- #1
Lonklin
- 5
- 0
Click For Summary
Discussion Overview
The discussion revolves around designing a mechanism to connect a stepper motor to two vertical metal pieces for a robotic arm's forearm. Participants explore various aspects of the design, including load capacity, rotational speed, and the type of connections and bearings needed.
Discussion Character
- Exploratory
- Technical explanation
- Conceptual clarification
- Debate/contested
Main Points Raised
- Participants inquire about the speed and load requirements for the stepper motor, with one suggesting a maximum rotation of 60 RPM.
- Questions are raised regarding the lateral forces the design must accommodate, particularly gravity when the rig is positioned on its side.
- There is discussion about whether the stepper motor bearings should carry the entire load or if additional heavier bearings are needed.
- Some participants propose using a rigid hub between the motor and the vertical plates, while others suggest the possibility of using a rubber hub.
- One participant suggests incorporating a reduction gear, potentially an epicyclic gearbox, to increase torque and facilitate the connection between the motor and the metal pieces.
- Another participant describes a potential design involving a ring gear and a cylindrical housing connected to the arm plates, emphasizing the importance of the motor's connection to the gearbox.
- One participant mentions a maximum weight capacity of 12 pounds for the robotic arm.
Areas of Agreement / Disagreement
Participants express multiple competing views regarding the design specifics, such as the type of hub to use and whether to include a gearbox. The discussion remains unresolved with no consensus on the optimal design approach.
Contextual Notes
Participants have not fully defined the assumptions regarding load distribution, the exact nature of the lateral forces, or the specific requirements for the gearbox connection.
- #2
DaveC426913
Gold Member
2025 Award
- 24,284
- 8,432
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
Science Advisor
2025 Award
- 16,769
- 10,427
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
- 5
- 0
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
- 5
- 0
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
Science Advisor
2025 Award
- 16,769
- 10,427
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
- 5
- 0
What do you think the gearbox should connect to?Baluncore said:
- #8
Flyboy
Gold Member
- 426
- 633
How much weight do you plan to carry?
- #9
Lonklin
- 5
- 0
Baluncore said:
12 pounds topsFlyboy said:
- #10
Baluncore
Science Advisor
2025 Award
- 16,769
- 10,427
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.
Similar threads
- · Replies 2 ·
- · Replies 9 ·
- · Replies 4 ·
- · Replies 6 ·
- · Replies 4 ·
- · Replies 14 ·
- · Replies 2 ·