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Re: [diy_3d_printing_and_fabrication] Servo motors

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  • Graham
    I doubt you would achieve suffiecient positioning resolution with that robot, the angle errors add up quickly, you really need extremely hi res encoders and
    Message 1 of 8 , Feb 27, 2013
      I doubt you would achieve suffiecient positioning resolution with that robot, the angle errors add up quickly, you really need extremely hi res encoders and servos, I doubt the installed encoders are up to it nor will the gearbox quality be up to it probably

      Graham



      On 27 Feb 2013, at 02:39, "prkeays" <prkeays@...> wrote:

      > Scorbot training robotic manipulator
    • Murilo Lana
      Take a look at www.keling.com They have servos and other stuff at a vey good price. About the encoder I recommend the AMT CUI capacitive encoders. They cost
      Message 2 of 8 , Feb 27, 2013
        Take a look at www.keling.com

        They have servos and other stuff at a vey good price.
        About the encoder I recommend the AMT CUI capacitive encoders. They cost about 25 bucks and have selectable resolution from 48 to 2048 PPR quadrature. Much simpler and cheaper than optical encoders. 

        Enviado via iPhone

        Em 27/02/2013, às 07:37, Graham <grezmos@...> escreveu:

         

        I doubt you would achieve suffiecient positioning resolution with that robot, the angle errors add up quickly, you really need extremely hi res encoders and servos, I doubt the installed encoders are up to it nor will the gearbox quality be up to it probably

        Graham

        On 27 Feb 2013, at 02:39, "prkeays" prkeays@...> wrote:

        > Scorbot training robotic manipulator

      • Graham Stabler
        if you do the sums to get say 0.1mm of resolution at the end effector needs much much more than 2048 ppr Graham ... if you do the sums to get say 0.1mm of
        Message 3 of 8 , Feb 27, 2013
          if you do the sums to get say 0.1mm of resolution at the end effector needs much much more than 2048 ppr 

          Graham



          On 27 Feb 2013, at 11:32, Murilo Lana <murilo@...> wrote:

           

          Take a look at www.keling.com

          They have servos and other stuff at a vey good price.
          About the encoder I recommend the AMT CUI capacitive encoders. They cost about 25 bucks and have selectable resolution from 48 to 2048 PPR quadrature. Much simpler and cheaper than optical encoders. 

          Enviado via iPhone

          Em 27/02/2013, às 07:37, Graham <grezmos@...> escreveu:

           

          I doubt you would achieve suffiecient positioning resolution with that robot, the angle errors add up quickly, you really need extremely hi res encoders and servos, I doubt the installed encoders are up to it nor will the gearbox quality be up to it probably

          Graham

          On 27 Feb 2013, at 02:39, "prkeays" prkeays@...> wrote:

          > Scorbot training robotic manipulator

        • Murilo Torres
          It’s quadrature, so you get 8192 readings per revolution. If you drive a 5mm lead ball screw with this resolution you would get 0,0006mm precision. De:
          Message 4 of 8 , Feb 27, 2013

            It’s quadrature, so you get 8192 readings per revolution. If you drive a 5mm lead ball screw with this resolution you would get 0,0006mm precision.

             

             

             

            De: diy_3d_printing_and_fabrication@yahoogroups.com [mailto:diy_3d_printing_and_fabrication@yahoogroups.com] Em nome de Graham Stabler
            Enviada em: quarta-feira, 27 de fevereiro de 2013 9:05
            Para: diy_3d_printing_and_fabrication@yahoogroups.com
            Assunto: Re: [diy_3d_printing_and_fabrication] Servo motors

             

             

            if you do the sums to get say 0.1mm of resolution at the end effector needs much much more than 2048 ppr 

             

            Graham


            On 27 Feb 2013, at 11:32, Murilo Lana <murilo@...> wrote:

             

            Take a look at www.keling.com

             

            They have servos and other stuff at a vey good price.

            About the encoder I recommend the AMT CUI capacitive encoders. They cost about 25 bucks and have selectable resolution from 48 to 2048 PPR quadrature. Much simpler and cheaper than optical encoders. 

