Patent Publication Number: US-11656684-B2

Title: Haptic gloves for virtual reality systems and methods of controlling the same

Description:
RELATED APPLICATION 
     This patent arises from a continuation of U.S. application Ser. No. 16/627,606, titled “Haptic Gloves for Virtual Reality Systems and Methods of Controlling the Same,” filed Dec. 30, 2019, which is hereby incorporated by this reference in its entirety. 
    
    
     FIELD OF THE DISCLOSURE 
     This disclosure relates generally to virtual reality systems and, more particularly, to haptic gloves for virtual reality systems and methods of controlling the same. 
     BACKGROUND 
     A virtual reality (VR) environment is a digital representation of an environment (e.g., a real or imaginary environment). A VR environment can be created using audio content and/or visual content. The VR environment can be displayed or presented to a user in any number of ways, for example, via a computer monitor, a virtual reality head-mounted device, speakers, etc. Some VR environments simulate a user&#39;s presence in the environment such that the user can interact with the virtual reality environment. For example, a hand movement such as a user gesture indicative of picking up an object can be reflected in the VR environment. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    illustrates an example virtual reality system utilizing example haptic gloves constructed in accordance with the teachings of this disclosure. 
         FIG.  2    illustrates an example ultrasonic array device that may be implemented in the example haptic gloves of  FIG.  1   . 
         FIG.  3    shows an example focused pressure point created by the example ultrasonic array device of  FIG.  2   . 
         FIG.  4    is a cross-sectional view of a finger section of one of the example haptic gloves of  FIG.  1   . 
         FIG.  5    is cross-sectional view of the finger section of  FIG.  4    taken along line A-A in  FIG.  4   . 
         FIG.  6    is a block diagram of an example control unit having an example haptic controller that may be implemented for controlling at least one of the example haptic gloves of  FIG.  1   . 
         FIG.  7    is a flowchart representative of example machine readable instructions that may be executed to implement the example haptic controller of  FIG.  6   . 
         FIG.  8    illustrates an example processor platform that may execute the example instructions of  FIG.  7    to implement the example haptic controller of  FIG.  6   . 
     
    
    
     The figures are not to scale. Instead, to clarify multiple layers and regions, the thickness of the layers may be enlarged in the drawings. Wherever possible, the same reference numbers will be used throughout the drawing(s) and accompanying written description to refer to the same or like parts. As used in this patent, stating that any part (e.g., a layer, film, area, or plate) is in any way positioned on (e.g., positioned on, located on, disposed on, or formed on, etc.) another part, indicates that the referenced part is either in contact with the other part, or that the referenced part is above the other part with one or more intermediate part(s) located therebetween. Stating that any part is in contact with another part means that there is no intermediate part between the two parts. 
     DETAILED DESCRIPTION 
     A virtual reality (VR) environment is a digital representation of an environment (e.g., a real or imaginary environment). VR systems simulate a VR environment using audio content and/or visual content. The VR environment can be displayed in any number of ways, for example, via a computer monitor, a virtual reality head-mounted device, speakers, etc. Some VR environments simulate a user&#39;s presence in the environment such that the user can interact with the virtual reality environment. Some known VR systems enable a user to interact with the VR environment using a controller, such as a joystick, or a handheld device. However, while known VR systems can provide excellent visual and audio simulation, these known VR systems have not yet provided the sensation of touch. 
     Disclosed herein are example methods, apparatus, systems, and articles of manufacture that provide the sense of touch to a user interacting with a VR environment. The example methods, apparatus, systems, and articles of manufacture may be used to provide touch sensation to a part of a user&#39;s body, such as the user&#39;s hand, for example, to simulate contact of the user&#39;s hand with an object in the VR environment. Disclosed herein are example haptic gloves that may be worn on the hands of a user. The example gloves may be worn while the user experiences the VR environment (e.g., via audio and/or visual content) and interacts with objects in the VR environment using the user&#39;s hands. The haptic gloves generate pressure on different sections of the user&#39;s hands to simulate the feeling of touching the objects in the VR environment. As such, the example gloves provide a realistic sense of touch. 
     An example haptic glove disclosed herein includes an ultrasonic array (referred to herein as an ultrasonic array device or an ultrasonic array chip) disposed on an inner surface of the glove. The ultrasonic array device includes a plurality of ultrasonic generators that are activated to produce ultrasonic waves at substantially the same frequency (e.g., within a tolerance level). The ultrasonic generators create sound waves in the ultrasound level, which is higher than the upper audible limit of human hearing (˜20 kilohertz (kHz)). The ultrasonic waves interact (known as sound interference) to generate a focused pressure point at a particular distance from the ultrasonic array device. The ultrasonic array device is positioned on the inside of the glove and separated from the skin of the hand of the user such that when the ultrasonic array device is activated, the focused pressure point is generated at or near the skin on the hand. For example, the ultrasonic array device may be disposed on an inside of the glove near the tip of the index finger. When the ultrasonic array device is activated, a focused pressure point is created at or near the skin on the tip of the index finger. This focused pressure point replicates the counter-force that would be applied by an object on the tip of the finger, thereby simulating the feeling of touching the object with the tip of the finger. The frequency and/or intensity of the ultrasonic array device can be changed to produce different pressures that can simulate different forces and/or textures or materials. For example, a higher intensity can be used to create a higher pressure, which may simulate a harder, more rigid surface (e.g., metal). Whereas a lower intensity can be used to create a lower pressure, which may simulate a softer surface (e.g., rubber). 
     In some examples, the haptic glove includes a plurality of ultrasonic array devices disposed on the inner surface of the glove. The ultrasonic array devices are positioned at different locations around the inside of the glove and aimed at different sections of the hand. For example, a plurality of ultrasonic array devices may be disposed along the bottom side of the index finger section, along the sides of the index finger section, and/or along the top side of the index finger section. Likewise, ultrasonic array devices can be disposed along the other finger sections, along the palm side of the glove, the back of the hand side of the glove, etc. The ultrasonic array devices can be activated, independently or simultaneously, to simulate touch sensation on different parts of the hand, thus giving a 360° full range experience to the user&#39;s hand. The frequency and/or intensity of the different ultrasonic array devices can be changed to simulate different forces and/or textures. 
     In some examples, the haptic glove includes a control unit that activates or triggers the ultrasonic array device(s). The control unit may be implemented as, for example, an integrated circuit, sometimes referred to as a chip. The control unit may be coupled to (e.g., sewn or embedded in) the material of the glove. In some examples, the control unit includes a power source (e.g., a battery) to power the ultrasonic array device(s) and/or other components of the control unit. In some examples, the control unit includes a haptic controller that determines when to activate one or more of the ultrasonic array device(s) and at what frequency and/or intensity. For example, the haptic controller may determine when the distance between a section of a user&#39;s hand (e.g., a tip of the index finger) and an object in the VR environment is zero or substantially zero. Then, the haptic controller may activate the ultrasonic array device(s) (e.g., by sending an instruction to an ultrasonic array device actuator) corresponding to that section of the glove, thereby creating a focused pressure point on the user&#39;s hand that simulates contact of the user&#39;s hand with the object in the VR environment. 
