In general RC cars vroom at speeds in between 40 – 80 km/hr. Since it is a tiny car and very difficult to control by means of conventional braking system. During races, as a remote operator I experienced problems such as skidding, forcefully slowing of car (even if not needed) etc. So we decided to go for our own design of braking system. Since it is our collage final year project and patented content and I will discuss only few parts of it.
For this purpose we studied different types of Brakes such as band brakes, drum brakes, disk brakes, anti-lock brakes etc. Among them Anti-lock braking system found to be good, since this is new to world and latest. These systems can stop vehicles more quickly than conventional brakes and does not allow them to skid especially on wet paved surfaces, icy or packed snow-covered roads etc. This is accomplished by momentarily releasing and reapplying brakes of wheels in order to maintain vehicle control and minimize breaking distance. Thus provides an advantage in emergency braking situations.
There are different types of ABS systems are present such as 4 channel and 4 sensor ABS, 3 channel and 3 sensor ABS etc. Thus conventional ABS uses components such as sensors, control unit, pump, valves etc that makes it heavy and complicated for a 3.2cc engine remote controlled car.
In this topic I will not explain in detail about ABS principles, but throw some light on braking system that we implemented on our car and this resembles to an Anti-lock braking system but does not uses any sensors. We simply call it as mechanical based ABS.
Components used in the mechanical based ABS
1. Solenoid
It is an electromechanical device and can be used efficiently to convert electrical energy into mechanical. Initially we studied different types of Solenoids and chose one that used in cars which uses LPG cylinders as fuel. Here it is used to lock and unlock gas supply from cylinder. For our car brakes we need a solenoid that must have a “to and fro” frequency of about 120 – 150 per minute. And for this purpose we designed a timer circuit and this really helped us to get frequency in the range of 10 – 1000 per minute. I really appreciate our effort to design such a circuit. To operate solenoid and timer circuit we used 1.2Ah 12V dry cell rechargeable battery.
2. ABS Switch
Don’t puzzle with terminology we used here as ABS switch. It is just a small switch and mounted on servo horn that is used to control throttle of engine. Definitely this is an important part of ABS system and used to control power supply to Solenoid.
Following figure is an actual implementation of Developed ABS by our team. The part in blue boundary constitutes a complete ABS and part in red constitutes ABS switch.
Following figure is an actual implementation of Developed ABS by our team. The part in blue boundary constitutes a complete ABS and part in red constitutes ABS switch.
Operation
The solenoid, timer circuit, ABS switch and battery are mounted on the car; the car is operated by a radio system that controls two servo motors. One servo is used to control steering system and other for throttle valve as well as ABS mechanism.
The throttle valve and ABS mechanism are made to operate in relative to each other in order to produce ABS effect and ABS switch acts as a sensor that assumes speed of the car based on the position of throttle. In our project solenoid produces braking effect only at constant frequency. But in actual ABS frequency of braking varies with speed of car. Any how our system works pretty well and we are satisfied with its performance and for this we won best design in IITM Chennai and succeeded in getting a fair amount of sponsorship amount from Karnataka State Council for Science and Technology a wing of a prestigious IISc Bangalore.
Here are some youtube links of our work.
1.In this video you can observe, that we are using simple steering mechanism.
2.Here we modified our car into a Truck with ABS installed.
3.In this video we showed full structure of ABS. It is little bit funny.
Here are some youtube links of our work.
1.In this video you can observe, that we are using simple steering mechanism.
2.Here we modified our car into a Truck with ABS installed.
3.In this video we showed full structure of ABS. It is little bit funny.
In the end I would like suggest that, I introduced this brief regarding ABS only to stimulate those mind that are having good knowledge regarding RC cars and really interested to make further research in RC car development. But I am not stopping beginners, yes can do it even further and sky is the limit. So once again I want to state that if you are having any doubts just drop me a mail at bpr890@gmail.com.