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From: Anthony J. <ant...@gm...> - 2010-04-23 04:12:09
|
http://sudarshantourism.com/home/index.php -- Regards, Anthony John K. Nathan |
From: cpf_123 <cp...@16...> - 2010-02-16 06:28:31
|
hopeing for discuss technology of UAVS . enjoy yourselves and have a fun. |
From: ego <ego...@gm...> - 2010-02-09 10:15:18
|
Hi Srinath, I've been busy, sorry for my late reply. I don't see how you get your Adisc matrix=[1 dt 0;0 1 -dt;0 0 1] In the original rotomotion code, xdot is the derivative of the state vector X over time. My state vector matrix X=[true_pos, true_velocity, accel_bias] xdot=A*X + B*u xdot=[pos_dot,vel_dot,a_bias_dot]=[vel,accel,0] vel(update)=vel+a*dt=vel+(a_measure-a_bias)*dt accel(update)=a_measure-a_bias So, my A matrix should be [0 1 -dt;0 0 -1;0 0 0] and B=[dt 1 0]; But then, I don't see how this filter is implemented, nor the theory that supports it. This kalman filter is different from what I have seen in the papers I read. The result of the corrected position is fairly good, but the corrected accelerometer error is unacceptable. It just doesn't track and correct the accelerometer error, which is my final goal. Let me know how it goes to you. This is the only code I have found to do what I'm trying to do. Best regards, Ego 2010/1/28 Srinath M <sri...@gm...> > Hi Ego > > Sorry to reply late, i am no expert on actual implementation, and am trying > to do the same thing as you. > I am not sure if your A matrix is correct > Shouldn't the continous system, just be represented as > xdot = Acontx +Bcontu + w > I assume like you that the state vector is [true_pos true_velocity > accelrometer_bias]. > Let us regard accelrometer reading as an input u to the system. > For this state vector Acont would be [0 1 0; 0 0 -1; 0 0 0],Bcont would be > [0;1;0] and w would be white noise > So for the discrete system, shouldn't A just be > Adisc=[1 dt 0;0 1 -dt; 0 0 1]. > and this doesn't match with your A > > Pls correct me if i am wrong. > I hv learnt KF's from this site. > http://www.cs.unc.edu/~welch/kalman/kalmanIntro.html > > Regards > Srinath > > > On Tue, Jan 19, 2010 at 5:45 , ego <ego...@gm...> wrote: > >> Hello to all, >> I'm new here, and already need your help!! >> >> I'm using a kalman filter to find out the linear position of a moving >> object (movement limited to a single axis), where I use a ADX202 >> accelerometer to measure the acceleration, and take some noisy measurements >> of the position as well. >> >> I'm adapting the rotomotion code for a tilt sensor, where tilt is measured >> with a 2 axis accelerometer and angular rate with a gyro. I guess this code >> is well known but I post the link here: >> http://scratchpad.wikia.com/wiki/RotomotionCode >> >> In my project the state vector would be: >> >> X=[position, velocity, acceleration_bias] >> >> And so the state functions: >> >> Xdot=[position_dot, velocity_dot, acceleration_bias_dot] >> >> position_dot=velocity >> velocity_dot= acceleration-acceleration_bias_dot >> acceleration_bias_dot=0 >> >> And the covariance matrix (initial state): >> >> P=[1 0 0] >> [0 0 0] >> [0 0 1] >> >> The jacobian of Xdot with respect to the states: >> >> A=[d(pos_dot)/d(position) d(pos_dot)/d(vel) d(pos_dot)/d(a_bias)] >> [d(vel_dot)/d(position) d(vel_dot)/d(vel) d(vel_dot)/d(a_bias)] >> [d(a_bias_dot/d(pos) d(a_bias_dot/d(vel) d(a_bias_dot/d(a_bias)] >> >> A=[0 1 -dt] >> [0 0 -1] >> [0 0 0] (is this correct??) >> >> Pdot=A*P+P'*A+Q >> >> where Q=[Q_pos 0 0] >> [0 Q_vel 0] >> [0 0 Q_accel] >> >> C matrix is: C=[1 0 0] >> >> >> As I said I measure the position with a noisy sensor and the acceleration >> so: >> >> accel = measured_accel - a_bias >> vel = vel + accel*dt >> pos= pos+vel*dt+1/2*accel*dt^2 >> >> Inn=pos_meas - p >> >> And then I update the elements of the matrix Pdot (Pdot=A*P+P'*A+Q) >> >> Then compute the covariance matrix P=P+Pdot*dt >> >> E=CPC'+R >> >> K=PC'inv(E) >> >> Then update the covariance matrix: P=P-KCP >> >> And finally update the state estimate X=X+K*Inn >> >> >> >> The results I get from this filter are quite good, but there is something >> I am not doing right. When the object is stopped, I get the correct >> position, velocity is zero, BUT the a_bias is not correct as it gives me a >> residual acceleration that is not zero. >> pos=correct (stopped) >> vel=0 >> accel=(a_meas-a_bias)<>0 >> >> I don't understand exactly how this kalman filter is implemented (and I >> cannot find any info on this way of implementing the filter, I mean updating >> the covariace matrix P=P+Pdot*dt). >> >> Can you help me? Do you see anything that I do wrong? >> >> Thanks for your help >> >> >> ------------------------------------------------------------------------------ >> Throughout its 18-year history, RSA Conference consistently attracts the >> world's best and brightest in the field, creating opportunities for >> Conference >> attendees to learn about information security's most important issues >> through >> interactions with peers, luminaries and emerging and established >> companies. >> http://p.sf.net/sfu/rsaconf-dev2dev >> _______________________________________________ >> http://autopilot.sourceforge.net/ Development mailing list >> https://lists.sourceforge.net/lists/listinfo/autopilot-devel >> >> > > > ------------------------------------------------------------------------------ > The Planet: dedicated and managed hosting, cloud storage, colocation > Stay online with enterprise data centers and the best network in the > business > Choose flexible plans and management services without long-term contracts > Personal 24x7 support from experience hosting pros just a phone call away. > http://p.sf.net/sfu/theplanet-com > _______________________________________________ > http://autopilot.sourceforge.net/ Development mailing list > https://lists.sourceforge.net/lists/listinfo/autopilot-devel > > |
From: Srinath M <sri...@gm...> - 2010-01-28 18:46:49
|
