Our team found the need of taking the aerobic exercise in the balance training, especially for the patients of elderly. That is why we developed a cable machine for taking the aerobic exercise and balance training simultaneously. The characteristics of back electromotive force (emf) of motor was studied. While using the cable machine, the winch was rotated by the cable and it drove the one-way rotating mechanism. The mechanism connect a BLDC motor. So the motor kept rotating intermittently. If the motor was driven the back emf produce against the rotation. The mechanical impedance (pulling force of cable) was affected by the resistance load of circuit and the rotation speed of motor. Thus the user can experience the resistance by changing the resistive load and the pull speed. For advanced application the controller of the exercise system can tune the strength automatically referring to the exercise prescription and the muscle is in the state of isotonic contraction.

The three-phase brushless direct current (BLDC) motor was used for the generator or electric brake when it was taken as the passive mechanism. According the characteristics of BLDC motor in mechanism and electromechanical properties, the mechanical impedance can be adjusted by the resistive load of circuit and rotating speed of the motor. For the cable exercise it reduced the complicated mechanism of the weight assignment if employing the motor solution. Besides based on the electric system it is helpful to integrate the IoT components. The obstacle to digitize the exercise industry can be overcome.

Startup unicorn Peloton was called Netflix in fitness. It represented the successful case of digital exercise system. The digitization trend will affect the exercise industry and its development. Our team designed a novel cable machine using BLDC motor. Its functions included the reciprocating motion, minimization of hardware, based on the internet of things and digital control. Not only designed for need of the aerobic exercise but also can be applied to resistance exercise and stretching training. It has the widely acceptable use.