     In some examples, a camera, such as a real-sense camera, is used to track the location of the user&#39;s hands. Image data collected by the camera can be processed by a processor (e.g., the haptic controller). Additionally or alternatively, one or more motion sensors may be used to detect the location of the user&#39;s hands. In some examples, the motion sensor(s) are wearable. For example, the sensor(s) may be mounted to, worn by, and/or carried on one or more body parts of the user. For instance, the haptic glove can include sensors such as flex sensor(s) to detect bending or flexing of the hand and/or fingers and/or an accelerometer to detect motion of the hand. Data collected by the sensors of the glove can be wirelessly transmitted to a processor for tracking hand motion. 
     The example haptic gloves disclosed herein have many benefits and can be used in numerous applications. For example, assume a user is interacting with a VR zoo of animals. The user may navigate around the zoo to see different animals (e.g., using a VR headset). Using the example gloves, the user can experience the feeling or sensation of touching the animals. In particular, the example gloves can simulate the feeling of touching the animals, which may enable the user to learn about and/or otherwise experience certain characteristics of the animals, such as the animal&#39;s size, weight, strength, hair texture, etc. 
     As another example, a user may be in a VR meeting with one or more other users. The users may view each other as avatars in the VR meeting. With the example gloves, the users can experience the feeling of shaking hands, hugging, and/or engaging in other contact with each other. This sort of haptic feedback builds a better relationship between the users (e.g., by experiencing a strong hand shake, a light hand shake, a high-five, etc.). 
     The example haptic gloves can similarly be used in other applications, such as online shopping, game playing, etc. Further, the haptic gloves may be used to create a feeling for something that does not exist. For example, the haptic gloves may create a touch feeling for each letter of the alphabet. A user can then read, communicate and/or otherwise experience these letters without actually seeing them. As another example, the example haptic gloves may be used to increase the effectiveness of gesture recognition processes, for example, by providing better feedback to the user when using hand gestures. Gesture recognition can also be used to determine when and what kinds of haptic feedback simulate with the gloves. 
       FIG.  1    illustrates an example virtual reality (VR) system  100  utilized by a user  102  to experience a VR environment. The example VR system  100  includes a visualization presenter  104  (e.g., a display screen) that displays a digital representation of the VR environment to the user  102 . In the illustrated example, the visualization presenter  104  is part of a VR headset  106  to be worn on a head  108  of the user  102 . The VR headset  106  may include a headband or other strap member to secure the visualization presenter  104  to the head  108  of the user. In other examples, the visualization presenter  104  may be implemented as another type screen, such as a television monitor, a computer monitor, a smartphone screen, etc. that is separated from the user  102 . In some examples, the VR system  100  includes one or more speakers to provide audio from the VR environment to the user  102 . From example, the VR headset  106  may include one or more speaker(s) to generate the audio content portion of the VR environment. 
     To provide the sense of touch to the user  102 , the example VR system  100  includes a pair of haptic gloves constructed in accordance with the teachings of this disclosure. The pair of haptic gloves includes a first glove  110  to be worn on the user&#39;s right hand (shown in broken lines) and a second glove  112  to be worn on the user&#39;s left hand (shown in broken lines). In some examples, only one of the first glove  110  or the second glove  112  may be used. The first and second gloves  110 ,  112  provide touch feeling to the user&#39;s hands based on the location of the user&#39;s hands and the location(s) of one or more objects in the VR environment. For instance, if the user&#39;s right hand is in contact with an object in the VR environment, the first glove  110  generates a pressure on the skin of the hand of the user  102  that simulates the contact between the user&#39;s right hand and the object. The pressure mimics the feeling of touch and provides a realistic sensation of touching the object. 
     In the illustrated example, the first and second gloves  110 ,  112  are substantially the same. Thus, to avoid redundancy, and for the sake of clarity, many of the examples of this disclosure are described only in connection with the first glove  110 . However, it is understood that these examples may be similarly implemented in connection with the second glove  112 . Thus, any of the features disclosed in connection with the first glove  110  may also be applied to the second glove  112 . 
     In the illustrated example, the first glove  110  includes a control unit  114  (which may be referred to as a control unit chip or a management chip). The control unit  114  receives information from one or more components of the VR system  100  (e.g., the visualization presenter  104 , the camera  116 , etc.) and determines when and/or where to apply pressure on the user&#39;s right hand. The control unit  114  may include a power source (e.g., a battery) and a transceiver. The control unit  114  may be implemented as, for example, an integrated circuit (sometimes referred to as a chip). An example of the control unit  114  is disclosed in further detail in conjunction with  FIG.  6   . In the illustrated example of  FIG.  1   , the control unit  114  is coupled to the first glove  110  on the back side of the hand section. For example, the control unit may be disposed within (e.g., sewn into or otherwise embedded in) the material of the first glove  110 . In some examples, the second glove  112  includes a similar control unit to control the second glove  112 . In some examples, the control unit  114  of the first glove  110  may process information for both the first glove  110  and the second glove  112  and communicate with the second glove  112 . In some examples, the control unit  114  on the first glove  110  includes a processor (e.g., the haptic controller  606  of  FIG.  6   ) that determines, based on information about the VR environment, when to where to apply pressure on the user&#39;s right hand. In other examples, the processor may be remote to the first glove  110 , and the control unit  114  may receive commands or instructions from the processor (disclosed in further detail herein). 
     In some examples, to determine the location of the first glove  110  (and, thus, the user&#39;s right hand) in the VR environment, the example VR system  100  includes a camera  116 . The camera  116  may be, for example, a real-sense camera to sense or detect a position of the user&#39;s hands. In the illustrated example, the camera  116  is carried by the VR headset  106 . The camera  116  obtains image or video data that can be processed to determine the location of the user&#39;s right. In some examples, an image of the user&#39;s right hand is displayed in the VR environment. For example, if the user  102  moves his/her right hand in front of the user&#39;s face, a digital hand may be displayed to the user  102  on the visualization presenter  104 . In some examples, the camera  116  may not be attached to the user  102 . Instead, the camera  116  may be disposed in another location near the user  102  (e.g., in a corner of a room and pointing toward the user  102 ). In some examples, more than one camera is utilized. In some such examples, the camera(s) may generate a collective or aggregate field of view for capturing one or more images (e.g., video) of the hands (and/or other body parts) of the user  102 . In some examples, in addition to or as an alternative to the camera  116 , the example VR system  100  may include one or more position-detecting device(s) to obtain data indicative of position and/or movement of one or more body parts of the user  102 , such as the user&#39;s hands. The position-detecting device(s) may include sensors, such as wearable sensors. The wearable sensor(s) may include, for example, a bend sensor(s), an accelerometer(s), a vibration sensor(s), a gravitational sensor(s), a force sensor(s), etc. and may be positioned to develop signals representative of movement(s) and/or position(s) of a body part on which the sensor is mounted. In some examples, one or more of the sensors are incorporated into the first glove  110 . In some examples, the first glove  110  includes an adjustment member (e.g., a Velcro® strap, an elastic strap, etc.) to tighten the wrist portion of the first glove  110  onto the wrist of the user  102 . In other examples, no adjustment member may be utilized. 
