Anyone, who has seen crash tests of cars, has seen the crash dummies. Yellow faceless dolls are used to monitor the movement of occupants of the vehicle during the collision. They provide a good idea, of what kind of improvements have to be done to improve safety of the people.
However, there is one fundamental flaw in such tests. Most of the people brace themselves moments before the accident and roughly half of drivers take defensive action, such as sudden braking or steering, to avoid collisions. Dummies cannot do any of these.
Japanese car manufacturer Toyota understood the issue and wanted to take these actions into account when considering safety of vehicles that company produces. Most of car manufacturers understood that posture of occupants of the car has a significant effect on body movement during a collision. In other words, whether a person is bracing oneself or is just relaxing in the seat makes a big difference. Since using conventional dummies is rather expensive and ineffective, car manufacturers and other organizations have developed virtual crash simulations, but even those are unable to simulate the reflexive defensive actions that humans take in the moments before an imminent collision.
Now Toyota improved human surrogate models. Company successfully added a new muscle model, which can simulate human postural states. That is the latest development of Toyota’s Total Human Model for Safety (THUMS) virtual human model software. Latest version of this program now can simulate a wide range of different postures of occupants of the car, from relaxed to braced, which allows for a more detailed computer analysis of injuries caused by collisions. Up until now THUMS was only able to simulate postural changes after the collision.
Since in the latest fifth version of Toyota’s virtual crash simulator changes in occupant posture prior to collisions can now be simulated, it is possible to accurately examine the effectiveness not only of seatbelts, airbags and other standard common safety equipment, but also of more modern, active safety technologies such as electronic pre-collision systems. This will provide necessary knowledge to create more advanced active safety technologies that are designed to prevent the collision in the first place, or to minimize the damage in the event of an accident.
THUMS program is not used only by Toyota. It has already been adopted by dozens of companies – other car manufacturers, automotive parts manufacturers, developers of electronic systems and so on. In other words, Toyota’s Total Human Model for Safety is contributing to vehicle safety research all over the world. It is one of the most advanced programs of this kind. It is capable of simulating a lot of characteristics of various body parts, like bones and skin, as well as its overall shape. THUMS allow for detailed analysis of possible injuries in the event of accident, such as bone fractures or severed ligaments. And now it can also take into account bracing before the collision.
Toyota has started developing THUMS back in 1997. The first version of the program was completed and commercially launched in 2000. Development of this software has not stopped and second version was launched in 2004 – a face and bones were added to the model. Third version, launched in 2006, had a precise brain model added. Fourth version was launched in 2010 and had a detailed modelling of internal organs. Fifth version, described in this article, has a precise muscle model, which can simulate the movement of the occupant of the vehicle before the impact.
Tools like this should improve vehicle safety significantly, because companies will have a better idea of what the moment before the collision means to its outcomes.