Cost reduction and increasing production rates are driving automation of
aerospace manufacturing. Articulated serial robots may replace bespoke gantry
automation or human operations. Improved accuracy is key to enabling operations
such as machining, additive manufacturing (AM), composite fabrication, drilling,
automated program development, and inspection. New accuracy standards are needed
to enable process-relevant comparisons between robotic systems.
Accuracy can be improved through calibration of kinematic and joint stiffness
parameters, joint output encoders, adaptive control that compensates for thermal
expansion, and feedforward control that compensates for hysteresis and external
loads. The impact of datuming could also be significantly reduced through
modeling and optimization. Highly dynamic end effectors compensate
high-frequency disturbances using inertial sensors and reaction masses. Global
measurement feedback is a high-accuracy turnkey solution, but it is costly and
has limited capability to compensate dynamic errors. Local measurement feedback
is a mature, affordable, and highly accurate technology where the robot is
required to position or align relative to some local feature. Locally clamped
machine tools are an alternative approach that can utilize the flexibility of
industrial robots while also enabling high-quality machined surfaces. Hybrid
high-accuracy control strategies will be required for many processes.
NOTE: SAE EDGE™ Research Reports are intended to identify and illuminate key
issues in emerging, but still unsettled, technologies of interest to the
mobility industry. The goal of SAE EDGE™ Research Reports is to stimulate
discussion and work in the hope of promoting and speeding resolution of
identified issues. SAE EDGE™ Research Reports are not intended to resolve the
issues they identify or close any topic to further scrutiny.