SAE EPR2019010

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.