Method and apparatus for providing high bandwidth force feedback with improved actuator feel
First Claim
1. A force feedback interface device for providing high-fidelity force sensations to a user of the device, said interface device being coupled to a host computer and allowing said user to interact with an application program implemented by said host computer, said force feedback interface device comprising:
- a user object graspable by said user and movable in at least one rotary degree of freedom;
a sensor for reporting a locative signal to said host computer, said locative signal indicating a position of said user object within said rotary degree of freedom;
an actuator coupled to said user object and to said host computer, said actuator outputting forces on said user object in response to signals from said host computer such that said forces are in response to said locative signal and are coordinated with events within said application program, said actuator having a reduced cogging effect such that said forces felt by said user are substantially free of force pulsations caused by said cogging effect when said user object is moved in said rotary degree of freedom, said actuator comprising;
a housing;
a set of magnets rigidly coupled to said housing, said magnets provided on opposing surfaces of an interior of said housing and creating a magnetic field;
a rotor rotatably coupled to said housing and to said user object and positioned between said magnets, said rotor operative to rotate about an axis of rotation approximately parallel to faces of said magnets, said rotor including a shaft and a plurality of teeth spaced apart equally about a circumference of said shaft, wherein said teeth and said magnets are provided in a skewed, helical arrangement relative to each other such that as said rotor rotates about said axis, a portion of one of said teeth exits said magnetic field as a portion of a next consecutive tooth is entering said magnetic field; and
a coil, wherein an electric current flows through said coil to cause said rotor to rotate about said axis of rotation; and
a drive transmission coupled between said actuator and said user object, said drive transmission amplifying said forces output by said actuator on said user object.
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Accused Products
Abstract
A method and apparatus for providing low-cost, realistic force feedback including an improved actuator. Force sensations are provided to a user and an interface device coupled to a host computer allows a user to interact with a host application program. A user object, such as a joystick, is moveable by a user in at least one rotary degree of freedom. A sensor reports a locative signal to the host computer to indicate a position of the user object. An actuator outputs forces on the user object in response to signals from the host computer and program. The actuator includes a housing, a set of grounded magnets provided on opposing surfaces of the housing and creating a magnetic field, and a rotor coupled to the user object positioned between the magnets. The rotor rotates about an axis of rotation and includes a shaft and teeth spaced around the shaft. An electric current flows through one or more coils on the teeth to cause the rotor to rotate. The teeth and the magnets are provided in a skewed, helical arrangement relative to each other so that, as the rotor rotates, a first tooth gradually exits the magnetic field as the next consecutive tooth gradually enters the magnetic field, thereby significantly reducing a cogging effect of the rotor when the user object is moved by the user and increasing the fidelity of forces experienced by the user.
278 Citations
27 Claims
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1. A force feedback interface device for providing high-fidelity force sensations to a user of the device, said interface device being coupled to a host computer and allowing said user to interact with an application program implemented by said host computer, said force feedback interface device comprising:
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a user object graspable by said user and movable in at least one rotary degree of freedom; a sensor for reporting a locative signal to said host computer, said locative signal indicating a position of said user object within said rotary degree of freedom; an actuator coupled to said user object and to said host computer, said actuator outputting forces on said user object in response to signals from said host computer such that said forces are in response to said locative signal and are coordinated with events within said application program, said actuator having a reduced cogging effect such that said forces felt by said user are substantially free of force pulsations caused by said cogging effect when said user object is moved in said rotary degree of freedom, said actuator comprising; a housing; a set of magnets rigidly coupled to said housing, said magnets provided on opposing surfaces of an interior of said housing and creating a magnetic field; a rotor rotatably coupled to said housing and to said user object and positioned between said magnets, said rotor operative to rotate about an axis of rotation approximately parallel to faces of said magnets, said rotor including a shaft and a plurality of teeth spaced apart equally about a circumference of said shaft, wherein said teeth and said magnets are provided in a skewed, helical arrangement relative to each other such that as said rotor rotates about said axis, a portion of one of said teeth exits said magnetic field as a portion of a next consecutive tooth is entering said magnetic field; and a coil, wherein an electric current flows through said coil to cause said rotor to rotate about said axis of rotation; and a drive transmission coupled between said actuator and said user object, said drive transmission amplifying said forces output by said actuator on said user object. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
