Development of small compact electric motor tricycle for shopping

We are developing a small compact electric motor tricycle with a low powered battery (7.2 V, approximately 2Ah in total) as the electric power source for shopping purposes. The reduction ratio should be adjusted per the driving situation because of the use of a low powered battery. We designed an actuator system with speed change mechanism for the compact electric motor tricycle. A consumer bicycle is used as the base vehicle, and we focused on the development of an actuator system. A multistep transmission mechanism was designed and fabricated using gears, chains, and sprockets. A 150 W maxon DC motor was used, and the motor speed was controlled using a PWM using MOS-FETs and a PIC microcomputer. Running experiments were conducted to observe the performance of the fabricated vehicle. We confirmed that the fabricated vehicle was able to operate over 30 minutes at a speed of over 3 km/h. Longer running duration must be addressed in future research.