# Revision history [back]

### DampingFactor of joint

I cannot understand the description of dampingFactor in http://gazebosim.org/tutorials/?tut=ros_urdf#Links "Exponential velocity decay of the link velocity - takes the value and multiplies the previous link velocity by (1-dampingFactor)." Is there any math to explain it?

I find the unit of dampingFactor and viscous friction coefficient in the motor which is usually expressed as Bm is (N*m)/(rad/s), so are they the same physical quantity?

If the dampingFactor = c and angular velocity = w, the damping force is c*w?

### DampingFactor of joint

I cannot understand the description of dampingFactor in http://gazebosim.org/tutorials/?tut=ros_urdf#Links "Exponential velocity decay of the link velocity - takes the value and multiplies the previous link velocity by (1-dampingFactor)." Is there any math to explain it?

I find the unit of dampingFactor damping coefficient referenced from http://gazebosim.org/tutorials/?tut=ros_urdf#Joints and viscous friction coefficient in the motor which is usually expressed as Bm is (N*m)/(rad/s), so are they the same physical quantity?quantity? I want to simulate a servo motor, what value should the damping coefficient be?

If the dampingFactor = c and angular velocity = w, the damping force is c*w?

### DampingFactor of joint

I find the unit of damping coefficient referenced from http://gazebosim.org/tutorials/?tut=ros_urdf#Joints and viscous friction coefficient in the motor which is usually expressed as Bm is (N*m)/(rad/s), so are they the same physical quantity? I want to simulate a servo motor, what value should the damping coefficient be?

If the dampingFactor damping coefficient = c and angular velocity = w, the damping force is c*w?

### DampingFactor of joint

I find the unit of damping coefficient referenced from http://gazebosim.org/tutorials/?tut=ros_urdf#Joints and viscous friction coefficient in the motor which is usually expressed as Bm is (N*m)/(rad/s), so are they the same physical quantity? I want to simulate a servo motor, what value should the damping coefficient be?

If the damping coefficient = c and angular velocity = w, the damping force is c*w?