1. Field of the Invention
This invention relates to haptic interfaces and, in particular, to enabling a user to selectively engage at least part of the haptic display of a haptic interface device to produce an enhanced interaction with an environment with which the user interacts using the haptic interface device.
2. Related Art
A “haptic interface device” provides a haptic sensation (haptic display) to a user of the haptic interface device in response to the user's interaction with an environment with which the haptic interface device is associated. “Haptic” refers to the sense of touch: haptic interface display devices thus produce sensations associated with the sense of touch, such as texture, force (e.g., frictional force, magnetic repulsion or attraction), vibration, mass, density, viscosity, temperature, moisture, or some combination of such sensations. Haptic interface devices can be embodied in a variety of different apparatus, such as, for example, apparatus for conveying force and/or vibrotactile sensation (e.g., a stylus, a movable arm, a wheel, a dial, a roller, a slider or a vibratory surface), apparatus for conveying thermal sensation (e.g., a thermally-controlled surface or air volume), and apparatus for conveying the sensation of moisture (e.g., a moisture-controlled surface or air volume). Haptic interface devices can be used in a wide variety of applications. For example, some joysticks and mice used with computers incorporate force feedback to provide a haptic display to a user of the joystick or mouse. Some paging devices are adapted to vibrate when a paging signal is received. Some toys produce vibrations as part of the interaction with the toy. These examples give an indication of the range of applications for which a haptic interface device can be used.
In a conventional haptic interface device, the character of the haptic display experienced by a user is determined by a haptic model that links the state of one or more aspects of the environment to the haptic sensation provided to the user. This is illustrated in FIG. 1A. A user 101 uses an environment interaction control apparatus 103 to interact with an environment 102 via an environment interaction model 104 (either directly or via a haptic model 106, as indicated in FIG. 1A by the dashed lines between the environment interaction model 104 and the environment 102, and the environment interaction model 104 and the haptic model 106). The haptic model 106 “interprets” the user interaction with the environment 102 (based on information concerning the user interaction obtained either from the environment interaction model 104 or the environment 102, as indicated in FIG. 1A by the dashed line between the environment interaction model 104 and the haptic model 106 and the dashed arrow head entering the haptic model 106 from the environment 102) to cause a haptic display apparatus 105 to produce a corresponding haptic display. The environment interaction model 104 can also cause a non-haptic display apparatus 107 to produce a non-haptic display (e.g., a visual display and/or an audio display). However, there need not necessarily be a non-haptic display (as indicated by the dashed lines between the non-haptic display apparatus 107 and the environment interaction model 104 and user 101).
For example, in a previous haptic interface device used for video browsing and/or editing, a knob can be rotated to advance through the frames of a video recording, a force being applied in opposition to rotation of the knob, to simulate a detent, as transition is made from one video frame to the next. The haptic model in that haptic interface device is a relationship between applied force and position of the knob (which position corresponds to a “position” within the video recording, i.e., whether a transition between video frames is occurring or not). The same haptic display is always provided to the user for any particular user interaction, e.g., a given amount of rotation of the knob always advances the video recording a corresponding number of frames and simulates passing through the corresponding number of detents.
The foregoing is true of many previous haptic interface devices, i.e., the same haptic display is always provided to the user for a particular user interaction (herein, for convenience, such a haptic interface device is said to exhibit “constant” haptic behavior). Such haptic interface devices have not been as versatile as may be desirable.
FIG. 1B is a block diagram of the functional components of a system including a reconfigurable haptic interface device. (The dashed lines and arrow heads in FIG. 1B indicate interactions between components of the system which can, but need not necessarily, occur, depending on the implementation and/or configuration of the system.) In FIG. 1B, a haptic model selection 108 results in the selection of one of two haptic models 106a or 106b for use in producing a haptic display with the haptic display apparatus 105 (i.e., the haptic model selection 108 can be used to reconfigure the haptic interface device). (More than two haptic models can be used; two are shown in FIG. 1B for simplicity.) The haptic model selection 108 may occur, for example, by specifying, before the user 101 begins using the haptic interface device, which haptic model 106a or 106b is to be used in producing the haptic display (e.g., by selecting for execution an appropriate computer program or programs used to implement the haptic model 106a or 106b). The haptic model selection 108 may or may not be made by the user 101 (as indicated by the dashed line between the user 101 and the haptic model selection 108). The haptic models 106a and 106b model different haptic behavior. Thus, unlike the haptic interface device shown in FIG. 1A, in the system shown in FIG. 1B, a particular user interaction can result in different haptic displays, depending on which of the haptic models 106a or 106b is being used to produce the haptic display (i.e., the haptic interface device does not exhibit constant haptic behavior).
In the system shown in FIG. 1B, a haptic interface device that is not constrained by constant haptic behavior (a reconfigurable haptic interface device) is enabled by providing multiple haptic models. There are limitations to such an approach. It may be expensive to develop, construct and/or maintain multiple haptic models. It may be difficult to establish compatibility between each of multiple haptic models and other components of the haptic interface device. It may be difficult or impossible to select a new haptic model during use of the haptic interface device by the user. Even if it is possible for the user to select a new haptic model during use of the haptic interface device, switching from one haptic model to another will result in a discontinuity in the haptic display that may be disconcerting to the user.
It is desirable to provide a haptic interface that is not constrained by constant haptic behavior and that eliminates or ameliorates one or more of the above-indicated limitations.