            Enviado via iPhone


            Em 27/02/2013, às 07:37, Graham <grezmos@...> escreveu:

             

            I doubt you would achieve suffiecient positioning resolution with that robot, the angle errors add up quickly, you really need extremely hi res encoders and servos, I doubt the installed encoders are up to it nor will the gearbox quality be up to it probably

            Graham

            On 27 Feb 2013, at 02:39, "prkeays" prkeays@...> wrote:

            > Scorbot training robotic manipulator

          • Graham Stabler
            except he is not driving a leadscrew he want to use it on a robot Graham Sent from my iPad ... except he is not driving a leadscrew he want to use it on a
            Message 5 of 8 , Feb 27, 2013
              except he is not driving a leadscrew he want to use it on a robot

              Graham

              Sent from my iPad

              On 27 Feb 2013, at 15:20, "Murilo Torres" <murilo@...> wrote:

               

              It’s quadrature, so you get 8192 readings per revolution. If you drive a 5mm lead ball screw with this resolution you would get 0,0006mm precision.

               

               

               

              De: diy_3d_printing_and_fabrication@yahoogroups.com [mailto:diy_3d_printing_and_fabrication@yahoogroups.com] Em nome de Graham Stabler
              Enviada em: quarta-feira, 27 de fevereiro de 2013 9:05
              Para: diy_3d_printing_and_fabrication@yahoogroups.com
              Assunto: Re: [diy_3d_printing_and_fabrication] Servo motors

               

               

              if you do the sums to get say 0.1mm of resolution at the end effector needs much much more than 2048 ppr 

               

              Graham


              On 27 Feb 2013, at 11:32, Murilo Lana <murilo@...> wrote:

               

              Take a look at www.keling.com

               

              They have servos and other stuff at a vey good price.

              About the encoder I recommend the AMT CUI capacitive encoders. They cost about 25 bucks and have selectable resolution from 48 to 2048 PPR quadrature. Much simpler and cheaper than optical encoders. 

              Enviado via iPhone


              Em 27/02/2013, às 07:37, Graham <grezmos@...> escreveu:

               

              I doubt you would achieve suffiecient positioning resolution with that robot, the angle errors add up quickly, you really need extremely hi res encoders and servos, I doubt the installed encoders are up to it nor will the gearbox quality be up to it probably

              Graham

              On 27 Feb 2013, at 02:39, "prkeays" prkeays@...> wrote:

              > Scorbot training robotic manipulator

            • Murilo Torres
              Ok... got it. Well, the angular resolution decreases when you get far from the axis. Using a planetary gear box or other precision reduction is a way to
              Message 6 of 8 , Feb 27, 2013

                Ok... got it.

                 

                Well, the angular resolution decreases when you get far from the axis. Using a planetary gear box or other precision reduction is a way to mechanically multiply the resolution, and of course, sacrificing the speed…

                 

                De: diy_3d_printing_and_fabrication@yahoogroups.com [mailto:diy_3d_printing_and_fabrication@yahoogroups.com] Em nome de Graham Stabler
                Enviada em: quarta-feira, 27 de fevereiro de 2013 12:37
                Para: diy_3d_printing_and_fabrication@yahoogroups.com
                Assunto: Re: RES: [diy_3d_printing_and_fabrication] Servo motors

                 

                 

                except he is not driving a leadscrew he want to use it on a robot

                 

                Graham

                Sent from my iPad


                On 27 Feb 2013, at 15:20, "Murilo Torres" <murilo@...> wrote:

                 

                It’s quadrature, so you get 8192 readings per revolution. If you drive a 5mm lead ball screw with this resolution you would get 0,0006mm precision.

                 

                 

                 

                De: diy_3d_printing_and_fabrication@yahoogroups.com [mailto:diy_3d_printing_and_fabrication@yahoogroups.com] Em nome de Graham Stabler
                Enviada em: quarta-feira, 27 de fevereiro de 2013 9:05
                Para: diy_3d_printing_and_fabrication@yahoogroups.com
                Assunto: Re: [diy_3d_printing_and_fabrication] Servo motors

                 

                 

                if you do the sums to get say 0.1mm of resolution at the end effector needs much much more than 2048 ppr 

                 

                Graham



                On 27 Feb 2013, at 11:32, Murilo Lana <murilo@...> wrote:

                 

                Take a look at www.keling.com

                 

                They have servos and other stuff at a vey good price.

