Because the sun gear in a hybrid unit is servo motor gear reducers pre-aligned within the gearhead and not affixed to the engine shaft, these gearheads can be utilized in contouring applications like a glue-dispensing nozzle for affixing a windshield to an automobile. Motion of the nozzle as it comes after the seam between a windshield and its window frame must be perfectly smooth; or else a ripple in velocity alters the bead diameter and causes messy glue application.

Smooth motion, this means the absence of torque and velocity variations (ripple), is important in contouring applications. But, it really is difficult to regularly achieve smooth movement where the sun equipment is installed on the electric motor shaft. Even a slight misalignment in the sun gear (engine 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 whole system. This info is usually offered from the gearhead producer.
Contouring applications generally involve end-effectors or tool-points that adhere to mathematically defined paths. Sealant and bonding machines, drinking water and flame cutters, laser welders and cutters, motion managed cameras, and CNC machine equipment are good examples.

Software compensation is achieved by commanding the electric motor to move beyond the apparently desired position by a quantity equal to the system’s lost movement, thereby bringing the strain to the truly desired position. For example, 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. dropped motion, then your controller tells the engine 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 extra space between two adjacent gear teeth and its engaging tooth; lost movement is the total looseness or motion at a reducer’s result shaft when the insight shaft is fixed. Lost motion contains backlash, plus losses from bearing looseness, tolerances and suits, and shaft and gear tooth compliance.
Servo controllers could be programmed to compensate for backlash and lost movement in planetary gearheads. This technique compensates for backlash actually where an application requires accuracy better than the minimal backlash of the gearhead.