The present invention relates generally to interface devices for allowing humans to interface with computer systems, and more particularly to low-cost computer interface devices that allow the user to provide input to computer systems and allow computer systems to provide haptic feedback to the user.
A user can interact with an environment displayed by a computer 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), navigate web pages, etc. Common human-computer interface devices used for such interaction include a mouse, joystick, trackball, gamepad, steering wheel, stylus, tablet, pressure-sensitive sphere, or the like, that is connected to the computer system controlling the displayed environment. Typically, the computer updates the environment in response to the user""s manipulation of a physical manipulandum such as a joystick handle or mouse, and provides visual and audio feedback to the user utilizing the display screen and audio speakers. The computer senses the user""s manipulation of the user object through sensors provided on the interface device that send locative signals to the computer. For example, the computer displays a cursor or other graphical object in a graphical environment, where the location of the cursor is responsive to the motion of the user object. In other applications, interface devices such as remote controls allow a user to interface with the functions of an electronic device or appliance.
In some interface devices, force (kinesthetic) feedback and/or tactile feedback is also provided to the user, more generally known collectively herein as xe2x80x9chaptic feedback.xe2x80x9d These types of interface devices can provide physical sensations which are felt by the user manipulating a user manipulandum of the interface device, such as a joystick handle, mouse, wheel, etc. One or more motors or other actuators are coupled to the joystick handle or mouse and are connected to the controlling computer system. The computer system controls forces on the joystick or mouse in conjunction and coordinated with displayed events and interactions by sending control signals or commands to the actuators. The computer system can thus convey physical force sensations to the user in conjunction with other supplied feedback as the user is grasping or contacting the interface device or manipulatable object of the interface device. For example, when the user moves the manipulatable object and causes a displayed cursor to interact with a different displayed graphical object, the computer can issue a command that causes the actuator to output a force on the physical object, conveying a feel sensation to the user.
One problem with current haptic feedback controllers in the home consumer market is the high manufacturing cost of such devices, which makes the devices expensive for the consumer. A large part of this manufacturing expense is due to the inclusion of complex and multiple actuators and corresponding control electronics in the haptic feedback device. In addition, high quality mechanical and force transmission components such as linkages and bearings must be provided to accurately transmit forces from the actuators to the user manipulandum and to allow accurate sensing of the motion of the user object. These components are complex and require greater precision in their manufacture than many of the other components in an interface device, and thus further add to the cost of the device.
Some low cost haptic devices exist, such as the vibrotactile gamepads for console game systems and personal computers, e.g. the Sony DualShock or Nintendo Rumble Pack. These devices generate tactile sensations by including a motor having a rotating shaft and an inertial mass connected to the shaft at an off-center point of the mass. The inertial mass is rotated around the motor shaft with respect to the interface device at various speeds. This can create sinusoidal force signals at various frequencies depending upon the current driven through the motor. The problem with such a methodology is slow response time because the spinning mass must accelerate and decelerate over time to achieve the rotational velocity corresponding to a desired frequency output. Also, this implementation applies forces in a continually changing direction confined to a plane of rotation of the mass, providing a xe2x80x9cwobblexe2x80x9d sensation. This can be particularly disconcerting to the user at slow frequencies and, in many embodiments, may be unsuitable for use with devices like a mouse, which also provide input in a plane that may overlap with the plane in which forces are exerted.
A need therefore exists for a haptic feedback device that is lower in cost to manufacture yet offers the user compelling haptic feedback to enhance the interaction with computer applications.
The present invention is directed toward an actuator assembly and an interface device including such an assembly that provides haptic sensations to a user. Inertial and/or contact forces are applied to a user with a low-cost actuator and mechanical structure, which allows a low-cost force feedback device to be produced.
More particularly, a haptic feedback interface device of the present invention is coupled to a host computer implementing a host application program and is manipulated by a user. The interface device includes a housing that is physically contacted by the user, a sensor device detecting said manipulation of said interface device by the user, and an actuator assembly that provides output forces to the user as haptic sensations.
In one embodiment, the actuator assembly includes an actuator that outputs a rotary force, and a flexure coupling the actuator to the device housing. The flexure is a unitary member and includes a plurality of flex joints allowing a portion of the flexure to be approximately linearly moved. The flexure converts the rotary force output by the actuator to the linear motion, where the linear motion causes a force that is transmitted to the user. Preferably, the linear motion is provided approximately along an axis that is perpendicular to a planar workspace in which the interface device may be moved by the user. In some embodiments, a portion of the flexure is coupled to an inertial mass so that the inertial mass is linearly moved when the actuator outputs the rotary force, where an inertial force caused by the inertial mass is transmitted to the user through the housing.
In another embodiment, the actuator assembly includes an actuator which outputs a force, and a mechanism coupling the actuator to the device housing, where the mechanism allows the actuator to be moved with respect to the device housing. The actuator acts as an inertial mass when in motion to provide an inertial force that is transmitted to the user. The mechanism can be a flexure including at least one flex joint or a mechanism with bearings, and the actuator can output a rotary force. The actuator can approximately linearly move along a z-axis substantially perpendicular to an x-y plane in which the user can move a manipulandum of the interface device. A method of the present invention similarly outputs a force from an actuator to move the actuator and provide haptic sensations to the user of the interface device.
In some embodiments, the mechanism or flexure is coupled to a moveable contact member which moves into physical contact with the user when said user is normally operating the interface device. For example, the contact member can include a cover portion that is at least a portion of a top surface of the interface device. The actuator can be driven bi-directionally to provide an output force that produces pulse or vibration sensations to the user. The flexure can include at least one stop to prevent motion of an actuator shaft of the actuator past a desired fraction of a full revolution.
Preferably, the interface device is a handheld interface device, such as a mouse, gamepad, or remote control device. The linear motion can be correlated with a graphical representation displayed by the host computer, where a position of a mouse in the planar workspace corresponds with a position of a cursor displayed in the graphical representation. The linear motion provides a pulse correlated with the interaction of a user-controlled cursor with a graphical object displayed in a graphical user interface. The linear motion can be included in a force sensation, such as a pulse, vibration, or texture force. The actuator preferably outputs the forces in response to commands or signals received by the interface device from the host computer.
The present invention advantageously provides a haptic feedback device that is significantly lower in cost than other types of haptic feedback devices and is thus well-suited for home consumer applications. One or more low-cost actuator assemblies of the present invention can be provided that apply a force in a particular degree of freedom, such as a Z-axis perpendicular to a support surface. A flexure is used is some embodiments to provide long-lasting and effective haptic sensations, and in some embodiments the actuator itself can be used as an inertial mass for inertial haptic sensations, saving cost and assembly time.
These and other advantages of the present invention will become apparent to those skilled in the art upon a reading of the following specification of the invention and a study of the several figures of the drawing.