Styrning och nödbroms av ModuLith
SteeringBreakingAutomaticElectric motorModuLithOff road vehicleModuLithFyrhjulingStyrningBromsAutomatiskElmotor
The purpose of this project is to get a fully functional, automatic steering system and a variable breaking system with an emergency breaking function to an off road vehicle. This off road vehicle is supposed to work as an aid in military situations. A team of two, Sebastian Attervall and Nichlas Gustafsson, got an order from Jonas Nyårds and the PreeRunners Project to construct a steering system that could manoeuvre an off road vehicle without any human involvement. To make this possible the vehicle would be guided by onboard sensors, cameras and computers. The team where also assigned to construct an automatic breaking system, there also no human would be involved. The breaking system should as well contain an emergency stop function to prevent any accidents. The team has solved the problems assigned by using theories by David G. Ullman. The system that was eventually chosen was a steering system containing a 48V, 250W DC motor. A planetary gear where chosen to increase the torque from the engine. To translate the torque from the planetary gear to the steering bar a chain with chainwheel where chosen, this because the chain and chainwheel could withstand the immense forces acting on the chain. Between the planetary gear and the chainwheel a skid clutch is placed to prevent destruction on the planetary gear due to overload. The whole steering system is monitored by two rotary encoders, one placed on the engine and one placed on the steering bar. The breaking system eventually chosen where a system build on the existing drum brakes, placed in the front. To make the system independent from any human interference a system containing a linear motor, an electromagnet and a spring where chosen. The system works by letting the spring act on the wire from the existing drum breaks. The spring is always compressed so a force will always act on the wire when the system is at rest. By compressing the spring further the force acting on the wire will decrease and by compressing it enough the breaks will be released. The force compressing the spring will come from the linear motor. And to make the system failsafe in case of an emergency an electromagnet will be placed between the linear motor and the spring. When the power is cut to the electromagnet the compressed spring will be released and the drum breaks will break. The breaking system as well will be supervised by encoders and in this case linear encoders.