1994 VR Conference Proceedings

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Teaching Orthopedically Impaired Children To Drive Motorized Wheelchairs In Virtual Reality

By: Dean P. Inman, Ph.D., John Peaks, M.A., Ken Loge, M.S., and Victor Chen, Ph.D.
Oregon Research Institute
Virtual Reality Labs

The notion that childhood development is directed related to being able to independently explore one's environment is now widely accepted among social scientists, cognitive psychologists, and early childhood education specialists. A significant body of research has presented evidence over the last twenty-five years that self-locomotion experience plays an important role in the development of spatial perceptual abilities and cognition (Held & Hein, 1963; Bertenthal, Campos & Barrett, 1984; Adolph, Gibson & Eppler, 1990; Acredolo & Evans, 1980; Kermoian & Campos, 1988; Bertenthal & Bai, 1987; Horobin & Acredolo, 1986). These skills form an integral part of how we interact with and utilize our environment. Spatial perception encompasses our ability to localize ourselves in space, depth perception, shape recognition, visually guided reaching, awareness of self-motion, as well as mapping and problem solving in multidimensional space (Wiley, 1982). This set of skills is necessary for many of the activities of daily life including mobility, vocational tasks, and independent social interaction. Children with motor dysfunctions often do not have access to self-locomotion experience during early developmental years (birth to five years). For children whose motor dysfunction is severe, mobility experience can be delayed until young adulthood and beyond. The effects of this deficit in ability experience is severe.

The purpose of this project is to demonstrate and evaluate a newly-emerging technology that may prove to be of great use in training children with severe physical disabilities to operate motorized wheelchairs. This technology will permit nonambulatory children to "move" freely and independently within diverse environments safely and with great realism. In so doing they will have a chance to enjoy and benefit from experiences that other children have routinely during their formative stages of development. With the advent of Virtual Reality technology, it is now possible to provide severely physically disabled children with a chance to explore, discover and to operate upon the physical environment in such a way that it is possible for them to learn mobility skills and to develop cognitive strategies and perceptual abilities that can only be learned through self-initiated experience.

Training is accomplished by having children experience a series of four Virtual Reality Scenarios, which are sequenced in terms of difficulty and setting. The high degree of realism provided by these simulated experiences is achieved in two ways. First, reality is simulated by the physical configuration of the student's workstation. Second, reality is simulated via software, that generates a three-dimensional, stereoscopic, real-time image which is directly responsive to input from the student's joystick and head position.

The physical configuration of the student's workstation is constructed to accommodate actual motorized wheelchairs of various sizes. Children who already have their own wheelchairs use them during the training, while children who do not already own wheelchairs are provided one for use in the training settings. Several features have been incorporated into the workstation that are designed to mimic reality and thus enhance the transfer of skills to real-world settings. For example, a student's motorized wheelchair is placed on rollers supported by a metal frame approximately six inches off the ground. A small ramp enables the chair to be pushed up onto the platform and into position. When in position the back wheels of the wheelchair rest on rollers that permit the wheels to rotate at normal speeds but which effectively prevent the chair from actually moving. Moreover, each back tire is situated on its own set of rollers which allows the right and left wheel to move independently of the other. Thus, when the joystick is moved to the left, which would normally cause the right rear wheel to turn faster than the left wheel, the apparatus permits differential axle speed to simulate the tactile, kinesthetic, and auditory feedback normally associated with making a left hand turn. Also, the roller surfaces are slightly irregular which causes the chair to vibrate very slightly as it would normally do on surfaces such as sidewalks and low-pile carpeting.

