servo gear reducer

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 like a glue-dispensing nozzle for affixing a windshield to an servo gear reducer automobile. Motion of the nozzle as it comes after the seam between a windshield and its window frame should be perfectly smooth; otherwise 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 important in contouring applications. But, it is difficult to regularly achieve smooth motion 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 procedure and noise.

Many servo controllers use software compensation, and their success depends on knowing the lost movement of the whole system. This information is usually available from the gearhead producer.
Contouring applications usually involve end-effectors or tool-points that adhere to mathematically defined paths. Sealant and bonding devices, water and flame cutters, laser welders and cutters, movement controlled cameras, and CNC machine tools are good examples.

Software compensation is accomplished by commanding the engine to go beyond the apparently desired position by an amount add up to the system’s dropped movement, thereby bringing the load to the truly desired position. For example, consider 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 go 110,000 encoder counts to get 1.0 in. of motion, therefore compensating for the 0.1-in. lost motion.

Backlash is the extra space between two adjacent equipment teeth and its engaging tooth; lost motion may be the total looseness or movement at a reducer’s result shaft when the input shaft is fixed. Lost motion contains backlash, plus losses from bearing looseness, tolerances and matches, and shaft and gear tooth compliance.
Servo controllers could be programmed to compensate for backlash and dropped movement in planetary gearheads. This technique compensates for backlash actually where an application requires accuracy better than the minimal backlash of the gearhead.

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