- #1
Lonklin
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SUMMARY
This discussion focuses on designing a forearm for a robotic arm utilizing a stepper motor for rotation. The stepper motor is expected to operate at a maximum of 60 RPM and needs to efficiently connect to two vertical metal pieces. Key considerations include the use of a gearbox, specifically an epicyclic gear system, to increase torque and manage lateral forces, particularly gravity. The design also emphasizes the importance of selecting appropriate bearings to support the load, which is estimated at 12 pounds.
PREREQUISITES- Understanding of stepper motor mechanics and specifications
- Knowledge of epicyclic gearing systems
- Familiarity with load-bearing calculations and bearing types
- Basic principles of robotic arm design
- Research "Stepper Motor Torque Calculations" for optimal performance
- Learn about "Epicyclic Gear Design" for effective torque management
- Explore "Bearing Selection for Robotics" to ensure load stability
- Investigate "Robotic Arm Kinematics" for improved design efficiency
Robotics engineers, mechanical designers, and hobbyists involved in robotic arm construction and stepper motor applications will benefit from this discussion.
- #2
DaveC426913
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How fast?
How much load?
What kind of lateral forces do you need to contend with?
How much load?
What kind of lateral forces do you need to contend with?
- #3
Baluncore
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Welcome to PF.
Will you use the stepper bearings to carry the entire load, or will there be some heavier bearings provided to carry the mass and any unbalanced load?
Should the hub between the stepper motor and the vertical plates be rigid, or can it be rubber?
Perhaps you can tell us what you are trying to do with the mechanism.
Will you use the stepper bearings to carry the entire load, or will there be some heavier bearings provided to carry the mass and any unbalanced load?
Should the hub between the stepper motor and the vertical plates be rigid, or can it be rubber?
Perhaps you can tell us what you are trying to do with the mechanism.
- #4
Lonklin
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Sorry yall for my abiguosity. I'm trying to design and make the forearm for a robotic arm. ONe lateral force then will be gravity since the rig will be on its side when in operation. I'm just not sure of an efficient way to connect the stepper motor shaft with the two pieces of metal in which it can spin or what hub to use. The motor will probably max rotate 60 rpm. The load of the arm will definitely vary depending on what the arm is picking up. I guess my question I would ask you is: What is an efficient way to connect this motor shaft in such a way that is spins those metal pieces? Assuming that the metal sheets will rotate on a bearing of some kind. Or not im a newbie.Baluncore said:
- #5
Lonklin
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Sorry yall for my abiguosity. I'm trying to design and make the forearm for a robotic arm. ONe lateral force then will be gravity since the rig will be on its side when in operation. I'm just not sure of an efficient way to connect the stepper motor shaft with the two pieces of metal in which it can spin or what hub to use. The motor will probably max rotate 60 rpm. The load of the arm will definitely vary depending on what the arm is picking up. I guess my question I would ask you is: What is an efficient way to connect this motor shaft in such a way that is spins those metal pieces? Assuming that the metal sheets will rotate on a bearing of some kind. Or not im a newbie.DaveC426913 said:
- #6
Baluncore
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The stepper motor is able to move much faster than 60 RPM. Maybe the joint should include a reduction gear, maybe epicyclic, to increase the torque available.
The gearbox then becomes the connection, not the thin motor shaft.
The gearbox then becomes the connection, not the thin motor shaft.
- #7
Lonklin
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What do you think the gearbox should connect to?Baluncore said:
- #8
Flyboy
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How much weight do you plan to carry?
- #9
Lonklin
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Baluncore said:
12 pounds topsFlyboy said:
- #10
Baluncore
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The biggest possible ring gear, with a cylindrical housing, is connected to the extended arm plates. The motor is mounted to the inside of a cylindrical input housing, that is attached to the robot's frame. The stepper motor drives the smallest possible sun gear pinion, for the greatest reduction ratio. The motor body is attached to the planet carrier.Lonklin said:
https://en.wikipedia.org/wiki/Epicyclic_gearing
The input and output housings are sleeved, so they can rotate and form a slow bearing.
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