Search Results for: black body radiator

The light we see is a mixture of different wavelengths in the visible region of the electromagnetic spectrum. The most common source of light is incandescence from a very hot body such as our sun or the filament of an old-fashioned light bulb. The spectrum, the amount of energy as a function wavelength, follows Planck’s […]

Incandescent light sources emit a lot of infrared radiation which we cannot see but can sense as heat. Non-incandescent sources such as fluorescent lights, cathode ray tubes and LEDs have quite different spectrums. When light travels through an absorbing medium, such as the atmosphere or water, different wavelengths are absorbed differently and this alters its […]

We recap the important points from this masterclass.

We will learn about the forces that are exerted on a robot’s joint by gravity acting on links, friction, and the coupling forces where the motion of one joint imparts a force on other joints.

We can factorise the joint torque expression into an elegant matrix equation with terms that describe the effects of inertia, Coriolis and centripetal and gravity effects.

If your knowledge of dynamics is a bit rusty then let’s quickly revise the basics of second-order systems and the Laplace operator. Not rusty? Then go straight to the next section.

We learn the mathematical relationship between angular velocity of a body and the time derivative of the rotation matrix describing the orientation of that body.

The orientation of a body in 3D can also be described by a unit-Quaternion, an unusual but very useful mathematical object.   In the MATLAB example starting at 3:48 I use the Quaternion class.  For Toolbox version 10 (2017) please use UnitQuaternion instead.

The orientation of a body in 3D can be described by three angles, examples of which are Euler angles and roll-pitch-yaw angles. Note that in the MATLAB example at 8:24 note that recent versions of the Robotics Toolbox (9.11, 10.x) give a different result: >> rpy2r(0.1,0.2,0.3)ans = 0.9363 -0.2751 0.2184 0.2896 0.9564 -0.0370 -0.1987 0.0978 […]