Hi Peter and John, I'm facing the same problem with getting acceleration from gazebo and i'm using a flying robot. Do you think it could be possible to have your code (i mean the imu interface and the gazebo files you modified)? I need to solve this problem and a "starting point" would be of great help! (Obviously i'll share with you my solution when i'll come to one :) Thanks in advance. Marco
@John: Thanks a lot for opening thread. It could be very useful! John Hsu-2 wrote: > > Hi, > I've opened a ticket for this issue > https://kforge.ros.org/gazebo/trac/ticket/24 > Please feel free to update the ticket. > Thanks, > <https://kforge.ros.org/gazebo/trac/ticket/24>John > > On Tue, Mar 29, 2011 at 7:25 AM, Peter Nordin <[email protected]> wrote: > >> Hello >> >> Unfortunately I do not think that I can help you, but I am having a >> similar problem. >> >> I am have been trying to use the IMU sensor, (I have added a few missing >> player interface related files), but in my case the acceleration is >> allways zero. Anyway I was not able to figure out why so I made some >> minor additions to the gazebo code and differentiated the linear >> velocity between each timestep. This way the reported acceleration will >> be the actual velocity derivative. The problem is that I wont get >> g=-9.81 in my output. This is OK in my ground robot case as I usually >> just remove the gravity component anyway. For flying robots I do not not >> know if this is Ok. >> >> I tried adding an additional "artificial" gravity vector (rotated into >> the curent body coordinate system) but realised that when the robot was >> moving along the Z-axis (very rarely), I would get double acceleration. >> -9.81 as well as the actual velocity derivative (-9.81 when free >> falling). I the end I removed the artificial gravity vector, as I actual >> have no real use for it. >> >> It is probably possible to solve this in some smart way but I have not >> had time to try and figure one out. >> >> I am using a fairly recent Gazebo svn version and player 3.0.2 >> >> /Peter >> >> >> On 03/28/2011 05:26 PM, Neostek wrote: >> > Hello everyone, >> > i'm using Gazebo to simulate a PD controller on a quadrotor UAV. >> > The control evalueates the force and torque to apply to the quadrotor >> and >> > then i use the methods >> > dBodyAddRelForce(body_id, 0, 0, thrust) and dBodyAddRelTorque(body_id, >> > roll_torque, pitch_torque, 0). >> > Now i would like to get information about position, velocity and >> > acceleration of the quadrotor. >> > To do so, i use the methods: >> > body->GetPosition() >> > body->GetLinearVel() >> > body->GetLinearAccel() >> > and the last one appears to give practically nonsense results (gravity >> > acceleration depending on the mass for instance...). >> > Browsing into the code i found out that GetLinearAccel() simply does >> > return this->GetForce() / this->GetMass(); >> > That is " F = m*a " as it should be. >> > Anyway the controller works and the quadrotor get still on the target >> point, >> > but the acceleration i get on the z axis is positive (e.g. = 19.6) even >> > though the quadrotor is not varying its height. >> > I really have no point...please help me! :) >> > Thanks in advance. >> > >> > Marco >> > >> > >> > For the sake of completeness i'm using the following software version: >> > Gazebo - 0.9.0 >> > Player - 2.1.3 >> >> >> ------------------------------------------------------------------------------ >> Enable your software for Intel(R) Active Management Technology to meet >> the >> growing manageability and security demands of your customers. Businesses >> are taking advantage of Intel(R) vPro (TM) technology - will your >> software >> be a part of the solution? Download the Intel(R) Manageability Checker >> today! http://p.sf.net/sfu/intel-dev2devmar >> _______________________________________________ >> Playerstage-gazebo mailing list >> [email protected] >> https://lists.sourceforge.net/lists/listinfo/playerstage-gazebo >> > ------------------------------------------------------------------------------ > Enable your software for Intel(R) Active Management Technology to meet the > growing manageability and security demands of your customers. Businesses > are taking advantage of Intel(R) vPro (TM) technology - will your software > be a part of the solution? Download the Intel(R) Manageability Checker > today! http://p.sf.net/sfu/intel-dev2devmar > _______________________________________________ > Playerstage-gazebo mailing list > [email protected] > https://lists.sourceforge.net/lists/listinfo/playerstage-gazebo > > -- View this message in context: http://old.nabble.com/Get-acceleration-tp31259367p31277669.html Sent from the playerstage-gazebo mailing list archive at Nabble.com. ------------------------------------------------------------------------------ Create and publish websites with WebMatrix Use the most popular FREE web apps or write code yourself; WebMatrix provides all the features you need to develop and publish your website. http://p.sf.net/sfu/ms-webmatrix-sf _______________________________________________ Playerstage-gazebo mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/playerstage-gazebo
