## Re: [Playerstage-users] Robot motion along a given curve ?

 Re: [Playerstage-users] Robot motion along a given curve ? From: Arkapravo Bhaumik - 2010-07-27 08:37:59 Attachments: Message as HTML Hi Nelson Many thanks, I will try to put it together as a program. On 27 July 2010 13:20, Nelson Goncalves wrote: > Hi, > > What you want is, in general, not trivial or simple to accomplish. > However there are known, simple solutions for your problem depending > on the type of drive of your robot. > > Essentially, you want a function that has as inputs: > - the position and orientation of the robot at time t, q(t) > - position and orientation of where the robot must be at time t, p(t) > > The function will then compute the output of each actuator so that > the error along the path is minimized: min \int_0^t (p(t) - q(t)) > > \int_0^t is the integral of a function from 0 up to t. > > I am making this much simpler than it is, and it is not possible to > write down a simple answer in the email without knowing more about > your robot or your background in mobile robotics. Try searching on > your local library (or the web) for "mobile robotic kinematics", > "control systems" and "path following". Often you can find simple > solutions for robots with tank like drives. > > As a final note, notice that you did not specify the orientation of > the robot along the circular path. This may seem obvious for some > types of drives, but an omni-directional robot can be made to move > along a circle *and* spin at the same time (like a ballet dancer). > > Also if you robot as a car like drive, then there is a lower bound on > the radius of the circle it can execute. As you can see the problem > is not trivial, even though it appears simple. > > Nelson Gon\c calves > > Em Tue, 27 Jul 2010 11:42:10 +0530 > Arkapravo Bhaumik escreveu: > > > Hi everyone > > > > I want my robot to move around in a given trajectory. Say a Cartesian > > (or Polar) curve is given and the robot executes a trajectory along > > that curve. For example if my program inputs x^2 + y^2 = 4, then my > > robot should move around the origin in a radius of 2 units. > > > > As of now, I do not have any clue as to how to put this to effect ! > > Any suggestions are welcome. > > > > Best regards > > > > Arkapravo > > > > > --- > Learning to eat soup with a knife > > ------------------------------------------- > Nelson Gonçalves > http://thinkingolivetree.blogspot.com/ > > > 

 [Playerstage-users] Robot motion along a given curve ? From: Arkapravo Bhaumik - 2010-07-27 06:12:36 Attachments: Message as HTML Hi everyone I want my robot to move around in a given trajectory. Say a Cartesian (or Polar) curve is given and the robot executes a trajectory along that curve. For example if my program inputs x^2 + y^2 = 4, then my robot should move around the origin in a radius of 2 units. As of now, I do not have any clue as to how to put this to effect ! Any suggestions are welcome. Best regards Arkapravo -- Arkapravo Bhaumik Websites : http://mobotica.blogspot.com/ E-mail : arkapravobhaumik@... Twitter : @abhaumik Facebook : Arkapravo Bhaumik Skype : arkapravo 
 Re: [Playerstage-users] Robot motion along a given curve ? From: Nelson Goncalves - 2010-07-27 07:50:32 Hi, What you want is, in general, not trivial or simple to accomplish. However there are known, simple solutions for your problem depending on the type of drive of your robot. Essentially, you want a function that has as inputs: - the position and orientation of the robot at time t, q(t) - position and orientation of where the robot must be at time t, p(t) The function will then compute the output of each actuator so that the error along the path is minimized: min \int_0^t (p(t) - q(t)) \int_0^t is the integral of a function from 0 up to t. I am making this much simpler than it is, and it is not possible to write down a simple answer in the email without knowing more about your robot or your background in mobile robotics. Try searching on your local library (or the web) for "mobile robotic kinematics", "control systems" and "path following". Often you can find simple solutions for robots with tank like drives. As a final note, notice that you did not specify the orientation of the robot along the circular path. This may seem obvious for some types of drives, but an omni-directional robot can be made to move along a circle *and* spin at the same time (like a ballet dancer). Also if you robot as a car like drive, then there is a lower bound on the radius of the circle it can execute. As you can see the problem is not trivial, even though it appears simple. Nelson Gon\c calves Em Tue, 27 Jul 2010 11:42:10 +0530 Arkapravo Bhaumik escreveu: > Hi everyone > > I want my robot to move around in a given trajectory. Say a Cartesian > (or Polar) curve is given and the robot executes a trajectory along > that curve. For example if my program inputs x^2 + y^2 = 4, then my > robot should move around the origin in a radius of 2 units. > > As of now, I do not have any clue as to how to put this to effect ! > Any suggestions are welcome. > > Best regards > > Arkapravo > --- Learning to eat soup with a knife ------------------------------------------- Nelson Gonçalves http://thinkingolivetree.blogspot.com/ 
 Re: [Playerstage-users] Robot motion along a given curve ? From: Arkapravo Bhaumik - 2010-07-27 08:37:59 Attachments: Message as HTML Hi Nelson Many thanks, I will try to put it together as a program. On 27 July 2010 13:20, Nelson Goncalves wrote: > Hi, > > What you want is, in general, not trivial or simple to accomplish. > However there are known, simple solutions for your problem depending > on the type of drive of your robot. > > Essentially, you want a function that has as inputs: > - the position and orientation of the robot at time t, q(t) > - position and orientation of where the robot must be at time t, p(t) > > The function will then compute the output of each actuator so that > the error along the path is minimized: min \int_0^t (p(t) - q(t)) > > \int_0^t is the integral of a function from 0 up to t. > > I am making this much simpler than it is, and it is not possible to > write down a simple answer in the email without knowing more about > your robot or your background in mobile robotics. Try searching on > your local library (or the web) for "mobile robotic kinematics", > "control systems" and "path following". Often you can find simple > solutions for robots with tank like drives. > > As a final note, notice that you did not specify the orientation of > the robot along the circular path. This may seem obvious for some > types of drives, but an omni-directional robot can be made to move > along a circle *and* spin at the same time (like a ballet dancer). > > Also if you robot as a car like drive, then there is a lower bound on > the radius of the circle it can execute. As you can see the problem > is not trivial, even though it appears simple. > > Nelson Gon\c calves > > Em Tue, 27 Jul 2010 11:42:10 +0530 > Arkapravo Bhaumik escreveu: > > > Hi everyone > > > > I want my robot to move around in a given trajectory. Say a Cartesian > > (or Polar) curve is given and the robot executes a trajectory along > > that curve. For example if my program inputs x^2 + y^2 = 4, then my > > robot should move around the origin in a radius of 2 units. > > > > As of now, I do not have any clue as to how to put this to effect ! > > Any suggestions are welcome. > > > > Best regards > > > > Arkapravo > > > > > --- > Learning to eat soup with a knife > > ------------------------------------------- > Nelson Gonçalves > http://thinkingolivetree.blogspot.com/ > > >