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Continuous Velocity Feedback Employing Integral and Average Derivative Signals

IP.com Disclosure Number: IPCOM000091311D
Original Publication Date: 1968-Jan-01
Included in the Prior Art Database: 2005-Mar-05
Document File: 2 page(s) / 33K

IBM

Related People

Halfhill, MO: AUTHOR [+1]

Abstract

This system continuously detects the instantaneous velocity of an object moved by a DC prime mover. It is assumed that the force generated by the prime mover is the sole significant force acting on the system. Therefore, a signal that is proportional to velocity can be obtained by integrating the current. This result is derivable from the equation F = ma where force F = KI and velocity v = integral ad(t) + a(c). Substituting provides v = (k/m) integral id(t) + I(c). This last equation shows it is essential to insure that the initial value of velocity is correct and thus avoid the effects of current required in overcoming any constant external forces on the system.

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Continuous Velocity Feedback Employing Integral and Average Derivative Signals

This system continuously detects the instantaneous velocity of an object moved by a DC prime mover. It is assumed that the force generated by the prime mover is the sole significant force acting on the system. Therefore, a signal that is proportional to velocity can be obtained by integrating the current. This result is derivable from the equation F = ma where force F = KI and velocity v = integral ad(t) + a(c). Substituting provides v = (k/m) integral id(t) + I(c). This last equation shows it is essential to insure that the initial value of velocity is correct and thus avoid the effects of current required in overcoming any constant external forces on the system.

The velocity detecting system is shown in use with a servo feedback system. In this application, the velocity detecting system avoids reliance on derivative feedback which is too noisy due to electrical and mechanical effects and which is subject to influence from mechanical resonance. The voltage representing the desired position Xc is applied to the plus input of the summing circuit 10. The present position of the desired object Xr is applied to the other input of circuit 10. The present position Xr can be derived, for example, by a potentiometer. The net difference comprises the position error which can then be modified by some function by circuitry 11. The modified function is then supplied to one input of summing circuit 1...