between the magnet head and the ground member,
`wherethe flexible members flex to allow the magnet head to
`move, provide a centering spring force to the magnet head,
`d limit th
`ti
`f th
`t head
`ang
`ame
`tne mowon ol
`ine magne’
`Head.
`
`20 Claims, 5 Drawing Sheets
`
`100°
`
`\
`
`APPLE 1004
`
`1
`
`APPLE 1004
`
`

`

`US 6,982,696 B1
`
`Page 2
`
`U.S. PATENT DOCUMENTS
`
`....... 720/682
`
`4/1986 Boothroyd
`4,581,491 A
`7/1986 Hladky etal.
`4,599,070 A
`1/1987 Brown et al. ......... eee 137/83
`4,638,830 A *
`11/1987 De Vriesetal.
`4,708,656 A
`12/1987 Alban
`4,713,007 A
`12/1988 Selinko
`4,794,392 A
`6/1989 Sakai oe eee cee 310/12
`4,839,544 A *
`10/1989 Ilollis, Jr
`4,874,998 A
`11/1989 Duimel
`4,879,556 A
`1/1990 McIntosh
`4,891,764 A
`6/1990 Baker
`4,930,770 A
`6/1990 McIntosh
`4,934,694 A
`5/1991 Kraft
`5,019,761 A
`6/1991 Freels
`5,022,384 A
`6/1991 Horchetal.
`5,022,407 A
`6/1991 Champagneet al.
`5,023,861 A *
`7/1991 Franklin
`5,035,242 A
`8/1991 Szakaly
`5,038,089 A
`1/1992 Bond
`5,078,152 A
`8/1992 Oudetetal.
`5,136,194 A
`9/1992 Hollis, Jv. et al.
`5,146,566 A
`11/1992 Johnson
`5,165,897 A
`12/1992 Danialet al.
`5,175,459 A
`5/1993 Louis
`5,212,473 A
`8/1993 Smithsonet al.
`5,240,417 A
`12/1993 Fischer
`5,271,290 A
`1/1994 Cook
`5,275,174 A
`2/1994 Aigner
`5,283,970 A
`4/1994 Pierce
`5,299,810 A
`5/1994 Everett
`5,309,140 A
`8/1994 Wherlock
`5,334,027 A
`3/1995 Brimahall
`5,396,266 A
`7/1995 Gutmanetal.
`5,436,622 A
`8/1995 Taylor
`5,437,607 A
`11/1995 Hogan
`5,466,213 A
`2/1996 Carlson
`5,492,312 A
`7/1996 Oudetetal.
`5,532,585 A
`8/1996 Yamasaki
`5,547,382 A
`11/1996 Hajianpour
`5,575,761 A
`8/1997 Kurita
`5,656,901 A
`11/1997 Hoyt et al.
`5,687,080 A
`11/1997 Rosenberg ctal.
`5,691,898 A
`6/1998 Sinclair
`5,766,016 A
`7/1998 Bobicketal.
`5,785,630 A
`8/1998 Salcudean etal.
`5,790,108 A
`9/1998 Rosenberg et al.
`5,805,140 A
`1/1999 Salamun ...... 137/636.1
`5,857,492 A *
`12/1999 Delsonet al.
`6,002,184 A
`4/2000 Schenaetal.
`6,050,718 A
`5/2000 Yuan et al. oe. 310/12
`6,069,417 A *
`8/2000 Zilles etal.
`6,111,577 A
`12/2000 Perry etal.
`6,160,489 A
`6,163,092 A * 12/2000 Soultanian .............. 310/15
`6,166,723 A
`12/2000 Schenaetal.
`3/2001 Shlomietal. ........... 137/625.5
`6,199,587 B1*
`6,201,533 B1
`3/2001 Rosenberg et al.
`6,219,034 B1
`4/2001 Elbing etal.
`6,259,382 B1*
`7/2001 Rosenberg .......... 341/20
`6,271,833 B1
`8/2001 Rosenberg et al.
`6,323,494 B1* 11/2001 Lee we 250/442.11
`7/2002 Thorneretal.
`6,422,941 B1
`FOREIGN PATENT DOCUMENTS
`
`JP
`JP
`JP
`
`H4-8381
`H5-192449
`H7-24147
`
`1/1992
`8/1993
`1/1995
`
`OTHER PUBLICATIONS
`
`Iwata, Pen-based Haptic Virtual Environment, 0-7803-1363-
`1/93 IEEE, pp 287-292, 1993.
`
`Russo, “The Design and Implementation of a Three Degree
`of Freedom Force Output Joystick,” MIT Libraries Archives
`Aug. 14, 1990, pp. 1-131, May 1990.