       FIG.  2    illustrates an example ultrasonic array  200 , referred to herein as the ultrasonic array device  200 , that may be utilized in the first glove  110  ( FIG.  1   ) to generate haptic feedback on the right hand of the user  102  ( FIG.  1   ) (e.g., via a pressure point on or near the skin on the right hand). The example ultrasonic array device  200  includes a set of ultrasonic generators  202  (one of which is referenced in  FIG.  2   ) disposed on a substrate  204 . The substrate  204  may be, for example, a circuit board or chip with electrical components (e.g., wires, electrical connections, resistors, etc.) to operate the ultrasonic generators  202 . In the illustrated example, the ultrasonic array device  200  includes nine ultrasonic generators  202 . However, in other examples, the ultrasonic array device  200  may include more or fewer ultrasonic generators  202 . In some examples, the ultrasonic generators  202  are arranged in a pattern, such as a pattern of rows and columns (e.g., a grid or matrix). For example, in the illustrated example of  FIG.  2   , the ultrasonic generators  202  are arranged in a 3×3 grid, spaced equidistant from each other. However, in other examples, the ultrasonic generators may be arranged in other patterns (e.g., 4×4, 5×5, etc.) and may be spaced further from or closer to each other. Further, while in the illustrated example of  FIG.  2    the substrate  204  is substantially flat or planar, in other examples, the substrate  204  may be curved. For example, the substrate  204  may be curved to match the curvature of a section of the hand (e.g., a finger). 
     Each of the ultrasonic generators  202  may be activated (e.g., triggered or excited) to generate an ultrasonic wave. When the ultrasonic generators  202  are activated, the waves generated by the ultrasonic generators  202  interact with each other (sometimes referred to as sound interference). In general, sound waves include a repeating pattern of high-pressure regions (compressions) and low-pressure regions (rarefactions) moving through a medium (e.g., air). When the compressions or rarefactions of two or more waves line up, the waves are strengthened to a higher intensity (known as constructive interference). On the other hand, when the compressions or rarefactions are out of phase, their interaction creates a wave with a dampened or lower intensity (known as destructive interference). At certain distances from the ultrasonic array device  200 , the compressions (e.g., crests or peaks) of the waves align, thereby creating a combined or constructed high-pressure point.  FIG.  3    shows an example of the ultrasonic waves generated by the ultrasonic array device  200 . Each of the ultrasonic generators  202  of the ultrasonic array device  200  are activated at the same frequency. At certain distances from the ultrasonic array device  200 , the compressions of certain ones of the waves align. At a particular distance from the ultrasonic array device  200 , the compression of all of the waves generated by each ultrasonic generators  202  are incident on a same point and the compressions combine to create a focused pressure point  300 . At the focused pressure point  300 , a resultant amplitude is formed that is equal to the vector sum of the amplitudes of the individual waves. By operating the ultrasonic generators  202  at the same frequency, the location of the construct interference remains the same. As will be disclosed in further detail herein, the ultrasonic array device  200  may be positioned to generate the focused pressure point  300  at or near the skin of the user  102  ( FIG.  1   ) to simulate or mimic the feeling of touch. 
     The location of the focused pressure point  300  is dependent on the frequency of the ultrasonic generators  202  (as well as the spatial arrangement of the ultrasonic generators  202 ). Thus, the frequency of the ultrasonic generators  202  may be changed to move the focused pressure point  300  closer to or further from the ultrasonic array device  200 . In general, the focused pressure point  300  is at least one wavelength away from the ultrasonic array device  200 . For example, at 20 kHz, the focused pressure point  300  may be about 17 millimeters (mm) from the ultrasonic array device  200 . This distance may be determined using the following equation: λ=c/f, where λ is wavelength, c is wave speed, and f is frequency. With a frequency f of 20 kHz and a wave speed c of 300 meters/s (m/s), the wave length λ is about 17 mm. At 200 kHz, for example, the focused pressure point may be about 1.7 mm from the ultrasonic array device  200 . Therefore, if the ultrasonic generators  202  are operable between 20 kHz and 200 kHz, for example, then the ultrasonic array device  200  should be spaced apart from the skin of the hand by at least about 1.7 mm. In some examples, the frequency may be higher and, thus, the needed spacing may be even lower than 1.7 mm. Thus, the focused pressured point  300  can be changed by changing the frequency of the ultrasonic waves. The ultrasonic generators  202  may be activated at different frequencies (of about 20 kHz and above) depending on the desired distance to create the focused pressure point  300 . 
     In some examples, the standard operating frequency is about 40 kHz, which has a wavelength of about 8.5 mm from the ultrasonic array device  200 . The focal distance and diameter ratio of the ultrasonic array device  200  may be about 0.65-0.85, which corresponds to a diameter of about 6.5-17 mm. If the frequency is at 40 kHz and the focal distance is 10 mm (larger than 8.5 mm), for example, then the diameter is 10/(0.65-0.85)=about 12-15 mm. 
     Further, the intensity (amplitude) of the ultrasonic waves can be increased or decreased (e.g., by increasing or decreasing the electrical signal to the ultrasonic generators  202 ) to increase or decrease the pressure at the focused pressure point  300 . In some examples, even a pressure of 0.1 Pascal (Pa) (0.00102 grams per square centimeter (g/cm 2 )) can be felt on the skin of a human and, thus, is sufficient to obtain haptic feeling. In other examples, the pressure generated at the focused pressure point  300  may be higher or lower. In some examples, the ultrasonic array device  200  generates a pressure of about 1.8 g/cm 2  to about 10 g/cm 2 . 
       FIG.  4    is a cross-sectional view of a finger section  400  of the first glove  110 . In the illustrated example, the first glove  110  includes a first layer  402  (e.g., an outer layer) and a plurality of the ultrasonic array devices  200   a - 200   n  coupled to an inner surface  404  of the first layer  402 . The first layer  402  may be constructed of, for example, cloth (e.g., cotton), knitted or felted wool, leather, rubber, latex, neoprene, chain-mesh, and/or any other material capable of being worn as a glove and supporting one or more ultrasonic array devices. In some examples, the first layer  402  may be relatively rigid to maintain a substantially cylindrical shape. In other examples, the first layer  402  may be relatively flexible to may bend or curve more with movement of the finger. 
