The robotic arm which is a system of simple machines is pushed and pulled by the pressure of hydraulics. The arm itself is a lever because it has the pivot point at the very end and because it raises up and down. The syringes push water back and forth which cause opposite forces on both the syringes and the arm which will push the arm and the syringe, but the syringe has more force which will make it turn, lift and move the claw back and forth. Each of the syringes has potential energy before you push it to make the water flow. When the water is flowing in the tube is kinetic energy.
Conclusion: robotic arms are a great help in society whether they are used in factories for manufacturing or for lifting heavy objects. To make the arm lift heavier objects you would probably use electricity instead of hydraulics and also more durable material like steel, or some type of metal.