`Brooks et al., “Hand Controllers for Teleoperation—AState-
`of-the-Art Technology Survey and Evaluation,”
`JPL
`Publication 85-11; NASA-CR-175890; N85-28559, pp. 1-
`84, Mar. 1, 1985.
`Jones et al. “A perceptual analysis of stiffness,” ISSN
`0014-4819
`Springer
`International
`(Springer-Verlag);
`Experimental Brain Research, vol. 79, No. 1, pp. 150-156,
`1990.
`
`Burdeaet al., “Distributed Virtual Force Feedback, Lecture
`Notes for Workshop on Force Display in Virtual Environ-
`ments and its Application to Robotic Teleoperation,” 1993
`IEEE International conference on Robotics and Automation,
`pp. 25-44, May 2, 1993.
`Snowet al., “Model-X Force-Reflecting-Hand-Controller,”
`NT Control No. MPO-17851; JPL Case No. 5348, pp. 1-4,
`Jun. 15, 1989.
`Ouh-Young, “Force Display in Molecular Docking,” Order
`No. 9034744, p. 1-369, 1990.
`Tadros, Control System Design for a Three Degree of
`Freedom Virtual Environment Simulator Using Motor/
`Brake Pair Actuators, MIT Archive © Massachusetts
`Institute of Technology, pp. 1-88, Feb. 1990.
`Caldwell et al., “Enhanced Tactile Feedback (Tele-Taction)
`Using a Multi-Functional Sensory System,” 1050-4729/93,
`pp. 955-960, 1993.
`Adelstein, “Design and Implementation of a Force Reflect-
`ing Manipulandum for Manual Control research,” DSC-vol.
`42, Advances in Robotics, Edited by H. Kazeroom,pp. 1-12,
`1992.
`
`Gotow et al., “Controlled Impedance Test Apparatus for
`Studying Human Interpretation of Kinesthetic Feedback,”
`WA11-11:00, pp. 332-337.
`Stanleyet al., “Computer Simulation of Interacting Dynamic
`Mechanical Systems Using Distributed Memory Parallel
`Processors,” DSC-vol. 42, Advances in Robotics, pp. 55-61,
`ASME 1992.
`
`Russo,“Controlling Dissipative Magnetic Particle Brakes in
`Force Reflective Devices,” DSC-vol. 42, Advances in
`Robotics, pp. 63-70, ASME 1992.
`Kontarinis et al., “Display of High-Frequency Tactile
`Information to Teleoperators,” Telemanipulator Technology
`and Space Telerobotics, Won S. Kim, Editor, Proc. SPIE vol.
`2057, pp. 40-50, Sep. 7-9, 1993.
`Patrick et al., “Design and Testing of A Non-reactive,
`Fingertip, Tactile Display for
`Interaction with Remote
`Environments,” Cooperative Intelligent Robotics in Space,
`Rui J. deFigueiredoet al., Editor, Proc. SPIE vol. 1387, pp.
`215-222, 1990.
`Adelstein, “A Virtual Environment System For The Study of
`Human Arm Tremor,” Ph.D. Dissertation, Dept. of Mechani-
`cal Engineering, MIT, Jun. 1989.
`Bejezy, “Sensors, Controls, and Man-MachineInterface for
`Advanced Teleoperation,” Science, vol. 208, No. 4450, pp.
`1327-1335, 1980.
`Bejezy,
`“Generalization of Bilateral Force-Reflecting
`Control of Manipulators,” Proceedings Of Fourth CISM-
`IFToMM, Sep. 8-12, 1981.
`McAffee, “Teleoperator Subsystem/Telerobot Demonstra-
`tor: Force Reflecting Hand Controller Equipment Manual,”
`JPL D-5172, pp. 1-50, A1-A36, B1-B5, C1-C36, Jan. 1988.
`
`2
`
`

