Development of a joystick with a two-degree-of-freedom mechanism based on cable-capstan transmission

This work presents the development of a joystick with two degrees of freedom. The joystick is designed considering a cable-capstan mechanism allowing the movement of the central axis for Pitch and Roll angles, where the central axis has a workspace in a plane (XY). The joystick design and instrumentation consider future haptic tasks and applications in practical engineering education courses. This device was designed based on fast prototype manufacturing, including 3D printed parts. The design is small and portable, and the development of the joystick includes a user interface to display and save data and graphs of different signals such as angular positions, central axis position, control signals, current of the motors, and errors, and allows tuning different parameters for the control implementation. In order to show the functionality of the designed mechanism, we show its performance in tracking trajectory tasks implementing a proportional, integral, derivative controller (PIDC) with a Super Twisting algorithm (STA). The results showed the joystick with the complete instrumentation and communication with the user interface in a personal computer. We compared the PIDC using an Euler's derivative vs. the PIDC with the STA's derivative estimated. The results of the trajectory tracking control with the PIDC-STA algorithm showed a better performance of the joystick with an average error norm of 2.73 degrees, taking the Pitch and Roll errors, compared with the PIDC- Euler controller with an average error norm of 3.22 degrees.