Computer graphics processing and selective visual display system – Display peripheral interface input device
Reexamination Certificate
2000-05-01
2001-08-14
Liang, Regina (Department: 2674)
Computer graphics processing and selective visual display system
Display peripheral interface input device
C414S005000
Reexamination Certificate
active
06275213
ABSTRACT:
TECHNICAL FIELD
This invention relates to a man-machine interface and in particular to an interface that provides tactile sensation to a user.
BACKGROUND OF THE INVENTION
Virtual reality (VR) is an immersive environment which is created by a computer and with which users have real-time, multisensorial interactions. Typically, these interactions involve some or all of the human senses through either visual feedback, sound, force and tactile feedback (i.e. reflection), smell and even taste. The key to immersive realism is the capacity of the user to use his/her hand to interactively manipulate virtual objects. Unfortunately, the majority of existing commercial virtual reality systems use hand-sensing devices that provide no haptic feedback. Nevertheless, some efforts have been made to provide means for presenting force and tactile information to the user's hand. By force information, it is meant the application of a set force to a selected part of the hand, for example, a finger. By tactile information, it is meant the application of a stimuli, e.g., a vibration, to a selected part of the hand, e.g., a fingertip pad. This stimulus, could simulate surface texture or dynamic conditions at the contact, for example. A few examples of existing force reflecting devices are the EXOS SAFiRE™, the Master II Hand Master device at Rutgers university, the PERCRO Force-Reflecting Hand Master and the Sarcos TOPS Force-Reflecting Hand Master. Some tactile feedback devices that have been developed include the PERCRO Position-Sensing and Tactile Feedback Hand Master and the EXOS TouchMaster™.
Virtual reality is not the only field where it is desirable to feed back force and tactile information to a human user/operator. Another common area is telerobotics. Some of the devices mentioned above are also often used as telerobotics interfaces. Some examples in the literature of feedback devices designed more specifically for telerobotics include the tactile shape sensing and display system developed by Kontarinis et al., the voice-coil based tactile feedback device used by Patrick et al. and the pin-based tactile display array developed by Kaczmarek and Bach-y-rita. Other applications for a vibrotactile unit of the subject invention include, but are not limited to, gesture recognition, music generation, entertainment and medical applications.
In an ideal case, it would be desirable to provide full force and tactile feedback to a user to make the virtual reality or telerobotic experience as realistic as possible. Unfortunately, most force feedback devices are cumbersome, heavy, expensive and difficult to put on and remove. Many of the tactile feedback solutions are also cumbersome, complex and fragile. Additionally, some of the tactile feedback devices described in the literature, such as small voice coils mounted to directly contact the skin, tend to numb the skin after only a few seconds of operation and then become ineffective as feedback devices.
SUMMARY OF THE INVENTION
An object of the invention is a man-machine interface which may be employed in such areas as interactive computer applications, telerobotics, gesture recognition, music generation, entertainment, medical applications and the like. Another object of the invention is a mass which is moved by a “mass-moving actuator” which generates a vibration that a user can feel. Yet another object of the invention is the generation of an activating signal to produce the vibrations either as a result of the user's state or as a result of environmental conditions, whether virtual or physical. Still another object of the invention is vibrating the bone structure of a sensing body part, as well as skin mechanoreceptors, to provide feedback. Yet still another object of the invention is the complex actuation of vibratory devices.
The tactile sensation that a user feels is generated by a vibrotactile unit mounted on, or in functional relation to, a sensing body part of a user by a fastening means. In one embodiment, the vibrotactile device comprises a mass connected eccentrically to a mass-moving actuator shaft (i.e. the center of mass of the mass is offset from the axis of rotation). Energizing the mass-moving actuator causes the shaft to turn, which rotates the eccentric mass. This rotating mass causes a corresponding rotating force vector. A rapidly rotating force vector feels to the user as a vibration. A slowly rotating force vector feels like a series of individual impulses. For a small number of rapid rotations, the rotating force vector feels like a single impulse. We will use the term “vibration” to denote a change in force vector (i.e., direction or magnitude). Examples of vibrations include, but are not limited to a single impulse, a sinusoidal force magnitude, and other functions of the force vector. We use the term “tactile sensation” to refer to the feeling perceived by a user when their sensing body part experiences vibrations induced by a vibrotactile unit.
A signal processor interprets a state signal and produces an activating signal to drive the mass-moving actuator. The variable components of the state signal may be physical (e.g., measured), or virtual (e.g. simulated, or internally generated); they may vary with time (e.g., the state variables may represent processes); and they may be integer-valued (e.g., binary or discrete) or real-valued (e.g., continuous). The signal processor may or may not comprise a computer which interprets and further processes the state signal. The signal processor comprises a signal driver which produces an activating signal supplying power to, or controlling the power drawn by, the vibrotactile unit. The power may be, but is not restricted to, electric, pneumatic, hydraulic, and combustive types. The driver may be, but is not restricted to, an electric motor controller comprising a current amp and sensor for closed loop control, a flow valve controlling the amount of a pressurized fluid or gas, a flow valve controlling the amount of fuel to a combustion engine and the like. The details of such a signal processor and mass-moving actuator are common knowledge to someone skilled in the art.
The state signal may be generated in response to a variety of conditions. In one embodiment, one or more sensors measuring physical conditions of the user and/or the user's environment may generate one or more components of a physical state signal. In another embodiment, a computer simulation may determine the one or more components of a virtual state signal from a simulated (e.g., virtual) state or condition. The virtual state may optionally be influenced by a physical state. The virtual state includes anything that a computer or timing system can generate including, but not restricted to, a fixed time from a previous event; the position, velocity, acceleration (or other dynamic quantity) of one or more virtual objects in a simulation; the collision of two virtual objects in a simulation; the start or finishing of a computer job or process; the setting of a flag by another process or simulation; combinations of situations; and the like. The virtual state signal is a machine-readable measurement of the virtual state variables.
The physical state signal is measured from physical state variables. These variables have relevance to the physical state of a body part of the user or the user's physical environment. The physical state variables includes any measurable parameter in the environment or any measurable parameter relating to a body part of the user. Some examples of measurable physical parameters in an environment include but are not restricted to, the state of a body part, the position of objects in the environment, the amount of energy imparted to an object in the environment, the existence of an object or objects in the environment, the chemical state of an object, the temperature in the environment, and the like. The state of a body part may include the physical position, velocity, or acceleration of the body part relative to another body part or relative to a point in the environment. The stat
Tremblay Mark R.
Yim Mark H.
Liang Regina
Riegel James R.
Virtual Technologies, Inc.
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