`

`US 6,982,696 B1
`Page 3
`
`Minsky, “Computational Haptics: The Sandpaper System
`for Synthesizing Texture for a Force-Feedback Display,”
`Ph.D. Dissertation, MIT, Jun. 1995.
`Jocobsen et al., “High Performance, Dextrous Telerobotic
`Manipulator With Force Reflection,” Intervention/ROV °91
`Conference & Exposition, Hollywood, Florida, May 21-23,
`1991.
`
`Shimoga, “Finger Force and Touch Feedback Issues in
`Dexterous Telemanipulation,” Proceedings of Fourth An-
`nual Conference on Intelligent Robotic Systems for Space
`Exploration, Rensselaer Polytechnic Institute, Sep. 30-Oct.
`1, 1992.
`IBM Technical Disclosure Bulletin, “Mouse Ball-Actuating
`Device With Force and Tactile Feedback,” vol. 32, No. 9B,
`Feb. 1990.
`
`Terry et al., “Tactile Feedback In A Computer Mouse,”
`Proceedings of fourteenth Annual Northeast Bioengineering
`Conference, University of New Hampshire, Mar. 10-11,
`1988.
`
`Howe, “A Force-Reflecting Teleoperated Hand System for
`the Study of Tactile Sensing in Precision Manipulation,”
`Proceedings of the 1992 IEEE International Conference on
`Robotics and Automation, Nice, France, May 1992.
`Eberhardt et al.. “OMAR—A Haptic display for speech
`perception by deaf and deaf-blind individuals,” [EEE Virtual
`Reality Annual International Symposium,Seattle, WA, Sep.
`18-22, 1993.
`tactile displays:
`al., “Multidimensional
`Rabinowitz et
`Identification of vibratory intensity, frequency, and contac-
`tor area,” Journal of The Acoustical Society of America, vol.
`82, No. 4, Oct. 1987.
`Bejezy et al., “Kinesthetic Coupling Between Operator and
`Remote Manipulator,” International Computer Technology
`Conference, The American
`Society
`of Mechanical
`Engineers, San Francisco, CA, Aug. 12-15, 1980.
`Bejezy et al., “A Laboratory Breadboard System For Dual-
`Arm Teleoperation,” SOAR °89 Workshop, JSC, Houston,
`TX, Jul. 25-27, 1989.
`
`Ouh-Young, “A Low-Cost Force Feedback Joystick and Its
`Use in PC Video Games,” IEEE Transactions on Consumer
`Electronics, vol. 41, No. 3, Aug. 1995.
`Marcus, “Touch Feedback in Surgery,” Proceedings of
`Virtual Reality and Medicine The Cutting Edge, Sep. 8-11,
`1994.
`Bejezy, et al., “Universal Computer Control System (UCCS)
`For Space Telerobots,” CH2413-3/87/0000/0318501.00
`1987 IEEE, 1987.
`Patrick, “Design, Construction, and Testing of a Fingertip
`Tactile Display for Interaction with Virtual and Remote
`Environments,” Master of Science Thesis, MIT, Nov. 8,
`1990.
`
`Cadler, “Design of A Force-Feedback Touch-Introducing
`Actuator For Teleoperator Robot Control,” Bachelor of
`Science Thesis, MIT, Jun. 23, 1983.
`Wiker, “Teletouch Display Development: Phase 1 Report,”
`Technical Report 1230, Naval Ocean Systems Center, San
`Diego, Apr. 17, 1989.
`Bliss, “Optical-to-Tactile Image Conversion for the Blind,”
`IEEE Transactions on Man-Machine Systems, vol. MMS-
`11, No. 1, Mar. 1970.
`Feedback
`‘Tactile
`Johnson,
`“Shape-Memory Alloy
`Actuator,” Armstrong Aerospace Medical Research Labora-
`tory, AAMRL-TR-90-039, Aug., 1990.
`Kontarinis et al., “Tactile Display of Vibratory Information
`in Teleoperation and Virtual Environments,’ PRESENCE,
`4(4):387-402, 1995.
`Kontarinis et al., “Tactile Display of Vibratory Information
`in Teleoperation and Virtual Environments,’ PRESENCE,
`vol. 4, No. 4, pp. 387-402, 1995.
`Lake, “Cyberman from Logitech,” GameBytes, 1994.
`“Taking a Joystick Ride”, Computer Currents, Tim Scannell,
`Nov. 1994, Boston Edition, vol. 9 No. 11.
`“Coaxial Control Shaker Part No. C-25502,” Safe Flight
`Instrument Corporation, 26 pages, Jul. 1, 1967; Revised Jan.
`28, 2002.
`
`* cited by examiner
`
`3
`
`

