# Questions tagged [torque]

Torque, moment, or moment of force is the tendency of a force to rotate an object around an axis, fulcrum, or pivot.

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19 views

### Calculate Torques & Forces From Jacobian Matrix

Dear Robotics Stack Exchange, I am trying to calculate the torques and forces for a 2DOF robot. I’m used the partial differentiation method to find the Jacobian matrix. I managed to find the ...
52 views

### Torque required to rotate arm with mass at end

I have to calculate the required torque to rotate a point mass of 15N on the end of an 1.2m long arm which I have calculated to be 10kg in mass. The rotation must have a constant angular velocity of ...
47 views

### Do hobby servos respond to step inputs with a step in torque?

I'm designing a piston that I need to expand a few cm in <100ms to load energy into a spring-mass system with around a pound of force (as shown below). Based on power specs alone, high-end hobby ...
26 views

### Force-torque sensor reading when a robot is stationary

Let's say I have a robot arm with a force-torque sensor on the wrist, between the final motor and the gripper. If the arm and wrist are stationary, then what would the reading on the sensor be? I know ...
49 views

### Quadrotor dynamics: How is torque created

I'm a software engineer and I've recently engaged into Robotics field. I've started by a course on Coursera which talks about Aerial robotics and thus quad-rotors. I'm trying to understand how quad-...
58 views

### Can I measure torque from this motor by only measuring the current?

I am new to robotics, please forgive/correct any errors. My Project Plan I want to use a PID controlled motor in a human-interface device where I need to measure the user's exerted force on an end ...
19 views

### What is the most accurate method to calculate Torque of 5 DOF Robotic arm

I am working for development of a 5 DOF Robotic arm , and I am confused in the Torque calculation This is a 5 Axis revolute Joints Robotic arm , where Motor for 1st axis will rotate the turning table ...
52 views

### When not to use pseudoinverse?

I know this equation: $\tau = J^T f$. In my case, the Jacobian $J$ is not square. Is it valid to use the pseudoinverse of $J^T$ to calculate end effector forces $f$ based on joint torques $\tau$? I ...
32 views

### Calculate body speed in m/s with weight in the equation?

UPDATE: I have clarified my question for answerers to better understand what I am asking If I have a flywheel, like the one shown in this image, and I know the torque, weight distribution, and weight. ...
22 views

### How to convert torque in oz-in into the weight it can withstand?

I am looking at servos to make a robot claw, and I want to make sure the one i am getting can turn under a specific amount of weight. The servos specify their torque in oz-in. I am not sure how to ...
106 views

### No electric motors can handle being stalled for even short periods of time, even at low power. Is this statement true in all cases?

We were using a regular POLOLU d.c motor whose stall current is 0.36A. We want to use this motor in a robotic hand where the motor will be stalled while holding the object. We are limiting the current ...
39 views

### Determining required torque for DC motor

How to determine the required torque while choosing a DC motor? Here is a simple scenario. Think of a 4WD or 2WD vehicle. The max load the vehicle will have is 100kg. Q1. How do I determine the ...
74 views

### Why aren't my 4x 612 RPM motors driving with only 12 lb load?

I have purchased x4 612 RPM actobotics motors. Every time I try to drive the motors on ground, the motors stall, as if the torque was too low to drive. The motor model: servocity.com model #: 638284 ...
63 views

### Controlling high torque servo motors with Raspberry Pi

I need to control 10 Standard Servo Motors (operating at 4.8-7V/300mA-1A/2.5kg-5kg torque) in my project. I'm using RPi as my processor and I was looking for a servo driver. I came across PCA9685 16-...
58 views

### Counterweight in arm designs

I wonder why most robotic arms use large J2 (shoulder) motors rather than counterweights. What sort of complexity do they add to the design beside increase in overall weight? In fact, rather than ...
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### Understanding KGf.CM in Camera Robotic Head Design

I am attempting to design a robotic camera head - however, I am struggling to calculate the torque (in terms of KGf.CM) I will require to rotate the Y (tilt) axis of the head. The motor I intend to ...
47 views

### How to calculate what motor I need to move weight

I'm working on a project trying to make some electric roller curtains. I can use 2 motors on this curtain, on each side to lift and pull down the curtain. Pulling down the curtain requires not as much ...
24 views

### Singular Configuration - Balanced Wrench F?

I've been asked to show that if a manipular is at a singular configuration, then the End Effector wrench can be balanced without any joint torques. I know that t = J*F where (t = torques, F= end ...
39 views

### How is this torque value arrived?

I'm going through this person's torque calculation of a simple crane setup. the servo used has a max torque of 57oz.in: At the top, if Mservo is 34.12oz.in, how is ...
80 views

### Rotating a lever with a small servo

I'm trying to rotate a lever link to gently "offload" a load using a servo. Here's a drawing: Here, the red is a lever, yellow pivot and black is the load. To offload, the lever needs to be turned 90 ...
54 views

### How to make a diff robot (2 traction wheels front and 2 castor wheels back) to go straight?

I’m developing a differential robot. My wheeled robot has two castor wheels in the back and two driven wheels in the front. The motor controller I’m using can handle two motors each with 90 cpr. Each ...
73 views

### Sensing torque of stepper motor

I need to sense the torque of a stepper motor at any given time. I'm planning to tension a wire by using a stepper motor, and in order to keep the wire at a fixed tension I would need to know the ...
135 views

### Servo motor torque

I am confused with the torque ratings of servo motors, or I guess it is general while choosing any motor. For example a servo's torque is rated as 10kg-cm, so does that mean it can handle a 100N ...
686 views

