1. Lead-through Programming (Programming Method)
Old Answer
Lead-Through Programming
Lead-through programming requires the operator to move the robot arm through the desired motion path during a teach procedure, thereby entering the program into the controller memory.There are two method of performing the lead-through teach procedure:
-Powered Lead-Through Programming, is commonly as the programming method for playback robots with point-to-point control. It involves the use of a teach pendant which has toggle switches or contact buttons for controlling the movement of the manipulator joints. Using the toggle switches or buttons, the programmer power drives the robot arm to the desired positions, in sequence, and records the positions in the memory. During subsequent playback, the robot moves through the sequence of positions under its power.
-Manuel Lead-Through Programming, is convenient for programming playback robots with continuous path control in which the continuous path is an irregular motion pattern such as in spray painting. This programming method requires to operator to physically grasp the end-of-arm or tools attached to the arm and manually move through the motion sequence, recording the path into memory. The motions are recorded as a series of closely spaced points. During playback, the path is recreated by the controlling the actual robot arm through the same sequence of points.
(A.K. Gupta, S.K.Arora, Industrial automation and robotics, Laxmi Pub. 2007, p.324)
New- Better Answer
Teach Pendant
This is also known as the lead-through method. It uses a control panel, called as teach pendant, which has buttons or switches that control the motion of the robot through a cable connected to the control system.
( Computer Aided Design And Manufacturing , Narayan L. , p. 461)
There are two methods of performing the lead-through teach procedure:
- Powered lead-throught
- Manual lead-through
(Industrial Automation and Robotics, Gupta A. , p. 324 )
2. Control of arc length (Manufacturing Control)
Old Answer
6-Control of arc length (in the welding process): Control of arc length in the welding process is important to ensure consistent heat input, constant melting rate, and stable performance of the process. In particular, arc length determines the transfer mode, arc stability, and the deposition rate.In GMAW, one simple way of controlling the arc length is to control the arc voltage. With a constant-current power source and variable wire-feed speed (WFS), the arc voltage (i.e., the process voltage) is used to drive the wire feed motor which in turn changes the arc length.On the other hand, with a constant-voltage power source and constant WFS, the changes in current are such as to provide a constant arc voltage (i.e., arc length).
(Modeling, Sensing and Control of Gas Metal Arc Welding,Desineni Subbaram Naidu, S. Ozcelik, K. Moore D. S. Naidu-1st edition, (2003),P.150)
Ertan TOPARLAK
503091329
New- Better Answer
(iii) Automatic control of arc length. From the description in the selection above, it can be seen that the arc length is automatically controlled (see Fig. 5.9). Assuming that at point C' the arc length is L1, due to the fact that the melting rate is smaller than the wire-feed rate, the arc length is gradually shortened; C' gradually approaches C and the arc length becomes L2. When C jumps to D', because the melting rate is greater than the wire-feed rate, the arc length gradually increases; the point D' gradually approaches D. At this moment, the arc length again becomes L1. The process repeats continuously in this way so that the arc length varies between L1 and L2. The magnitudes of L1 and L2 are defined by the output characteristic CD, which can be set in advance. The difference between L1 and L2 or deltaL, can be set as one diameter of a metal droplet; this difference, in fact, is the technological requirement of the welding process. It can be said that the arc length is
(Arc welding control, Jiluan Pan, p. 136-137 )
3. DC Interfacing Motors ( Control )
Old Answer
DC Interfacing Motors
Controlling DC motors, the emphasis has been simple on-off type switching. It is possible with a digital system to actually provide speed control using a tecnique called pulse widht modulation.
With a DC motor, there are two technique for controlling the motor speed: The first is to reduce the DC voltage to the motor. The higher the voltage, the faster it will turn. At low voltages, the control can be a bit hit and miss and the power control is innefficient. The alternative technique called pulse widht modulation. (PWM) will control a motor speed not by reducing the voltage to the motor but the reducing the time that the motor is swithed on.
This is done by generating a square wave at afrequency of several hundreds hertz and changing the mark/space ratio of the wave form. With a large mark and the low space, the voltage is applied to the motor for almost all of the circle time, and thus the motor will rotate very quickly. With a small mark and a large space, the opposite is true. The diagram shows the waveforms for medium, slow and fast motor control.
(Steve Heath,Embedded system desing,Second Edition,page 185-186)
New Answer ( Better )
To
interface an electromagnet, we consider voltage, current, and inductance.
First, we need a power supply at the desired voltage requirement of the coil.
If the only available power supply is larger than the desired coil voltage, we
use a voltage regulator (rather than a resistor divider) to create the desired
voltage.
...
The
other way to interface the coil is to use PNP transistor to drive the positive
side of the coil +V. The computer can turn the current on and off by
controlling the base of the transistor.
( Embedded
Microcomputer Systems: Real Time Interfacing, Jonathan
W. Valvan, p.435 )
 |
( Contemporary Computing: Third
International Conference, IC3 2010, Noida ...
Yazar: Sanjay Rank, p. 248 )
|
 |
( PIC
microcontroller: an introduction to software and hardware interfacing
Yazar: Han-Way Huan, p, 380 ) |
4. Expandable Mold (production technique)
there is no old answer
.................................
The more advanced development of the expandable mld allows the mold to expand in more than one plane so that a complex part can be molded with this method.
...
Reversal coining(also known as Expandable mold or Breathin mold):
Mold is filled 100% full first, and then the mold to will crack open with a controlled distance when enough skin is formed and the core is still hot and soft enough to make foam.
( Microcellular Injection Molding, Jingyi Xu, pages are unnumbered )
5. Graph-Based Method
(Feature Recognition)
Old Answer
Graph-Based Method
Topological
relationships between geometric entities of a CAD model can be represented
using a graph approach that simplifies the analysis of the geometric entities
for feature recognition. Simple heuristics can be applied to the graph to
identify features. In this approach, the B-rep of a part is translated into a
graph whose nodes and arcs represent the information of a part. Feature
recognition is achieved by finding a sub graph from the shape of a designed
object where the subgraph is isomorphic to the feature graph.
(Nasr E. A. &
Kamrani A. K., Computer-Based Design and Manufacturing, p. 109)
New Answer (better one)
Graph-Based Method
Graph-base methods became popular in the 1980’s due to the
well-established techniques of graph algorithms that can be readily adapted to feature-based
modeling. When dealing with a boundary representation of a component, faces can
be considered as nodes of the graph and face-face relationships form the
arc/links of the graph. Take the notch feature in Figures 5.2 and 5.3 as an
example. Faces 1, 2 and 3 form the notch feature, which is originated form a
corner where faces 4, 5 an 6 meet. The
diagraph as shown in Figure 5.3 (b) is called “face adjacency graph (FAG)”. It
illustrates the neighbourhood relationships of the faces concerned. The feature
recognition methods utilizing the graph-based techniques usually have two
steps. First of all, the component model is represented in a FAG. Then,,
parsers are developed to decompose this FAG into pre-defined FAGs that
correspond to various features. Pattern matching is eventually carried out to
identify the features from the component. This type of graph-based feature
recognition method is purely based on topologic information. To take into
account some geometric information, FAG can be augmented or attributed with
information such as the type of face, edge and vertex. This leads to an
improved graph-based method named “attributed face adjacency graph (AFAG)”.
( Integrating advanced computer-aided design, manufacturing, and numerical
...,
Xun Xu, p. 93 )
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