[David Caille]

Hi,

I think someone like Sword can do this easily.

A ghost car who read its speed on the track. A speed code is painting in the slot all along the track, the ghost car read it and adjust its speed.

Like all digital systems use a PWM signal, this ghost car would be compatible with all of them. you just have to paint the a fast speed in straits and different slow speeds behind and in curves.

 

[SWoRd]

QUOTE (blst @ 15 Jan 2005, 22:04)I think someone like Sword can do this easily.We are planning to integrate a feature like this in our CarDCC digital system.

IMO the biggest problem is to have frequent syncronisation of the car position on the track. It might work with just a lap timer, but I'm leaning more towards a sector timing system, where you use the lane change controllers for sector timing as well.

That should allow the system to syncronise the car position several times per lap. This is especially important if you're driving close to the limit, where a bit of wheel spin can cause the ghost car control algorithm to loose track of the car.

It might even be possible to develop an algorithm that can drive the track, based on the knowledge of the track design and a few car parameters?.

 

[David Caille]

Hi Sword,

I know this system with synchronisation, and I think that it is a little bit complexe.
I think it's easier to read the good speed on the track by a sensor in the ghost car.

after, you can adjust the speed scale in the car's chipset according to tyres adhesion.

no

 

[SWoRd]

Hi Blst
QUOTE (blst @ 16 Jan 2005, 09:05)I know this system with synchronisation, and I think that it is a little bit complexe.That's very interresting.

Perhaps you could point me to a description of a system that uses this principle.

... or perhaps just tell me the name of the system.

QUOTE I think it's easier to read the good speed on the track by a sensor in the ghost car.

after, you can adjust the speed scale in the car's chipset according to tyres adhesion.Could you please elaborate a bit on the function of this car sensor? ... like what is the principle of detection etc.?.

 

[David Caille]

Hi,

The little track where we want a ghost car and the speeds on different points. the car read the speed and keep it while it read another speed.

The speed is coded in two parts, synchro and data. the "barrecode" is printed on a silver sticker for a better reading.

an IR transmeter and receiver read the code and transmet it to a decoder (pic for exemple) who drive the motor by PWM.

clear

 

[SWoRd]

Hi Blst

Thank you for the explanation.

QUOTE (blst @ 16 Jan 2005, 21:22)The speed is coded in two parts, synchro and data. the "barrecode" is printed on a silver sticker for a better reading.

an IR transmeter and receiver read the code and transmet it to a decoder (pic for exemple) who drive the motor by PWM.Yes, I get the picture.

There are a couple of points regarding our CarDCC car controller prototypes:

1) The current design won't support the described functionality, as there is no IR receiver on the car controller. It would be possible to make another design that could implement this feature though.

2) If you want to reuse the IR transmitter for both lane change sensor and speed sensor, you have to place the barcode on the bottom of the slot. I suppose it could be done, but you need a reflective detector wit a long focus range (about 10mm), and you might have trouble getting reliable performance on curved sections.

3) If you want to place the barcode closer to the sensor (i.e. on the track surface), you need a seperate IR transmitter and receiver. This can also be done, but you need a processor with more I/O's.

There is also a possibility with the CarDCC system: if we use the guide blade to code the cars with different slits in the guide blade. Not only could the lane change controller detect the car-id and the time of passing, but using the absolute timing between the slit pulses, it could also calculate the speed of the car.

This could then be sent to the track controller together with the timing information. You could either implement the ghost car algorithm in the track controller, or the track controller could send it to a PC, that could implement the algorithm and handle the ghost car control real time.

If you want to experiment with this on your own, you should feel free to use the system specification and interface protocol specification from the CarDCC project. That will allow you to use the other components, like track controller and lane change controller, without modification, and just focus on a CarDCC compatible car controller.

Good luck with your project.

 

[David Caille]

Hi,

Thanks Sword, like always, your answer is very complete.

I have seen specification of CNY70 sensor who have a focus around 10mm.
For lane changing, my system is automatic, it's not a problem.
For car id detection, it's crictical. someone want yes, others no.
I think if you want to race alone with ten ghost cars, car id detection is not necessary.

best regards

 

[SWoRd]

Hi David
QUOTE (blst @ 17 Jan 2005, 08:01)I have seen specification of CNY70 sensor who have a focus around 10mm.That sounds about ideal for a reflective pattern at the bottom of the slot.

QUOTE For lane changing, my system is automatic, it's not a problem.
For car id detection, it's crictical. someone want yes, others no.
I think if you want to race alone with ten ghost cars, car id detection is not necessary.If your lane change is automatic, then you don't need the car id for that. The automatic lane change feature sounds very interresting.

If you want the system to keep track of individual car positions, lap times and perhaps even sector times, then you need car id detection.

The CarDCC system should be able to work very well with automatic lane changing. If you leave the solenoid outputs unconnected, you can use only the timing functions of the lane change controllers ... and you'll still have the option of a manually controlled pit lane entry.