help needed with my space marine animatronic project

hi there, i’m very new to arduino, basically learning as i go trying to complete a project for a friend. i build full size costumes for cosplayers, sci fi addicts and lots of kids wanting to be iron man LOL. i have attached a current work in progress, a full size, 2.3 metre tall Space Marine from the warhammer 40000 miniature series, which will be worn to a sci fi convention. this gives some kind of idea as to the scale of the projects im working on. i have begun work on a new project, a space marine terminator (wow, im sounding like such a nerd right now haha). this will be a full 3 metres tall, and be fully wearable. i have completed modeling the whole armor, and will begin the actual build next week.

i have so far built functioning hands controlled by flex resistors after following a tutorial i found online. it works brilliantly, with only minor tweaks needed to achieve a full range of motion. my problem is with the new project being so large, the user would need 1.5 meter long arms to be able to bend the elbow. i am looking at using the same flex resistor controlled setup to control an elbow joint.

i was wondering what type of setup you guys recommend to be able to scale up the concept from the small servos i used on the fingers, to something capable of lifting at least 4kg at the end of the arm. what would the best type of motor to use? and electronics wise, what would i need, in regards to powering and controlling the motor.

sorry to be so vague about everything, this is a complete first for me, but hopefully something i will be able to keep learning and improving upon. thanks in advance :slight_smile: