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Pressure sensor throttle and generally rc esc problems

Posted: Feb 11, 2012 11:45 am
by snoopshomme86
Hi guys i´m starting now my first tread.
a couple of month ago i decited to build an rc powered bike .
After some searching for the perfect bike i bought an kmx venom and ordered an ms drive from matt.
But i think i will make an other topic for the hardware things. :lol:
An other story is the trottle design.I was thinking about many times because i dont like the trottles that on the web. :cry:
so i ordered an pressure sensor (i hope its right) at an german warehouse and it runns!! :mrgreen:
http://www.conrad.de/ce/de/product/5033 ... Detail=005
And i can adjust the max trottle with the servo tester poti .i hope this is usefull for someone
i don`t realy know how i can insert pics but i think i will post some soon
greets!

Re: Pressure sensor trottle

Posted: Feb 11, 2012 12:15 pm
by snoopshomme86
now the pics!
Image
Image
Image

Re: Pressure sensor trottle

Posted: Feb 11, 2012 12:48 pm
by snoopshomme86

Re: Pressure sensor trottle

Posted: Feb 11, 2012 1:03 pm
by snoopshomme86
Image

This is the "experimental" setup i ordert some sensors in tiny 8mm i think its more stealth :D

Re: Pressure sensor throttle

Posted: Feb 12, 2012 9:41 am
by Miles
Welcome snoops!

I like this idea 8) Thanks for the write up!

Re: Pressure sensor throttle

Posted: Feb 12, 2012 7:35 pm
by sn0wchyld
neat mate. makes me wonder if you could make a pedalec that adjusts the assistance power according to the difference in pressure between your feet, ie pedal hard, get full throttle on the motor, pedal lightly, get light throttle, stand up on your pedals for jumps etc, get no power! would be even better if it was running as a current based assistance, so the extra torque you get from the motor is directly proportional to the pressure you put on your driving pedal.

Re: Pressure sensor throttle

Posted: Feb 13, 2012 6:03 am
by snoopshomme86
maybe its possible with an freeweelcrank
something to lock the freeweel with the crankarms but a little bit space for an spring to reduce the torc on the sensor (its from 1g to 10kilo ) but you need an rotor contact system
i mean something like this http://www.google.lu/imgres?q=schleifri ... 9,r:9,s:15

Re: Pressure sensor throttle

Posted: Feb 13, 2012 1:57 pm
by snoopshomme86
Today the small sensors arrived but they are really verry small
Image 8)
i will test them if they have the same sensitivity
greets

Re: Pressure sensor throttle

Posted: Feb 13, 2012 1:58 pm
by snoopshomme86
oh its an m8 screw

Re: Pressure sensor throttle

Posted: Feb 19, 2012 6:52 am
by snoopshomme86
so im testet the small pressure sensor with an experimental friction drive setup and they´re realy more sensitive than the big one.But the reduction as friction drive was a little bit to long so my align was cooking verry fast.
Image

Re: Pressure sensor throttle

Posted: Feb 26, 2012 4:19 pm
by adrian_sm
I like the pressure sensor throttle. Are you happy with how it works? Have you tried actually riding the bike and using it?

Oh and what is the diameter and kv of the motor, and battery voltage?

Cheers, Adrian

Re: Pressure sensor throttle

Posted: Feb 27, 2012 1:30 pm
by snoopshomme86
The friction drive setup was only to test the throttle.Its an 149 kv Sk3 with 59mm dia.
The sensor turns the trottle very sensitive if you turn the poti to much .(Hope you understand what i mean)
But i found the right setup.
I tried 2 servo testers ,with the first one i had no full throttle range with the sensor.next i will by an servo tester building kit because there´s more space between the components to solder.
Actually i have no running setup.I´m still waiting for matts reduction drive .I´m planning to conect it with my alfine hub.
Yesterday i would make a test drive with my prototyp but i burnt the esc.

Re: Pressure sensor throttle and generally rc esc problems

Posted: Mar 11, 2012 9:03 am
by snoopshomme86
I was a little bit confuesed about the problems of rc esc´s with half trottle
after some serching of generally design from rc esc´s i found out that most of the esc´s are blockcomultating (hope it´s right)
i think thats the main problem so they designed for most time full throttle.
I found an esc thats designed for lower throttle but its a little pricy.
Otherwhise i think for the same money you will get an bicycle fork or an crank or.... so for high quality rc drive setup´s its maybe an option.

here´s an translation from the highlights

Conventional controllers are usually blockkommutierte on achieving and maintaining a designed maximum speed ('Vollgas' operation). This reached a peak drive its performance. (Power is proportional to RPM * Torque - the torque is limited by the maximum motor current -.. Possible more power is so only by increasing the speed) the same time a blockkommutierter controller operates at maximum speed in a relatively favorable operating point, as compared with the operating at partial load switching operations take place only a few of the power semiconductor switching losses are minimized and therefore in the power semiconductors. Only state losses are incurred and must be dissipated as heat.
If a regulator blockkommutierter operated at part load, will fall significantly more switching operations (PWM frequencies usual amount for the part-load operation 8kHz, 16kHz, 32kHz) and therefore switching losses. For such loss control services are usually blockkommutierte not designed to overheat if they are a long time operated at part load. This controller does not die blockkommutierte the 'heat death' is that only the complete shutdown of the drive as a way out. In practice, we encounter this problem with simple avoidance of the part-load ("never between 70% -90%") or a time limit of such a partial load condition 'by feel'.
Certain corrective gain additional heat sink and fan assembly, which are mostly cultivated by the user himself. This theory, an extension of the allowed part-time load is reached and the shutdown of the controller are delayed. Poor thermal connectivity of individual power semiconductors lead to failure of this method on a regular basis - a single overheated power semiconductors leads to the failure of the entire controller. In addition to the extra weight does not stay with this additional heat sink and / or fan unmentioned. Not should be mentioned: Some blockkommutierte regulator handle the situation elegantly by hochgeschalten is above a certain (even non-critical) part-load to 100%. Partial load does not exist for this control in the upper area!

When sinusoidal power controller makes use of field-oriented control mandatory also at full load with a relatively high frequency PWM switch - the motor current should eventually be controlled even at full load to a sinusoidal shape. The SLS has to be interpreted by its thermal design that is the 'worst case' full load. This also means that each state equal to full load operation (ie, every conceivable part-load operation) less power dissipation on the regulator with the result and thus is critical! The SLS is thus part load full!
As the largest loss of heat is obtained at full load, it is possible for the SLS of imminent overheating of the power output reduced (ie to go into partial load) and thus automatically to provide cooling. The SLS also switched not off when over-temperature, but continues to operate with reduced power, just enough that no temperature overshoot is observed. A non-vernachläßigender safety aspect!


OK, at full load incurred with more losses than SLS block-commutated controllers, which result out of the SLS higher switching losses. However, by the sine-flow losses avoided in the engine (keyword: harmonics), which compensate for the additional losses in more than SLS. So comparing a complete drive train "SLS + engine" with a "+ motor controllers blockkommutierter" the system with SLS in efficiency is better! ... and thus also in the expected flight time!
In addition, should in practice the very fact of not having to fly at full throttle most additional flight time based on a battery charge dysfunction!

http://www.sinusleistungssteller.de/index.html
did anyone know if there is a cheaper controller with sinusoidal power control?
greets and nice weekend