Research Areas

        Machinery and Structure Malfunction Detection and Diagnosis

        Smart Machines and Structures

        Sensor and Signal Processing Applications

        Vibration Analysis and Control

        Intelligent Systems and Manufacturing Automation

        Machine Learning and Computational Intelligence

        Integrated Manufacturing Planning and e-Manufacturing

        Manufacturing Engineering and Systems

        Machining Process Monitoring and Control

 

 

 

Current and Recent Research

 

Research Activities

The objectives of my research group are to develop building blocks and architecture for smart machines, smart factories, and e-manufacturing. The main thrusts include the development of the following:

 

       A Machine and Structure Health Management System for detecting, classifying and locating faults, predicting their growth, and recommending actions. A wide range of signal processing tools such as various wavelet transform techniques, de-noising and filtering methods, blind source separation methodologies, ICA, EMD, adaptive/statistical signal processing, and hidden Markov model have been or are being applied in the development of the system. Simplicity, non-intrusiveness, and diagnostic/predictive accuracy are the main goals in the design of the system. Particular effort is being made for renewable energy facility condition monitoring, e.g., wind turbines. Hardware implementation of the developed system modules is an imperative aspect of our work (Please see some of the system modules: 1) A prototype for Oil-Debris Signal Enhancement, patent pending, 2) A prototype for on-line rotating machinery fault detection, patent pending).

      An Intelligent Machining Control System for adaptive control of different machining processes in response to dynamic changes of tool/machine conditions, cutting geometry and workpiece material properties. Both conventional and fuzzy control approaches have been adopted. The focus is on versatility and planning-goal guidance.

       An Integrated Planning System which is able to: a) synchronize various manufacturing activities for maximizing profitability; and b) reconfigure manufacturing systems for rapid and sustainable responsiveness to changes. A network of models/agents is being developed for a distributed and collaborative planning environment. Neural, fuzzy and evolutionary computing tools are used to design algorithms for on-line decision making. Efforts are also being made to develop Web-based interactive planning tools for multi-site enterprises.

 

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Current Projects

Some of the projects we are currently working on are:

 

         Wind turbine condition monitoring 

         Helicopter gearbox early failure signature detection

         Gearbox fault diagnosis

         Real time engine oil debris monitoring and analysis

         Condition-based machinery health management using streamlined sensing systems

         Integrated machine and process fault detection and diagnosis

         Chatter detection and suppression in machining processes

         Detection of tool wear and breakage using acoustic methods

         Intelligent control of CNC machining processes

         Integrated manufacturing/production planning and control

Demonstrations

         Demo1: In-line oil debris detection

 

Play the Video

 

           This demonstration shows the metal particle detection using on-line oil-debris monitoring (ODM) sensor under 2-directional vibrations. The lubricant oil passes the sensing region of the sensor through the tube. To simulate the severe vibration near the engine in practice, the shakers were used to apply external vibrations in the horizontal and the vertical directions. The particle detection algorithm was written using the NI LabVIEW.

 

         CNC on-line machining control

       Introduction

          CNC milling machines with open-loop control are designed to rigidly execute NC codes regardless of the on-line cutting geometry variation, tool conditions, and the dynamics of the cutting process, thus leading to under-utilization of machine capacity, unsafe machining processes, and excessive human intervention. This situation can be improved by performing either off-line planning or on-line control.  
    The main idea of off-line planning is to apply different feed rates for different depth of cut, width of cut, or volume of material to be removed. This is mostly done off-line before the actual machining process, ignoring the on-line cutting and tool conditions. In addition, this method adjusts only feed rate, overlooking the mismatch of feed rate and spindle speed, and thus causing low productivity, chatters, and pre-mature tool failure.  
    On the other hand, the on-line control approach adjusts machining parameters in response to the tool conditions, thus providing near optimal material removal rate. Current CNC on-line machining control methods use traditional control algorithms and dynamometers, and thus are sensitive to machine, cutter, and workpiece material changes. In addition, they all require lengthy modeling processes, which do not suit today¨s machining environment, i.e. small batch sizes, frequent tool, workpiece and machine changes. Another disadvantage is that dynamometer are very expensive, in the range of $30,000
~$60,000. The workpieces are usually mounted on the top of a dynamometer. A dynamometer could be ruined due to the direct exposure to chips, cutting fluid, and possible overload. In addition, the use of dynamometers involves tedious setups and may cause instability.
    To avoid those problems, a novel on-line machining control system has been developed at the University of Ottawa which has the following features. 
   a)      Capable of adjusting multiple machining parameters.
   b)      Insensitive to machine-tool-workpiece changes.
   c)      Non-intrusive, i.e., it does not interrupt normal cutting processes and it does not restrict workpiece sizes.
   d)     Inexpensive and durable. 
    The new control system was designed using fuzzy logic control based on power input. The fuzzy control is robust because it tolerates imprecise or incomplete information and knowledge and does not require exact information about the dynamics of a system and hence avoids lengthy modeling process. Due to its robustness, the same system can be implemented on different machines.  
   
Power sensors are in-expensive, non-intrusive and durable. The power sensor is separated from the cutting process, and therefore it does not restrict workpiece size and does not require additional setups. Since the power sensor is not exposed to the harsh cutting conditions, the fluids, chips, potential overload and collision can not cause any damage to the sensor.
 

                  Summary of cutting processes
          
  Cutting Process 1
Play the Video
Cutting Process 2
Play the Video
Tool 9/16-inch 4-flute high-speed steel end mill 1-inch dia. with 2 carbide inserts
Workpiece material Steel Aluminum
Workpiece profile 3-step changes Irregular shape
Control parameters Feed rate & Spindle speed Feed rate & Spindle speed
Control target Constant power level Constant power level

 

         Fault detection

       Play the Video

 

         Oil debris signature extraction

       Play the Video

 

 

Major Funding

The activities of this research group are funded in part by:

 

         NSERC Discovery Grant

         NSERC Research Tools and Instruments Grant

         Ontario Centers of Excellence Directed Collaborative Research Program

 

Collaborations

         GasTOPS, Ltd. (Canada)

         National Research Council (Canada)

         Okuma (USA)