### Specification calculation for choosing a proper stepper motor for Ball Lead / Screw system

I'm trying to build a motorized stage which moves in one direction as below picture based on this article. Desired characteristic properties are: 1. screw length = 150 mm 2. screw diameter = 14mm ...
46 views

### How can a motor be run at higher voltage for longer?

A 12V windshield wiper motor to run at 24V for more speed but near-equal driving force. Testing with a variable DC supply between 21.6V & 26.4V showed the current maxes at 3.72 - 3.90A, as ...
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### Torque Disturbance Observer for Manipulator Arms

Is there a tutorial/guide apart from the research papers ( paper 1 and paper 2 ), for implementation of torque disturbance observers on multi-DOF robotic manipulators to determine sudden collision ...
1k views

### Jacobian of a 6DOF arm

I have a robot with 6 DOF. I read a lot of tutorial on how to compute the Jacobian, but usually all examples are for planar robots with 2DOF. I don't understand how can I get the Jacobian of a 6 DOF ...
410 views

### How to calculate effort/torque values of a joint

I have a robotic arm with 6 DOF. For each joint, I get get the Joint Wrench, which is composed by the force and torque of the parent and child links of the joints. In other works, for joint 1 I can ...
832 views

### Calculating torque required to rotate a platform

I am trying to spec out a motor's torque required to rotate a platform about an axis. This diagram makes it better to understand(it's like a rotisserie): Dimensions are in cm: I have an arbitrary ...
102 views

### Practically implementing a torque controller

I'm currently working on a robotics project where i have to build a quadruped. i have somewhat finished the designing for the time being and now moving into simulations. I have followed a inverse ...
2k views

### What servos are suitable for a robot like Boston Dynamics’ Atlas?

I have seen Boston Dynamics’ robot Atlas do some pretty impressive things, like a backflip, which must put quite large torques on the servomotors. What servos are there that can generate torques like ...
260 views

### DJI E310 Thrust Coefficient

I am reading Denis M. Filatov et al.'s paper "Parameters identification of thrust generation subsystem for small unmanned aerial vehicles" (https://www.semanticscholar.org/paper/Parameters-...
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### Calculate torque required to rotate and hold a platform

I wish to rotate a rectangular platform about its length. It is attached to a shaft that runs through the length of the platform at width/2. How can I compute the torque of the motor required to ...
467 views

### How can I measure the torque a servo motor is applying very precisely?

Is there any cheap way to measure how hard a servo is turning? I am looking to measure changes of about 0.1 oz-in. What are the common ways to measure servo torque, how much do they cost, and how ...
797 views

### Increasing Torque by either doubling servos or building a gear box

I'm looking here for suggestions. I have a HS-805BB with Torque (Kg-cm/Oz-in): 24.7/343 @ 6.0 V to rotate a robot body up and down from one side. It seems to me that this servo is always running at ...
73 views

### Torque commands for velocity reference motor

I have a controller board for a motor, where I can read the motor current (to transform to torque), the position, the velocity and I can give a velocity command. There is not really a torque mode on ...
354 views

### How to maximize stall torque of a motor

I'm looking to use 3-phase motor without gearbox for robotics application. It will always work at near stall situation never rotating more than 360deg. I'm looking for arrangement that will produce ...
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### Measuring torque of Vex gear shaft - highest accuracy for lowest price [closed]

I am seeking to collect data for my IB Physics IA (internal assessment). My question seeks to establish the relationship between speed and torque by adjusting gear ratios. (I am aware that gear ratios ...
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### Transforming position to torque

first question in this forum :D so i started creating a 2 link robotic arm in SIMULINK and made a function that builds its trajectory (cubic spline) and used it as an input for my joint. so my input ...
147 views

### How to calculate the pull force of scissors?

i want to use a stepper motor to move a brush to a industrial scissor machine to cut material of brushes. The stepper motor will use a worm gear box to increase torque and smooth movement. The ...
38 views

### Help with DC Gearmotor Specs

I need help understanding the specs of this RS Pro DC Geared Motor, Brushed, (RS: 238-9670). It has an operating range of 4.5-15V and a nominal voltage of 12V, so does that mean that it provides 0....
111 views

### From a linear force actuator that spans multiple links and joints to the equivalent motor torque

I am programming/using a rigid body joint-space dynamics solver for robots in which I want to implement linear force actuators between links with their equivalent torque sources that are 'spanned' by ...
5k views

### Using brushless motors for very high torque

I'm currently building an robotic arm and I want the elbow joint to be comparable to a human one But here's the problem, electric linear actuators are too slow and have low torque, same goes with ...
679 views

### How do I choose the stepper motor torque for my robotic arm

I'm a communication engineer so my knowledge about robotics is very little. I know the basic formula of torque T=mgL in my project I have 2 arms & 2 motors i used a torque calculator online ...
4k views

### Robotic arm select servo motors

Hi i´m designing a robotic arm based on this idea of the NOVABOT I only want to change its structural parts by aluminum tubes. In this design 3D model it use the servo hs-311 wish have a max torque of ...
58 views

### cable-controlled flexion and extension

I'm new, please be gentle :-) I'd like to control the position of a single-axis joint using one cable for flexion and another for extension. In many of the anthropomorphic designs I've seen each of ...
3k views

### Thrust and Torque on Quad Rotor

I am a beginner on Drones. I would like to understand the how each motor contribute to thrust on the whole drone. And what is the direction of torque created on each propeller. Everywhere I find a ...
33 views

### Stepper Motor Torque [duplicate]

Tried searching for this answer in a simple way but can't seem to find the answer.. I have a 3 axis Bipolar Nema 17(Took off my 1st 3d printer =) ) robotic arm(Homemade) and provides 28oz-57oz of ...