Controlling current flowing through MR damper

Hi

I am working on a project in which i have to control the damping of magnetorheological (MR) damper. As mentioned in the datasheet the device operates at 12 V and by varying the current the damping can be altered/controlled in real time.

I am interested in varying the current to the device through micro-controller for instance lets say Arduino. What are the possible electronic/electrical components for building circuit through which i can vary current flowing through the damper and hence control its resistance.

The datasheet of the damper is attached for reference.

A DAC driving a DC-amplifier capable of upto 2A into 6 ohms. It may be possible to use PWM directly
but the datasheet doesn't say anything about that - it is almost certainly a high inductance coil that
you are driving given its creating a magnetic field.

A possible circuit is a programmable current source/sink using shunt-resistor for feedback. A free-wheel
diode would be needed as the load is likely inductive.

Something like: Current sink stability

Using an Arduino I would do as Mark suggested above.Years ago I had to come up with some for magnetic brake assemblies. Using an Arduino I would buy one of the ready made DAC boards available which will afford you a programmable voltage source. Next you can build or buy a programmable current source which is a Transconductance Amplifier which is a fancy way of saying voltage in and proportional current out. Years ago a company named Calex sole what they called a Calex Model 930 which had versions with up to an amp out. I haven't a clue if they are still around. A Google of Programmable Current Source should get you some hits. Finally they are a relatively easy build with a basic op amp a few resistors and an output transistor (or MOSFET) which will handle the current. Anyway I would approach it using a DAC using an Arduino.

Ron

MarkT:
A DAC driving a DC-amplifier capable of upto 2A into 6 ohms. It may be possible to use PWM directly
but the datasheet doesn’t say anything about that - it is almost certainly a high inductance coil that
you are driving given its creating a magnetic field.

A possible circuit is a programmable current source/sink using shunt-resistor for feedback. A free-wheel
diode would be needed as the load is likely inductive.

Something like: Current sink stability

Dear Mark

Thank you for the reply i will study you suggestions and will get back to you if any further help is required.

Ron_Blain:
Using an Arduino I would do as Mark suggested above.Years ago I had to come up with some for magnetic brake assemblies. Using an Arduino I would buy one of the ready made DAC boards available which will afford you a programmable voltage source. Next you can build or buy a programmable current source which is a Transconductance Amplifier which is a fancy way of saying voltage in and proportional current out. Years ago a company named Calex sole what they called a Calex Model 930 which had versions with up to an amp out. I haven't a clue if they are still around. A Google of Programmable Current Source should get you some hits. Finally they are a relatively easy build with a basic op amp a few resistors and an output transistor (or MOSFET) which will handle the current. Anyway I would approach it using a DAC using an Arduino.

Ron

Thank you, your comment in combination with one of Mark helped to understand the concept. If any further help required will get back to you.

You might look at constant current LED drivers. Many are PWM controlled. You might need a current sensor to measure actual current as I doubt the drivers have any sort of reliable calibration.