Because the sun gear in a hybrid unit is pre-aligned within the gearhead and not affixed to the motor shaft, these gearheads can be utilized in contouring applications like a glue-dispensing nozzle for affixing a windshield to a car. Motion of the nozzle as it follows the seam between a windshield and its own window frame must be perfectly smooth; otherwise a ripple in velocity alters the bead diameter and causes messy glue software.
Smooth motion, which means the lack of torque and velocity variations (ripple), is important in contouring applications. But, it is difficult to consistently achieve smooth movement where the sun equipment is mounted on the electric motor shaft. A good slight misalignment in sunlight gear (motor shaft runout or coupling inaccuracies) can cause rough operation and noise.
Many servo controllers use software compensation, and their success depends upon knowing the lost motion of the entire system. This info is usually obtainable from the gearhead producer.
Contouring applications generally involve end-effectors or tool-points that follow mathematically defined paths. Sealant and bonding devices, drinking water and flame cutters, laser welders and cutters, movement managed cameras, and CNC machine tools are good examples.
Software servo gear reducer compensation is accomplished by commanding the engine to move beyond the apparently desired position by an amount equal to the system’s dropped motion, thereby bringing the load to the 
truly desired position. For instance, look at a servomotor, gearhead, and leadscrew mixture in a pick-andplace robot. If 100,000 encoder counts equals 1.0 in. of linear motion and the system has 0.1-in. lost motion, then the controller tells the electric motor to move 110,000 encoder counts to obtain 1.0 in. of motion, therefore compensating for the 0.1-in. lost motion.
Backlash is the excess space between two adjacent equipment teeth and its engaging tooth; lost movement may be the total looseness or movement at a reducer’s output shaft when the insight shaft is fixed. Lost motion includes backlash, plus losses from bearing looseness, tolerances and matches, and shaft and gear tooth compliance.
Servo controllers can be programmed to compensate for backlash and lost movement in planetary gearheads. This system compensates for backlash actually where a credit card applicatoin requires accuracy much better than the minimal backlash of the gearhead.