10
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Accepted
Simple equation to calculate needed motor torque
How quickly do you want to go from stopped to 10rpm? This will define your angular acceleration.
Regarding calculations, first you should convert to standard units, so meters instead of centimeters ...
- 16k
7
votes
Accepted
Using brushless motors for very high torque
Your expectations are rather aggressive for a DC motor.
First - 40Nm (350in-lbs) is A LOT of torque! Ex: A max rated torque for 1/4-20 bolt is only 75 in-lb (8.5Nm).
Second - The mechanical power ...
- 705
6
votes
What are some ways to estimate torque/load on a robotic arm joint
Model Based:
Low cost solution is always software:
Develop a dynamic model which computes the load on the motors based on the motions (e.g. with Recursive Newton Euler Algorithm or Lagrange-Euler ...
- 6,652
5
votes
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What is the required theory behind building a robotic arm?
There are 2 (or 3, depending on how the planned lifetime of the robot is) thing thats you have to consider.
Static load:
The motors stall (zero revolution) torques have to be able to hold the weight ...
- 6,652
5
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How to further understand the computed torque model controller
One of the most common controllers is a computed-torque controller, also known as the inverse dynamics. The preceding controller is based on the feedback linearization principle which is an approach ...
- 2,453
5
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Why do series elastic actuators have more accurate and stable force control?
Series elastic actuators tend to have more stable force control because the spring filters out the high-frequency motion of the mechanism. A low frequency in the system dynamics means that you can use ...
- 4,385
5
votes
Jacobian of a 6DOF arm
Write the forward kinematic equations $$\vec(x) = F\vec(\theta)$$
Taking the partial derivatives of each $\vec (x)$ term with respect to each joint variable $\vec(\theta)$ will give you $J$.
- 4,386
4
votes
Dynamic torque simulation for a 6 DOF robotic arm
The dynamics of robotic arms are fairly complex, especially when there are more than three joints to consider. The problem is that the movement of each joint moves all the links beyond it, which can ...
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What types of actuators do these industrial bots use?
Actuation is a complex subject that cannot be reduces to 1 component alone. It is the interaction of software electronics and mechanics. "Toy" servos tend to incorporate everything in one small ...
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4
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What is the torque/force required to rotate the base of a robot arm?
You need enough torque to overcome friction, and to accelerate the load.
If you know the friction torque ($\tau_f$), and the mass moment of inertia along the motor axis ($I$), then the minimum motor ...
- 385
4
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What servos are suitable for a robot like Boston Dynamics’ Atlas?
The Boston Dynamics’ Atlas robot doesn't actually use servo motors. It uses electrically-powered hydraulic actuation.
I saw a presentation by Boston Dynamics' Marc Raibert where (if I remember ...
- 1,054
4
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No electric motors can handle being stalled for even short periods of time, even at low power. Is this statement true in all cases?
Electric motors designed for stall torque can handle stall torque just fine. One giveaway sign of high stall torque motors is forced cooling (cooling with a powered fan and not just a fan mounted ...
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4
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Accepted
Will increasing voltage on brushless DC motor increase torque, if speed is kept constant?
It depends on various other factors as well. If the motor outputs 60RPM @24V under load, given the motor is rated for 12V - 60V and the load is kept the same, then by doubling the voltage from 24V to ...
- 71
3
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Dynamic torque simulation for a 6 DOF robotic arm
I think you may be going about this problem wrong. If you find a simulator that reports joint torques, then what? Are you going to iterate through every possible start and end location?
You should ...
- 16k
3
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Which kind of motors and how powerfull should they be for a robotic arm
This type of question "how much torque does my robot arm need" has been answered many times on this site:
Simple equation to calculate needed motor torque
Design and construction of universal robotic ...
Ben♦
- 5,825
3
votes
What types of actuators do these industrial bots use?
A robot like the one you refer to probably has a mix of transmission types that increase in power-to-weight ratio and decrease in size and stiffness as you move outwards on the kinematic chain. The ...
- 106
3
votes
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What is the torque transmission efficiency using a bycicle chain/setup for robot?
I agree with @Andy 's answer, that chain efficiency is over 90%. I'll point out that your terminology is not quite right - using bicycle chain (or any other transmission) affects power transmission ...
- 16k
3
votes
Simple equation to calculate needed motor torque
Since the arm is in a vertical plane, certainly, motor torque is required to counteract the gravitational torque. Since it is a simple 1DOF arm with a rotary joint, the gravitational torque is
$ \...
- 173
3
votes
Should the therotical parameters match the physical setup constraints when modeling a robot?
If your computed torques are out of the range for your robot, then you are no longer modelling your robot but a different one. You can ignore the torque limits as good as the joint angle limits of ...
- 1,355
3
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Suitable gear construction for a robotic extender - plastic?
I've done a couple worm drive designs and I threw the numbers you gave (Assuming sd-spi nylatron gears) into my calculations.
I'm using AGMA 6022-C93 Worm gear design guidelines for tooth width and ...
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3
votes
Suitable gear construction for a robotic extender - plastic?
What's the point of the middle gear? It's not doing anything for you reduction-wise because it's on a different shaft than the larger gear.
There's an equation here that should give you the maximum ...
- 16k
3
votes
Accepted
How to get Max Torque on Robot arm 's Joints (RRR)
Torque is pretty easy to calculate for a single static arm configuration. Torque is just the length of the moment arm * the perpendicular force. And it is easy to decompose the problem into X and Y ...
Ben♦
- 5,825
3
votes
Accepted
Will this have more or less lifting strength
Every action has an equal and opposite reaction. Each motor/joint in a linear chain of actuators (snake) needs to be capable of supplying the appropriate reaction forces.
This mean that, if you have ...
- 16k
3
votes
Accepted
How to maximize stall torque of a motor
One relevant equation is the lorentz force equation. which suggests that if you want to reduce current then you need to increase the magnetic field.
The magnetic circuit is complex, with different ...
- 4,385
3
votes
Accepted
Specification calculation for choosing a proper stepper motor for Ball Lead / Screw system
When looking for motors, you usually are trying to figure out specific things with specific requirements.
Holding Torque
Torque at Speed
Resolution (for steppers)
NEMA size
Positional Accuracy vs ...
- 543
3
votes
Accepted
Force-torque sensor reading when a robot is stationary
The answer is $\vec{G}$! and also any $\vec{\tau}$ torque caused by it, if the axis connecting the geometrical center of the sensor (assuming it measures torques relative to its geometrical center) to ...
- 6,652
2
votes
Attaching a M5 screw shaft to a cog wheel
A full answer depends on what plastic and what the load will be. Having a depth of 30 mm does give you a lot of options.
You can drill and tap ABS just fine, and I've had success drilling and ...
- 4,386
2
votes
Do these motors really have enough torque to lift 130 pounds
Where did you get that number?
The first page of the datasheet posted on the page you linked states, "Max 15VDC and 7A" (near the top).
So the maximum input power for the motor is $P=IV$, or $P=(7)(...
- 16k
2
votes
What is the required theory behind building a robotic arm?
It sounds like you are developing a robotic manipulator from scratch so I also assume you will be writing software for position control too. Both the design and control depend on not only the dynamics ...
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2
votes
Accepted
Is this supposed to be a bearing?
A shaft stopper like that is made to let you assemble the device more precisely. The bearings look like they are in the "Tail Gear Case Plate" subassemblies. By using a shaft stopper you can insert ...
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