Dear Ihsan,

I suggest you to see links and attached files on topic.

-Control Design and Analysis for Underactuated Robotic Systems

https://books.google.dz/books?isbn=144716251X

-Block Backstepping Design of Nonlinear State Feedback Control Law ...

https://books.google.dz/books?isbn=9811019568

-Theoretical Preliminaries - Springer

https://www.springer.com/cda/.../9789811019555-c2.pdf?...0...

-Nonlinear Control and Reduction of Underactuated Systems with ...

citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.73...

Best regards

Mohamed-Mourad Lafifi Zeashan Khan

I am not looking for how to control under-actuated systems. The under-actuated systems which I have studied so far, were all in non-strict feedback form and I have quite a few strategies how to control it.

I was thinking under-actuated systems in strict feedback form don't exist.

But I have got the following example of strict-feedback under-actuated system.

http://data.mecheng.adelaide.edu.au/robotics/projects/2007/BallBeam/Wei_Final_Thesis.pdf

THANKS FOR YOUR CONCERNS

Hi Afridi,

I think you are mixing up two different terminologies. The under-actuation is something related to dynamics limitation while 'strict feedback form' is something more mathematical. These two are not related in any sense because the same actuating input may appear in multiple states or in other way one input might be integrated in several chains like a tree.

Naveed Mazhar

Not at all.

Every dynamic system have a mathematical model ( including under-actuated systems ). So if the mathematical model is in strict-feed back form, we can say the system is in strict-feedback form.

What you are describing is a kind of non-strict feedback form system and very common in under-actuated systems .

I was searching for strict-feedback under-actuated systems and already found one.

Ihsan ullah Afridi

I also meant to say the same. Good to know that your problem is resolved.

Cheers!