Hi Ego Sorry to reply late, i am no expert on actual implementation, and am trying to do the same thing as you. I am not sure if your A matrix is correct Shouldn't the continous system, just be represented as xdot = Acontx +Bcontu + w I assume like you that the state vector is [true_pos true_velocity accelrometer_bias]. Let us regard accelrometer reading as an input u to the system. For this state vector Acont would be [0 1 0; 0 0 -1; 0 0 0],Bcont would be [0;1;0] and w would be white noise So for the discrete system, shouldn't A just be Adisc=[1 dt 0;0 1 -dt; 0 0 1]. and this doesn't match with your A Pls correct me if i am wrong. I hv learnt KF's from this site. http://www.cs.unc.edu/~welch/kalman/kalmanIntro.html Regards Srinath On Tue, Jan 19, 2010 at 5:45 , ego <ego...@gm...> wrote: > Hello to all, > I'm new here, and already need your help!! > > I'm using a kalman filter to find out the linear position of a moving > object (movement limited to a single axis), where I use a ADX202 > accelerometer to measure the acceleration, and take some noisy measurements > of the position as well. > > I'm adapting the rotomotion code for a tilt sensor, where tilt is measured > with a 2 axis accelerometer and angular rate with a gyro. I guess this code > is well known but I post the link here: > http://scratchpad.wikia.com/wiki/RotomotionCode > > In my project the state vector would be: > > X=[position, velocity, acceleration_bias] > > And so the state functions: > > Xdot=[position_dot, velocity_dot, acceleration_bias_dot] > > position_dot=velocity > velocity_dot= acceleration-acceleration_bias_dot > acceleration_bias_dot=0 > > And the covariance matrix (initial state): > > P=[1 0 0] > [0 0 0] > [0 0 1] > > The jacobian of Xdot with respect to the states: > > A=[d(pos_dot)/d(position) d(pos_dot)/d(vel) d(pos_dot)/d(a_bias)] > [d(vel_dot)/d(position) d(vel_dot)/d(vel) d(vel_dot)/d(a_bias)] > [d(a_bias_dot/d(pos) d(a_bias_dot/d(vel) d(a_bias_dot/d(a_bias)] > > A=[0 1 -dt] > [0 0 -1] > [0 0 0] (is this correct??) > > Pdot=A*P+P'*A+Q > > where Q=[Q_pos 0 0] > [0 Q_vel 0] > [0 0 Q_accel] > > C matrix is: C=[1 0 0] > > > As I said I measure the position with a noisy sensor and the acceleration > so: > > accel = measured_accel - a_bias > vel = vel + accel*dt > pos= pos+vel*dt+1/2*accel*dt^2 > > Inn=pos_meas - p > > And then I update the elements of the matrix Pdot (Pdot=A*P+P'*A+Q) > > Then compute the covariance matrix P=P+Pdot*dt > > E=CPC'+R > > K=PC'inv(E) > > Then update the covariance matrix: P=P-KCP > > And finally update the state estimate X=X+K*Inn > > > > The results I get from this filter are quite good, but there is something I > am not doing right. When the object is stopped, I get the correct position, > velocity is zero, BUT the a_bias is not correct as it gives me a residual > acceleration that is not zero. > pos=correct (stopped) > vel=0 > accel=(a_meas-a_bias)<>0 > > I don't understand exactly how this kalman filter is implemented (and I > cannot find any info on this way of implementing the filter, I mean updating > the covariace matrix P=P+Pdot*dt). > > Can you help me? Do you see anything that I do wrong? > > Thanks for your help > > > ------------------------------------------------------------------------------ > Throughout its 18-year history, RSA Conference consistently attracts the > world's best and brightest in the field, creating opportunities for > Conference > attendees to learn about information security's most important issues > through > interactions with peers, luminaries and emerging and established companies. > http://p.sf.net/sfu/rsaconf-dev2dev > _______________________________________________ > http://autopilot.sourceforge.net/ Development mailing list > https://lists.sourceforge.net/lists/listinfo/autopilot-devel > > |
From: Hugo M. <h.m...@te...> - 2010-01-19 17:26:34
|
Hi, There are only a few readers left here... Here is a bug report that was posted on this forum on 7/22/2008 by Achim Walther. Maybe it can be of some help to you... ------------------------------------------------------------------- I know there's not much going on in this list and that is still understatement, but I want to report a bug in the autopilot code to the few remaining readers. (For amusement or whatever ;-) I own a Rotomotion 6DOF IMU. To use it with a Multiplex EasyStar I had to reduce the size of the main board by applying SMD components. I'm using the IMU only for data gathering and doing the maths with a Gumstix computer. Therefore I had to port the Kalman filtering code. I chose the code from ahrs.c that comes in directory autopilot-2.5/onboard/avr. Which may be a mistake because it now looks like an abandoned version branch to me. However, line 156 in function kalman_update tries to invert matrix E by saying m33_inv( E, T2 ); but does the opposite. The correct function call would be m33_inv( T2, E ); since E is the source and T2 is the target. Having fixed that, my 3D visualisation of the Kalman filter works fine and I hope it will do the same in the airborne software. But - as I said - I'm afraid of having used an old branch... Regards, Achim. ------------------------------------------- Regards and success, Hugo I know there's not much going on in this list and that is still understatement, but I want to report a bug in the autopilot code to the few remaining readers. (For amusement or whatever ;-) I own a Rotomotion 6DOF IMU. To use it with a Multiplex EasyStar I had to reduce the size of the main board by applying SMD components. I'm using the IMU only for data gathering and doing the maths with a Gumstix computer. Therefore I had to port the Kalman filtering code. I chose the code from ahrs.c that comes in directory autopilot-2.5/onboard/avr. Which may be a mistake because it now looks like an abandoned version branch to me. However, line 156 in function kalman_update tries to invert matrix E by saying m33_inv( E, T2 ); but does the opposite. The correct function call would be m33_inv( T2, E ); since E is the source and T2 is the target. Having fixed that, my 3D visualisation of the Kalman filter works fine and I hope it will do the same in the airborne software. But - as I said - I'm afraid of having used an old branch... Regards, Achim. ego wrote: > Hello to all, > I'm new here, and already need your help!! > > I'm using a kalman filter to find out the linear position of a moving > object (movement limited to a single axis), where I use a ADX202 > accelerometer to measure the acceleration, and take some noisy > measurements of the position as well. > > I'm adapting the rotomotion code for a tilt sensor, where tilt is > measured with a 2 axis accelerometer and angular rate with a gyro. I > guess this code is well known but I post the link here: > http://scratchpad.wikia.com/wiki/RotomotionCode > > In my project the state