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 used in contouring applications such as a glue-dispensing nozzle for affixing a windshield to a car. servo gear reducer Motion of the nozzle as it follows the seam between a windshield and its window frame should 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 consistently achieve smooth movement where the sun gear is mounted on the electric motor shaft. Even a slight misalignment in the sun gear (motor shaft runout or coupling inaccuracies) could cause rough operation and noise.
Many servo controllers use software compensation, and their success depends on knowing the lost movement of the entire system. This details is usually available from the gearhead producer.
Contouring applications usually involve end-effectors or tool-points that follow mathematically defined paths. Sealant and bonding machines, water and flame cutters, laser welders and cutters, movement 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 an amount equal to the system’s dropped movement, thereby bringing the load to the truly desired position. For example, consider a servomotor, gearhead, and leadscrew mixture 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 motor to go 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 gear teeth and its engaging tooth; lost motion may be the total looseness or movement at a reducer’s result shaft when the insight shaft is fixed. Dropped motion includes backlash, plus losses from bearing looseness, tolerances and suits, and shaft and equipment tooth compliance.
Servo controllers can be programmed to pay for backlash and dropped movement in planetary gearheads. This system compensates for backlash also where a credit card applicatoin requires accuracy better than the minimal backlash of the gearhead.