On the final assembly lines of premium car plants in Swabia and Bavaria, every servo-driven nut runner must deliver precisely the same torque to every wheel bolt—regardless of whether the line is running at full speed or slowing for a model change. The analog current controller sits inside each servo amplifier, translating the torque demand from the PLC into the exact peak current the motor needs for that single tightening cycle. Because the controller responds in microseconds, the amplifier can follow the rapid current spikes without overshoot, so the nut runner never under- or over-torques a bolt. The result is a consistent clamp load across every wheel, shift after shift, while the same controller quietly handles the regenerative braking energy when the spindle reverses, feeding it back into the DC bus instead of wasting it as heat. In adjacent body shops, the same part governs the servo weld guns that spot-weld aluminum closures; here it ensures the weld current profile is identical for every pulse, so the nugget size stays within the narrow tolerance that keeps the door panel from warping.