vector would be: > > X=[position, velocity, acceleration_bias] > > And so the state functions: > > Xdot=[position_dot, velocity_dot, acceleration_bias_dot] > > position_dot=velocity > velocity_dot= acceleration-acceleration_bias_dot > acceleration_bias_dot=0 > > And the covariance matrix (initial state): > > P=[1 0 0] > [0 0 0] > [0 0 1] > > The jacobian of Xdot with respect to the states: > > A=[d(pos_dot)/d(position) d(pos_dot)/d(vel) d(pos_dot)/d(a_bias)] > [d(vel_dot)/d(position) d(vel_dot)/d(vel) d(vel_dot)/d(a_bias)] > [d(a_bias_dot/d(pos) d(a_bias_dot/d(vel) d(a_bias_dot/d(a_bias)] > > A=[0 1 -dt] > [0 0 -1] > [0 0 0] (is this correct??) > > Pdot=A*P+P'*A+Q > > where Q=[Q_pos 0 0] > [0 Q_vel 0] > [0 0 Q_accel] > > C matrix is: C=[1 0 0] > > > As I said I measure the position with a noisy sensor and the > acceleration so: > > accel = measured_accel - a_bias > vel = vel + accel*dt > pos= pos+vel*dt+1/2*accel*dt^2 > > Inn=pos_meas - p > > And then I update the elements of the matrix Pdot (Pdot=A*P+P'*A+Q) > > Then compute the covariance matrix P=P+Pdot*dt > > E=CPC'+R > > K=PC'inv(E) > > Then update the covariance matrix: P=P-KCP > > And finally update the state estimate X=X+K*Inn > > > > The results I get from this filter are quite good, but there is > something I am not doing right. When the object is stopped, I get the > correct position, velocity is zero, BUT the a_bias is not correct as > it gives me a residual acceleration that is not zero. > pos=correct (stopped) > vel=0 > accel=(a_meas-a_bias)<>0 > > I don't understand exactly how this kalman filter is implemented (and > I cannot find any info on this way of implementing the filter, I mean > updating the covariace matrix P=P+Pdot*dt). > > Can you help me? Do you see anything that I do wrong? > > Thanks for your help > ------------------------------------------------------------------------ > > ------------------------------------------------------------------------------ > Throughout its 18-year history, RSA Conference consistently attracts the > world's best and brightest in the field, creating opportunities for Conference > attendees to learn about information security's most important issues through > interactions with peers, luminaries and emerging and established companies. > http://p.sf.net/sfu/rsaconf-dev2dev > ------------------------------------------------------------------------ > > _______________________________________________ > http://autopilot.sourceforge.net/ Development mailing list > https://lists.sourceforge.net/lists/listinfo/autopilot-devel > |
From: ego <ego...@gm...> - 2010-01-19 13:17:09
|
Hello to all, I'm new here, and already need your help!! I'm using a kalman filter to find out the linear position of a moving object (movement limited to a single axis), where I use a ADX202 accelerometer to measure the acceleration, and take some noisy measurements of the position as well. I'm adapting the rotomotion code for a tilt sensor, where tilt is measured with a 2 axis accelerometer and angular rate with a gyro. I guess this code is well known but I post the link here: http://scratchpad.wikia.com/wiki/RotomotionCode In my project the state vector would be: X=[position, velocity, acceleration_bias] And so the state functions: Xdot=[position_dot, velocity_dot, acceleration_bias_dot] position_dot=velocity velocity_dot= acceleration-acceleration_bias_dot acceleration_bias_dot=0 And the covariance matrix (initial state): P=[1 0 0] [0 0 0] [0 0 1] The jacobian of Xdot with respect to the states: A=[d(pos_dot)/d(position) d(pos_dot)/d(vel) d(pos_dot)/d(a_bias)] [d(vel_dot)/d(position) d(vel_dot)/d(vel) d(vel_dot)/d(a_bias)] [d(a_bias_dot/d(pos) d(a_bias_dot/d(vel) d(a_bias_dot/d(a_bias)] A=[0 1 -dt] [0 0 -1] [0 0 0] (is this correct??) Pdot=A*P+P'*A+Q where Q=[Q_pos 0 0] [0 Q_vel 0] [0 0 Q_accel] C matrix is: C=[1 0 0] As I said I measure the position with a noisy sensor and the acceleration so: accel = measured_accel - a_bias vel = vel + accel*dt pos= pos+vel*dt+1/2*accel*dt^2 Inn=pos_meas - p And then I update the elements of the matrix Pdot (Pdot=A*P+P'*A+Q) Then compute the covariance matrix P=P+Pdot*dt E=CPC'+R K=PC'inv(E) Then update the covariance matrix: P=P-KCP And finally update the state estimate X=X+K*Inn The results I get from this filter are quite good, but there is something I am not doing right. When the object is stopped, I get the correct position, velocity is zero, BUT the a_bias is not correct as it gives me a residual acceleration that is not zero. pos=correct (stopped) vel=0 accel=(a_meas-a_bias)<>0 I don't understand exactly how this kalman filter is implemented (and I cannot find any info on this way of implementing the filter, I mean updating the covariace matrix P=P+Pdot*dt). Can you help me? Do you see anything that I do wrong? Thanks for your help |
From: <sga...@go...> - 2010-01-02 11:52:37
|
Ausente por vacaciones hasta el 4 de Enero Contactar con com...@go... I have left for christmas vacation/holiday and will be back again on 4th January. Please contact com...@go... Muchas gracias / Thank you Sergio Garrido |
From: <jH...@t-...> - 2010-01-02 11:51:56
|
<span style="font-family: arial,helvetica,sans-serif; color: #000000;">Happy New Year to all members of the autopilot list!<br /><br />Thanks for your continued input! Currently my favourite solution is this one:<br /><br />http://www.rls.si/default.asp?prod=am8192b<br /><br />I must admit that I am a bit reluctant to use optical means since I feel that the <br />processing might be much harder. It will probably summer (or winter again.?.;-) <br />until I have my test rig up and running so bear with me folks.<br /><br />So long,<br /><br /><br />Juergen<br /><br /><br /><br /> <br /> -----Original-Nachricht-----<br /> Subject: Re: [Autopilot] Rotor twist angle<br /> Date: Thu, 31 Dec 2009 20:04:53 +0100<br /> From: Tom Becker <GTBecker@RighTime.com><br /> To: "jH...@t-..." <jH...@t-...>, Development and design discussion on the UAV <aut...@li...><br /> <br /> Another optical method:<br /> <br /> Mount two - or several - chip LEDs on the tips at strategic locations. <br /> Run small wiring for power from a battery and current-limiting <br /> resistance at the hub through the blade or along the leading edge. Run <br /> the blade in darkness and photograph the resulting trace with a long <br /> shutter and pop a single flash to illuminate an optional scale. <br /> Appropriate camera placement and measurements should yield your data - <br /> and provide intuitive interpretation of oddities like flex, <br /> oscillations, etc.