`

`U.S. Patent
`
`Jan. 3, 2006
`
`Sheet 1 of 5
`
`US 6,982,696 B1
`
`HEAR
`
`VIEW
`
`HOST COMPUTER SYSTEM
`
`12
`
`SYSTEM CLOCK
`
`18
`
`AUDIO OUT-
`PUT DEVICE
`
`16
`
`21
`
`20
`
`HOST
`PROCESSOR
`
`DISPLAY
`DEVICE
`
`L I
`
`FORCE FEEDBACK
`TERFACE DEVICE
`N
`— ee ee -orocrrr re
`36
`
`LOCAL MI
`PROCES
`
`CRO-
`SOR
`
`SENSOR
`INTER-FACE
`
`SENSORS
`
`ACTUATOR
`INTERFACE
`
`SAFETY
`SWITCH
`
`ACTUATORS
`
`POWER
`
`41
`
`30
`
`40
`
`Figure 1
`
`~~
`
`4
`
`
`

`

`U.S. Patent
`
`Jan. 3, 2006
`
`Sheet 2 of 5
`
`US 6,982,696 B1
`
`120
`
`5
`
`

`

`U.S. Patent
`
`Jan. 3, 2006
`
`Sheet 3 of 5
`
`US 6,982,696 B1
`
`105!
`
`
`
` |
`
`[Se|
`108!
`106 \___-
`
`6
`
`