                About the encoder I recommend the AMT CUI capacitive encoders. They cost about 25 bucks and have selectable resolution from 48 to 2048 PPR quadrature. Much simpler and cheaper than optical encoders. 

                Enviado via iPhone


                Em 27/02/2013, às 07:37, Graham <grezmos@...> escreveu:

                 

                I doubt you would achieve suffiecient positioning resolution with that robot, the angle errors add up quickly, you really need extremely hi res encoders and servos, I doubt the installed encoders are up to it nor will the gearbox quality be up to it probably

                Graham

                On 27 Feb 2013, at 02:39, "prkeays" prkeays@...> wrote:

                > Scorbot training robotic manipulator

              • Graham Stabler
                well the angular resolution stays the same as it is an angle but with a longer arm you get more movement for a given angular resolution so I know what you
                Message 7 of 8 , Feb 27, 2013
                  well the angular resolution stays the same as it is an angle but with a longer arm you get more movement for a given angular resolution so I know what you mean. Adding gearing is good if it has extremely low backlash, ideally you want to stick the encoder on the output and have a really good gearbox like a harmonic drive to stop servo oscillation. You can get high res encoders fairly cheaply, there are some 16bit absolute Avago (formally HP) ones that not too horrendously expensive and some of the magnetic ones have lots of bits, not sure of the accuracy though.

                  It can be done but not easy just need to do the sums and check your wallet :)

                  Graham



                  On 27 Feb 2013, at 15:53, "Murilo Torres" <murilo@...> wrote:

                   

                  Ok... got it.

                   

                  Well, the angular resolution decreases when you get far from the axis. Using a planetary gear box or other precision reduction is a way to mechanically multiply the resolution, and of course, sacrificing the speed…

                   

                  De: diy_3d_printing_and_fabrication@yahoogroups.com [mailto:diy_3d_printing_and_fabrication@yahoogroups.com] Em nome de Graham Stabler
                  Enviada em: quarta-feira, 27 de fevereiro de 2013 12:37
                  Para: diy_3d_printing_and_fabrication@yahoogroups.com
                  Assunto: Re: RES: [diy_3d_printing_and_fabrication] Servo motors

                   

                   

                  except he is not driving a leadscrew he want to use it on a robot

                   

                  Graham

                  Sent from my iPad


                  On 27 Feb 2013, at 15:20, "Murilo Torres" <murilo@...> wrote:

                   

                  It’s quadrature, so you get 8192 readings per revolution. If you drive a 5mm lead ball screw with this resolution you would get 0,0006mm precision.

                   

                   

                   

                  De: diy_3d_printing_and_fabrication@yahoogroups.com [mailto:diy_3d_printing_and_fabrication@yahoogroups.com] Em nome de Graham Stabler
                  Enviada em: quarta-feira, 27 de fevereiro de 2013 9:05
                  Para: diy_3d_printing_and_fabrication@yahoogroups.com
                  Assunto: Re: [diy_3d_printing_and_fabrication] Servo motors

                   

                   

                  if you do the sums to get say 0.1mm of resolution at the end effector needs much much more than 2048 ppr 

                   

                  Graham



                  On 27 Feb 2013, at 11:32, Murilo Lana <murilo@...> wrote:

                   

                  Take a look at www.keling.com

                   

                  They have servos and other stuff at a vey good price.

                  About the encoder I recommend the AMT CUI capacitive encoders. They cost about 25 bucks and have selectable resolution from 48 to 2048 PPR quadrature. Much simpler and cheaper than optical encoders. 

                  Enviado via iPhone


                  Em 27/02/2013, às 07:37, Graham <grezmos@...> escreveu:

                   

                  I doubt you would achieve suffiecient positioning resolution with that robot, the angle errors add up quickly, you really need extremely hi res encoders and servos, I doubt the installed encoders are up to it nor will the gearbox quality be up to it probably

                  Graham

                  On 27 Feb 2013, at 02:39, "prkeays" prkeays@...> wrote:

                  > Scorbot training robotic manipulator

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