<br /> <br /> Green is most visible to the eye, but red woks best for silicon image <br /> sensors. Chip LEDs can often be found on discarded electronics.<br /> <br /> Tom<br /> <br /> ------------------------------------------------------------------------------<br /> This SF.Net email is sponsored by the Verizon Developer Community<br /> Take advantage of Verizon's best-in-class app development support<br /> A streamlined, 14 day to market process makes app distribution fast and easy<br /> Join now and get one step closer to millions of Verizon customers<br /> http://p.sf.net/sfu/verizon-dev2dev <br /> _______________________________________________<br /> http://autopilot.sourceforge.net/ Development mailing list<br /> https://lists.sourceforge.net/lists/listinfo/autopilot-devel<br /> </span> |
From: Tom B. <GTBecker@RighTime.com> - 2009-12-31 19:31:48
|
Another optical method: Mount two - or several - chip LEDs on the tips at strategic locations. Run small wiring for power from a battery and current-limiting resistance at the hub through the blade or along the leading edge. Run the blade in darkness and photograph the resulting trace with a long shutter and pop a single flash to illuminate an optional scale. Appropriate camera placement and measurements should yield your data - and provide intuitive interpretation of oddities like flex, oscillations, etc. Green is most visible to the eye, but red woks best for silicon image sensors. Chip LEDs can often be found on discarded electronics. Tom |
From: Ben A. <a_...@ho...> - 2009-12-31 07:19:28
|
even the root will have some twist due to the blade being physically connected to the rest of the blade that is twisting. It's not connected to an immovable object :) The video at the bottom of Jurgen's next email I think demonstrates why high speed photography is virtually a necessity... with dynamics like that, the laser idea is gonna be tough as hell... Even the twist-sensor idea Jurgen had is going to be majorly swamped by noise at the resolution he wants to achieve.... I'm going to go back to the original high-speed camera (chdk canon + flash sync for cheap price option, mega-buck high speed video if money is no object) + photoshop idea as my favourite for even getting close to the measurement he wants.... Ben. Tom Becker wrote: > As I read my last message, I realize that lift will also cause laser > beam deflection from a mirror on the tip. It might be necessary, then, > to use two laser pointers working off two points on the blade tip, > perhaps one at the crown of the airfoil and one at the trailing edge. > Lift will cause both points to rise, but the difference between the > points should be due to twist alone, I think. > > A mirror at the hub, however, should not be affected by lift. > > > Tom > > ------------------------------------------------------------------------------ > This SF.Net email is sponsored by the Verizon Developer Community > Take advantage of Verizon's best-in-class app development support > A streamlined, 14 day to market process makes app distribution fast and easy > Join now and get one step closer to millions of Verizon customers > http://p.sf.net/sfu/verizon-dev2dev > _______________________________________________ > http://autopilot.sourceforge.net/ Development mailing list > https://lists.sourceforge.net/lists/listinfo/autopilot-devel > > > _________________________________________________________________ Use Messenger in your Hotmail inbox Find out how http://windowslive.ninemsn.com.au/hotmail/article/823454/web-im-for-hotmail-is-here |
From: <jH...@t-...> - 2009-12-31 06:59:07
|
<div id="post_message_337705">Dear all,<br /> <br /> the use of lasers seems an idea to ponder but I feel there might be snags along that way.<br /> For once the motion of a blade tip resembles a fairly wild dance at operational rpm.<br /> Have a look at the video in the lower part of this page:<br /> <br /> <a href="http://www.aunaocio.com/zonaweb/giroferetro/pagina22466.htm" target="_blank">http://www.aunaocio.com/zonaweb/giro...agina22466.htm</a><br /> <br /> Trying to find mirrors at the blade tip might be akin to throwing peas at a rabbit from a merry-go-round...;-)<br /> (But maybe I just have the wrong idea about how the setup works)<br /> <br /> Because of the somewhat eratic movement of the tip I deemed it necessary to collect like 100 samples per second and then <br />use e.g. a Kalman filter to extract the angle information, if that is true I feel it rules out any use of optical measurements, be it <br />cameras or laser.<br /> <br /> <br /> <br /> Cheers,<br /> <br /> <br /> Juergen</div> <!-- / message --> <!-- edit note --> <hr style="color: #d5d8e5; background-color: #d5d8e5;" size="1" /> <br /><span style="font-family: arial,helvetica,sans-serif; color: #000000;"> <br /> -----Original-Nachricht-----<br /> Subject: Re: [Autopilot] Rotor twist angle<br /> Date: Thu, 31 Dec 2009 01:43:34 +0100<br /> From: Tom Becker <GTBecker@RighTime.com><br /> To: Development and design discussion on the UAV <aut...@li...><br /> <br /> As I read my last message, I realize that lift will also cause laser <br /> beam deflection from a mirror on the tip. It might be necessary, then, <br /> to use two laser pointers working off two points on the blade tip, <br /> perhaps one at the crown of the airfoil and one at the trailing edge. <br /> Lift will cause both points to rise, but the difference between the <br /> points should be due to twist alone, I think.<br /> <br /> A mirror at the hub, however, should not be affected by lift.<br /> <br /> <br /> Tom<br /> <br /> ------------------------------------------------------------------------------<br /> This SF.Net email is sponsored by the Verizon Developer Community<br /> Take advantage of Verizon's best-in-class app development support<br /> A streamlined, 14 day to market process makes app distribution fast and easy<br /> Join now and get one step closer to millions of Verizon customers<br /> http://p.sf.net/sfu/verizon-dev2dev <br /> _______________________________________________<br /> http://autopilot.sourceforge.net/ Development mailing list<br /> https://lists.sourceforge.net/lists/listinfo/autopilot-devel<br /> </span> |
