BSc: Mechatronics

Mechatronics

• Course name: Mechatronics
• Course number:
• Knowledge area: Sensors and actuators; Robotic control; Electromechanical systems.

Course characteristics

Key concepts of the class

• System design
• Feedback control
• Electric motor selection and control

What is the purpose of this course?

Industrial requirements for modern mechatronics and robotics engineers are such that, given an automation task, they must be able to identify and model the targeted physical process or system, select appropriate sensors, actuators and transmission mechanisms to control it, and design and implement control algorithm to ensure the system achieves desired performance. Therefore, the purpose of this class is to familiarize the students with the most fundamental aspects of all the key areas described above while focusing on typical real-world exercises and examples.

Course Objectives Based on Bloom’s Taxonomy

- What should a student remember at the end of the course?

By the end of the course, the students should be able to remember and recognize

• Various types of sensors, their pros and cons,
• Working principles of electric actuators (DC motors),
• Operation principles of motion transmission mechanisms,
• Fundamentals of linear feedback control systems, and
• Principles of controller design for mechatronic systems.

- What should a student be able to understand at the end of the course?

By the end of the course, the students should be able to describe and explain

• How to select sensors for a given application,
• How to choose appropriate transmission mechanisms and account for their efficiency,
• How to integrate all selected parts to create a mechatronic system,
• Typical nonlinearities that originate from electronic and mechanical sources and their effects on system performance, and
• How to tune control system for selected motor and desired performance specifications.

- What should a student be able to apply at the end of the course?

By the end of the course, the students should be able to

• Drive differential equations of motion describing behavior of physical systems with several degrees of freedom,
• Calculate motor and sensor requirements for a given physical system, control task or application,
• Select appropriate motor that provides enough power while avoiding overheating,
• Tune control system for selected motor, transmission mechanism and sensor to achieve desired response and stability.

Course evaluation

Course grade breakdown

		Proposed points
Labs/seminar classes	20	0
Interim performance assessment	30	60
Exams	50	40

If necessary, please indicate freely your course’s features in terms of students’ performance assessment:

The course grades are given according to the following rules: Homework assignments (4) = 20 pts, Quizzes (4) = 40 pts, Term project = 40 pts.

Grades range

Course grading range

		Proposed range
A. Excellent	90-100
B. Good	75-89
C. Satisfactory	60-74
D. Poor	0-59

If necessary, please indicate freely your course’s grading features.

Resources and reference material

Main textbook:

• “Mechatronics,” Sabri Cetinkunt. John Wiley & Sons., 2007.

Other reference material:

• “System dynamics: modeling, simulation, and control of mechatronic systems,” Dean C. Karnopp, Donald L. Margolis, and Ronald C. Rosenberg. John Wiley & Sons, 2012.
• “Mechatronics: Electronic Control Systems in Mechanical and Electrical Engineering” (6th Edition), William Bolton. Pearson Education, 2003.

Course Sections

The main sections of the course and approximate hour distribution between them is as follows:

Section	Section Title	Teaching Hours
1	Dynamics and electrodynamics	6
2	Electric motors	6
3	Transmission mechanisms and sensors	4
4	Control systems	6

Section 1

Section title:

Dynamics and electrodynamics

Topics covered in this section:

• Free body motion
• Kinetic and potential energy
• Differential equations of motion
• Basics of linear electric circuits
• Impedance

What forms of evaluation were used to test students’ performance in this section?

|a|c| & Yes/No
Development of individual parts of software product code & 0
Homework and group projects & 1
Midterm evaluation & 0
Testing (written or computer based) & 1
Reports & 0
Essays & 0
Oral polls & 0
Discussions & 1

Typical questions for ongoing performance evaluation within this section

1. Find kinetic and potential energy of a given physical system.
2. Write differential equations of motion of a mechanical system.
3. Find system transient response when external force is applied.
4. Solve for voltages and currents in a given electric circuit.
5. Find electric power produced by individual circuits’ components.

Typical questions for seminar classes (labs) within this section

1. In MATLAB or other software, do the following for a second-order system:
   • Write a program to simulate its dynamics;
   • Plot step response and find its parameters;
   • Calculate and plot system energy with time.
2. Find and analyze frequency response (Bode plot) of a dynamic system.
3. Find impedance of a given linear electric circuit.
4. Write differential equations describing voltages and currents of dynamic circuit.
5. How does electric energy exchange in an RLC circuit?

Test questions for final assessment in this section

1. Use Kirchoff’s voltage and current laws to drive differential equations of a given electric circuit.
2. What are the analogies between three main mechanical (mass, damper, spring) and electrical (resistance, capacitance, inductance) components?
3. Find impedance of electrical circuit and draw a corresponding mechanical system schematically.

