This work presents a novel optimal control strategy for precision motion control of flexible ball-screw feed drives. Typically, ball-screw feed drive control relies on state feedback taken both from motor and the load sides. The controller designed in this thesis is based on the non-collocated framework, where all the feedback...
This thesis presents accurate and time-optimal smooth reference trajectory generation techniques for manufacturing equipment such as high-speed machine tools (MT) and industrial robots (IR). Typical machining tool-paths for MTs and IRs are defined as a series of discrete linear moves. Although Point-to-Point (P2P) feed motion can be generated by interpolating...
High-performance mechatronic systems are widely used in precision manufacturing equipment such as CNC machine tools, 3D-Printers, photolithography systems, industrial robots, and Coordinate Measuring Machines (CMMs). These equipment are utilized in producing parts and components for aviation, semiconductor, optics, and many other emerging industries, with geometric features and surface properties within...
Modulation assistance is widely employed to improve chip management in turning. This process is also known as modulated turning. Modulated turning transforms continuous cutting into intermittent cutting by periodically disengaging the tool tip from the workpiece, resulting in the generation of short, easily managed chips. This novel method improves the...
This thesis presents novel feedback and feedforward control system design strategies for active to passive vibration mitigation of residual vibrations on high speed machine tools. Residual vibrations on high-speed machine tools are triggered when the machine axes (table) undergo large accelerations, which induce sudden inertial forces and excite the lightly...
This work presents a new approach to enable accurate machining cycle-time prediction. While conventional computer-aided manufacturing (CAM) software estimates cycle times for given toolpaths, huge errors occur due to neglecting interpolator dynamics of numerical control (NC) systems. Typically, the machine changes its feedrate such as slowing down and speeding up...
This thesis presents mechanics and dynamics of Low Frequency Vibration Assisted Turning (LFV-T). First, a mechanistic model for analytical cutting force and specific cutting energy prediction is presented. Kinematics of the process is used to analyze the cut surface topography and derive the uncut chip thickness variation for various modulation...
Prediction and mitigation of chatter vibrations in machining operations and optimizing overall machining mechanics are crucial for achieving greater productivity and manufacturing efficiency. This thesis first explores effect of directional relationships on chatter stability in milling process. Based on the directional relationships, a geometry-based chatter stability index (CSI) is proposed...
Snowpack base temperatures vary during accumulation and diurnally. Their measurement
provides insight into physical, biological and chemical processes occurring at the snow/soil interface.
Recent advances in Raman-spectra instruments, which use the scattered light in a standard
telecommunications fiber-optic cable to infer absolute temperature along the entire length of the fiber,...
Optical sensing technologies are pivotal in the manufacturing process, specifically in defect detection, tool condition estimation, and monitoring. The research aims to enhance the accuracy, efficiency, and reliability of manufacturing metrology by employing optical sensing technologies, such as laser profilometers and image processing techniques. The dissertation proposes intelligent and flexible...