Question

(b) An electric unicycle is composed of a single wheel and an electric motor. The manufacturer specifications state that it must accelerate from 0 to 10 mph in 3.8 seconds, for a given torque T. The wheel would rotate with 1000 rpm if it is travelling at 10 mph. According to the motor’s manufacturer, the same electric motor with the same torque T would accelerate from rest to 1000 rpm in 0.95 seconds, assuming the damping and losses to be negligible. The unicycle is assumed to be a solid cylinder, with inertia of Jcyl = 1.9 kg·m2, excluding the motor. The wheel is assumed to run at the same speed as the motor (no gearbox). The motor can only provide up to 70 Nm of torque. Determine if this motor torque will be sufficient to accelerate the unicycle as specified.

NOTE: the inertia of this system is composed of the unicycle’s wheel (Jcyl), as well as the inertia of the motor. There is only one motor.

Answer 1