     In the illustrated example, the ultrasonic array devices  200   a - 200   n  are disposed along the inner surface  404  of the first layer  402  and pointed inwardly, toward the skin of the user&#39;s finger. The ultrasonic array devices  200   a - 200   n  may be substantially the same as the ultrasonic array device  200  depicted in  FIGS.  2  and  3   . Each of the ultrasonic array devices  200   a - 200   n  may have the same or a different number of ultrasonic generators, which may be arranged in various patterns. In the illustrated example of  FIG.  4   , twelve (12) ultrasonic array devices  200   a - 2001  are depicted as being disposed along a top and a bottom side of the finger section  400 . In other examples, the finger section  400  may include more or fewer ultrasonic array devices and/or the ultrasonic array devices may be disposed in other locations and/or spaced differently. The ultrasonic array devices  200   a - 200   n  may also be disposed around the sides of the finger. For example,  FIG.  5    illustrates a cross-sectional view of the finger section  400  taken along line A-A in  FIG.  4   . As shown in  FIG.  5   , six (6) ultrasonic array devices  200   e ,  200   h ,  200   m ,  200   n ,  200   o ,  200   p  are disposed around the circumference of the finger section  400  at the cross-section. In other examples, more or fewer ones of the ultrasonic array devices  200   a - 200   n  may be disposed around the circumference of the finger section  400  and/or spaced differently. Likewise, a plurality of the ultrasonic array devices  200   a - 200   n  may be distributed around the circumference of the finger section  400  at other cross-sections of the finger section  400 . In the illustrated example, the ultrasonic array devices  200   a - 200   n  are curved to match the curvature of the user&#39;s finger. However, in other examples, the ultrasonic array devices  200   a - 200   n  may be substantially flat or planar (e.g., similar to the ultrasonic array device  200  depicted in  FIG.  2   ). 
     Depending on where the touch sensation is to be applied, one or more of the ultrasonic array devices  200   a - 200   n  may be activated to generate haptic feedback on different section of the user&#39;s hand (e.g., by producing pressure at or near the skin of the user&#39;s hand). For example, if the bottom side of the user&#39;s finger is in virtual contact with an object in the VR environment, the ultrasonic array devices  200   a - 200   f , which are along the bottom side of the user&#39;s finger, can be activated to create focused pressure points along the bottom side of the user&#39;s finger, thereby simulating contact with the object in the VR environment. Each of the ultrasonic array devices  200   a - 200   n  corresponds to a particular section of the first glove  110  and, thus, the associated section of the user&#39;s hand. In some examples, only one of the ultrasonic array devices  200   a - 200   n  is activated. In other examples, multiple ones of the ultrasonic array devices  200   a - 200   n  are activated. 
     As described above in connection with  FIGS.  2  and  3   , each of the ultrasonic array devices  200   a - 200   n  produces a focused pressure point at a certain distance from the respective ultrasonic array device  200   a - 200   n . Therefore, the ultrasonic array devices  200   a - 200   n  are to be spaced apart from the skin of the user&#39;s hand. In some examples, the ultrasonic array devices  200   a - 200   n  are to be separated from the skin at least about 1.7 mm (e.g., for operating at 200 kHz). In other examples, the ultrasonic array devices  200   a - 200   n  may be spaced closer to or further from the skin based on the intended frequency to be applied. 
     To separate the ultrasonic array devices  200   a - 200   n  from the user&#39;s hand, the example first glove  110  may include one or more spacers (e.g., a rib, a web, etc.). For instance, in the illustrated example of  FIG.  4   , the finger section  400  includes a first spacer  406  and a second spacer  408 . The first and second spacers  406 ,  408  are coupled to the inner surface  404  of the first layer  402  and extend inwardly toward the finger. As the finger bends and/or moves, the spacers  406 ,  408  are moved in the same direction to maintain the first layer  402  (and, thus, the ultrasonic array devices  200   a - 200   n ) separated from the skin of the finger. Thus, a substantially constant gap or space is maintained between the ultrasonic array devices  200   a - 200   n  and the skin of the finger. In some examples, the first and second spacers  406 ,  408  are rings that extend around the user&#39;s finger. In other examples, the first and second spacers  406 ,  408  may be formed of one or more individual members that extend inward from the first layer  402  (e.g., similar to spokes on a wheel). In the illustrated example of  FIG.  4   , the first spacer  406  is positioned near one knuckle (e.g., a joint) of the finger and the second spacer  408  is positioned near the other knuckle of the finger. In other examples, the first spacer  406  and/or the second spacer  408  may be disposed in other locations. Also, while in the illustrated example two example spacers  406 ,  408  are implemented, in other examples, the finger section  400  may include more (e.g., three, four, etc.) or fewer (e.g., one) spacers in the finger section  400 . 
     In some examples, the first glove  110  includes a second layer  410  (e.g., an inner layer) that is disposed within and separated from the first layer  402 . The second layer  410  may be relatively tight and sticks to the hand of the user  102 . For example, the second layer  410  may be constructed of a latex material that substantially conforms to the shape of the hand. In other examples, the second layer  410  may be constructed of other types of materials. The first and second spacers  406 ,  408  may be coupled between the first layer  402  and the second layer  410 . As such, when the user moves his/her hand, the first layer  402  (and, thus, the ultrasonic array devices  200   a - 200   n ) remain separated (distanced) from the second layer  410  and, thus, the skin of the user. The ultrasonic array devices  200   a - 200   n  may be spaced apart from the second layer  410  and/or operated at a particular frequency that produces a focused pressure point at or near the second layer  410 , which can be felt against the skin of the hand that is in contact with the second layer  410 . 
     In some examples, one or more wires and/or other electrical connectors are coupled to (e.g., embedded in) the first layer  402 . The wires and/or other electrical connectors electrically couple the ultrasonic array devices  200   a - 200   n  to the control unit  114  ( FIG.  1   ), which may be coupled to the first glove  110  near a back side of the hand. The control unit  114  may activate one or more of the ultrasonic array devices  200   a - 200   n  by providing an electrical signal (e.g., an alternating signal at an ultrasonic frequency) to the ultrasonic array device(s)  200   a - 200   n . The control unit  114  may control the frequency and/or intensity of the ultrasonic wave(s) produced by the ultrasonic array device(s)  200   a - 200   n . In particular, the control unit  114  may activate the ultrasonic array devices  200 - 200   n  at particular frequencies and/or intensities to generate the desired focused pressure point on the skin of the user. In some examples, each of the ultrasonic array devices  200   a - 200   n  is spaced the same distance from the skin of the user. In other examples, the ultrasonic array devices  200   a - 200   n  may be spaced differently. In some examples, two or more ultrasonic array devices may be combined into a group and separated from the skin of the user by different distances. For example, three ultrasonic array devices may be stacked on top of each other. The ultrasonic array devices may be slightly offset or include openings to allow the waves of the lower ultrasonic array devices (the ultrasonic array devices further from the hand) to pass through. The ultrasonic array devices of the group can be activated simultaneously or independently to simulate different feelings on the particular section of the skin of the user. 
     While only one finger section of the first glove  110  is illustrated in  FIG.  4   , one or more other sections of the first glove  110  may include a similar arrangement of the ultrasonic array devices  200   a - 200   n . In particular, one or more of the ultrasonic array devices  200   a - 200   n  may be similarly disposed along the inner surface  404  of the first glove  110  and used to create pressure on different sections of the user&#39;s hand. For example, each finger section of the first glove  110  may be similar to the finger section  400 . The finger sections may include the same or different numbers of ultrasonic array devices, and the ultrasonic array devices may be disposed in various locations around the respective fingers. Additionally or alternatively, ultrasonic array devices may be similarly disposed along the inner surface  404  of the first glove  110  along the back of the hand section and/or the palm section. Thus, ultrasonic array devices can be disposed all around the skin of the hand to provide a 360° touch experience. 
