The potentiometer of the industrial joystick is used to manually change the resistance in the circuit or to measure the potential difference across the circuit; therefore, the potentiometer is called a voltage-measuring device. The potentiometers of the electronically controlled joystick are passive electronic devices, that is, they do not generate energy, they only store or dissipate energy in the form of electrical current.

Joystick manufacturers tell you that a potentiometer is a multifunctional device; besides measuring potential differences, it is used for other purposes, such as dividing voltages, comparing emfs of batteries, and, of course, as a variable resistor. If a constant current flows through a resistor body, the voltage drop across any part of a uniform resistor body is proportional to the length of the wiper (ideally).
So the Joystick manufacturers tell you that if the potential difference between any two parts of the wiper is zero, no current will flow through the circuit. In a potentiometer, the input voltage is applied to the entire length of the resistive wire and the output voltage is measured between the sliding contact and the fixed end of the circuit. The position of the regulator (sliding contact) is varied over the length of the uniform resistance wire to find the zero position.
Through the above introduction and analysis of the Joystick manufacturers introduce the usage principle of the potentiometer, hope it helps you.