From: Tom B. <GTBecker@RighTime.com> - 2009-12-31 00:44:11
|
As I read my last message, I realize that lift will also cause laser beam deflection from a mirror on the tip. It might be necessary, then, to use two laser pointers working off two points on the blade tip, perhaps one at the crown of the airfoil and one at the trailing edge. Lift will cause both points to rise, but the difference between the points should be due to twist alone, I think. A mirror at the hub, however, should not be affected by lift. Tom |
From: Tom B. <GTBecker@RighTime.com> - 2009-12-30 17:11:11
|
> ... The most important information I want to glean from the test is how the twist angle of the rotor blade depends on the flap angle. Measuring the flap angle is easy since it is controlled by a linear movement of the control cables so the question remains how to measure the angle of twist in real time while the rotor is spinning at 450-500 rpm and transfer the data to a computer. The maximum angle would be about +/- 10 degrees and the required resolution is 0.1 degree or better. I have two potential methods, although the camera suggestion is practical, even with an inexpensive video camera under bright lighting, synchronized to the passing blade tip. You can achieve effective shutter speeds of 1/100000Sec even with cheap CMOS modules today. Still, constructing such a test would be a project in itself - but practical and not expensive, I believe. One idea is to mount a flex sensor on the tip. http://www.sparkfun.com/commerce/product_info.php?products_id=8606 This device is ~10cm long, though. If your blade tip chord is less, it will not serve well, I think. Also, any electronic sensor on the blade needs to have the signal transported to the stationary world. One might initially think of sliprings, but they are difficult and, for commercial solutions, expensive. An inductive path can be built, two coaxial coils near one another that carry a modulated signal - or a wireless link, like Bluetooth, can be used to convey the data. Electronic methods will require power on the rotating apparatus, likely a small battery, in addition to the electronics. An optical solution might be your best bet. You might be able to mount a small front-surface mirror to the flying surface and reflect a laser pointer beam off of it as it passes some point. A long throw distance from the mirror, perhaps to a distant wall, will multiply the deflection to a practical measurable tangent. Or, if you can bring the blade rotation to the hub through the blade, a mirror at the hub will make a brighter deflection possible, since it can perhaps be continually illuminated by the laser beam. In that case, the deflection will result in an increasing-diameter drawn circle. Again, a longer throw distance will make measurement easier. An interesting project. Tom |
From: Ben A. <a_...@ho...> - 2009-12-30 16:03:43
|
A simple calibration chart photographed attached to the end of the blade should be sufficient to get the resolution you need. Reading off the result would be as simple as overlaying the in-test photo on top of the calibration photo in photoshop (or equivalent). Read it off directly. The optical method is also good for checking your assumptions about how the blade is behaving dynamically, non-linearities in twist, warping, flexing, and so on can all be seen by simple inspection. I do like the bouncing-laser idea mentioned by Neils. Cheaper, more real-time. I'm somewhat nervous about it's ability to hit your accuracy requirement though, should be easy enough to test when combined with the high-speed photo. What's the goal of your experiment? Ben. jH...@t-... wrote: Ben, cameras have been used for these measurements for quite some time but I figure they would be a bit unwieldy to use since much handiwork is required to get the angle information from a picture. There is software there to automate that process but that would probably not be cheap to buy and is definitely beyond me to program. I am looking for something like an encoder. I am thinking of having a light rod attached to a rib at the rotor tip and which runs inside the blade beeing free to rotate all the way down to the root (my blade is made up of a pine main spar with ribs and balsa sheets for covering). The encoder would be attached to the blade root. The rod has to be torsionally stiff enough not to be twisted itselfe by what littel moment the encoder would put on it but that should be easy. This setup would also allow to record time histories of twist angles when the flap is used for cyclic variation of blade pitch. It will take some month still until I can start since I also have to build a test rig to spin the rotor but if I have some results I will post them to the autopilot list. Thanks for your input, Juergen -----Original-Nachricht----- Subject: Re: [Autopilot] Rotor twist angle Date: Wed, 30 Dec 2009 13:12:34 +0100 From: Ben Anderson To: "jH...@t-..." , Development and design discussion on the UAV <aut...@li...> if you want cheap and reliable, I would suggest high speed camera is your best option. check out CHDK on cannon cameras, eg here: http://chdk.wikia.com/wiki/Samples:_High-Speed_Shutter_&_Flash-Sync I'd love to see your results! Regards, Ben. jH...@t-... wrote: Dear all, I am currently building a 1:5 model of a rotor with a trailing edge flap for collective and cyclic control. The most important information I want to glean from the test is how the twist angle of the rotor blade depends on the flap angle. Measuring the flap angle is easy since it is controlled by a linear movement of the control cables so the question remains how to measure the angle of twist in real time while the rotor is spinning at 450-500 rpm and transfer the data to a computer. The maximum angle would be about +/- 10 degrees and the required resolution is 0.1 degree or better. My experience in that area of measuring is quite limeted so any idea for a cheap (and still reliable) way to achive this is appreciated. Unfortunately the autopilot group is not very active so I'd also like to learn about other groups where I could ask that question. Thanks in advance, Juergen ------------------------------------------------------------------------------ This SF.Net email is sponsored by the Verizon Developer Community Take advantage of Verizon's best-in-class app development support A streamlined, 14 day to market