Section 2

Section title:

Electric motors

Topics covered in this section:

• Electric and magnetic fields
• Operating principles of DC motors
• Electromechanical dynamic model of DC motors
• Steady-state torque-speed characteristics, power
• AC motors
• Linear motors
• Energy losses in electric motors

What forms of evaluation were used to test students’ performance in this section?

|a|c| & Yes/No
Development of individual parts of software product code & 0
Homework and group projects & 1
Midterm evaluation & 0
Testing (written or computer based) & 1
Reports & 0
Essays & 0
Oral polls & 0
Discussions & 1

Typical questions for ongoing performance evaluation within this section

1. What devices around us are based on principles of electromagnetism?
2. Describe what happens when an conductive wire is placed in magnetic field.
3. How to create a rotating magnetic field, and what happens to magnetic objects placed inside of it?
4. How to find electrical and mechanical power of electric motor?
5. What happens when a motor is running in the generator mode?

Typical questions for seminar classes (labs) within this section

1. Drive differential equations governing the motion of a DC motor.
2. Draw a block diagram of a DC motor based on differential equations and convert them into state-space form.
3. Calculate maximum DC motor speed in no-load and loaded conditions.
4. Assuming a DC motor, calculate stall torque and maximum torque for given speed.

Test questions for final assessment in this section

1. Draw a schematic diagram of electrical and mechanical parts of DC motor and explain their interplay.
2. What is the physical meaning of mechanical time constant of a DC motor? What about electrical time constant? How to calculate them?
3. Explain how to select a DC motor based on known force-velocity profile of the application.

Section 3

Section title:

Transmission mechanisms and sensors

Topics covered in this section:

• Rotary-to-rotary transmission
• Rotary-to-translational motion transmission mechanisms
• Shaft misalignments and flexible couplings
• Position sensors
• Velocity and acceleration sensors
• Force and torque sensors

What forms of evaluation were used to test students’ performance in this section?

|a|c| & Yes/No
Development of individual parts of software product code & 0
Homework and group projects & 0
Midterm evaluation & 0
Testing (written or computer based) & 1
Reports & 0
Essays & 0
Oral polls & 1
Discussions & 1

Typical questions for ongoing performance evaluation within this section

1. What applications of gears do you know? What about belts and pulleys?
2. What are the possible sources and effects of shaft misalignments on electric motors and gears?
3. Give an example of sensors used in conventional home appliances.
4. Typical applications where we need velocity and acceleration measurements.
5. Given a particular real-world device (system), which transmission mechanisms and sensors does it use in your opinion?

Typical questions for seminar classes (labs) within this section

1. What are potential drawbacks and nonlinearities of conventional motion transmission mechanisms?
2. What effect does a transmission mechanism have on required motor speed and torque?
3. What are the pros and cons of each conventional position sensor type?
4. Name applications where position measurement is not feasible.
5. What are the main issues of conventional force-torque sensors?

Test questions for final assessment in this section

1. Derive differential equations of motion when a load is connected to DC motor shaft via transmission and analyze its contribution to overall system dynamics.
2. For an application of motion control with desired accuracy and given a DC motor, select appropriate transmission mechanism and sensor resolution to satisfy performance specifications.
3. List pros and cons of conventional position sensor types and briefly describe their preferable application areas.

Section 4

Section title:

Control systems

Topics covered in this section:

• Feedback control systems
• Stabilization and trajectory tracking
• Linear regulators (P, PD, PID)
• Digital control (sampling, quantization)
• DC motor controller tuning
• Stability of dynamic systems

What forms of evaluation were used to test students’ performance in this section?

|a|c| & Yes/No
Development of individual parts of software product code & 0
Homework and group projects & 1
Midterm evaluation & 0
Testing (written or computer based) & 1
Reports & 0
Essays & 0
Oral polls & 1
Discussions & 1

Typical questions for ongoing performance evaluation within this section

1. Give examples of real-world biological and physical closed-loop (feedback) systems
2. Drive error dynamics equations for a given feedback control law
3. What are the physical analogies of each term in PID-controller?
4. How to implement PD regulator in MATLAB software?

Typical questions for seminar classes (labs) within this section

1. In MATLAB, simulate behavior of a linear second-order ODE for the following controller types: P, PD, PID.
2. Analyze stability of a given feedback control system.
3. How does sampling affect system stability?
4. Tune controller for a given motor-transmission-sensor combination.

Test questions for final assessment in this section

1. What is the physical analog of PD-regulator in application to control over second-oder mechanical systems?
2. What are the effects of time delays, quantization, and sampling rates on stability of digital control systems?
3. For a given application, select DC motor and tune its control system.