Tentafrågor m.m Flashcards
Describe the different sections of a robot manipulator?
- Body-and-arm, which usually consists of three joints connected by large links - for positioning of objects in the robot’s work volume
- Wrist assembly, consisting of two or three compact joints – for orientation of objects
Which are the two main joint types in an industrial robot?
Revolute and Prismatic
What does Professor Bolmsjö state must be included to be defined as a robot simulation system? (1-3)
*World model: Define and create 3D model through inbuilt modeling capability or import models to define the world model.
*Hierarchical link mechanisms: Define and build link mechanisms, which can bepart of the simulation as robot or other devices.
*Kinematics and dynamics simulation: of robots and other mechanisms
What does Professor Bolmsjö state must be included to be defined as a robot simulation system? (4-6)
*Analysis to detect collisions: and other events such as configuration solution of a robot manipulator, joint motions of a device or cycle times
*Translator: of a task program for a robot to a target robot system
*Calibration: module to support various forms of calibration of models of programs to represent a realphysical robot system
What is the difference between platform-based simulation systems and silo-based systems?
Platform-based simulation system enable single-source of truth and collaboration
What is the difference between deterministic simulation systems and stochastic simulation systems, and when do you
choose one over the other?
Deterministic always gives the same result. Deterministic is typical for robot simulation. Stocchastic is used in descrete event simulation
What is the difference between joint movements and linear movements, and when do you choose to use one over the other?
Joint-move does not move on line/curves, but is easier for robot to handle. Less risk for singularities.
What is a singularity in the context of industrial robots, and how can they be avoided?
Singularity is a position that cannot be calculated by the inverse kinematics
What is virtual commissioning and why is it difficult? What is different between the traditional approach and the virtual
approach?
Virtual commissioning enables activities to be done in parallel; hence giving more time for the Production ramp
What is Machine Learning in an industrial robotics context?
Machine Learning at its most basic is the practice of using algorithms to parse data, learn from it, and then make a determination or prediction about something in the world
What is the difference between realistic robot simulation 2 (RRS-2) compared to RRS-1?
- I/O: Transfer of binary, analog and serial communication lines
- File System: Transfer of single files and complete file systems
- User Interface: Generic functions like start/stop and handling of controller specific (native) user interfaces
Describe the arm configuration and working volume of a spherical robot arm
A spherical arm has a spherical joint structure that allows for movement in any direction within a three-dimensional space.
The working volume of a spherical robot arm is defined by the space within which the arm can operate. In the case of a spherical arm, the working volume is a three-dimensional sphere centered on the base of the arm
In summary, a spherical robot arm consists of interconnected spherical joints, providing rotational motion around multiple axes. It operates within a three-dimensional spherical workspace, allowing for omnidirectional movement and positioning.
What two industrial robot applications is used in 50% of all installed industrial robots. Why have these applications become so dominating?
70% of Industrial Robots global supply have 2 main applications : Handling and Welding
Reasons: Dangerous work environments
*Consistency and accuracy
*Monotonous labor
*High demand on quality, thus repetitiveness
*Increase efficiency to keep industry from being oursourced
*Flexibility compared to other machine systems
Describe 3 coordinate systems used when programming an industrial robot.
Motivate/explain when they are especially useful.
*Global cordinates
*Base cordinates
*TCP
*User cordinates
*Object cordinates
Explain what TCP means, and why it is used?
Tool Center Point – The main reference point of the effector. E.g. for welding tools the contact point of the welding gun.
Every Point in that range is reachable with the Tool Center Point
Explain the words: programming error, absolute error, relative error in conjunction with industrial robot programming.
*Programming error refers to a mistake in the code or instructions controlling the robot
*Absolute error quantifies the deviation between the desired and actual values, reflecting the accuracy of the robot’s positioning or trajectory
*Relative error expresses the accuracy relative to the magnitude of the quantity being measured or controlled.
Describe six central demands on an advanced off-line programming system
hmm
Describe what parts is included in a harmonic drive, what is the incoming and outgoing axis, how does it work?
Wave Generator: The wave generator is the central component of a harmonic drive. It consists of an elliptical or wave-shaped mechanism with a set of ball bearings or needle bearings.
Flex Spline: The flex spline is a thin, flexible, and internally toothed ring. It surrounds the wave generator and meshes with the circular spline.
Circular Spline: The circular spline is a rigid outer ring with external teeth. It meshes with the flex spline and provides the output interface for the harmonic drive.
The incoming axis of a harmonic drive refers to the input side where the driving motion or torque is applied.
The outgoing axis of a harmonic drive refers to the output side where the motion or torque is transmitted to the driven system.
What are the different safety methods in human-robot collaboration? explain them briefly
Safety Monitored Stop
Hand guiding method
Speed and Separations monitoring
Power and Force Limiting
Along with a brief description of the above (Tentasvar?)
What was the name of the first industrial robot that hit the market? Who were the first customer and why did they deploy industrial robots in their production?
Unitmate. First customer was GM. They had hazardous environment, wearout of humans, and many repetitive tasks. It was more cost-effective using robots.
