In order for the CMS simulator to be fully effective, CMS provide the driver with a range of carefully co-ordinated “cues”.  The primary sensory cues come from the visual display and these provide the brain with a large amount of information on the surroundings and on the vehicle motion relative to the surroundings. A “first level” simulation is achieved when the visual inputs are augmented with co-ordinated aural inputs and force feedback to the muscles through the controls. However, for high performance applications the degree of driver mental engagement with the simulation needs to be higher than that which can be achieved with a “first level” system. This enhanced degree of engagement is achieved by going to “second level” simulation. In “second level” simulation a range of co-ordinated cues are provided to cover acceleration, deceleration, cornering forces, skidding, track surface condition etc. These allow a driver to “experience” the handling of the car at the limit of its performance.

Within the CMS simulator, the vestibular and visual systems must be stimulated to induce the perception of self-motion.  The perception of self-motion is enhanced if the tactile, or somatic, systems and the auditory system is also stimulated.

CMS applies its patent protected technology and expertise to meet the requirements of high performance motor racing. In the racing environment, the important loads are experienced in the longitudinal and lateral directions, whereas, in flight, the largest loads are in the normal (vertical) direction. This is a fundamental difference resulting from breaking and cornering where lateral loads of up to 4 – 5 G are commonly experienced.

To provide effective motion cueing, it is also necessary to consider the effects applied to the whole body, in particular the upper torso, with longitudinal acceleration / deceleration and lateral acceleration cues to simulate tyre slip, cornering and vibration. Cues are provided in three ways:

• Eye position movement (kinaesthetic)
• Sustained Pressure (somatic) cues from actuators placed around the seat    bucket as well as harness tension variation.
• True vibration cues, based on real vehicle data, are put in via an Ethernet connection and aerodynamic buffet, engine, track, tyre variations, driving over the curb and other vibration based cues can also be applied.

CMS provide a series of onset and sustained cues by means of a combination of actuators applying displacements to the vehicle itself (onset cue) or by providing sensory stimuli to the driver to represent the forces experienced on the torso and legs whilst driving the race car around a track. These cues are provided by the following sub-systems: -

• Sustained Motion Cueing System (SMCS)
• XYZ Table (XYZ)
• Vehicle Actuator Frame (VAF)

The Vehicle Actuator Frame (VAF) is a combination of structures each offering driven displacement in its own plane, vertical, lateral or roll. The VAF is designed to operate in a variety of configurations to optimise the cueing process. Typically the system will allow 5 degrees of roll and 2 degrees of pitch.

Functional Objectives

• Vehicle pitch due to acceleration and deceleration - resultant changes in driver eye point position
• Track undulation – resultant changes in driver eye point position
• Kerbing - resultant high frequency, high amplitude vibration
• Car bottoming out on the track surface - resultant sharp positive G vertical displacement
• Cornering - resultant roll sensation
• Braking, deceleration and acceleration – resultant is the apparent slowing or speeding up of the vehicle relative to the visuals
• To provide the driver with the difference between front and rear lateral velocities
• To provide the driver with direct feedback of the front and rear tyre slip angles
• Cornering, resultant: lateral displaced (onset cue)
• Cornering / side slip, resultant. large side ward displacement of rear wheels

The XYZ Table is used to complement the Sustained Motion Cueing System (SMCS) by providing rapid (less than 20ms) onset cues and vibration to the driver’s seat. As with the VAF any three demands can be summed on to any of the axis at any one time. This function provides the provision of onset cues as will as sustained and vibration cues simultaneously and / or the sum of two different frequencies and amplitude.

The SMCS is situated in and around the monocoque. Actuators are situated around the driver’s seat structure, at those points where the driver experiences pressure as a result of the forces induced by high speed driving. The cues provided by the SMCS are progressive (proportional to relevant g demand) and sustained until the demand is removed.

Braking – resultant; driver will feel as if his being forced in to the seat pan and feels an increase in harness tension.
Longitudinal acceleration – Resultant; driver will feel as if he is forced back into the seat.
Cornering – resultant; the driver will feel pressure to his torso as if he is being forced into the side of the seat / monocoque.
    
All of the above are sustained cues and impart forces upon the driver according to the desired g loading.