`

`U.S. Patent
`
`Jan. 3, 2006
`
`Sheet 4 of 5
`
`US 6,982,696 B1
`
`
`
`7
`
`

`

`U.S. Patent
`
`Jan. 3, 2006
`
`Sheet 5 of 5
`
`US 6,982,696 B1
`
`
`
`8
`
`

`

`US 6,982,696 B1
`
`1
`MOVING MAGNET ACTUATOR FOR
`PROVIDING HAPTIC FEEDBACK
`
`CROSS REFERENCE TO RELATED
`APPLICATIONS
`
`This application claimspriority to U.S. Provisional Appli-
`cation No. 60/142,155, filed Jul. 1, 1999, entitled, “Provid-
`ing Vibration Forces in Force Feedback Devices,” and which
`is incorporated by reference herein.
`This invention was made with government support under
`Contract Number N00014-98-C-0220, awarded by the
`Office of Naval Research. The governmenthascertain rights
`in this invention.
`
`BACKGROUND OF THE INVENTION
`
`invention relates generally to producing
`The present
`forces in force feedback interface devices, and more par-
`ticularly to the output and control of vibrations and similar
`force sensations from actuators in a force feedback interface
`device.
`Using an interface device, a user can interact with an
`environment displayed by a computer system to perform
`functions and tasks on the computer, such as playing a game,
`experiencing a simulation or virtual reality environment,
`using a computer aided design system, operating a graphical
`user interface (GUI), or otherwise influencing events or
`images depicted on the screen. Common human-computer
`interface devices used for such interaction include a joystick,
`mouse, trackball, steering wheel, stylus, tablet, pressure-
`sensitive ball, or the like, that is connected to the computer
`system controlling the displayed environment.
`In some interface devices, haptic or tactile feedback is
`also provided to the user, also known as “force feedback.”
`These types of interface devices can provide physical sen-
`sations which are felt by the user using the controller or
`manipulating the physical object of the interface device. One
`or more motorsor other actuators are used in the device and
`are connected to the controlling computer system. The
`computer system controls forces on the force feedback
`device in conjunction and coordinated with displayed events
`and interactions on the host by sending control signals or
`commandsto the force feedback device and the actuators.
`
`Manylow cost force feedback devices provide forces to
`the user by vibrating the manipulandum and/or the housing
`of the device that is held by the user. The output of simple
`vibration force feedback requires less complex hardware
`components and software control over the force-generating
`elements than does more sophisticated haptic feedback. For
`example, in many current controllers for game consoles such
`as the Sony Playstation and the Nintendo 64, a motor is
`included in the controller which is energized to provide the
`vibration forces. An eccentric massis positioned on the shaft
`of the motor, and the shaft is rotated quickly to cause the
`motor and the housing of the controller to vibrate. The host
`computer (console) provides commandsto the controller to
`turn the vibration on or off or to increase or decrease the
`frequency of the vibration by varying the rate of rotation of
`the motor. These current implementations of vibrotactile
`feedback, however, tend to be limited and produce low-
`bandwidth vibrations that tend to all feel the same, regard-
`less of the different events and signals used to command
`them. The vibrations that these implementations produce
`also cannotbe significantly varied, thus severely limiting the
`force feedback effects which can be experienced by a user of
`the device.
`
`10
`
`15
`
`20
`
`25
`
`30
`
`35
`
`40
`
`45
`
`50
`
`55
`
`60
`
`65
`
`2
`SUMMARYOF THE INVENTION
`
`invention is directed to moving magnet
`The present
`actuators that provide haptic sensations in a haptic feedback
`device that is interfaced with a host computer. The present
`invention provides actuators that output high magnitude,
`high bandwidth vibrations for more compelling force
`effects.
`invention relates to an
`the present
`More specifically,
`actuator for providing vibration forces in a haptic feedback
`device. The actuator
`includes a core member
`that
`is
`grounded to a ground member. A coil is wrapped around a
`central projection of the core member, and a magnethead is
`positioned so as to provide a gap between the core member
`and the magnet head. The magnet head is movedin a degree
`of freedom based on an electromagnetic force caused by a
`current flowed through the coil. An elastic material
`is
`positioned in the gap between the magnethead and the core
`member, where the elastic material
`is compressed and
`sheared when the magnet head moves and substantially
`prevents movement of the magnet head past a range limit,
`the range limit based on an amount which the elastic
`material may be compressed and sheared.
`Preferably, the elastic material is a material such as foam.
`The actuator can be driven bya drive signal that causes said
`magnet head to oscillate and produce a vibration in the
`ground member. The ground membercan bea housingof the
`haptic feedback device, such as a gamepad controller. In
`some embodiments,at least one flexible member can also be
`coupled between the magnet head and the ground memberto
`allow the magnet head to move in the degree of freedom.
`The degree of freedom of the magnet head can be linear or
`rotary.
`In another aspect of the present invention, an actuator for
`providing vibration forces in a force feedback device
`includes a core member that
`is grounded to a ground
`member, a coil wrapped around a central projection of the
`core member, and a magnethead positioned adjacent to the
`core member, where the magnet head is moved in a degree
`of freedom based on an electromagnetic force caused by a
`current flowed throughthe coil. At least one flexible member
`is coupled between the magnet head and the ground member,
`where the flexible member(s) flex to allow the magnet head
`to move in the degree of freedom and provide a centering
`spring force to the magnet head. The flexible members limit
`the motion of the magnet head such that the magnet head
`does not impact a hard surface. The flexible members can be
`coupled between the magnet head and a ground surface to
`which the core member is coupled, or can be coupled
`between the magnet head and a ground surface to a side of
`the core member. The flexible members can also be coupled
`to a housing of the actuator as the ground surface. The
`degree of freedom of the magnet head can belinearorrotary.
`An elastic material can also be positioned in a gap between
`magnet head and core member which is compressed and
`sheared when the magnet head moves. A haptic feedback
`device including any of the above embodiments of actuator
`is also described.
`The present invention advantageously provides an actua-
`tor for a haptic feedback device that can output high quality
`vibrotactile sensations. Both the frequency and amplitude of
`the vibrations can be controlled using bi-directional control,
`and features such as the elastic material and flexures con-
`
`tribute to a high quality and high bandwidth vibration force
`output.
`These and other advantages of the present invention will
`become apparent to those skilled in the art upon a reading of
`
`9
`
`