Under normal conditions when a motorized wheelchair is driven into a wall or an object, the driver feels a distinct bump and the chair's progress is halted. In three out of the four training scenarios developed, the student learners have the opportunity to safely "crash" into objects or walls during the Virtual Reality training experience. To simulate the experience of crashing, the following features are built into the training platform. If the student learner crashes into an object or wall in the Virtual Reality training environment two things happen to simulate the crash experience. First, the software program sends a signal to the right, left, or both roller assemblies (depending on which part of the Virtual motorized wheelchair makes contact with the obstacle or wall), which functions to operate a breaking device that immediately stops the wheels from turning. This jolts the student driver in a manner that is very similar to the actual experience of crashing into an immovable object. In any crash situation the sound, feel and immediacy of bumping into an object is quite realistic from the student driver's point of view. A major advantage of the Virtual Reality training experience is that there is no danger to the student driver or others during the driving education experience.

Once the wheelchair is in place, the student driver is fitted with a helmet, through which the visual and auditory components of the VR training program are presented. Inside the visor of the helmet are two video screens, one for each eye, through which a three-dimensional representation of a Virtual Reality World is presented. Also in the helmet are two earphones, one for each ear, through which a stereophonic program can be presented to coincide with the visual images displayed in the visor. It should be noted, however, that the earphones in the helmet do not block out sound from the real world during the training process. Thus, it is possible to talk with students as they experience the Virtual Reality training scenarios and they are able to hear the motors of the wheelchair turning as they drive the rear wheels at different speeds.

The project's goals are to develop, demonstrate, and evaluate at least four Virtual Reality training scenarios through which we hope to develop and/or enhance mobility skills in severely orthopedically impaired children. Each scenario is intended to provide learners with motivating mobility training experiences that permits them to function with more competence, independence, and safety in school and community settings. Scenarios One and Two are designed to promote independent exploration, discovery, cause and effect relationships, and visual memory (skills prerequisite to independent mobility that orthopedically impaired children often lack). These Virtual Realities are safe, highly entertaining situations where the student learner is allowed to roam freely during the discovery process. Scenario Three provides a more structured indoor driver education experience in which the student learner is taught to navigate within a school environment. The emphasis here is on moving from class to class independently and functioning within the classroom with sufficient skill to promote independent functional mobility. Scenario Four is set within the community and attempts to establish appropriate and safe street crossing skills using a crosswalk protected by a traffic light. Although many other scenarios are possible, we have limited the scope of our initial efforts to demonstrating and evaluating these four scenarios.

In the first Virtual World, the child is able to explore a large, wall-less space that has no obstacles or impediments of any kind. The child is free to go forward and backward at any speed within the limits of the software and hardware. In addition, the child can choose to go in circles; large slow ones or very short tight ones. The floor consists of black and white tiles over which the child drives. This enhances the sensation of movement and speed as the child drives across the floor. In this Virtual World a child can experience the joy of independent mobility without fear and without constraints. It provides the basis upon which all other mobility skills are based.

In the second Virtual World the student learner is allowed to explore an area which is approximately 2000 feet by 2000 feet. If the child runs into anything while moving about, the brakes to the wheels are triggered and the chair "crashes". Additional sound effects appropriate to crashing are provided by the software. Once an obstacle is struck, the chair must be moved right or left away from the obstacle in order to continue. Also, it should be noted that the strength of the crash varies depending upon the speed that the chair is "moving" when it encounters the obstacle. This is to simulate accurately yet safely the consequences of moving in the real world.

Scattered around this Virtual World are audio/visual (A/V) stations that the child can discover while exploring the environment. Each A/V station becomes activated when the child comes within two to three feet of it. The A/V stations are placed on platforms or pedestals approximately three feet high, thus permitting the student driver to crash into the pedestal without damaging the audio/visual apparatus.

The A/V stations are intended to be highly entertaining, and we expect that each student will develop his/her own personal favorites from among them. Some stations may produce visual images that are very beautiful and dynamic, such as birds, waterfalls, or light displays, together with auditory programs of music or nature sounds. Other displays portray cataclysmic events, such as supernovas, with matching sound effects. Still, other stations provide experiences which are primarily auditory, for example, Beethoven's Pastoral Symphony No. 6, Ravel's "Bolero", or Madonna's "Like a Prayer". These stations are currently under development.

