# Questions tagged [dynamics]

Dynamics is a branch of applied mathematics (specifically classical mechanics) concerned with the study of forces and torques and their effect on motion, as opposed to kinematics, which studies the motion of objects without reference to its causes.

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### Unit of force used in UUV Simulator

I am building my AUV dynamics model with UUVSimulator. There is something wrong when it comes to the thrust configuration. What is the unit of thrust, N or kg?
35 views

### Derivation of Newton-Euler Inverse Dynamics

I'm currently studying from the book Modern Robotics - Mechanics, Planning, and Control, and I'm having a hard time following the derivation of the Newton-Euler inverse dynamics algorithm, ...
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### Gazebo does not calculate dynamics when joint_trajectory_controller with position command_interface is used

I was wondering why Gazebo does not calculate dynamics (velocity, acceleration, effort) when JointTrajectoryController is used with ...
1 vote
25 views

### Designing the kinematics and Dynamics of a spherical joint as 3 revolute Joint

I am working on a project where I am trying to mimic human like motion and for that I am designing a 7 DOF arm with the spherical joint in shoulder as 3R joints and 2R joints for elbow and 2R joint ...
38 views

### How does joint torque varies wrt joint velocities in Recursive Newton Euler algorithm?

I'm currently working on solving the inverse dynamics of a 6-axis articulated robot, similar to the UR5, using the recursive Newton-Euler algorithm. I'm very confused with the results I'm getting, as ...
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1 vote
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### Issues with Torque Distribution in State-dependent Differential Riccati Equation (SDRE) Controller for 4W SSMR Trajectory Tracking

I am currently working on implementing a State-dependent Differential Riccati Equation Controller (SDRE) to track the trajectory of a 4-wheel skid steer mobile robot (SSMR), where torque serves as the ...
13 views

### Hexacopter Simulation

I am doing a project to simulate a hexacopter with the mathematical model and its dynamics with PID. I've got the theoretical knowledge but am stuck on simulation. Would any of you happen to have any ...
33 views

### Help with clarifying UR10e center of mass

I'm doing an assignment related to the Universal Robot UR10e robot for a robotics class. I have to use the center of mass of each link to solve the problem. I found the information on the link below (...
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### How to reduce the turbulence of a robotic arm, when it's end effector touches a surface?

I am working on a project related to tele-robotic ultrasound where I have to tele-operate a virtual UR5 robotic arm with a end-effector(a thin rod) through a haptic device in PyBullet. When I make the ...
128 views

### Dynamic model of a robotic arm

I have a question regarding the dynamic model of a robotic manipulator. It is commonly written as follows: $$\tau = M(q)\ddot{q} + C(q,\dot{q})\dot{q} + G(q) + J^\intercal F_{ext}$$ From what I have ...
1 vote
147 views

### Gazebo joint velocities do not agree with joint displacement

In a simulation that I am running, which is described below, the angular velocities that I get from the joint_states topic, do not give me the angular displacement I calculate from the joints angular ...
195 views

### kinetic and potential energy of 3 DOF robot having 2 cylindrical links

Assume two uniform cylindrical links robot has 3 DOF as shown in the figure. Where link one has 1 dof that is rotation on its main axis. The second link has 2 DOF yaw and pitch movements. I can ...
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123 views

### Is the angular velocity vector the derivative of a time-varying quantity?

On page 111 (section 4.6) of Robot Modeling and Control (Second Edition) by Spong, Hutchinson and Viyasagar, the authors define a "body velocity" vector $\xi$ of the end-effector as follows: ...
1 vote
112 views

### PD control with gravity compensation

Given the robot dynamics of the form $$M(\theta)\ddot{\theta}+C(\theta, \dot{\theta})\dot{\theta}+G(\theta)=u$$ where the notations have the standard meaning ($M$ is the inertia matrix, $C$ is ...