This might not be the right place to talk sensors but it is automotive.

I would like to simulate a safety system that I have seen fitted to training motorcycles. These bikes have got switch activating levers trailing out the back of the rear of the bike that activate whenever the back drops to a certain height. eg. If the front wheel raises more than x-distance, then the back must lower by y-distance and the switches activate.
As I do not want any levers hanging out the back of this particular bike, I sourced an ultrasonic distance sensor.

https://www.pepperl-fuchs.com/global/en/classid_186.htm?view=productdetails&prodid=24957

I cannot make any comment on its speed or accuracy as yet due to a much bigger problem I have found. This seems to detect the distance OK but only at an angle of 90 deg to the road surface. As the angle of the bike changes through its arc, the distance sensing becomes unreliable.

Any ideas?

(I have discounted any solid state gyro sensors as I believe they only measure change in state and not absolute position - unless I can find a real gyroscope form a fighter plane but size & cost are a factor)

 

Can you go by angle rather than absolute height? You can figure the angle with an accelerometer.

Accelerometers

 

Having been a biker for over 55 years, done speedway, motocross (scrambling in my days) road riding, (That's how I got the nickname Recklessrog from my friends!) I cannot see how it could differentiate between angle change due to a "wheelie" or going over a short bump that compresses the rear suspension. What is the sensors going to do? if the front comes up enough to activate and chops the throttle, the front wheel will drop back down and most likely chuck an inexperienced rider down the road. Bike training?? to be a good biker you need to "feel" everything the bike is doing, those that lack that ability usually either give up or at least shouldn't ride a motorbike or they will end up in a hedge somewhere!
Like my Lotus in my avatar, No power steering, No ABS, No traction control, over 300bhp and only 800Kg. The onboard computer is the DRIVER!!! Awesome fun!

 

As the angle of the bike changes through its arc, the distance sensing becomes unreliable.

At what angle does it stop working?

 

At what angle does it stop working?

For some reason there is nothing on the spec sheet for angle for the sensor I have.
I will try to accurately measure the working angle of the sensor and compare that to what I need.

 

Can you go by angle rather than absolute height? You can figure the angle with an accelerometer.

Accelerometers

Angle would work but I have never played with accelerators before.
Can you suggest any simple projects that might get me started?

 

The onboard computer is the DRIVER!!! Awesome fun!

You are 100% right but not everyone has the skills to stand a bike up without a huge chance of getting it wrong.
With the technology we have today, it must be possible to make it foolproof.

As for chopping the throttle and throwing the rider ....... I plan to reduce power gradually depending on the speed of angle change.

 

You are 100% right but not everyone has the skills to stand a bike up without a huge chance of getting it wrong.
With the technology we have today, it must be possible to make it foolproof.

As for chopping the throttle and throwing the rider ....... I plan to reduce power gradually depending on the speed of angle change.

Practice makes perfect, why not make a sensor system to do away with stabilisers on kiddies bikes?? (only kidding) sorry, but some things are best learnt the hard way.

 

some things are best learnt the hard way.

Sounds like a good epitaph.

 

Sounds like a good epitaph.

I did say "SOME" things lol

 

Angle would work but I have never played with accelerators before.
Can you suggest any simple projects that might get me started?

Neither have I except in my phone. Judging by the number of accelerometers on that Sparkfun page there must be many projects "out there".

 

You are 100% right but not everyone has the skills to stand a bike up without a huge chance of getting it wrong.
With the technology we have today, it must be possible to make it foolproof.

If the machine has to think for you you don't need to be on it to begin with because at minimal you are a legitimate danger to others and that's where everyone should have a problem with having unqualified unskilled people on the road or anywhere else.

When a person first starts riding a motorcycle they start with a smaller sized one thy can physically handle and work their way up. Technology is not a solution to lazy, ignorant and impatient.

 

If the machine has to think for you you don't need to be on it to begin with because at minimal you are a legitimate danger to others and that's where everyone should have a problem with having unqualified unskilled people on the road or anywhere else.

When a person first starts riding a motorcycle they start with a smaller sized one thy can physically handle and work their way up. Technology is not a solution to lazy, ignorant and impatient.

I'm with you but I consider your point more wishful thinking than reality. Every day there is a new technology which takes some thought and skill out of life, leaving more and more room for incompetence and idiocy. There's no reason for the TS to abandon his quest based on this. If he doesn't design it, someone else will.

