This paper describes the design and modeling of a robot that swings on the end of a tether. Its height above the ground is controlled by the length of the tether. Its location on a spherical shell at the end of the tether is controlled by a pair of ducted fans. The vertical orientation of its body is determined by the point at which the horizontal thrust force acts relative to the centre of gravity (cog). The system acts like a double pendulum with two modes of natural movement. It is modeled with coordinate frames at the ends of the tether and at the cog. Due to the second mode of motion it may oscillate around its centre of gravity while it swings or flies in a circle. From the dynamic model we develop a model for simulating the motion of the tethered robot.

When a mobile robot is constructed the odometry must be calibrated. Calibrating a 4-wheel robot requires the accurate measurement of steering angle as well as translation and rotation. Some measurements are made with a tape measure and some with ultrasonic sensors. The measurements are used to determine the parameters of the odometry calibration matrix and the steering kinematic model. A procedure for calibrating a 4-wheel robot is discussed.

In the Titan project we applied a new approach to prototyping mobile robots by choosing tools which are commonly used by leading aerospace manufacturers and many other industries. We have gained substantial experience when using the LabVIEW real-time programming environment coupled with the industrial quality data acquisition cards, both are made by National Instruments. The methodology of virtual instruments software tools combined with the graphical programming environment was found to be very efficient for interactive cycles of design and testing, which are at the core of robotics prototyping.