What is the definition of a robot?
An actuated mechanism programmable in two or more axes, with a degree of autonomy, moving with its environment, to perform intended tasks
What are the two main ways we can catagorise robots?
- Field of Application e.g. Medical / Industrial
- Mobile and Stationary Robots
What are the 6 levels of autonomy that we could see in a car?
- No autonomy
- Basic assistance (Cruise Control)
- Steer and Acceleration under driving monitoring
- The driver doesn’t need to monitor in certain conditions
- The car can drive on its own in most situations
- Fully autonomous (No driver needed)
What are the programming methods we can use for robots?
- Offline: The robot trajectory and program is pre-computed based on kinematics
- Teaching: The operator will use the teaching pendant to move the robot and save specific points
- Lead-Through: The operator will manipulate the robot directly which will memorize the trajectory
What is the difference between Task space trajectory and Joint space trajectory?
Task space trajectory has a set path and moves directly between the two points
Joint space trajectory has set points, and then the path is determined by the system each time
What are the two types of joints?
- Revolute Joints: Limits the motion between two points to a rotation
- Prismatic Joints: Limits the motion between two points to a translation
What is meant by degrees of freedom?
The number of independent relative motions between the links of the robot
What is the formula for the Degrees of Freedom?
DoF = m(N-1-J) + The sum of the mobilities of joint i
m = 6 for 3D robots, and 3 for planar robots
N = Number of links (including the ground
J = Number of joints
What type of robot is a SCARA robot?
RRP
What are the two types of coordinates do we use for robotics?
- Joints coordinates: Give the rotation or position of every joint of the robot. We denote q the vector of joint coordinates
- Cartesian coordinates: Gives the position and orientation of the end effector in the reference frame
What is the aim of forward kinematics?
To determine the end effector’s position and orientation, knowing the joint coordinates and link length
What is the aim of inverse kinematics?
To determine the joint coordinates from the knowledge of the end effector’s cartesian position and orientation
What do static studies of robotics analyse?
The effect of gravity, the backlash, the joint or link flexibility, the payload and torque equilibrium
What do dynamic studies of robots consider?
The inertial effect due to accelerations
What is the control resolution of a robot?
The capability of the robot’s positioning system to divide the range of the joint into closely spaced points, called addressable points
What is the formula for the Control Resolution?
CR = R / (2^n - 1)
R = Actuator Range
n = Number of bit storage register devoted to a particular part
What is the repeatability of a robot for it’s movements?
r = Plus or minus 3 * Standard deviation of the robot error distribution
What is the accuracy of a robot?
It’s the difference between the speciied position and the actual position
Ac = CR/2 + r
What are the names of the Tait Byran angles?
Roll, Pitch and Yaw