What is IMMA?
Stands for Intelligently Moving Manikin.
From what you have learned in MPR213, what are the most difficult challanges to deploy industrial robots and where are the major areas for further development the next 10 years?
Must include:
Sensor integrated to increase the number of sences
Machine learning to speed-up programming
Collaboration to avoid fences and lower the cost
Define a spherical robot
- A robot where the arm consists of two revolute joints and one prismatic joint.
Define collision range!
- The area of space used by the robot for the execution of all movements.
- This area is larger than the working range.
Define continuous vs. Discrete!
- Continuous: When the modeled system changes continuously over time
- Discrete: Changes occur only at separate points in time
Define Deterministic vs Stochastic!
- Deterministic: A model that are used when the random variation in the system being modelled is not of concern because it does not affect the result of cannor influence the decisiosn to be taken
- Stochastic: Models that do not ignore random variation in the system.
Define Forward kinematics
- Describes tool cordinate system (TCS) in terms of the known joint variables
Define working range!
- The room area that can be reached with the Tool Center Point (TCP)
In practice what happens in a singularity?
- It happens when two or more joint axes align
Name 3 benefits with using PLM
(Product Life-cycle Management)
- Accelerate time to market
- Increase production and maximize resource utilization
- Standardize and reuse processes and resources
Name 3 joint drive systems in industrial robots
- Electric
- Hydralic
- Pneumatic
Name 4 elements in fixtures!
- Locators (Pickup)
- Clamps
- Supports
- Structure (body)
Name 4 reasons for robot inaccuracy
- Geometric: inaccurarices in manufacturing of parts of the robot
- Thermal: Expansive properties of material used in the robot structure
- Dynamic: internal loading and structural resonance affecting the robot path
- System: improper calibration, sensor inaccuracies, drive train backlash and poorly tuned servos.
Name 4 types of joints in robotics!
- Revolute joint
- Prismatic joint
- Universal joint
- Ball joint
Name 5 abstraction levels of robot programming
- Joint oriented programming
- Robot oriented programming
- Object oriented programming
- Process oriented programming
- Goal oriented programming
Theoretically, what happens in singularities?
- The determinant of the Jacobian is zero.
What 4 charachteristics does an industrial robot have?
- automatically controlled
- reprogrammable
- multipurpose
- 3 or more axis
What 5 types of mechanical joints exists?
- Collinear joint (transational)
- Orthogonal joint (transational)
- Rotational joint (rotary)
- Twisting joint (rotary)
- Revolving joint (rotary)
What are a pickup (locator) in fixtures?
- A pickup holds the workpiece in accurate position during the manufacturing process
What are Flags in fixtures?
- The unit that goes in between the structure an locator
What are key characteristics of collaborative robots?
- Safety
- Ease-of-use
- Productivity
- Flexibility
What are the 3 requirements of an Industrial Robot?
- Automatically controlled
- Reprogrammable
- Programmable in 3 or more axes
What are the 5 abstraction levels of robot programming?
- Joint oriented programming
- Robot oriented programming
- Object oriented programming
- Process oriented programming
- Goal oriented programming
What are the benefits of modular fixtures?
- Reduced time to market
- Smaller batch size
- Faster configuration
- Good for prototyping
- Simplifies computerization
What are the characteristics of a Hydraulic joint drive system?
- High power lift capacity
- Explosion proof
- Cumbersom in maintenance
What are the characteristics of an electric joint drive system
- Fast, accurate and easy
- Preffered drive system in todays robots
What are the definition of a fixture?
- Work-holding or support device
- Used to securely locate and support the work.
What are the definition of a jig?
- A workpiece locating and holding device that positions and guides/controls a cutting tool.
What are the difference between Static and Dynamic
- Static: A model that are the representation of a system at a singe point in time
- Dynamic: A model that describes the behaviour of the system through time
What are the drawbacks of dedicated fixtures? (4)
- Expensive
- Long lead time
- Non-flexible
- Requires long eperience
What are the drawbacks of modular fixtures
- Costly to machine precise parts
- Pays for unused fixtures
- Mostly aluminium based, needs to be tougher
What are the purpose and relationship of the robot arm and wrist?
- The arm supports the position and motion of the wrist
- The wrist supports the position and motion of the end-effector.
What does degeneracy mean?
- A special case of redundancy-infinate number of solutions
What does redunancy means?
- We have reduncancy when a robot can reach a target position in more than one way (configuration)
What is an articulated robot
- A robot whose arm has at at least three rotary joints
What is the homogeneous transformation matrix?
- Describes a new coordinate frame (N) with the respect to a reference frame (R)
What opportunities does VR have? (3)
- Verification of safety zones
- Remote support
- Operator interfaces
Different Levels of Collaboration for COBOTS?
- Cell (Robot is closed off)
- Coexistence (Different workstaion next to each other)
- Synchronized (Taking turns on the same part in the work area)
- Cooperation (Working on different parts in same work area)
-Collaboration (Working on same workpiece)