     While in the illustrated example of  FIG.  4    a plurality of ultrasonic array devices are implemented in the finger section  400  of the first glove  110 , in other examples, the finger section  400  may include only one ultrasonic array device. For example, one ultrasonic array device may be positioned near the bottom side of the finger. In some examples each finger section of the first glove  110  includes one ultrasonic array device, which may provide touch sensation to just the tips of the fingers, for example. In other examples, any of the finger sections, the back section, and/or the palm section of the first glove  110  may include any number of ultrasonic array devices. 
     Also, while in the illustrated example of  FIG.  1    the first glove  110  covers the entire right hand, in other examples, the example first glove  110  may be implemented as covering to be worn around just a portion of a hand of a user. For example, an individual finger sleeve, similar to the finger section  400  of  FIG.  4   , may be worn on one finger of the user  102 . In some examples, individual finger sleeves may be disposed on each of the fingers. In such an example, no ultrasonic array devices are used on the back and palm sections of the hand. 
     Further, while the example first glove  110  is described as being disposed on a hand of a user, the example structures disclosed in connection with the first glove  110  may be similarly implemented in other types of garments, such as a shirt, a pair of pants, a hat, etc. For example, a shirt may include a plurality of ultrasonic array devices coupled to an inner surface of the shirt and aimed toward different sections of the user&#39;s body. Similar to the example first glove  110 , the ultrasonic array device(s) on the shirt can be activated to create pressure at or near the skin of the user to simulate touch between the user&#39;s body and one or more object(s) in the VR environment. 
       FIG.  6    is a block representation of the example control unit  114  that may be used for controlling the first glove  110 . In the illustrated example, the control unit  114  includes an ultrasonic array actuator  600  (e.g., a controller), referred to herein as the ultrasonic device actuator  600 , which controls the activation of the ultrasonic array device(s)  200   a - 200   n  (e.g., via one or more control signals). The example control unit  114  also includes a battery  602 . The battery  602  supplies power to the component(s) of the control unit  114  and to the ultrasonic array device(s)  200   a - 200   n . In some examples, the battery  602  may be recharged by connecting a cord or wire to the battery  602 . In other examples, the battery  602  may be removed from the first glove  110  and recharged separately, away from the first glove  110 . The ultrasonic device actuator  600  may selectively supply power (at a particular intensity and/or frequency) to the ultrasonic array device(s)  200   a - 200   n  to generate the desired ultrasonic waves. 
     To communicate with the visualization presenter  104 , the camera  116 , and/or other component(s) of the VR system  100  ( FIG.  1   ), the example control unit  114  includes a wireless transceiver  604 , which operates as a receiver and a transmitter. The transceiver  604  may be, for example, a Bluetooth® transceiver. In other examples, other types of wireless transceivers may be implemented. Additionally or alternatively, a communication line (e.g., a wire, a cord, etc.) may be physically coupled between the control unit  114 , the visualization presenter  104 , the camera  116  and/or any other component of the VR system  100 . 
     In the illustrated example, the control unit  114  includes an example haptic controller  606  that determines when and/or which one(s) of the ultrasonic array devices  200   a - 200   n  to activate. In the illustrated example, the haptic controller  606  includes an object location determiner  608 , a hand location determiner  610 , a distance calculator  612 , an ultrasonic array device (UAD) selector  614 , a frequency/intensity determiner  616  and a memory  618 . In the illustrated example, the object location determiner  608  of the example haptic controller  606  determines the location(s) of one or more objects in the VR environment. The location(s) may include the coordinates or boundaries of the surface(s), edge(s), etc. of the respective object(s). In some examples, the object location determiner  608  determines the location of the one more objects based on VR environment data received via the transceiver  604 . The VR environment data may include information relating to the layout of the VR environment, the user&#39;s current position in the VR environment, the type of object(s) in the VR environment, the location(s) of the object(s) in the VR environment, what VR scene is being displayed to the user  102 , etc. In some examples, the VR environment data is transmitted from the visualization presenter  104  or the VR headset  106  to the control unit  114 . In other examples, a separate processor or module may transmit the VR environment data to the control unit  114  and/or other components of the VR system  100 . 
     The hand location determiner  610  of the example haptic controller  606  determines the location one or both of the user&#39;s hands in the VR environment. To avoid redundancy, only the right hand is described below. In some examples, the hand location determiner  610  determines the location of the right hand by determining a location of the first glove  110 . In some examples, the hand location determiner  610  receives image or video information from the camera  116  and determines the location, orientation, etc. of the first glove  110  (and/or the user&#39;s hand) in the VR environment based on the information from the camera  116 . Additionally or alternatively, one or more motion sensors may be coupled to the first glove  110  to detect movements and/or other information about the location of the first glove  110 . The information may be transmitted to the control unit  114  (and received via the transceiver  604 ), and the hand location determiner  610  may determine the location of the first glove  110  based on the information. In some examples, the first glove  110  ( FIG.  1   ) is divided into a plurality of discrete sections, such as a bottom tip of each finger, a bottom middle section of each finger, a top tip of each finger, etc., and one or more of the ultrasonic array devices  200   a - 200   n  may associated with each of the sections. The location of each of the sections and the corresponding ultrasonic array devices  200   a - 200   n  may be stored in the memory  618  (e.g., a first ultrasonic array device is associated with the bottom tip of the index finger, a second ultrasonic array device is associated with the bottom tip of the middle finger, etc.). In some examples, the hand location determiner  610  determines the location of the different sections of the first glove  110  in the VR environment, which may be used to determine which of the ultrasonic array devices  200   a - 200   n  to activate (as discussed in further detail herein). 
     In the illustrated example, the distance calculator  612  calculates distances between the locations of the different sections of the first glove  110  (and/or the right hand), as determined by the hand location determiner  610 , and the locations (e.g., boundaries) of the one or more objects in the VR environment, as determined by the object location determiner  608 . If a distance is zero or substantially zero (e.g., within a tolerance of zero) between a section of the first glove  110  and the location of an object in the VR environment, the user&#39;s hand or a section/part of the user&#39;s hand is in virtual contact with the object in the VR environment. In such an instance, the UAD selector  614  determines which one(s) of the ultrasonic array device(s)  200   a - 200   n  that correspond to the section of the first glove  110  or the hand that is in virtual contact with the object and sends an instruction to the ultrasonic device actuator  600  to activate the associated one(s) of the ultrasonic array device(s)  200   a - 200   n . In some examples, the distance calculator  612  continues calculating and recalculating the distances between the different sections of the first glove  110  and the objects in the VR environment based on updated location information about the right hand. If the distance(s) is no longer zero or substantially zero (e.g., because the user  102  move the right hand away from the object), the UAD selector  614  sends an instruction to the ultrasonic device actuator  600  to cease activation of the associated ultrasonic array devices  200   a - 200   n . This process may be repeated constantly during the VR session. 