`

`US 6,982,696 B1
`
`3
`the following specification of the invention and a study of
`the several figures of the drawing.
`
`BRIEF DESCRIPTION OF THE DRAWINGS
`
`FIG. 1 is a block diagram of a haptic feedback system
`suitable for use with the haptic feedback device of the
`present invention;
`FIG. 2 is a side elevational view of one embodimentof a
`
`linear actuator of the present invention;
`FIG. 3 is a side elevational view of one embodimentof a
`
`rotary actuator of the present invention;
`FIG. 4 is a top plan view of the actuator of FIG. 2 having
`flexures in a different location; and
`FIG. 5 is a perspective view of another embodimentof the
`actuator of FIG. 4.
`
`DETAILED DESCRIPTION OF PREFERRED
`EMBODIMENTS
`
`FIG. 1 is a block diagram illustrating a force feedback
`interface system 10 for use with the present
`invention
`controlled by a host computer system. Interface system 10
`includes a host computer system 12 and an interface device
`14.
`
`Host computer system 12 can be any of a variety of
`computer systems, such as a home video game systems
`(game console), e.g. systems available from Nintendo, Sega,
`or Sony. Other types of computers may also be used, such as
`a personal computer (PC, Macintosh,etc.), a television “set
`top box”or a “network computer,” a workstation, a portable
`and/or handheld game device or computer, etc. Host com-
`puter system 12 preferably implements a host application
`program with which a user 22 is interacting via peripherals
`and interface device 14. For example, the host application
`program can be a video or computer game, medical simu-
`lation, scientific analysis program, operating system, graphi-
`cal user interface, or other application program that utilizes
`force feedback. Typically,
`the host application provides
`images to be displayed on a display output device, as
`described below, and/or other feedback, such as auditory
`signals.
`Host computer system 12 preferably includes a host
`microprocessor 16, a clock 18, a display screen 20, and an
`audio output device 21. Microprocessor 16 can be one or
`more of any of well-known microprocessors. Random
`access memory (RAM), read-only memory (ROM), and
`input/output (I/O) electronics are preferably also included in
`the host computer. Display screen 20 can be used to display
`images generated by host computer system 12 or other
`computer systems, and can be a standard display screen,
`television, CRT, flat-panel display, 2-D or 3-D display
`goggles, or any other visual interface. Audio output device
`21, such as speakers, is preferably coupled to host micro-
`processor 16 via amplifiers,filters, and other circuitry well
`knownto those skilled in the art and provides sound output
`to user 22 from the host computer 12. Other types of
`peripherals can also be coupled to host processor 16, such as
`storage devices (hard disk drive, CD ROM/DVD-ROM
`drive, floppy disk drive, etc.), communication devices,print-
`ers, and other input and output devices. Data for implement-
`ing the interfaces of the present invention can be stored on
`computer readable media such as memory (RAM or ROM),
`a hard disk, a CD-ROM or DVD-ROM,etc.
`An interface device 14 is coupled to host computer system
`12 by a bi-directional bus 24. Interface device 14 can be a
`gamepad controller, joystick controller, mouse controller,
`
`10
`
`15
`
`20
`
`25
`
`30
`
`35
`
`40
`
`45
`
`50
`
`55
`
`60
`
`65
`
`4
`steering wheel controller, or other device which a user may
`manipulate to provide input to the computer system and
`experience force feedback. The bi-directional bus sends
`signals in either direction between host computer system 12
