i’m a beginner in robotic. only knw a bit about coding (programming).
anyway, i’m starting my project today, 6 arm robot with a gripper, 7 servo actually as i need 1 small servo to control the gripper to hold the load. the length of the arm would be 70cm. i’m expecting to be longer like 150cm total with payload 1kg.
here is my design in attachment. sorry it look like back to 19th century but yes, i’m a programmer, not a cad and even i don’t have any idea about autocad and 3ds max. perhaps i should giveit a try next time. fortunately i have a nice backup… a lovely workshop which will do my nasty design into reality
and here is the servo i got from the market (in the attachment also), with D shaped shaft, r: 4mm.
those servo are 100kgfcm (10Nm) and 180kgfcm (18NM), daisy chain, digital, the seller claimed that the servo can give the feedback about bla bla bla which i just need the current angel position. but the servo don’t come with a specific built controller instead of normal H bridge or kind of servo shield for arduino uno or mega. not sure.
*in short: i don’t know about how to choose the correct position sensor/solution
**sure… the seller is cute by saying “ouw… our servo is accurate, digital, 4096 digit, can connect to other servo like daisy chain and u can call each servo by each ID”. honesty, i don’t have experience on this but still it seems this kind of servo is my best bet to go for this project. what do you think? any opinion would be apreciated. i’m a beginner.
anyway, i have basic several questions.
arm joint construction. it seems i have problem. the servo looks wow with that torque but after i did my simple calculation, gosh… i need even bigger torque around 50NM or even more if i use longer arm. should i use pulley and belt solution with let’s say 10:1 ratio? then how can i detect the recent angle of my arm as this is my main concern for robot arm. that’s really painful. any idea about this? 180kgfcm using belt and pulley 10:1 so i can have 1800kgfcm in the shoulder? perhaps there is some generous guys here want to share a bit about belt and pulley implementation as i’m absoluetely zero in this field. in my dummy head, it’s only “attach the servo with horn, then screw it in one side of the arm”. that works if the arm is small but just wondering how to synch the rotation between right side and left side of the arm chassis? using rod? pipe? shaft? i don’t even know the name of the components to move the joints.
can i move the robot arm manually by hand, for teaching? so i can record the position and save it for certain movement set. i see servo.read() can only return the previous position but not the actual angle if i move the arm manually by hand, even when the power is on (power must be on coz i need to keep the arduino alive and my best bet is i move the hand and arduino record it if i press kind of save button )
that’s all guys. please share your idea. i’ll use arduino due at 3.3V for the sake of more computing power and not sure, i’ll bet for AC servo with 1 controller for each servo. but i don’t have any idea how to wire/connect all 7 controllers to 1 cute tiny arduino. i wish i can stick with my first plan and go with that.
thanks guys in advance and pls help for opinion, strategy like position sensor, or anything.