By Chris Chitty
Bungy-jumping first began on the Pacific Island of Vanuatu where men sought to prove their manhood by tying springy vines to their ankles and throwing themselves off very tall wooden towers. In the 1980s AJ Hackett and Henry van Asch experimented with modern-day equivalents and, a year after a notorious jump off the Eiffel Tower in 1987, the first commercial Bungy site was established in Queenstown.
Many thousands of jumps later our company, Wellington-based research and development studio Robotechnology, was asked by New Zealand’s national museum, Te Papa to redesign the bungy-jumping experience with a key difference: simulated rather than actual freefall. Robotechnology was contracted to design and build a machine capable of simulating the experience of doing a bungy jump, something that had never been done before, and no mean feat!
Our over-riding concern was to make the virtual experience totally authentic.
This initially involved analysing each and every sensation that goes into making up the experience of a bungy jump – from handing over the money to the elation of being back on terra firma, having flung oneself into the abyss and escaped unscathed.
We identified these experiences as including:
Putting your life into the hands of a complete stranger and an oversized rubber band
Having your feet tightly bound
Having someone reassuring you, while drawing your attention to the impending fall
Shuffling to the edge of the platform
Waving at the other people on the bridge watching you
The flight the fall and the fear
The roar of the wind in your ears, and the force of the wind on your face
The ground rushing up to meet you
The relief at having your fall arrested
Spinning uncontrollably as you dangle at the end of the cord
Each of these sensations is very real and must be present to create a convincing simulation. But faking each of these presented some significant design hurdles, and the final product carefully manipulates the jumper.
As the jumpers are enclosed and inverted within the machine, it must therefore comply with strict industrial health and safety codes and be design-approved, inspected and registered with the appropriate Government department. The machine needed to be capable of being operated by a single operator, and to operate continuously over a ten-hour day 364 days of the year.
The simulation consists of a rotating ride capsule. This rotating motion is combined with the inversion, in sync with stereo images and sounds from a head-mounted video display of an actual jump. These physical sensations, video images and sounds combine to form the central experience of the virtual bungy jump.
Just as with a real bungy jump, you pay before you plunge. After handing over your money you jump on a set of scales and are weighed. In the real situation this is to calculate the size and length of bungy to be used. In our situation it is purely for effect.
The jumper then climbs three deck-plate metal stairs, which is a change of experience from the familiar marble floor of the museum. This increases the sense of foreboding, anticipation and anxiety as the jumper enters the machine, because it parallels the experience of walking out on the bridge in the real bungy jump situation.
Now on the loading platform, the jumper is the centre of attention, visible and exposed to all waiting in the queue and the spectators. The jumpmaster (the machine operator) fits the safety harness to the jumper. Once again this action heightens the anticipation of danger. The jumper is then seated whilst the jumpmaster attaches the tight-fitting ankle clamps. This is a direct parallel to the bindings attached to the ankles of the real jumper prior to having the bungy cord fitted. Also a direct parallel is the removal of all small change and loose items from the pockets of the jumper.
All the time the jumpmaster is making conversation – giving details of height, danger and so on. The jumper is in a threatening, industrial environment surrounded by flashing lights and warning signs. While these do not parallel the bungy experience, they are a psychological device used to instil fear and foreboding.
Once fitted into the ankle clamps, the jumper is then led through the steel mesh doors, and across the drawbridge. Below the drawbridge can be seen a scale model of the canyon floor. The jumper enters the capsule and places his or her feet on two painted yellow footprints. The jumpmaster then locks the ankle clamps on to the floor of the capsule so that when the capsule is inverted, the feet are free from the floor, and the person is effectively hanging from the ankles as they would in a real bungy jump.
The safety harness is hooked to the karabiners inside the capsule and the head-mount display is fitted. From this point the jumper will be under the instruction of the virtual jumpmaster, although at this stage there is no sound or picture. The steel capsule doors clang shut behind the jumper and there is now no going back. When the door is closed it automatically sends a start signal that initialises the audio-visual sequence and starts the countdown for the mechanical sequence as well. As this is happening the jumper is being guided by the virtual jumpmaster to look at parts of the scenery, to look down, and so on.
The jumper can hear the shouts of the spectators as the the virtual jumpmaster begins a countdown from five. At the count of two the inversion procedure begins. Because this is happening a little earlier than expected, the jumper is taken by surprise, which again serves to heighten the fear factor. They may also try to withdraw from the jump and find that there is no escape!
In time with the video, the jumper falls forward as air is pumped through the duct and the sound of wind comes through the headset. Whilst horizontal, the weight of the person is taken through the harness clipped to the inside of the capsule, which is now rotating on its axis, again in sequence with images on the headset video, which shows the ground rushing up to meet the jumper. As the capsule reaches full inversion and the jumper is at the longest extension of the cord his or her weight is taken through the ankle clamps. As the jumper rebounds, the rotating and tilting movements remain in sync with the headset visuals.
At the point of recovery the video shows the arrival of a jetboat, which they are then lowered into. As this happens, the capsule is returned to the upright position.
The popularity and reputation of this machine has traveled internationally. From this we can conclude that the attention we have paid to the different senses and sensations, and the interaction between them, has set a new standard in virtual reality. This is the way we believe things will be going with respect to robots used in entertainment.
Chris Chitty is the CEO of Wellington-based Robotechnology.