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15. A force feedback interface device manipulated by a user and communicating with a host computer system implementing a host application program, said host application program displaying images on a computer display apparatus, said host computer system updating said host application program in response to user manipulation of said interface device and commanding force feedback sensations on said user in response to said manipulations and in coordination with events in said host application program, said force feedback interface device comprising:
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a user object movable in a degree of freedom by a user and being physically contacted by said user; a gimbal mechanism rotationally coupled to a support, said gimbal mechanism providing a plurality of rotary degrees of freedom to said user manipulatable object with respect to said support; a grounded actuator coupled between said gimbal mechanism and said support for applying a rotational force along a first one of said degrees of freedom to said user object in accordance with a force signal from said host computer, said force signal causing said force to be coordinated with said host application program, thereby causing a feel sensation that corresponds with a relevant event within said host application program, said actuator including a grounded magnet and a rotor having skewed teeth with respect to said magnet to reduce force pulsations caused by a cogging effect of said actuator during movement of said user object in said first degree of freedom and to provide said feel sensation as felt by said user substantially without said force pulsations caused by said cogging effect; an amplification transmission coupled between said actuator and said gimbal mechanism, said amplification transmission amplifying said force provided by said actuator, said amplified force being applied to said user object; and a sensor for detecting a position of said user object along at least one of said degrees of freedom and outputting locative signals to said host computer system, said locative signals including information representative of said position of said user object, wherein said host application program updates said images in response to said locative signals and said position of said user object and said user interacts with said host application program by moving said user object. - View Dependent Claims (16, 17, 18, 19, 20, 21, 22)
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23. A force feedback interface device manipulated by a user and communicating with a host computer system implementing a host application program, said host application program displaying images on a computer display apparatus, said host computer system updating said host application program in response to user manipulation of said interface device and commanding force feedback sensations on said user in response to said manipulations and in coordination with events in said host application program, said force feedback interface device comprising:
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a user object movable in a degree of freedom by a user and being physically contacted by said user; a gimbal mechanism rotationally coupled to a support, said gimbal mechanism providing a plurality of rotary degrees of freedom to said user manipulatable object with respect to said support; a grounded actuator coupled between said gimbal mechanism and said support for applying a rotational force along a degree of freedom to said user object in accordance with a force signal, said force signal causing said force to be coordinated with said host application program, thereby causing a feel sensation that corresponds with a relevant event within said host application program; a sensor for detecting a position of said user object along at least one of said degrees of freedom and outputting locative signals to said host computer system, said locative signals including information representative of said position of said user object, wherein said host application program updates said images in response to said locative signals and said position of said user object and said user interacts with said host application program by moving said user object; and a device microprocessor, separate from said host computer system, for communicating with said host computer system via a communication bus by receiving a host force command from said host computer system, said host force command being output from said host computer system in response to and coordinated with events within said host application program, said microprocessor executing a local process in parallel with said execution of said host application program for receiving and decoding said host force command and outputting said force signal to said actuator in response to a decoded host command, wherein said local process is stored in a local memory separate from said host computer and accessible to said device microprocessor, and wherein said host commands include at least one of; direct host commands for commanding said microprocessor to immediately output a desired force according to a force routine selected by said direct host command, reflex commands for commanding said microprocessor to output a desired force according to a force routine selected by said reflex command and when said microprocessor determines that predetermined conditions have been met, and custom profile commands for commanding said microprocessor to receive a set of data from said host computer to command said microprocessor to output a sequence of forces over time based on said set of data. - View Dependent Claims (24, 25, 26, 27)
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Specification