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A system for reducing motion sickness on a moving platform such as a ship, aircraft or land vehicle is presented. The system is called MOCOVE for Motion Coupled Visual Environment. Human subject tests have shown that MOCOVE reduces motion sickness by a factor of five, to about a fifth of peak levels experienced without MOCOVE. For MOCOVE to be effe...
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... system for reducing motion sickness on a moving platform such as a ship, aircraft or land vehicle is presented. The system is called MOCOVE for Motion Coupled Visual Environment. Human subject tests have shown that MOCOVE reduces motion sickness by a factor of five, to about a fifth of peak levels experienced without MOCOVE. For MOCOVE to be effective, users must look at an electronic display, and this creates system engineering challenges for incorporating MOCOVE into military platforms. This paper summarizes experimental results and discusses how naval engineers tasked with implementing MOCOVE aboard ships may address systems engineering issues. Sea sickness is a malady as old as sea travel. With modern transportation, land vehicles and aircraft bring with them the related ills of car sickness and air sickness. The virtual world is not exempt. With simulated motion comes real sickness in the form of simulator sickness and virtual reality sickness. Navies of the world have accepted mal de mar as a fact of life, but this may not be prudent as crew sizes are reduced and as technologies are introduced that may actually increase sea sickness levels. These technologies include the increased use of large format displays, decreasing craft size, unusual hull forms and an overall trend towards operations anywhere but on deck. Motion sickness may be an old enemy and even viewed as a right of passage, but its effects can be effectively reduced, thereby increasing overall readiness levels and even, perhaps, assisting in the retention of trained personnel. We present a method for reducing motion sickness that is akin to fighting fire with fire. It is based on the theory that motion sickness is primarily due to a disagreement between the inertial environment one senses through their vestibular and proprioceptive receptors and the perceived visual environment. MOCOVE uses an electronic display to present a scene to users that, when viewed, serves to reduce overall motion sickness levels. We first summarize results of supporting human subjects research, and then discuss how MOCOVE could be engineered into ships, submarines, small craft, aircraft and even land vehicles. The theory underlying MOCOVE is called “visual entrainment.” The concept is to cause the eyes to move in a way that would be expected by the inertial environment, that is, the motion environment to which the body is subjected. In Fig. 1, the cross- section of a boat is shown rolling with the sea. The MOCOVE sensor, located near, and oriented with the display, senses the ship’s motion. The window within the electronic display is rolled in the opposite direction, causing the eye to adjust to the scene as if the window were a view of the horizon. In its most basic form, MOCOVE consists of a sensor, processing software and a display. An example of a MOCOVE sensor is shown in Fig. 2. Two micro-machined silicon accelerometer chips with two orthogonal sensors each, are placed orthogonally, for a total of four accelerometers, one of which is redundant. A micro-controller records data, performs digital filtering of high-frequency vibration, compensates for temperature variations, and formats data for RS232 communication over a standard 9-pin serial port. The data is received by a software driver on the computer side and used to modify the user’s viewpoint in a virtual scene or window. Fig. 3 shows a virtual scene used in several MOCOVE experiments. It features a near-field display of a control panel and a highly textured far field view. Typically, the craft is shown as traveling along a path, and MOCOVE adjusts the craft’s orientation relative to the water surface based on sensed inertial readings. For example, if the actual environment rolls, the craft appears to roll in likewise manner. To aid human subject testing, we added many features to the virtual environment. For example, the experimenter is provided with a control panel (Fig. 4) permitting adjustment of pitch, heave, and roll coupling with a panel of sliders. A small map shows the driver and his scene orientation. Using NRL’s Ship Motion Simulator (SMS) (Fig. 5), data were collected on 11 subjects. On the first day of exposure, subjects looked at a computer generated scene that was stationary relative to the movement of the SMS. On the second day, subjects looked at a computer generated scene that was modified using MOCOVE. Subjects reported, on average, five times more symptoms on Day 1 (no-MOCOVE across day, average = 10) compared to Day 2 (MOCOVE across day, average = 2) (F[1/10]) = 5.7, p<0.05) (Cohn, et. al 2003). Results are shown in Fig. 6. The overall sickness levels in the with-MOCOVE condition are significantly less at all times. In addition, the scatter in subject responses was significantly less in the with-MOCOVE condition as compared with the no- MOCOVE condition. This indicates a nearly unanimous agreement in effects by this set of subjects. In another set of experiments using the Brandeis Vertical Linear Oscillator (VLO), ten subjects were exposed to vertical motion (0.2 Hz, 0.85m amplitude) while immersed in a virtual environment or exposed to the natural scene within the laboratory. With MOCOVE engaged, the level of motion sickness in the virtual environment was equivalent to that of the natural scene. With MOCOVE off, the virtual environment created significantly more sickness. These results are sufficiently encouraging to prompt exploration of different ways to integrate MOCOVE into naval systems. In general terms, MOCOVE technology applies to personnel who are either engaged in looking at a display or who may have the option of viewing a display if they choose. We define four classes of users: • Operators using displays such as radar, sonar and command and control interfaces • Passengers • Personnel in off-duty hours • Virtual Environment (VE) training system users A typical MOCOVE set-up may resemble that in Fig. 7. A passenger on a ship, aircraft or even vehicle such as the AAAV may view a display located in a prominent position within the compartment. The required components are a MOCOVE sensor, a computer and a display. There are many low-cost and rugged displays and computers on the market, and MOCOVE, being a solid-state device built of common COTS components, is surely amenable to ruggedization. Integration of MOCOVE into existing platforms raises several issues, ...
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Citations
... Specifically, this effort capitalizes on the notion that artificial horizons may provide a re-orienting effect in individuals, such as pilots, who may be exposed to disorienting cues (Rolnick & Bles, 1989). Previous results, in which users were exposed to a provocative environment either with or without this device, suggest that this approach may hold promise (Cohn, et al, 2002, Brendley, Cohn, Marti, Muth & Stripling, 2003). Current work is focused on developing a seamless interface for providing this reorienting effect in users while they are training in VE systems, thereby enabling them to continue their training session. ...
As the military continues to focus on reducing the overall cost of training while increasing the efficiency with which this training is provided -without sacrificing quality-Virtual Environment (VE) systems will become an increasingly attractive alternative. While current VE development efforts typically focus on supporting the individual user, rather than a broader, integrated collaborative environment, it is precisely this type of distributed, integrated and cross-platform environment within which the military typically operates and for which such VE systems must be developed. The VIRtual Technologies and Environments (VIRTE) research program was developed, through the Office of Naval Research, to support a solid Science and Technology base from which to expand this narrow development focus. VIRTE's research thrusts unite elements from the Modeling and Simulation communities with those from the Human Factors and Experimental Psychology fields in order to develop VE systems that are both technologically sound and performance enhancing, within a distributed virtual battlespace. VIRTE's component systems are based on real-world operational requirements and are designed to easily transition. The systems include: a Virtual Environment Landing Craft, Air Cushion (VELCAC), a Virtual Environment Advanced Amphibious Assault Vehicle (VEAAAV), and a Virtual Environment Helicopter (VEHelo). These domains were selected precisely because military doctrine for Expeditionary Warfare including Marine Corps Strategy 21 and Sea Power 21 rely on elements from each of the real world vehicle analogues in order to be effective, thus forming a natural collaborative, integrated environment. The virtual systems are designed with the dual purpose of supporting training at the individual level, as well as at the level of distributed, team-based events, operating within a shared synthetic battlespace. This paper will describe the human centric process that was applied to the simulation development, the role of continuous training effectiveness evaluation, and key findings from this program that should be considered for future simulation development efforts.
