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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 ...
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8 votes
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Calculating Required Torque

This is a standard dynamics problem. Let's use this figure I drew: Some definitions: $$ \begin{align} m & \mbox{, the mass of the vehicle in kg.} \\ \mu_{\mbox{rolling}} & \mbox{, the ...
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7 votes
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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 ...
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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 ...
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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 ...
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5 votes
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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 ...
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5 votes

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 ...
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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 $J$.
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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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4 votes
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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 votes

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 ...
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4 votes

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 ...
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4 votes

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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3 votes

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 ...
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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 ...
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3 votes
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2Nm small motor

First I would like to caution your choice of motor torque. I don't know how you generated the drawing of your wrist, but CAD packages like Inventor or Solidworks can easily generate masses and ...
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3 votes
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Verifying motor selection calculations

I think your Pmotor calculation is correct. The reason for the difference with the CIRC link is in the P=F*v equation they are referring to the linear velocity. Your conversion is converting the ...
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  • 181
3 votes

How can I replace acceleration in the dynamic model of the robot?

Probably I'm missing your point, but the fundamental dynamics equation of a manipulator describes physical relations among quantities irrespective of the particular electronics/mechanics running ...
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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 $ \...
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3 votes

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 ...
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3 votes

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 ...
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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 ...
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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 ...
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3 votes
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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 ...
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3 votes
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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 ...
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3 votes
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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 ...
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3 votes
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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 ...
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3 votes
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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 ...
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2 votes

How Can I Measure the torque applied by a servo motor?

There are lots of ways of measuring torque from first principles. Obviously the first problem is that you need a sensor, you have lots of options: You can use a torque sensor. ( e.g. imada.com/...
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