Before I begin talking about the mecha control systems, let me just say that I haven't seen much sentai so MagiKing and GekiTouja are my favorite so far. The ones I've seen (at the time of this post) are Gekiranger, Gokaiger, Gobusters, half of Magiranger, Dairanger, and Shinkenger, Kyoryuger, and Liveman.
Mechas are pretty much a staple of the franchise. Throughout the entire franchise, there have been many many mecha each with various types of control systems. Most have just been the standard seats with steering wheels or joysticks. However there have been a few who haven't used that type including, Gekiranger, Magiranger, Dairanger, Kyoryuger, and Shinkenger. Out of all the control systems I've seen, here are my top 3:
Number 3: Dairanger's Ki powered control systems.
Dairanger's mecha are controlled by the rangers' Ki. By placing their hands on the sphere in the cockpit they can control their mechas in a fight. This one earned my number 3 spot for the sheer fact that I'm stumped on how it works other than Ki power.
Number 2: Gekiranger's movement and thought control system.
Gekiranger's mechas have no control panels at all and the rangers just stand on a white floor and move their bodies to fight with the mecha mirroring their movements. This leads me to believe that their mecha is more thought controlled than the other sentai mecha.
Number 1: Magiranger's (specifically MagiKing) chess board system.
The Magiranger's mecha by far has the most unique way of movement I've ever seen. Once Kai and his siblings combine their Magin to form MagiKing their minds are put into the cockpit. There they move like chess pieces in order to control MagiKing. This type of control system in theory forces the Magirangers to think strategically in order to simply move their mecha.
I really love just thinking about how control systems could be applied to real life. In sense, dissecting them and figuring out how they work is just awesome to me. Can you imagine what it would be like if we were able to actually operate machines like this?