I am looking at sizing a motor for lifting a mass a set distance in a set time and have found multiple design notes that have allowed me to complete this task. For example https://www.maxonmotor.com/medias/sys_master/root/8815460712478/DC-EC-Key-Information-14-EN-42-50.pdf?attachment=true or http://www.machinedesign.com/motorsdrives/how-pick-motors-linear-motion
However, my main qualm lies in understanding the ability to dictate and obtain a trapezoidal profile. Taking the the second source as an example, for acceleration/deceleration the torque required is 0.3582 Nm and 0.3309 Nm for constant velocity.
1) I understand the concept of the torque constant, but how do you control the current supply to obtain these constant torques for acceleration and constant velocity? Could it be implemented by measuring the current to the motor, turning off the voltage supply when it hits this limit, and turn it back on when it falls below, until it reaches the target speed and then turning off this limiter?