Because the sun equipment in a hybrid unit is pre-aligned within the gearhead and not affixed to the engine shaft, these gearheads can be utilized in contouring applications such as 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 window frame must be perfectly smooth; otherwise a ripple in velocity alters the bead diameter and causes messy glue software.
servo motor gear reducers smooth motion, which means the absence of torque and velocity variations (ripple), is important in contouring applications. But, it really is difficult to consistently achieve smooth motion where the sun gear is mounted on the engine shaft. Even a slight misalignment in sunlight gear (engine shaft runout or coupling inaccuracies) could cause rough procedure and noise.
Many servo controllers use software compensation, and their success depends on knowing the lost motion of the entire system. This details is usually offered from the gearhead manufacturer.
Contouring applications generally involve end-effectors or tool-points that stick to mathematically defined paths. Sealant and bonding machines, water and flame cutters, laser beam welders and cutters, movement managed cameras, and CNC machine tools are good examples.
Software compensation is achieved by commanding the electric motor to move beyond the apparently desired position by an amount add up to the system’s dropped motion, thereby bringing the load to the truly desired position. For instance, consider a servomotor, gearhead, and leadscrew combination in a pick-andplace robot. If 100,000 encoder counts equals 1.0 in. of linear movement and the system has 0.1-in. dropped motion, then the controller tells the electric motor to move 110,000 encoder counts to obtain 1.0 in. of motion, hence compensating for the 0.1-in. lost motion.
Backlash is the excess space between two adjacent equipment teeth and its own engaging tooth; lost motion is the total looseness or movement at a reducer’s output shaft when the insight shaft is fixed. Lost motion contains backlash, plus losses from bearing looseness, tolerances and fits, and shaft and gear tooth compliance.
Servo controllers can be programmed to pay for backlash and dropped motion 
in planetary gearheads. This technique compensates for backlash actually where an application requires accuracy much better than the minimal backlash of the gearhead.