Because the sun gear 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 an automobile. Motion of the nozzle as it follows the seam between a windshield and its own window frame must be perfectly smooth; or else a ripple in velocity alters the bead diameter and causes messy glue app.

Smooth motion, which means the absence of torque and velocity variations (ripple), is essential in contouring applications. But, it really is difficult to regularly achieve smooth movement where the sun equipment is installed on the motor shaft. Even a slight misalignment in the sun gear (motor 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 movement of the entire system. This info is usually available 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, motion managed cameras, and CNC machine tools are good examples.

Software compensation is accomplished by commanding the engine to go beyond the apparently desired position by a servo gear reducer quantity add up to the system’s dropped movement, thereby bringing the strain to the truly desired position. For example, look at a servomotor, gearhead, and leadscrew combination 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 your controller tells the electric motor to move 110,000 encoder counts to get 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 motion is the total looseness or motion at a reducer’s result 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 pay for backlash and lost motion in planetary gearheads. This technique compensates for backlash even where an application requires accuracy better than the minimal backlash of the gearhead.