`and the interface device. An interface port of host computer
`system 12, such as an RS232 or Universal Serial Bus (USB)
`serial interface port, parallel port, game port, etc., connects
`bus 24 to host computer system 12. Alternatively, a wireless
`communication link can be used.
`
`Interface device 14 includes a local microprocessor 26,
`sensors 28, actuators 30, a user object 34, optional sensor
`interface 36, an actuator interface 38, and other optional
`input devices 39. Local microprocessor 26 is coupled to bus
`24 and is considered local to interface device 14 and is
`dedicated to force feedback and sensor I/O of interface
`device 14. Microprocessor 26 can be provided with software
`instructions to wait for commandsor requests from com-
`puter host 12, decode the commandorrequest, and handle/
`control input and output signals according to the command
`or request. In addition, processor 26 preferably operates
`independently of host computer 12 by reading sensorsignals
`and calculating appropriate forces from those sensor signals,
`time signals, and stored or relayed instructions selected in
`accordance with a host command. Suitable microprocessors
`for
`use
`as
`local microprocessor
`26
`include
`the
`MC68HC7111E9 by Motorola,
`the PIC16C74 by Micro-
`chip, and the 82930AX by Intel Corp., for example. Micro-
`processor 26 can include one microprocessor chip, or mul-
`tiple processors and/or co-processor chips, and/or digital
`signal processor (DSP) capability.
`Microprocessor 26 can receive signals from sensors 28
`and providesignals to actuators 30 of the interface device 14
`in accordance with instructions provided by host computer
`12 over bus 24. For example, in a preferred local control
`embodiment, host computer 12 provides high level super-
`visory commands to microprocessor 26 over bus 24, and
`microprocessor 26 manages low level force control loops to
`sensors and actuators in accordance with the high level
`commandsand independently of the host computer 12. The
`force feedback system thus provides a host control loop of
`information and a local control loop of information in a
`distributed control system. This operation is described in
`greaterdetail in U.S. Pat. No. 5,734,373, incorporated herein
`by reference. Microprocessor 26 can also receive commands
`from any other input devices 39 included on interface
`apparatus 14, such as buttons, and provides appropriate
`signals to host computer 12 to indicate that
`the input
`information has been received and any information included
`in the input information. Local memory 27, such as RAM
`and/or ROM, can be coupled to microprocessor 26 in
`interface device 14 to store instructions for microprocessor
`26 and store temporary and other data (and/orregisters of the
`microprocessor 26 can store data). In addition, a local clock
`29 can be coupled to the microprocessor 26 to provide
`timing data.
`Sensors 28 sense the position, motion, and/or other char-
`acteristics of a user manipulandum 34ofthe interface device
`14 along one or more degrees of freedom and provide
`signals to microprocessor 26 including information repre-
`sentative of those characteristics. Rotary or linear optical
`encoders, potentiometers, photodiode or photoresistor sen-
`sors, velocity sensors, acceleration sensors, strain gauge, or
`other types of sensors can be used. Sensors 28 provide an
`electrical signal to an optional sensor interface 36, which can
`be used to convert sensor signals to signals that can be
`interpreted by the microprocessor 26 and/or host computer
`system 12. For example, these sensor signals can be used by
`
`10
`
`10
`
`

