Test 1 Flashcards
What Engineering disciplines support the field of robotics?
- ME
- IE
- EE
- Computer science
What is a robot?
A robot is a reprogramable multifunctional manipulator designed to move material parts, tools or specialized devices through programmed motions to achieve specified tasks.
Define Degree Of Freedom (DOF)
DOF is a number of linearly independent kinematic coordinates necessary to describe the position of a physical system in space.
Define accuracy and repeatability
Accuracy - how close the manipulator can come to a given point within it’s workspace
Repeatability - how close the manipulator return to a previously taught point.
What is steady state error?
SSE is defined as the difference between the input command and the output of a system as the limit goes to infinity(when the response has reached SS)
What is a singularity
A singularity signifies a lost degree of freedom.
In kinematics, singularity points have infinite velocity (very high velocity in practice)
What is reachable workspace?
The volume in space within the end-effector can reach
What is dextrous workspace?
(A subset of the reachable workspace) consists of points that the manipulator can reach taking into consideration orientational reachability of the end-effector
What is a PID controller?
PID controller is a linear control loop feedback mechanism that continuously calculates error of the desired point and measured point and applies correction based on (Proportional Integral and derivative terms)
By changing PID parameters, you can change response of the system without changing mechanical parameters!
Why do we need negative feedback? (Adjusts for error)
Negative feedback subtracts from the input signal therefore continually changing the gain to counteract the change of the output.
What is a disturbance?
A disturbance is a signal in the system not based on desired behaviors (i.e. environment)
Define a linear system
a mathematical model of a system based on the use of a linear operator. (Satisfy the property of superposition)
What is forward kinematics?
is finding the position/orientation of the tool when joint variables are given. (more commonly used)
What is inverse kinematics?
is finding the joint variables when the position/orientation of the tool is given. (more commonly used)
What is a rotational matrix?
A rotational matrix specifies the orientation of the current coordinate frame (x1,y1,z1) relative to the base frame or previous frame (x0,y0,z0)
What are properties of a rotational matrix?
- Its inverse is equal to its transpose
- orthogonal
- Det = +1
What are 3 definitions of a rotational matrix?
Rx = [(1,0,0),(0,c(),-s()),(0,s(),c())] Ry = [(c(),0,s()),(0,1,0),(-s(),0,c())] Rz = [(c(),-s(),0),(s(),c(),0),(0,0,1)]
What is a redundant robot?
A kinematically redundant robot has more DOF than needed for a given task. (more than 6 DOF)
What is controller resolution?
Controller resolution is the smallest increment of motion that the controller can sense.
What are the basic industrial fields where robots are applied today?
manufacturing
- pick and place
- welding
- packaging and labeling
- product inspection
What two types of joints exist?
- Rotational
- Linear
How are robots classified in respect to physical configuration?
Cartesian (PPP) Articulated (RRR) Cylindrical (PPR) Spherical (RPR) Scara (RRP)
- Geometry (kinematic structure)
- type of application used for
- Power source
- Application area
- Method of control
What two types of joints exist?
- Rotational
- Linear
What is a world coordinate frame?
an established fixed coordinate system which all objects including the manipulator are referenced.
What is an absolute coordinate frame?
a frame that is established that relative to the world coordinate system by some angle or translation
What is a jacobian?
Defines the dynamic relationship between two different representations of a system (like end-effector position and joint angles).
What is relative velocity?
is measured in a reference frame that itself is at rest or moving with respect to the absolute frame
What is absolute velocity?
is measured only in a frame of reference that is at absolute rest.
How are linear and angular velocities related?
Linear velocity is the cross product of radius vector and angular velocity. (v = w x r)
What are the 4 D’s
- Dirty
- Dangerous
- Dear (expensive)
- Dull (boring)
