ROBOTICS- Exam #1

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Terms in this set (...)

Industrial robots
Multi-functional, reprogrammable manipulators able to move parts, devices, and materials through computer controlled motion.
Robotics
knowledge base of designing, applying, and using robots in human endeavors.
Robot manufacturers
FANUC- Japan
ABB- Sweden
Adept- USA
Robot manipulator
consists of a series of link and joint combinations to gauge the movement of the robot arm and body.
Power supply
Electric or pneumatic
Robot controller
a combination of hardware and software programs that command motion in a closed loop control system.
Teach pendant
the remote operational interface between the programmer and the robot.
Robot end-effector
a gripper or tool device that is located at the end of the robotic arm to interact with the environment.
Robot peripheral devices
tool that carries out pre-determined tasks through wireless communication with the robot.
Industrial robot motion configuration
the robot arm is a manipulator in an open-chain mechanism formed by joints and links.
How many DOF does a rigid body have?
6 (dX, dY, dZ, yaw, pitch, roll)
How many degrees of freedom does a robot joint have?
1
Types of joints
Linear (prismatic)
Rotational
Twisting
Revolving
Rotational joint
joint axis is perpendicular to both input and output links.
Twisting joint
joint axis is parallel to both input and output links.
Revolving joint
joint axis is parallel to input and perpendicular to output link axes.
Cartesian robot
3 linear joints
Characteristics of Cartesian robots
cubic work envelope
all linear axes
high accuracy
large payload
limited TCP access.
Cylindrical robot
2 linear, 1 revolute joints
Types of cylindrical robots
TLL
LVL
Characteristics of cylindrical robots
work envelope is cylindrically shaped.
ball-screw drive for linear axes.
electrical power.
Spherical robot
2 revolute, 1 prismatic joints
Types of spherical robots
TLP
VVL
Characteristics of spherical robots
spherical shaped work envelope.
Articulate robot
3 revolute joints
Types of articulate robots
TRR
Characteristics of articulate robots
irregular work envelope.
very good TCP access.
powered by AC motors.
What are the robot wrist joints?
yaw, pitch, roll
Yaw
left, right
Pitch
up, down
Roll
twisting
World Frame R
x-axis goes out from front of robot.
y-axis follows right hand rule.
z-axis goes up.
Default TCP
x-axis goes up.
y-axis follows right hand rule.
z-axis points out of faceplate.
Default Joint Frame
x-axis assigns the zero position.
y-axis follows the right hand rule.
z-axis is assigned along joint axis.
What has the highest robot motion control authority?
the teach pendant
robot accuracy
how precise a specified point can be reached during the teaching of robot position.
0.001 in or better
robot repeatability
how accurately the same point can be reached with repeated motions when running the robot program.
+-0.02 mm
Payload
the maximum weight attached to the robot wrist under the robot accuracy and in robot weakest pose.
Work envelope
the collection of points of the origin the Def-TCP can reach.
Measurement of aTb
a is fixed, b is moving; noted as a frame transformation from frame b to frame a.
Two variables of aTb?
position
orientation
3 successive rotations of frame a
yaw- how many degrees frame b rotates about the positive x-axis of frame a.

pitch-how many degrees frame b rotates about the positive y-axis of frame a.

roll-how many degrees frame b rotates about the positive z-axis of frame a.
UT [k] measurement
measured relative to Def-TCP frame
What is the UT [k]?
user tool frame
What is the three-point method?
allows user to define UT [k] that has different origin position and the same orientation relative to the Def-TCP frame.
How to set up three-point method on teach pendant?
menu --> setup --> frame --> tool frame --> three-point method
What are the three points according to the three-point method of UT [k] setup?
point 1- vertical down for the z-axis
point 2- side approach for x-axis
point 3- an angular approach for y-axis
How to know if UT [k] is accurate?
Origin of the UT [k] should be exactly at the bottom of the round tip pointer.
How to activate the UT [k] frame?
press SHIFT and COORD keys together and type the number of the UT [k] frame you wish to activate.
What is the UF [h]?
user frame
How is the UF [h] defined?
defined relative to the robot World Frame R; noted as a frame transformation rTuf[h].
How many frames are in the FANUC system for UT [k] setup?
9 frames
How many frames are in the FANUC system for UF [h] setup?
10 frames
How is the three-point method used for setup in the UF [h]?
point 1- defines the origin of UF [h].
point 2- defines the positive x-axis of UF [h].
point 3- defines the positive y-axis of UF [h].
How to test accuracy of UF [h] setup?
the x-y plane of the UF[h] should be the same, or at least parallel to, the part's reference surface.
How to setup UF[h] using three-point method on the teach pendant?
menu --> setup --> frame --> user frame --> clear UT [k] frame --> three-point method
Importance of UF [h] frame
UF [h] allows the tool to move about a specified part reference surface according to the robot World Frame R.
What is the robot point P [n] defined as?
P [n] is defined as the frame transformation uf[h]Tut[k].
Measurement of the P [n]
(x,y,z) define the position of UT [k] relative to UF [h].

(w, p, r) define the position of UT [k] relative to UF [h].

UT [k] is moved with the robot arm and tool.
How are robot programs for robot points defined?
ex: L p[1] 125 mm/s FINE
Motion type
Destination of UT [k]
Speed of UT [k]
Motion termination
What are point requirements?
how many points and where the points are.
Test-run in Step-Mode
executes the program in line-by-line fashion.
Test-run in Continuous-Mode
executes entire program continuously.
Robot Joint Frame
robot designer assigns a fixed cartesian coordinate system (Fi-1) to the input link(i-1) of robot joint (i) by using the D-H method.
Numbering joint frames
J1 --> F0
J2 --> F1
J3 --> F2
....
Which joint frame serves as World Frame R?
J1 --> F0 serves as robot World Frame R.
Which joint frame serves as Def-TCP?
Def-TCP is assigned to the output link of the joint 6 faceplate.
D-H assignment of robot joint frame
z-axis: assigned along the physical motion axis of the joint.

x-axis: must be perpendicular and intersecting to the z-axis of the previous joint frame.

y-axis: follows right hand rule.
Robot kinematic definition
the mathematical relationship between the robot joint variables and the values of rTdef-tcp
Robot Forward Kinematics
given a known robot pose that is defined by the known robot joint variables of (q1-q6), find the values of rTdef-tcp.
Robot Inverse Kinematics
given a known rTdef-tcp, find the values of joint variables (q1-q6).
What do forward kinematics equations determine?
robot forward kinematics equations determine where the robot Def-TCP frame will be relative to the robot's World Frame R, if all the joint variables are known.
What do inverse kinematic equations determine?
robot inverse kinematics equations determine what each joint variable must be in order to move the robot Def-TCP frame to a given position and orientation relative to robot World Frame R.