process makes app distribution fast and easy Join now and get one step closer to millions of Verizon customers http://p.sf.net/sfu/verizon-dev2dev _______________________________________________ http://autopilot.sourceforge.net/ Development mailing list https://lists.sourceforge.net/lists/listinfo/autopilot-devel ------------------------------------------------------------------------------ This SF.Net email is sponsored by the Verizon Developer Community Take advantage of Verizon's best-in-class app development support A streamlined, 14 day to market process makes app distribution fast and easy Join now and get one step closer to millions of Verizon customers http://p.sf.net/sfu/verizon-dev2dev _______________________________________________ http://autopilot.sourceforge.net/ Development mailing list https://lists.sourceforge.net/lists/listinfo/autopilot-devel _________________________________________________________________ Looking for a great date? Meet singles at ninemsn dating http://clk.atdmt.com/NMN/go/150855801/direct/01/ |
From: Niels H. A. <ni...@ho...> - 2009-12-30 14:49:32
|
How many measurements do you need? If it is a tolerable amount (e.g. 10 or 20) you could try using a laser striper synchronized to the rotation to illuminate the blade at one position only, a reflective covering on the blade, and a ordinary camera to fotograph the reflection of the stripe on a wall or on the roof. You could calibrate such a setup with stationary and/or stiff blades, and draw a coordinate system on the surface you are projecting onto from the test runs. The interpretation of the pictures could easily be done in software, if you need a lot of measurements, as the line shapes is your data for the entire length of the blade. The tip rotation is the defection of the last pixel. In this way, you can also detect vibration (widening of the laser line), and it is much less intrusive than the encoder idea. Not enough resolution? Find a taller room or place a large mirror on the roof! I am actually rather fond of this idea - it could be fun to do! Good luck, and let us know how it works out. /Niels On Wed, Dec 30, 2009 at 14:30, jH...@t-... <jH...@t-...> wrote: > Ben, > > cameras have been used for these measurements for quite some time but I > figure they would be a bit unwieldy to use since much handiwork is required > to get the angle information from a picture. There is software there to > automate that process but that would probably not be cheap to buy and is > definitely beyond me to program. I am looking for something like an encoder. > I am thinking of having a light rod attached to a rib at the rotor tip and > which runs inside the blade beeing free to rotate all the way down to the > root (my blade is made up of a pine main spar with ribs and balsa sheets > for covering). The encoder would be attached to the blade root. The rod has > to be torsionally stiff enough not to be twisted itselfe by what littel > moment the encoder would put on it but that should be easy. This setup would > also allow to record time histories of twist angles when the flap is used > for cyclic variation of blade pitch. > > It will take some month still until I can start since I also have to build > a test rig to spin the rotor but if I have some results I will post them to > the > autopilot list. > > Thanks for your input, > > > Juergen > > > -----Original-Nachricht----- > Subject: Re: [Autopilot] Rotor twist angle > Date: Wed, 30 Dec 2009 13:12:34 +0100 > From: Ben Anderson <a_...@ho...> > To: "jH...@t-..." <jH...@t-...>, Development and design > discussion on the UAV <aut...@li...> > > > > if you want cheap and reliable, I would suggest high speed camera is your > best option. > > check out CHDK on cannon cameras, eg here: > http://chdk.wikia.com/wiki/Samples:_High-Speed_Shutter_&_Flash-Sync > > I'd love to see your results! > > Regards, > Ben. > > jH...@t-... wrote: > > > Dear all, > > I am currently building a 1:5 model of a rotor with a trailing edge flap > for collective and cyclic control. The most important information I want to > glean from the test is how the twist angle of the rotor blade depends on the > flap angle. Measuring the flap angle is easy since it is controlled by a > linear movement of the control cables so the question remains how to measure > the angle of twist in real time while the rotor is spinning at 450-500 rpm > and transfer the data to a computer. The maximum angle would be about +/- 10 > degrees and the required resolution is 0.1 degree or better. > > My experience in that area of measuring is quite limeted so any idea for a > cheap (and still reliable) way to achive this is appreciated. > Unfortunately the autopilot group is not very active so I'd also like to > learn about other groups where I could ask that question. > > > Thanks in advance, > > Juergen > > ------------------------------ > ------------------------------------------------------------------------------ This SF.Net email is sponsored by the Verizon Developer Community Take advantage of Verizon's best-in-class app development support A streamlined, 14 day to market process makes app distribution fast and easy Join now and get one step closer to millions of Verizon customers http://p.sf.net/sfu/verizon-dev2dev > > ------------------------------ > _______________________________________________ http://autopilot.sourceforge.net/ Development mailing list https://lists.sourceforge.net/lists/listinfo/autopilot-devel > > > > ------------------------------------------------------------------------------ > This SF.Net email is sponsored by the Verizon Developer Community > Take advantage of Verizon's best-in-class app development support > A streamlined, 14 day to market process makes app distribution fast and > easy > Join now and get one step closer to millions of Verizon customers > http://p.sf.net/sfu/verizon-dev2dev > _______________________________________________ > http://autopilot.sourceforge.net/ Development mailing list > https://lists.sourceforge.net/lists/listinfo/autopilot-devel > > |
From: <sga...@go...> - 2009-12-30 14:23:14
|
Ausente por vacaciones hasta el 4 de Enero Contactar con com...@go... I have left for christmas vacation/holiday and will be back again on 4th January. Please contact com...@go... Muchas gracias / Thank you Sergio Garrido |
From: <jH...@t-...> - 2009-12-30 13:55:39
|