`

`US 6,982,696 B1
`
`5
`the host computer to influence the host application program,
`e.g. to steer a race car in a game or movea cursoracross the
`screen.
`
`One or more actuators 30 transmit forces to the interface
`
`device 14 and/or to manipulandum 34ofthe interface device
`14 in response to signals received from microprocessor 26.
`In one embodiment,
`the actuators output forces on the
`housing of the interface device 14 which is handheld by the
`user, so that the forces are transmitted to the manipulandum
`through the housing. Alternatively,
`the actuators can be
`directly coupled to the manipulandum 34. Actuators 30 can
`include two types: active actuators and passive actuators.
`Active actuators include linear current control motors, step-
`per motors, pneumatic/hydraulic active actuators, a torquer
`(motor with limited angular range), voice coil actuators, and
`other types of actuators that transmit a force to move an
`object. Passive actuators can also be used for actuators 30,
`such as magnetic particle brakes, friction brakes, or pneu-
`matic/hydraulic passive actuators. Active actuators are pre-
`ferred in the embodimentsof the present invention. Actuator
`interface 38 can be connected between actuators 30 and
`
`microprocessor 26 to convert signals from microprocessor
`26 into signals appropriate to drive actuators 30, as is
`described in greater detail below.
`Other input devices 39 can optionally be included in
`interface device 14 and send input signals to microprocessor
`26 or to host processor 16. Such input devices can include
`buttons, dials, switches, levers, or other mechanisms. For
`example, in embodiments where the device 14 is a gamepad,
`the various buttons and triggers can be other input devices
`39. Or,if the user manipulandum 34is a joystick, other input
`devices can include one or more buttons provided, for
`example, on the joystick handle or base. Power supply 40
`can optionally be coupled to actuator interface 38 and/or
`actuators 30 to provide electrical power. A safety switch 41
`is optionally included in interface device 14 to provide a
`mechanism to deactivate actuators 30 for safety reasons.
`Manipulandum (or “user object”) 34 is a physical object,
`device or article that may be grasped or otherwise contacted
`or controlled by a user and which is coupled to interface
`device 14. By “grasp”, it is meant that users may releasably
`engage, contact, or grip a portion of the manipulandum in
`some fashion, such as by hand, with their fingertips, or even
`orally in the case of handicapped persons. The user 22 can
`manipulate and move the object along provided degrees of
`freedom to interface with the host application program the
`user is viewing on display screen 20. Manipulandum 34 can
`be a joystick, mouse, trackball, stylus (e.g. at the end of a
`linkage), steering wheel, sphere, medical instrument (lap-
`aroscope, catheter, etc.), pool cue (e.g. moving the cue
`through actuated rollers), hand grip, knob, button, or other
`object.
`In a gamepad embodiment, the manipulandum can be a
`fingertip joystick or similar device. Some gamepad embodi-
`ments may not include a joystick, so that manipulandum 34
`can be a button pad or other device for inputting directions.
`In other embodiments, mechanisms can be used to provide
`degrees of freedom to the manipulandum, such as gimbal
`mechanisms,slotted yoke mechanisms, flexure mechanisms,
`etc. Various embodiments of suitable mechanisms are
`described in U.S. Pat. Nos. 5,767,839, 5,721,566, 5,623,582,
`5,805,140, 5,825,308, and patent application Ser. Nos.
`08/965,720, 09/058,259, 09/156,802, 09/179,382,
`and
`60/133,208, all incorporated herein by reference.
`
`6
`Moving Magnet Actuator
`
`FIG. 2 is a side elevational view of an actuator 100 of the
`
`invention which can be included in a handheld
`present
`controller 14 or coupled to manipulandum 34 as actuator 30
`for providing force feedback to the user of the controller 14
`and/or manipulandum 34in the interface device 14 of FIG.
`1. In one embodiment, the actuator 100 can be coupled to the
`housing of the interface device 14, e.g. the housing of a
`handheld gamepad controller as used with console game
`systems or personal computers. In other embodiments, the
`actuator can be coupled to a manipulandum 34 or other
`member.
`Actuator 100 is a moving-magnet actuator in which a
`grounded metal core 102 includes a wire coil 104 that is
`wrapped around a central projection of the core as shown
`(shown in cross section in FIG. 2). A magnet head 105
`includes two magnets 106 and 108 which have opposite
`polarities facing the coil 104 and are coupled together as
`shown and spaced from the coil 104 and core 102. Magnet
`head 105 also includes a metal piece 110 coupled to the
`magnets 106 and 108 to provide a flux return path for the
`magnetic flux of the actuator. A plastic housing 112 provides
`a structure for the magnets and metal piece of the magnet
`head 105.
`The actuator 100 operates by producing a force on the
`magnet head 105 in the linear directions indicated by arrows
`114 when a current is flowed through the coil 104. The
`direction of the current dictates the direction of force on the
`
`head 105. The operation of E-core actuators similar to the
`components 102-110 of actuator 100 is described in greater
`detail in co-pending application Ser. No. 60/107,267, incor-
`porated herein by reference, and in U.S. Pat. No. 5,136,194.
`The magnet head 105 can be movedto either side from the
`center position shownin FIG. 2.
`Actuator 100 is intended to be used in the present inven-
`tion for producing vibrations which are transmitted to the
`housing of the interface device 14 and/or to a user manipu-
`landum 34. In other embodiments, the actuator 100 can be
`used to produce other force feedback effects. The motion of
`the head 105 is desired to be constrainedto a particular range
`of motion to provide an oscillatory motion as desired for the
`bi-directional mode of operation as described above. How-
`ever, if mechanical stops are provided to limit the range of
`motion of the magnet head 105, the impact of the head 105
`with the stops causes harmonics and disturbances in the
`vibration force feedback which the user can feel.
`
`To reduce the disruptive effect of such hard stops, the
`present invention provides several features. Flexures 120 are
`coupled between the grounded core 102 and the moving
`magnet head 105, and can flex in the directions shown to
`allow motion of the magnet head 105 in its linear degree