1994 VR Conference Proceedings

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The Role of Virtual Reality Driving Simulators For Rehabilitation and Assessment of Disabled Persons

By: Lois A. Turner
AGC Simulation Products
675 Sycamore Drive
Milpitas, CA 95035
(408) 434-1770

Virtual reality driving simulators (VRDS) are now available that can make a positive addition to the world of assessment and rehabilitation of the disabled driver. They provide a safe driving environment for the evaluator as well as the patient. While a VRDS is not a substitute for the real world, it can provide a tool to get the disabled driver back into the real world's driving environment. The therapist/evaluator can use the VRDS to judge the driver's ability before he/she is taken on the public roadways.

New technology is also making changes in the other fields of driver training and assessment. Law Enforcement agencies across the United States are already using VRDS in their EVO (Emergency Vehicle Operations) training centers. The licensing agencies of several states are considering simulation as a viable pre-assessment tool to be used before the on-the-road test. Community groups around the nation are forming coalitions to study what can be done to decrease fatalities and injury. Legislation is also being considered which will provide funding for the high risk drivers. In each these areas simulation is being considered as a part of the solution to these various problems.

Driving is a very complicated task. Drivers on the public roadway encounter and interact with other drivers who possess different abilities, attitudes and experience. Also mixed into this equation are the road, vehicle and weather conditions. A good driver must be always aware of the ever changing environment and adjust to each situation in a safe manner. For a disabled driver these driving tasks become even more difficult.

VRDS Driver Controls

Each VRDS is equipped with the following controls:

The VRDS utilizes complex vehicle dynamics algorithms which are computed using high speed microprocessors to model the physical motion of the vehicle within its synthesized environment. The "vehicle model" algorithms include such factors as suspension spring coefficients and dampening factors, drive-train torque curve, tire patch dynamics, vehicle mass and center of gravity. Although the simulator itself does not move, the tactile, visual, and aural feedback create a compelling illusion that the driver is behind the wheel of an actual vehicle. If the wheels encounter a bump in the road, as when tracking off or on to the shoulder, the forces of the bump transmitted through the steering linkage are simulated by a proportional jolt in the steering wheel.

VRDS Configuration

When VRDS are configured as standard vehicles or equipped with adaptive hand and foot controls, it creates a simulated real-time driving experience. The simulator recreates both visual experience and the "feel" of driving an automobile. The simulated vehicle is operated within a computer synthesized interactive three dimensional "universe" which is displayed from the driver's point of view. All the objects contained in the synthesized universe are represented as three dimensional solid objects which can be viewed from any angle, such as when driving around the rear of a building. Also any impact with a solid object, such as with another vehicle, will result in a collision. The shapes of these objects have been designed to be easily recognized and generically representative of real world objects such as office buildings, houses, road signs, without being specific for one particular location. Objects which will interact with the driver (cars, bicycles, pedestrians) can be programmed to appear to create hazards. The simulator's city universe allows the driver to operate his/her vehicle in any manner he/she chooses. The driver can turn into any of the streets and enter any of the roads that he/she feels is appropriate. The simulator provides the driver the ability to brake and accelerate appropriately in the training scenarios. When VRDS are linked together both drivers can interact with each other as if they were on a real roadway.

Assessment of Patient Capabilities and Needs

A VRDS placed in a hospital or rehabilitation environment can provide a patient the chance to be assessed while still in bandages. Since mobility is a major factor in most patient's lives, this could provide the patient some sense of getting back to "normal" and a positive attitude toward future rehabilitation therapy.

The VRDS can provide a self-paced retraining experience in a non-threatening manner. It provides an environment which allows repetitive tasks to be performed without a therapist being present. The patients performance can be recorded on a disk and reviewed by both patient and therapist.

The VRDS provides the versatility to customize the assessment and rehabilitation process for each individual patient. Assessment can be performed either by direct observation of the disabled driver's performance or by analysis of the data provided by the simulator or a combination of both. Data such as the position, velocity, and acceleration of the vehicle and the driver's operation of the vehicle's controls can be plotted with respect to position on the roadway. A computer provides the capability to collect and analyze specific parameters generated by the simulator during training or testing exercises that can be used to evaluate driver performance. The steering wheel movements, brake pedal pressure, and throttle application are just a few of the typical driver control inputs which can be monitored. The timing between specific events in the simulation can be stored, measured and replayed on the screen for student self-evaluation or instructor analysis. This data can be printed graphically in hard copy form.

The evaluator can design and program scenarios which will look for specific deficiencies in the disabled patient. The following are just a few which could be observed and assessed:

Cognitive Deficiencies

Perceptual Deficiencies


Since the VRDS is programmable, the evaluator can create numerous scenarios and environments for the patient. The following are some variations which are available:

Evaluation and Familiarization of Adaptive Controls

Since the steering column, gas and brake pedals are positioned like a real vehicle, industry standard controls can be placed on the VRDS for evaluation to ascertain which controls are appropriate to the needs of the patient. With this established, the patient is able to practice on the VRDS before going out on the public roadway.


The VRDS can be the interface between the patient and the real world driving environment to achieve the patient's ultimate goal of mobility. It can identify the deficiencies of the disabled driver as it applies to the "whole" driving task and not just it's "parts".

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