<span style="font-family: arial,helvetica,sans-serif; color: #000000;">Ben,<br /><br />cameras have been used for these measurements for quite some time but </span>I figure they would be a bit unwieldy to use since much handiwork is required to get the angle information from a picture. There is software there to automate that process but that would probably not be cheap to buy and is definitely beyond me to program. I am looking for something like an encoder. I am thinking of having a light rod attached to a rib at the rotor tip and which runs inside the blade beeing free to rotate all the way down to the root (my blade is made up of a pine main spar with ribs and balsa sheets for covering). The encoder would be attached to the blade root. The rod has to be torsionally stiff enough not to be twisted itselfe by what littel moment the encoder would put on it but that should be easy. This setup would also allow to record time histories of twist angles when the flap is used for cyclic variation of blade pitch. <br /><br />It will take some month still until I can start since I also have to build a test rig to spin the rotor but if I have some results I will post them to the<br />autopilot list.<br /> <br /> Thanks for your input,<br /><br /><br />Juergen<br /> <br /><span style="font-family: arial,helvetica,sans-serif; color: #000000;"> <br /> -----Original-Nachricht-----<br /> Subject: Re: [Autopilot] Rotor twist angle<br /> Date: Wed, 30 Dec 2009 13:12:34 +0100<br /> From: Ben Anderson <a_...@ho...><br /> To: "jH...@t-..." <jH...@t-...>, Development and design discussion on the UAV <aut...@li...><br /> <br /> <br /> if you want cheap and reliable, I would suggest high speed camera is your best option.<br /> <br /> check out CHDK on cannon cameras, eg here: <a class="moz-txt-link-freetext" href="http://chdk.wikia.com/wiki/Samples:_High-Speed_Shutter_&_Flash-Sync">http://chdk.wikia.com/wiki/Samples:_High-Speed_Shutter_&_Flash-Sync</a><br /> <br /> I'd love to see your results!<br /> <br /> Regards,<br /> Ben.<br /> <br /> <a class="moz-txt-link-abbreviated" href="mailto:jH...@t-...">jH...@t-...</a> wrote: <blockquote><span style="font-family: arial,helvetica,sans-serif; color: #000000;"><br /> Dear all,<br /> <br /> I am currently building a 1:5 model of a rotor with a trailing edge flap for collective and cyclic control. The most important information I want to glean from the test is how the twist angle of the rotor blade depends on the flap angle. Measuring the flap angle is easy since it is controlled by a linear movement of the control cables so the question remains how to measure the angle of twist in real time while the rotor is spinning at 450-500 rpm and transfer the data to a computer. The maximum angle would be about +/- 10 degrees and the required resolution is 0.1 degree or better.<br /> <br /> My experience in that area of measuring is quite limeted so any idea for a cheap (and still reliable) way to achive this is appreciated.<br /> Unfortunately the autopilot group is not very active so I'd also like to learn about other groups where I could ask that question.<br /> <br /> <br /> Thanks in advance,<br /> <br /> Juergen<br /> </span> <pre> <hr size="4" /> ------------------------------------------------------------------------------ This SF.Net email is sponsored by the Verizon Developer Community Take advantage of Verizon's best-in-class app development support A streamlined, 14 day to market process makes app distribution fast and easy Join now and get one step closer to millions of Verizon customers <a class="moz-txt-link-freetext" href="http://p.sf.net/sfu/verizon-dev2dev">http://p.sf.net/sfu/verizon-dev2dev</a> </pre> <pre> <hr size="4" /> _______________________________________________ <a class="moz-txt-link-freetext" href="http://autopilot.sourceforge.net/">http://autopilot.sourceforge.net/</a> Development mailing list <a class="moz-txt-link-freetext" href="https://lists.sourceforge.net/lists/listinfo/autopilot-devel">https://lists.sourceforge.net/lists/listinfo/autopilot-devel</a> </pre> </blockquote> </span> |
From: Ben A. <a_...@ho...> - 2009-12-30 12:41:03
|
if you want cheap and reliable, I would suggest high speed camera is your best option. check out CHDK on cannon cameras, eg here: http://chdk.wikia.com/wiki/Samples:_High-Speed_Shutter_&_Flash-Sync I'd love to see your results! Regards, Ben. jH...@t-... wrote: > > Dear all, > > I am currently building a 1:5 model of a rotor with a trailing edge > flap for collective and cyclic control. The most important information > I want to glean from the test is how the twist angle of the rotor > blade depends on the flap angle. Measuring the flap angle is easy > since it is controlled by a linear movement of the control cables so > the question remains how to measure the angle of twist in real time > while the rotor is spinning at 450-500 rpm and transfer the data to a > computer. The maximum angle would be about +/- 10 degrees and the > required resolution is 0.1 degree or better. > > My experience in that area of measuring is quite limeted so any idea > for a cheap (and still reliable) way to achive this is appreciated. > Unfortunately the autopilot group is not very active so I'd also like > to learn about other groups where I could ask that question. > > > Thanks in advance, > > Juergen > ------------------------------------------------------------------------ > > ------------------------------------------------------------------------------ > This SF.Net email is sponsored by the Verizon Developer Community > Take advantage of Verizon's best-in-class app development support > A streamlined, 14 day to market process makes app distribution fast and easy > Join now and get one step closer to millions of Verizon customers > http://p.sf.net/sfu/verizon-dev2dev > ------------------------------------------------------------------------ > > _______________________________________________ > http://autopilot.sourceforge.net/ Development mailing list > https://lists.sourceforge.net/lists/listinfo/autopilot-devel > |
From: <jH...@t-...> - 2009-12-30 08:47:06
|
