Because the sun equipment in a hybrid unit is pre-aligned within the gearhead rather than affixed to the motor shaft, these gearheads can be used in contouring applications such as a glue-dispensing nozzle for affixing a windshield to a car. Movement of the nozzle since it comes after the seam between a windshield and its own window frame must be perfectly smooth; otherwise a ripple in velocity alters the bead diameter and causes messy glue software.
Smooth motion, which means the lack 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 engine shaft. A good slight misalignment in sunlight gear (motor shaft runout or coupling inaccuracies) can cause rough procedure 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 manufacturer.
Contouring applications generally involve end-effectors or tool-points that stick to mathematically defined paths. Sealant and bonding devices, water and flame cutters, laser beam welders and cutters, motion controlled cameras, and CNC machine tools are good examples.
Software compensation is accomplished by commanding the motor to go beyond the apparently desired position by a quantity add up to the system’s lost motion, thereby bringing the strain to the truly desired position. For instance, 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 go 110,000 encoder counts to get 1.0 in. of motion, thus compensating for the 0.1-in. lost motion.
servo gear reducer Backlash is the extra space between two adjacent equipment teeth and its own engaging tooth; lost movement is the total looseness or motion at a reducer’s output shaft when the input shaft is fixed. Lost motion includes backlash, plus losses from bearing looseness, tolerances and fits, and shaft and gear tooth compliance.
Servo controllers could be programmed to compensate 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.