عملگر Principles of Mechatronic Systems مبانی سیستم هاي مکاترونیکی موتورهاي گامی (پله اي) By: Reza Tikani Mechanical Engineering Department Isfahan Un

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1 عملگر Principles of Mechatronic Systems مبانی سیستم هاي مکاترونیکی موتورهاي گامی (پله اي) By: Reza Tikani Mechanical Engineering Department Isfahan University of Technology Stepper Motor VB PM HB DC Actuator ١

2 Camera Positioning ٢

3 Stepper Motor Step by Step coecsl.ece.illinois.edu Rotor Stator Outside Casing Coils Stator Rotor ٣

1. Full Stepping (90 degrees) 2. Half Stepping (45 degrees) 1. Full Stepping (90 degrees) 2. Half Stepping (45 degrees) Stators Rotor www.

Half Stepping (45 degrees) 1. Full Stepping (90 degrees) 2. Half Stepping (45 degrees) www.t4.

4 1. Full Stepping (90 degrees) 2. Half Stepping (45 degrees) 1. Full Stepping (90 degrees) 2. Half Stepping (45 degrees) Stators Rotor Four Steps per revolution i.e. 90 deg. steps. 1. Full Stepping (90 degrees) 2. Half Stepping (45 degrees) 1. Full Stepping (90 degrees) 2. Half Stepping (45 degrees) Eight steps per. revolution i.e. 45 deg. steps. Eight steps per. revolution i.e. 45 deg. steps. ۴

5 CCW CW Drive translator PLC indexer translator Roboeq.com ۵

6 Indexer 15/step 12.5 rpm Detent torque Dynamic torque Holding torque ۶

7 40 oz. 1 in 12 oz. 1 oz.in= N.m N S VR Unifilar winding Bifilar winding on/off ٧

established, experience mechanical forces that tend to align them in such a

8 VR VR Pieces of highly permeable materials such as iron, situated in an ambient medium of low permeability such as air in which magnetic field is established, experience mechanical forces that tend to align them in such a way to minimize the reluctance of the system. emsa.gastli.net/chapter5 VR a b VR 1 2 ٨

9 VR electronics.com ٩

10 p Full Stepping ١٠

Consider a stepper motor with nr=5, ns=2, and p=2.

11 Consider a stepper motor with nr=5, ns=2, and p=2. A schematic representation is given in Figure. In this case, θr=360 /5=72 and θs=360 /2=180. Δθ=180 -r 72. Here, the largest feasible value for r is 2, which corresponds to a step angle of Δθ = =36. This is further confirmed by another equation, which gives Δθ =72 /2=36. unstable equilibrium position Microstepping: Toothed pole en.wikipedia.org ١١

Microstepping: http://en.nanotec.com/main_en.

com The hybrid stepper motor combines the

12 Microstepping: The hybrid stepper motor combines the features of the PM and VR stepper motors and is the type in most common use today. The rotor is toothed, which allows for very small step angles (typically 1.8 ), and it has a permanent magnet providing a small detent torque even when the power is off. ١٢

13 Suppose that we turn the rotor clockwise from this stable equilibrium position, using an external rotating mechanism (e.g., by hand). At position C, which is the previous detent position where Phase 1 would have been energized under normal operation, there is a positive torque that tries to turn the rotor to its present detent position D. At position B, the static torque is zero, because the force from the N pole of Phase 1 exactly balances that from the S pole. This point, however, is an unstable equilibrium position. The maximum static torque occurs at position M, which is located approximately halfway between positions B and D. ١٣

Consider a three-phase stepping motor with seventy-two steps per revolution. If the static load torque is 10% of the maximum static torque of the motor, determine the static position error.

14 Consider a three-phase stepping motor with seventy-two steps per revolution. If the static load torque is 10% of the maximum static torque of the motor, determine the static position error. Note that this is less than 5% of the step angle. A stepper motor with a Houdaille damper: d A Lanchester damper is similar to a Houdaille damper except that the former depends on nonlinear (Coulomb) friction instead of viscous damping. ١۴

15 These direct techniques of damping have undesirable side effects, such as excessive heat generation, reduction of the net output torque of the motor, and decreased speed of response. Electronic damping methods have been developed to overcome such shortcomings. 1.The pulse turn-off method: Turn off the motor (all phases) for a short time. Three common methods: 1.The pulse turn-off method: Turn off the motor (all phases) for a short time. 2.The pulse reversal method: Apply a pulse in the opposite direction (i.e., energize the reverse phase) for a short time. 3.The pulse delay method: Maintain the present phase beyond its detent position for a short time. 2.The pulse reversal method: Apply a pulse in the opposite direction (i.e., energize the reverse phase) for a short time. 3.The pulse delay method: Maintain the present phase beyond its detent position for a short time. ١۵

16 A schematic diagram of an industrial conveyor unit is shown in the figure. In this application, the conveyor moves intermittently at a fixed rate, thereby indexing the objects on the conveyor through a fixed distance d in each time period T. A triangular speed profile is used for each motion interval, having an acceleration and a deceleration that are equal in magnitude. The conveyor is driven by a stepper motor. A gear unit with step-down speed ratio p:1, where p >1, may be used if necessary, as shown in the figure. ١۶

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System Design and Setup of a Robot to Pass over Steps Abstract In the research, one special type of robots that can pass over steps is designed and se

8051 8051 System Design and Setup of a Robot to Pass over Steps Abstract In the research, one special type of robots that can pass over steps is designed and setup. This type of robot uses two kinds of