Robotic systems require motors to actuate different degrees of freedom. Currently, one motor is necessary to actuate one degree of freedom. This can be expensive and can lead to complicated designs in trying to avoid motors interfering with one another. A question is whether different degrees of freedom can be actuated from one motor/axis. A new motor has been designed which aims to answer this question; it is a multi-axis (hybrid) stepper motor which offers 3 independently-actuating axles. To compare its performance to a set of single-axis motors, a 2-DoF marble maze was chosen as the application.
This application was designed and constructed using two hobby servos, TSS 10-MG, as the set of single-axis motors. One motor tilts the maze along the roll axis, and the other tilts an external supporting base on the pitch axis. The whole set-up is suspended by two supporting towers. The multi-axis motor was attached to the same set-up using a set of motor horns and links, and its respective kinematics were calculated. The performance of the motors in set-point tracking and marble-maze solving were compared.
The multi-axis motor was able to outperform the single-axis motors in most regards, offering more stable control, more accurate tracking, and better dynamic performance with similar delay. These results are promising, and future work would include making use of the 3rd axis in a similar design. However, the motor becomes very hot during operation, and future work is not recommended without the use of active cooling.
