I just read (with interest) the Rate-of-change experiment:
http://www.allaboutcircuits.com/vol_6/chpt_3/18.html
I'm considering a project which involves a DC motor which needs to have its speed modified over time so that a mechanical arm maintains a constant rate of angular change. The differentiator circuit sounds like it might be a feasible way to achieve this but I'm an electronics newb so I don't know whether it's the best option for me to investigate.
The project involves 2 arms connected with a hinge and driven apart by linear actuator controlled by a PWM circuit (the actuator is the 3rd side of the triangle). However, if the linear actuator is driven apart at a constant (linear) rate, then the rate of *angular change* between the arms increases slowly (ie. it isn't a linear rate). I was considering attaching a potentiometer at the hinge to reduce the motor speed as the angle between the arms increases, but wasn't sure how to achieve this.
When I saw the differentiator idea I thought maybe it could somehow measure the rate of change of the potentiometer at the hinge and, if the rate is increasing, then reduce the speed of the motor to bring the rate of change back to constant. BTW: this would all be running very slowly, only 15 degrees/hour - would that be too slow to register?
Does this make sense? Is it feasible? Or are there already gadgets/circuits that are more appropriate?
Thanks,
A.
http://www.allaboutcircuits.com/vol_6/chpt_3/18.html
I'm considering a project which involves a DC motor which needs to have its speed modified over time so that a mechanical arm maintains a constant rate of angular change. The differentiator circuit sounds like it might be a feasible way to achieve this but I'm an electronics newb so I don't know whether it's the best option for me to investigate.
The project involves 2 arms connected with a hinge and driven apart by linear actuator controlled by a PWM circuit (the actuator is the 3rd side of the triangle). However, if the linear actuator is driven apart at a constant (linear) rate, then the rate of *angular change* between the arms increases slowly (ie. it isn't a linear rate). I was considering attaching a potentiometer at the hinge to reduce the motor speed as the angle between the arms increases, but wasn't sure how to achieve this.
When I saw the differentiator idea I thought maybe it could somehow measure the rate of change of the potentiometer at the hinge and, if the rate is increasing, then reduce the speed of the motor to bring the rate of change back to constant. BTW: this would all be running very slowly, only 15 degrees/hour - would that be too slow to register?
Does this make sense? Is it feasible? Or are there already gadgets/circuits that are more appropriate?
Thanks,
A.