We are developing a small compact electric vehicle for shopping purposes. In this study, we fabricated an experimental vehicle, that uses only six small rechargeable AA batteries (7.2 V, approximately 2 A·h) as an electric power source. The vehicle user can select between two driving positions: standing and sitting. A compact transmission with a 90-W DC motor and a speed controller that uses pulse width modulation control was designed as an actuating system. Running experiments were conducted to observe the performance of the fabricated vehicle on a flat floor in a gymnasium. The fabricated vehicle was able to operate for 52 min at a speed of 2.73 km/h. The getting-on and getting-off processes in the vehicle were repeated many times during shopping. The human leg strain while getting on and off the vehicle was investigated by electromyogram measurement. During the getting-on and getting-off processes in the vehicle, the myoelectric potential of the quadriceps increased in the sitting position but did not increase in the standing position. The experimental results show that a user suffers more strain in the sitting position than in the standing position.
Pulse-Width-Modulation Control of a Heat Pump Dryer with Cascade Evaporators and Parallel-Flow Condensers
