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Servo motors

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  • prkeays
    Hello all. I m kind of new to this stuff. I don t know to much about the electrical and the programming of these machines but I have worked as a welder in a
    Message 1 of 8 , Feb 26, 2013
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      Hello all.
      I'm kind of new to this stuff. I don't know to much about the electrical and the programming of these machines but I have worked as a welder in a machine shop for the last 37 years so I have a grasp on building hardware. I have noticed the printers are based on stepper motors. In the early 80s I built a plotter using steppers but it was so slow you could time it with a calendar. I have a Scorbot training robotic manipulator I picked up at a garage sale but like the commercial said " I pick things up and put them down " and that is about all it.
      It has seven heavy duty encoded servo motors. I also have the controller that connects to the computer and supplies the power to the motors. My question is could I build a printer using this hardware and is there software that will do the job?
      I still have three of the stepper motors from the old plotter but would have to get all new controllers and software because I'm not sure where the old Apple II is.
    • 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 2 of 8 , Feb 27, 2013
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        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 3 of 8 , Feb 27, 2013
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          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 4 of 8 , Feb 27, 2013
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            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 5 of 8 , Feb 27, 2013
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              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 6 of 8 , Feb 27, 2013
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                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 7 of 8 , Feb 27, 2013
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                  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 8 of 8 , Feb 27, 2013
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                    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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