# Questions tagged [screw-theory]

A method of representing the mechanics (kinematics and dynamics) of a system using 6-element vectors (such as a twist or a wrench) which combine both the angular and linear components.

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### How to get the analytic Jacobian from the geometric Jacobian expressed in the body frame

I'm trying to obtain the whole analytic Jacobian $J_a(\theta)$ (i.e. both the linear and angular parts) from the geometric Jacobian expressed in the body frame $J_b(\theta)$ (i.e. in the screw theory ...
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### Why is Screw Theory used in Robotics when you can do everything with regular kinematics?

I was seeing some Robotics lectures and a word which keeps coming up is "Screw Theory", on looking it up, I find that everything you can do with it practically, you can do with vector ...
1 vote
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### In which frame this wrench is expressed?

Take a look at this question below. The relationship between torques and wrenches are $$\tau = J_b^T(\theta) \mathcal{F}_b = J_s^T(\theta) \mathcal{F}_s$$ where the subscripts $\{b,s\}$ indicate in ...
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### Robotic manipulator Jacobian by product of exponentials

I've taken a class and started a thesis on robotics and my reference for calculating the Jacobian by product of exponentials seems incorrect, see: http://www.cds.caltech.edu/~murray/books/MLS/pdf/...
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### Adding an Actuator or Force to a (Featherstone) Articulated Rigid Body Model

I'm working on a project where I need to model a system that is essentially comprised of a series of ball-and-socket joints attached to a base, which is attached in turn to a prismatic joint (rail). ...
1 vote
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### How to find the body jacobain, for each link in a robot manipulator?

The links twist could be obtained, and thus The spatial manipulator Jacobian could be done, but when it comes to the body Jacobian, it is becomes difficult. Moreover, the adjoint transformation ...
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### How to get the 4*4 matrix from the twist using product of exponentials, in robot kinematics?

In robot kinematics, we have $e^{(\theta*twist)}$, where $twist$ is 6*1 vector. How do I get the 4 by 4 transformation matrix by using product of exponentials?
1 vote