     In some examples, the frequency and/or intensity of the ultrasonic waves may be varied to create different haptic effects. In the illustrated example, the frequency/intensity determiner  616  of the example haptic controller  606  may determine the frequency and/or intensity at which to activate the ultrasonic array device(s)  200   a - 200   n  based on the desired pressure and/or texture to be applied. For example, by activating the ultrasonic array device(s)  200   a - 200   n  at a higher intensity (amplitude) (e.g., with a stronger electrical signal), the focused pressure point has a higher pressure, which simulates a greater force on the skin of the user&#39;s hand. Also, the frequency can be changed to move the location of the focused pressure point. Moving the focused pressure point closer to or further from the skin of the user may also create different feelings on the skin of the user  102 , which may be used to mimic different textures (e.g., wood, water, glass, sand, hair, etc.). In some examples, a table of textures and the corresponding frequencies/intensities is stored in the memory  618 . The frequency/intensity determiner  616  may select a certain frequency and/or intensity based on the desired pressure or texture to be replicated. 
     While in the illustrated example of  FIG.  6    the haptic controller  606  is depicted as part of the control unit  114  (e.g., integrated into the first glove  110 ), in other examples, the haptic controller  606  may be integrated in other components of the VR system  100 . For example, the haptic controller  606  may be incorporated into the VR headset  106 . In such an example, the haptic controller  606  may transmit one or more signals to the control unit  114  indicating which ones of the ultrasonic array device(s)  200   a - 200   n  to activate, when to activate the corresponding ultrasonic array device(s)  200   a - 200   n , the frequency and/or intensity to activate the corresponding ultrasonic array device(s)  200   a - 200   n , etc. 
     While an example manner of implementing the haptic controller  606  is illustrated in  FIG.  6   , one or more of the elements, processes and/or devices illustrated in  FIG.  6    may be combined, divided, re-arranged, omitted, eliminated and/or implemented in any other way. Further, the example object location determiner  608 , the example hand location determiner  610 , the example distance calculator  612 , the example UAD selector  614 , the example frequency/intensity determiner  616 , the example memory  618  and/or, more generally, the example haptic controller  606  of  FIG.  6    may be implemented by hardware, software, firmware and/or any combination of hardware, software and/or firmware. Thus, for example, any of the example object location determiner  608 , the example hand location determiner  610 , the example distance calculator  612 , the example UAD selector  614 , the example frequency/intensity determiner  616 , the example memory  618  and/or, more generally, the example haptic controller  606  could be implemented by one or more analog or digital circuit(s), logic circuits, programmable processor(s), application specific integrated circuit(s) (ASIC(s)), programmable logic device(s) (PLD(s)) and/or field programmable logic device(s) (FPLD(s)). When reading any of the apparatus or system claims of this patent to cover a purely software and/or firmware implementation, at least one of the example object location determiner  608 , the example hand location determiner  610 , the example distance calculator  612 , the example UAD selector  614 , the example frequency/intensity determiner  616 , and/or the example memory  618  is/are hereby expressly defined to include a tangible computer readable storage device or storage disk such as a memory, a digital versatile disk (DVD), a compact disk (CD), a Blu-ray disk, etc. storing the software and/or firmware. Further still, the example haptic controller  606  of  FIG.  6    may include one or more elements, processes and/or devices in addition to, or instead of, those illustrated in  FIG.  6   , and/or may include more than one of any or all of the illustrated elements, processes and devices. 
     A flowchart representative of example machine readable instructions for implementing the example haptic controller  606  of  FIG.  6    is shown in  FIG.  7   . In this example, the machine readable instructions comprise a program for execution by a processor such as the processor  812  shown in the example processor platform  800  discussed below in connection with  FIG.  8   . The program may be embodied in software stored on a tangible computer readable storage medium such as a CD-ROM, a floppy disk, a hard drive, a digital versatile disk (DVD), a Blu-ray disk, or a memory associated with the processor  812 , but the entire program and/or parts thereof could alternatively be executed by a device other than the processor  812  and/or embodied in firmware or dedicated hardware. Further, although the example program is described with reference to the flowchart illustrated in  FIG.  8   , many other methods of implementing the example haptic controller  606  may alternatively be used. For example, the order of execution of the blocks may be changed, and/or some of the blocks described may be changed, eliminated, or combined. Additionally or alternatively, any or all of the blocks may be implemented by one or more hardware circuits (e.g., discrete and/or integrated analog and/or digital circuitry, a Field Programmable Gate Array (FPGA), an Application Specific Integrated circuit (ASIC), a comparator, an operational-amplifier (op-amp), a logic circuit, etc.) structured to perform the corresponding operation without executing software or firmware. 
     As mentioned above, the example process of  FIG.  7    may be implemented using coded instructions (e.g., computer and/or machine readable instructions) stored on a non-transitory computer and/or machine readable medium such as a hard disk drive, a flash memory, a read-only memory, a compact disk, a digital versatile disk, a cache, a random-access memory and/or any other storage device or storage disk in which information is stored for any duration (e.g., for extended time periods, permanently, for brief instances, for temporarily buffering, and/or for caching of the information). As used herein, the term non-transitory computer readable medium is expressly defined to include any type of computer readable storage device and/or storage disk and to exclude propagating signals and to exclude transmission media. “Including” and “comprising” (and all forms and tenses thereof) are used herein to be open ended terms. Thus, whenever a claim lists anything following any form of “include” or “comprise” (e.g., comprises, includes, comprising, including, etc.), it is to be understood that additional elements, terms, etc. may be present without falling outside the scope of the corresponding claim. As used herein, when the phrase “at least” is used as the transition term in a preamble of a claim, it is open-ended in the same manner as the term “comprising” and “including” are open ended. 
       FIG.  7    is a flowchart  700  representative of example machine readable instructions that may be executed by the example haptic controller  606  of  FIG.  6   . At block  702 , the example object location determiner  608  determines a location of an object in the VR environment. Therefore, the object location determiner  608  provides means for determining a location of an object in a virtual reality environment. In some examples, the location may be defined by the coordinates of the surface(s), edge(s), etc. that define the object in the 3D space of the VR environment. In some examples, the object location determiner  608  determiners the location of the object based on VR environment data transmitted by the visualization presenter  104  and/or another component of the VR system  100 . 
     At block  704 , the example hand location determiner  610  determines the location of the first glove  110  (which substantially corresponds to the location of the right hand) in the VR environment. In some examples, the hand location determiner  610  determines the location of the first glove  110  based on image or video data from the camera  116 . Additionally or alternatively, one or more motion sensors (e.g., a wearable sensor mounted to the first glove  110 ) may be used to detect the location of the first glove  110 . In some examples, the hand location determiner  610  determines the location of the different sections or parts of the first glove  110  (e.g., the palm section, the back of the hand section, top and/or bottom sides of the thumb section, the index finger section, the middle finger section, the ring finger section, and/or the pinky finger section, etc.). Therefore, the hand location determiner  610  provides means for determining a location of a section of the first glove  110  in the virtual reality environment. 