<span style="font-family: arial,helvetica,sans-serif; color: #000000;"><br /> Dear all,<br /><br />I am currently building a 1:5 model of a rotor with a trailing edge flap for collective and cyclic control. The most important information I want to glean from the test is how the twist angle of the rotor blade depends on the flap angle. Measuring the flap angle is easy since it is controlled by a linear movement of the control cables so the question remains how to measure the angle of twist in real time while the rotor is spinning at 450-500 rpm and transfer the data to a computer. The maximum angle would be about +/- 10 degrees and the required resolution is 0.1 degree or better.<br /><br />My experience in that area of measuring is quite limeted so any idea for a cheap (and still reliable) way to achive this is appreciated.<br />Unfortunately the autopilot group is not very active so I'd also like to learn about other groups where I could ask that question.<br /><br /><br />Thanks in advance,<br /><br />Juergen<br /> </span> |
From: Hugo M. <h.m...@te...> - 2009-12-10 01:59:48
|
Hi, You will find a lot of information and more for your project here: http://www.mikrokopter.de/ucwiki/en/MikroKopter Greetings, Hugo Ricci Harris wrote: > Hello, > > I'm currently doing my Final Year Project at university. My project > title is 'Design and build a UAV', and i'm looking mainly > at quad-rotor design. First and foremost I want to keep this as simple > as possible with my main aim being to apply a force to a hovering UAV > and for it to return to its original position. It's designed mainly > for indoor use and should be able to carry a 200g load. If anyone has > any information or help that could aid me with my project that would > be great. If anyone else has done a similar project to mine, a list of > what parts you used to make it and where you got them from would be > incredibly helpful. > > Any feedback would be much apreciated. > > Ricci Harris > ------------------------------------------------------------------------ > > ------------------------------------------------------------------------------ > Return on Information: > Google Enterprise Search pays you back > Get the facts. > http://p.sf.net/sfu/google-dev2dev > > ------------------------------------------------------------------------ > > _______________________________________________ > http://autopilot.sourceforge.net/ Development mailing list > https://lists.sourceforge.net/lists/listinfo/autopilot-devel > |
From: Jeffrey J. <ort...@gm...> - 2009-12-09 22:55:16
|
Although not very specific to Quad-Rotors ... have you checked out DIYDrones.com? On Wed, Dec 9, 2009 at 2:36 PM, Ricci Harris <ric...@go...> wrote: > Hello, > > I'm currently doing my Final Year Project at university. My project title is > 'Design and build a UAV', and i'm looking mainly at quad-rotor design. First > and foremost I want to keep this as simple as possible with my main aim > being to apply a force to a hovering UAV and for it to return to its > original position. It's designed mainly for indoor use and should be able to > carry a 200g load. If anyone has any information or help that could aid me > with my project that would be great. If anyone else has done a similar > project to mine, a list of what parts you used to make it and where you got > them from would be incredibly helpful. > > Any feedback would be much apreciated. > > Ricci Harris > ------------------------------------------------------------------------------ > Return on Information: > Google Enterprise Search pays you back > Get the facts. > http://p.sf.net/sfu/google-dev2dev > > _______________________________________________ > http://autopilot.sourceforge.net/ Development mailing list > https://lists.sourceforge.net/lists/listinfo/autopilot-devel > > |
From: Ricci H. <ric...@go...> - 2009-12-09 22:36:28
|
Hello, I'm currently doing my Final Year Project at university. My project title is 'Design and build a UAV', and i'm looking mainly at quad-rotor design. First and foremost I want to keep this as simple as possible with my main aim being to apply a force to a hovering UAV and for it to return to its original position. It's designed mainly for indoor use and should be able to carry a 200g load. If anyone has any information or help that could aid me with my project that would be great. If anyone else has done a similar project to mine, a list of what parts you used to make it and where you got them from would be incredibly helpful. Any feedback would be much apreciated. Ricci Harris |
From: Dinuka A. <the...@gm...> - 2009-12-01 03:10:36
|
Can somebody tell me how to access the archives of the mailing list ? On Tue, Dec 1, 2009 at 4:13 AM, Peralta, Miguel H < Mig...@ho...> wrote: > Hi everyone, > > > > I’m very happy to be allowed membership into the autopilot-development > list. My background is in electrical engineering with a keen interest in > control theory. I hope that I can help out in any way I can to further the > progress already made by everyone on this project. > > > > I also hope to learn as much about the technology that all of you have put > together as well as help to remove some of the existing obstacles. > > > > Regards, > > Miguel H. Peralta > > > > > > > ------------------------------------------------------------------------------ > Join us December 9, 2009 for the Red Hat Virtual Experience, > a free event focused on virtualization and cloud computing. > Attend in-depth sessions from your desk. Your couch. Anywhere. > http://p.sf.net/sfu/redhat-sfdev2dev > _______________________________________________ > http://autopilot.sourceforge.net/ Development mailing list > https://lists.sourceforge.net/lists/listinfo/autopilot-devel > > -- Dinuka Abeywardena Mobile : +94-71 -3017248 |
From: Peralta, M. H <Miguel.Peralta@Honeywell.com> - 2009-11-30 22:44:16
|
Hi everyone, I'm very happy to be allowed membership into the autopilot-development list. My background is in electrical engineering with a keen interest in control theory. I hope that I can help out in any way I can to further the progress already made by everyone on this project. I also hope to learn as much about the technology that all of you have put together as well as help to remove some of the existing obstacles. Regards, Miguel H. Peralta |
From: David Z. <da...@tz...> - 2009-11-07 12:06:13
|
Hi, i read in the comments of the module 'fast-ahrs.h/.cpp', that it is 'almost ready for use on microcontrollers'. Could you please tell me, what you mean by 'almost'? After all, the code looks pretty optimized to me. Best, David -- Ich widerspreche der Nutzung oder Übermittlung meiner Daten für Werbezwecke und für die Markt- oder Meinungsforschung. |