Source: Tesla autopilot.

 

I'm with you but I consider your point more wishful thinking than reality. Every day there is a new technology which takes some thought and skill out of life, leaving more and more room for incompetence and idiocy. There's no reason for the TS to abandon his quest based on this. If he doesn't design it, someone else will.

Source: Tesla autopilot.

And that implementation of auto pilot where the vehicle does 100% of the driving and the person is just the passenger is exactly how one designs a machine to be foolproof by operator actions.
It takes the fool totally out of the position of having control over anything while in operation. Something that I doubt can ever be done practically on a motorcycle.

As for accelerometers I cannot see how they would work an motorcycle where constant changes in velocity and tilt are taking place simply by function of the machine would work. On top of that, if a motorcycle has enough power to flip itself over if the someone dumps the clutch or hits the throttle too hard clearly that machine is way overpowered for the skill sets and competency of the operator and they do not belong on it to begin with.

Also as for active acceleration control on a motorcycle that would require some form of active throttle and braking control that overrides the operators commands which as far as I am aware of no major motorcycle design as of yet have full drive by wire clutch, throttle and brake control systems.

To me this whole concept of what the OP is wishing for stinks of someone wanting to 'look cool' driving a big powerful motorcycle without ever putting in the time and work it takes to actually learn to properly handle and operate it which makes them a huge safety and liability concern for everyone else on the road.

 

Almost all the top bike manufacturers are using accelerators on current road bikes. I just read that since BMW introduced electronic rider aids to their training school fleet, they have 40% less accidents. Launch control, ABS, traction control & anti-wheelie systems. There is also a system that prevent you stuffing the brakes on too hard if you are lent over too much.

How many car manufacturers scrapped ABS just because someone said "It takes the skill out of stopping"?

I am not trying to 'look cool' on a bike that I cannot ride (I think the law prevents that with a driving test).
The anti-flip switches that are talked about at the top are a bit of safety kit that are working very well in most wheelie schools. It gives riders a safe experience of clutch & throttle control to the point of getting the bike into a wheelie. The point of this project is to work out if it can be home built without physical switches.

As for 'learning the hard way'. Do you leave razor blades in your kids bedroom to teach them not to get cut?

 

I actually said "SOME" things should be learnt the hard way, no one in their right mind would seriously leave razor blades lying around for the reason you say, Use common sense! (although that doesn't seem to be all that common nowadays)

So what happens when the "trainee" learns on a bike that won't flip, fall over, lock up, high or low side you, then gets on a normal bike that has none of this?? Quick trip to the mortuary I guess!

 

I honestly can't see why this is such an issue!
You would learn how to be comfortable with the bike at balance. Once you think you know what you are doing, you can dial the safety system back a little. It will still be there to stop an accident if you make a mistake. It is a learning tool and you can't say that tools do not have purpose.
No one in their right mind would use a safety system just once and then go full solo.

Does a tight rope walker use a net just for the first try?
A lion tamer take a chair & whip only for the first meeting?
How about a pilot take an instructor up just once?
A speedway rider only use a crash helmet just once because he didn't crash last time?

 

As for 'learning the hard way'. Do you leave razor blades in your kids bedroom to teach them not to get cut?

No, that stupid and baiting the question.

They get what we all got in life as we learned about the cold hard uncaring reality of life. Warned a few times, shown some hard earned scars brought into existence by our own stupidity and then largely left to find out the hard way what not listening to those who have experience gets you, which is your own scars to show your own kids someday when they hit that point in life.

 

Your own reply makes the point very well. Quote.... "once you THINK you know what you are doing"
I and many of my biker friends have survived real life sudden real life riding situations that called on every last ounce of learned skills from learning the hard way @ moto cross speedway, off road etc riding, that have kept us alive today. anyone who misses out on learning what happens when you overcook it, ain't gonna live long! better than making a bike think and react for you, provide the off road spaces and training in REAL biking skills. Other than that, drive a car.

 

anyone who misses out on learning what happens when you overcook it, ain't gonna live long!.

Now your sounding like the sort of person who removes the gel strips from your razor blades because you like living on the edge.
I can't believe that you do not see any place in this world for safe training, driver aids or practice tools other than a 'stick your finger in the fire, bet you won't do it again' mentality.