     At block  706 , the example distance calculator  612  calculates the distance(s) between the location of the object (e.g., coordinates of the surfaces or boundaries that define the object) and the location(s) of one or more section(s) of the first glove  110  in the VR environment. Therefore, the example distance calculator  612  provides means for calculating a distance between a location of a section of a glove and a location of an object in the virtual reality environment. At block  708 , the example distance calculator  612  determines if any of the distances are zero or substantially zero (e.g., within a threshold, such as 2 mm). 
     If the distance between one or more of the sections of the first glove  110  and the object is zero or substantially zero, the example UAD selector  614 , at block  710 , selects or identifies the one or more of the ultrasonic array devices  200   a - 200   n  that correspond to the associated section(s) of the first glove  110 . Therefore, the UAD selector  614  provides means for selecting one or more of the ultrasonic array devices  200   a - 200   n  to activate. At block  712 , the frequency/intensity determiner  616  determines a frequency and/or an intensity at which to activate each of the selected ultrasonic array device(s)  200   a - 200   n . Therefore, the frequency/intensity determiner  616  provides means for determining at least one of a frequency or an intensity at which to activate an ultrasonic array device. In some examples, each of the selected ultrasonic array device(s)  200   a - 200   n  is to be activated at the same frequency and intensity. In other examples, the selected ultrasonic array device(s)  200   a - 200   n  are to be activated a different frequencies and/or intensities than each other. At block  714 , the UAD selector  614  instructs the ultrasonic device actuator  600  to activate the selected ultrasonic array device(s)  200   a - 200   n  at the determined frequencies and/or intensities. The activated ultrasonic array device(s)  200   a - 200   n  generate focused pressure points at or near the skin on the hand of the user that simulates contact with the object in the VR environment. Therefore, the UAD selector  614  and/or the ultrasonic device actuator  600  provide means for activating an ultrasonic array device when the calculated distance is zero or substantially zero (e.g., within a threshold). 
     At block  716 , the distance calculator  612  recalculates the distances between the section(s) of the first glove  110  and the location of the object (e.g., based on updated location data of the first glove  110 ) to determine if the distances between the section(s) of the first glove  110  and the object has/have increased (or is/are no longer zero or substantially zero). An increased distance indicates the corresponding section of the first glove  110  (and, thus, the user&#39;s right hand) is no longer in virtual contact with the object in the VR environment. If the distance has not changed (i.e., is still zero or substantially zero), the ultrasonic device actuator  600  continues to activate the selected ultrasonic array device(s)  200   a - 200   n . Otherwise, if the distance has increased (and is no longer zero or substantially zero), at block  718 , the UAD selector  614  instructs the ultrasonic device actuator  600  to cease activation of the selected ultrasonic array device(s)  200   a - 200   n.    
     At block  720 , the haptic controller  606  determines whether the VR session has ended (e.g., by user interaction with an on/off switch). If the VR session has not ended, control returns to block  702  and the example process of  FIG.  7    repeats again. The example process of  FIG.  7    may be performed for the same object and/or a different object in the VR environment. In some examples, the process of  FIG.  7    is performed simultaneously for multiple objects in the VR environment. For example, the haptic controller  606  may continuously check the distances between the different sections of the user&#39;s hands and the location of the different objects in the VR environment. Otherwise, if the VR session has ended, the example process of  FIG.  7    ends. 
       FIG.  8    is a block diagram of an example processor platform  800  capable of executing the instructions of  FIG.  7    to implement the haptic controller  606  of  FIG.  6   . The processor platform  800  can be, for example, an embedded processing device, a server, a personal computer, a mobile device (e.g., a cell phone, a smart phone, a tablet such as an iPad™), a personal digital assistant (PDA), an Internet appliance, a DVD player, a CD player, a digital video recorder, a Blu-ray player, a gaming console, a personal video recorder, a set top box, or any other type of computing device. 
     The processor platform  800  of the illustrated example includes a processor  812 . The processor  812  of the illustrated example is hardware. For example, the processor  812  can be implemented by one or more integrated circuits, logic circuits, microprocessors or controllers from any desired family or manufacturer. The hardware processor may be a semiconductor based (e.g., silicon based) device. In this example, the processor  812  may implement the example object location determiner  608 , the example hand location determiner  610 , the example distance calculator  612 , the example UAD selector  614 , the example frequency/intensity determiner  616 , and/or, more generally, the example haptic controller  606 . 
     The processor  812  of the illustrated example includes a local memory  813  (e.g., a cache). The processor  812  of the illustrated example is in communication with a main memory including a volatile memory  814  and a non-volatile memory  816  via a bus  818 . The volatile memory  814  may be implemented by Synchronous Dynamic Random Access Memory (SDRAM), Dynamic Random Access Memory (DRAM), RAMBUS Dynamic Random Access Memory (RDRAM) and/or any other type of random access memory device. The non-volatile memory  816  may be implemented by flash memory and/or any other desired type of memory device. Access to the main memory  814 ,  816  is controlled by a memory controller. 
     The processor platform  800  of the illustrated example also includes an interface circuit  820 . The interface circuit  820  may be implemented by any type of interface standard, such as an Ethernet interface, a universal serial bus (USB), and/or a PCI express interface. 
     In the illustrated example, one or more input devices  822  are connected to the interface circuit  820 . The input device(s)  822  permit(s) a user to enter data and commands into the processor  812 . The input device(s) can be implemented by, for example, an audio sensor, a microphone, a camera (still or video), a keyboard, a button, a mouse, a touchscreen, a track-pad, a trackball, isopoint and/or a voice recognition system. In this example, the input device(s) may include the visualization presenter  104 , the camera  116 , and/or other components of the VR system  100 . 
     One or more output devices  824  are also connected to the interface circuit  820  of the illustrated example. The output device(s)  824  can be implemented, for example, by display devices (e.g., a light emitting diode (LED), an organic light emitting diode (OLED), a liquid crystal display, a cathode ray tube display (CRT), a touchscreen, a tactile output device, a printer and/or speakers). The interface circuit  820  of the illustrated example, thus, typically includes a graphics driver card, a graphics driver chip or a graphics driver processor. In this example, the output device(s)  824  may include the ultrasonic device actuator  600  and/or the ultrasonic array devices  200   a - 200   n.    
     The interface circuit  820  of the illustrated example also includes a communication device such as a transmitter, a receiver, a transceiver, a modem and/or network interface card to facilitate exchange of data with external machines (e.g., computing devices of any kind) via a network  826  (e.g., an Ethernet connection, a digital subscriber line (DSL), a telephone line, coaxial cable, a cellular telephone system, etc.). 
     The processor platform  800  of the illustrated example also includes one or more mass storage devices  828  for storing software and/or data. Examples of such mass storage devices  828  include floppy disk drives, hard drive disks, compact disk drives, Blu-ray disk drives, RAID systems, and digital versatile disk (DVD) drives. The mass storage device(s)  828  may implement the memory  618 . 
     Coded instructions  832  of  FIG.  7    may be stored in the mass storage device  828 , in the volatile memory  814 , in the non-volatile memory  816 , and/or on a removable tangible computer readable storage medium such as a CD or DVD. 
