Design & Manufacturing an Inclined Elevator United Arab Emirates University College of Engineering Design & Manufacturing an Inclined Elevator Ali Hussain 200000240 Mohammed Obaid 200000297 Habib Al-Saffar 200000318 Project Advisor : Prof. Kamal Moustafa Second Semester 2005/2006

Outline Introduction Objectives Mechanical system Control system Results and discussion Conclusion

Introduction An elevator is a transporting device used to move goods or people vertically, horizontally or inclined. Inclined elevators are used in such places that can not use vertical space or used by disabled persons that can not use an escalator.

Objectives GPI GPII Carrying out complete dynamic force analysis. Applying engineering sciences. Designing elevator components such as brakes, roping system, buffers … etc. GPII Selecting proper components according to the design analysis. Building a prototype with control devices.

Mechanical System Counterweight Car Selection of suspension rope Door Traction drive Elevator machine Car Door Guiding rails

Real Design Layout

Scaling Scaling can be defined as the determination of the interdependency of variables in a physical system. Advantage Used in solving cost effective problems. A model was made with same geometric, kinematics and dynamic similarities as the real design. The selected scaling factor was 1000:88.

2D AutoCAD drawings

Cont.

Cont. (Cabin) Cabin mass= 1.13 Kg

Cont. (Counter-weight)

3D AutoCAD drawing

Prototype pictures

Motor recalculation

Control System Objectives: Controlling DC motor (Up, Down). Controlling motor acceleration & deceleration. Controlling level stops. Operating system accessories (fan, light and door-lock).

Closed-loop control diagram

Sensor Rotary optical encoder 256 pulses. It is a digital electronic device used to convert the angular position of a shaft to a number of pulses. 256 pulses. The input voltage is 5 volts.

Cont. Coupling Sensor

Control device Microcontroller unit (MCU): Advantages: Defined as a computer on a chip which is used to control electronic devices. Advantages: A microcontroller unit can be a powerful tool when building electro-mechanical systems. It interacts with both hardware and user.

Atmega8 (MCU( 8-Kbyte self-programming Flash. Two timers. 28 Input and Output Pins. Input voltage between 4.5 to 5.5 V. Output current is equal to 40 mA. Operating at 4 MHz frequency.

Atmega8 (MCU( Pins Diagram

Actuator Motor speed control: A PWM technique works by making a pulsating DC square wave with a variable on-to-off ratio.

Duty cycle The duty cycle of the pulses exiting the MCU was calculated as following:

Motor direction controller How does a motor turn in two directions ? By two ways: Manually. Automatically by a computer or a microprocessor.

Bipolar junction circuit H-bridge technique has four switching elements at its corners and the motor forms the cross bar.

Cont.

Relay H-Bridge

Relay operation A current flows through the coil, the resulting magnetic field attracts the armature. The movement either makes or breaks a connection with a fixed contact. When the current to the coil is switched off, the armature is returned to the first position. At the switching off action, the collapsing magnetic field will generate a spike of current that could damage the rest of the circuit.

Single Pole Double Throw (SPDT) Used to reduce the number of relays from four to two. Two relays with 20A current each were used.

Circuit components Opto-coupler An opto-coupler is an optical link and it connects two circuits via this link. Used as insulation and a switch for any circuit.

Cont. Transistor array MOSFET power transistor Used to increase the current level in order to operate the relays (amplifier). MOSFET power transistor Supplies 110 A current to the motor.

Cont. Crystal filter It provides a very exactly defined centre frequency which leads to stabilize the input frequency. Supply frequency equals to 4 MHz. Voltage regulator Automatically maintains a constant voltage level Supplies 5 V after changing it from 12 V.

Cont. And Gate A logic gate is an arrangement of controlled switches used to calculate operations in digital circuits. It is a multiplication operation between the three input variables (A,B and D). Input 1 Input 2 Input 3 Output 1

Cont. Diode Seven-segment display It allows an electrical current to flow in one direction. Seven-segment display A method of displaying decimal numeric feedback on the internal operations of devices.

Printed circuit board (PCB) Used to mechanically support and electrically connect electronic components using conductive pathways made from copper sheets on a non-coductive material. PCBs are inexpensive, fast, and consistent in high volume production.

Power supplying and direction schematic

Power supplying and direction circuit

MCU schematic

MCU circuit

Complete control system circuit

BASIC COMPILER

Cont

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Results & Discussion Cycle period:

Cont. Acceleration operation

Cont. The obtained frequency from the oscilloscope was equal to 1.9 KHz. The percentage error between the theoretical and experimental values was equal to 5%.

Cont. The velocity of the cabin was measured experimentally after the acceleration and before the deceleration operation periods.

Cont. The percentage error of velocity was equal to 13%. This error was formed by two factors; The slip between the rope and the sheave groove. Random error.

Conclusion All objectives of the project were met. Modifying the project can be done by two ways: Adding limit-switch at each floor. Enhancing the sheave contact area with the rope (V-groove).