I'm involved with a project that will need a servo motor to generate a high torque and a high speed in a short amount of time. Using typical speed/torque graphs and taking into account a certain gear ratio, it's possible to find a (small, and expensive) variety of motors that suit our specifications. One example chosen at random might be this servo motor.
One thing that worries me, however, is whether the motor we select can accelerate in the time we're asking for (<1sec); as far as I know, speed/torque graphs are measured assuming steady state operation.
What would be the parameters to look for to estimate whether a given motor will have the transient behaviour we require? In other words, is it possible to approximate the step response of such a motor?
(Edit: after I wrote this question I realised it is probably necessary to specify what sort of motor control I'd be using; i.e., torque control, speed control, or position control. Ideally it would be good to have the step response of the torque output under a range of loads since the others would follow from that. As discussed in the answers, this might be impossible to know from a data sheet.)