     From the foregoing, it will be appreciated that methods, apparatus, systems, and articles of manufacture have been disclosed herein to provide touch sensation to a user interacting with a VR environment. Disclosed examples utilize one or more ultrasonic array devices disposed in a glove or other covering (e.g., a garment) to create focused pressure points on the skin of the user that mimic or simulate the feeling of touching an object in a VR environment. Thus, disclosed examples provide more realistic interaction with objects in a VR environment than known VR systems. Further, the example gloves disclosed herein are portable and can be easily transported and used at any time or place. 
     Example methods, apparatus, systems, and articles of manufacture to provide haptic feedback to a user are disclosed herein. Further examples and combinations thereof include the following: 
     Example 1 includes an apparatus including a glove to be worn on a hand of a user, an ultrasonic array disposed on an inner surface of the glove, and a control unit to activate the ultrasonic array to generate haptic feedback on the hand of the user. 
     Example 2 includes the apparatus of Example 1, wherein the ultrasonic array includes a substrate and a plurality of ultrasonic generators disposed on the substrate. 
     Example 3 includes the apparatus of Example 2, wherein the plurality of ultrasonic generators are arranged in a pattern of rows and columns on the substrate. 
     Example 4 includes the apparatus of Example 2, wherein the control unit is to activate the plurality of ultrasonic generators at substantially a same frequency. 
     Example 5 includes the apparatus of Example 1, wherein the glove includes an outer layer and an inner layer, the inner layer to be in contact with the hand, the outer layer to be spaced apart from and surrounding the inner layer, the inner surface of the glove corresponding to an inner surface of the outer layer, and the ultrasonic array coupled to the inner surface of the outer layer and facing the inner layer. 
     Example 6 includes the apparatus of Example 5, wherein the glove includes a spacer between the inner layer and the outer layer to separate the outer layer from the inner layer. 
     Example 7 includes the apparatus of Example 1, wherein the ultrasonic array is disposed in a finger section of the glove. 
     Example 8 includes the apparatus of Example 1, wherein the control unit is coupled to the glove near a back side of the hand. 
     Example 9 includes the apparatus of Example 1, wherein the control unit includes a power source to power the ultrasonic array. 
     Example 10 includes the apparatus of Example 1, wherein the control unit includes a transceiver to receive information about a virtual reality environment experienced by the user. 
     Example 11 includes the apparatus of Example 1, further including a plurality of ultrasonic arrays disposed on the inner surface of the glove, the plurality of ultrasonic arrays to generate haptic feedback on different sections of the hand. 
     Example 12 includes the apparatus of any of Examples 1-11, wherein the ultrasonic array is to generate haptic feedback by generating a focused pressure point at or near skin on the hand of the user. 
     Example 13 includes an apparatus including a covering to be worn around at least a portion of a hand of a user and a plurality of ultrasonic arrays disposed on an inner surface of the covering. The plurality of ultrasonic arrays are to create focused pressure points at or near different sections of the hand of the user. 
     Example 14 includes the apparatus of Example 13, further including a control unit to selectively activate one or more of the plurality of ultrasonic arrays. 
     Example 15 includes the apparatus of any of Examples 13 or 14, further including a spacer coupled to the inner surface of the covering, the spacer to separate the covering from the hand of the user. 
     Example 16 includes a virtual reality system including a headset to be worn by a user, the headset having a visualization presenter to display a virtual reality environment to the user, and a glove to be worn on a hand of the user. The glove includes an ultrasonic array to generate a pressure on the hand of the user to simulate contact with an object in the virtual reality environment. 
     Example 17 includes the virtual reality system of Example 16, further including a haptic controller to determine a distance between a location of the object in the virtual reality environment and a location of the glove in the virtual reality environment. 
     Example 18 includes the virtual reality system of Example 17, wherein the glove includes an ultrasonic array actuator, the ultrasonic array actuator to activate the ultrasonic array based on an instruction from the haptic controller. 
     Example 19 includes the virtual reality system of Example 17, wherein the haptic controller is integrated into the glove. 
     Example 20 includes the virtual reality system of any of Examples 16-19, wherein the glove includes a transceiver to receive information about the virtual reality environment from the headset. 
     Example 21 includes a non-transitory machine readable storage medium including instructions that, when executed, cause a machine to at least determine a location of an object in a virtual reality environment, calculate a distance between a location of a section of a glove worn on a hand of a user and the location of the object in the virtual reality environment, and activate an ultrasonic array disposed inside of the glove when the distance is zero or substantially zero. 
     Example 22 includes the non-transitory machine readable storage medium of Example 21, wherein the instructions, when executed, further cause the machine to determine at least one of a frequency or an intensity at which to activate the ultrasonic array. 
     Example 23 includes the non-transitory machine readable storage medium of Example 21, wherein the instructions, when executed, further cause the machine to, prior to calculating the distance, determine the location of the section of the glove in the virtual reality environment. 
     Example 24 includes the non-transitory machine readable storage medium of Example 23, wherein the instructions, when executed, further cause the machine to determine the location of the glove based on image or video information from a camera. 
     Example 25 includes the non-transitory machine readable storage medium of Example 21, wherein the instructions, when executed, further cause the machine to recalculate the distance between the section of the glove and the location of the object and cease activation of the ultrasonic array if the recalculated distance has increased. 
     Example 26 includes the non-transitory machine readable storage medium of any of Examples 21-25, wherein the ultrasonic array is a first ultrasonic array, and wherein a plurality of ultrasonic arrays are disposed inside of the glove. 
     Example 27 includes the non-transitory machine readable storage medium of Example 26, wherein the instructions, when executed, further cause the machine to select multiple ones of the plurality of ultrasonic arrays to activate. 
     Example 28 includes an apparatus including means for determining a location of an object in a virtual reality environment, means for calculating a distance between a location of a section of a glove worn on a hand of a user and the location of the object in the virtual reality environment, and means for activating an ultrasonic array disposed inside of the glove when the distance is zero or substantially zero. 
     Example 29 includes the apparatus of Example 28, further including means for determining at least one of a frequency or an intensity at which to activate the ultrasonic array. 
     Example 30 includes the apparatus of Example 28, further including means for determining the location of the section of the glove in the virtual reality environment. 
     Example 31 includes the apparatus of Example 30, wherein the location of the glove is determined based on image or video information from a camera. 
     Example 32 includes the apparatus of Example 28, wherein the means for calculating is to recalculate the distance between the section of the glove and the location of the object, and the means for activating is to cease activation of the ultrasonic array if the recalculated distance has increased. 
     Example 33 includes the apparatus of any of Examples 28-32, wherein the ultrasonic array is a first ultrasonic array, and wherein a plurality of ultrasonic arrays are disposed inside of the glove. 
     Example 34 includes the apparatus of Example 33, further including means for selecting multiple ones of the plurality of ultrasonic arrays to activate. 
     Although certain example methods, apparatus, systems, and articles of manufacture have been disclosed herein, the scope of coverage of this patent is not limited thereto. On the contrary, this patent covers all methods, apparatus and articles of manufacture fairly falling within the scope of the claims of this patent.