Two other facets of Scenario Two should be mentioned. First, the student driver always starts from the same position within the world. This way, the child learns that the exploration activities always begin from the same point of departure, permitting him or her to eventually memorize the world's configuration. Second, the A/V stations placed throughout the world will remain constant over time. Again, this permits children to create a visual memory of the world's layout and permits them to begin exploring from where they left off at the end of the previous session or to revisit sections of the world they found particularly amusing or interesting. This consistency enhances each child's ability to (a) memorize the world's features, (b) foster systematic and deliberate exploration of an environment, and (c) discover cause-and-effect relationships between volitional activity and activation or de-activation of devices or apparatuses that are contained within the environment. This type of simulated adventure is intended to foster a sense of curiosity, personal control, and an appreciation for the benefits of independent mobility. These subjective experiences are essential to a child's ability to benefit from more advanced mobility training because they form the motivation that drives the desire to learn mobility skills.

In the Third Virtual World children are able to explore a simulated school building. The floor plan is based on an actual public school building in Eugene, Oregon, and includes hallways, lockers, classroom doors, a cafeteria, bathrooms, and various classrooms. Each classroom contains desks, chairs, aisles and workstations based on actual classrooms found in sample elementary and middle schools. Each classroom is different and in each at least one interesting activity occurs (i.e., something the child enjoys watching or participating in).

This Virtual World is designed to build on and refine the exploration and discovery skills developed in Scenario Two so as to enhance a child's ability to navigate within a public school environment. In addition, we may further complicate Scenario Three by arranging for "moving obstacles", such as people or opening doors, in order to foster a realistic need to avoid hitting objects or people whose movements are unpredictable and typical of the real world.

Scenario Four of the Virtual World consists of a street crossing scenario in the community. Obviously, the community environment is extremely complicated with a myriad of situations that could be targeted for training. We have chosen, however, to focus on developing and evaluating a street-crossing scenario because of its frequency and importance for safe mobility in the community. This VR program begins with the child on a sidewalk bordered by a lawn on one side and a two-way street with moving cars on the other. At a point 50 to 100 yards beyond the starting position, a crosswalk (complete with stoplight and pedestrian crossing sign) is available. On the other side of the street is another sidewalk perpendicular to the first one. The child's task is to (a) approach the crosswalk appropriately, (b) wait for the light and crosswalk sign to operate, signaling the cars to stop, (c) drive across the street within the boundaries of the crosswalk, and (d) negotiate the turn onto the opposite sidewalk. The child is able to go back and forth across the street as many times as desired.

It is important to recognize that Scenarios Three and Four, while being the closest approximations to the real world, are also the least interesting from the student driver's point of view. However, because we are most interested in evaluating the extent to which Virtual Reality training will permit a child to drive a motorized wheelchair safely and independently in school and community environments, it is important that students practice and achieve competence in these practical situations.

Experience has taught us that motivation is of critical importance in maintaining "best effort attempts" during the acquisition process. Initially, we use Scenarios One and Two to acquaint the students with the technology and to inspire their curiosity and interest. When students move on to the driver education program in Scenarios Three and Four we use access time to Scenarios One and Two as a reinforcer for making progress. Children are rewarded for diligence and effort, their interest is maintained, and appropriate conceptual motor skills are rehearsed throughout training and while engaging in play activities that follow training. We strive to ensure that each student driver is motivated to do his or her best at each stage of training. Mass-practice of simple motor skills in a repetitive environment is not over emphasized. Rather, we prefer to err on the side of excitement and fun, permitting each student driver to challenge him or herself to the maximum extent possible without becoming terrified.

Of course, we also want to build skills systemically and in such a way that at the end of training each child is able to do more and go farther as independently as possible at the end of training. Again, this sequencing requires good decisions based on input from teachers, aides, parents, project staff and the children themselves. By the end of the project we hope to have amassed enough data and experience to begin specifying how to best use the technology in order to optimize training results.

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Reprinted with author(s) permission. Author(s) retain copyright.