Professional Microsoft® Robotics Developer Studio

Chapter 8. Simulating Articulated Entities

This chapter explains how to create articulated entities such as robotic arms and jointed robots in the simulation environment. Wheeled robots are fine for some applications, but sometimes you need a robot that can reach out and grab things.

The primary mechanism for defining articulated entities is the Joint object. This chapter begins by describing how to use a joint to join two entities and all of the options that are available. Then you will learn how to build a robotic arm with multiple joints.

The Joint Class

A Joint is an object that joins two entities together. It has up to six degrees of freedom (three angular and three linear), which means it can be configured in a number of different ways. The simplest joint is a revolute joint, which has a single angular degree of freedom unlocked, and it behaves much like a door hinge. A joint with a single linear degree of freedom unlocked would operate somewhat like a shock absorber or a worm gear, with the joined entities able to move closer or farther along a single direction. A joint with all degrees of freedom unlocked can move in any direction and rotate and twist into any possible orientation.

The Joint class is defined in the Microsoft.Robotics.PhysicalModel namespace, which is implemented in the RoboticsCommon DLL. This Joint class is available for all services to use, not just simulation services. Its most important member is the JointProperties member called State. These properties ...