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Tony's Intertwingled Memex • Reference Manual

Robotics and Telemetry Tracking Actuator (Computer & Robotics Engineering)

Formulas & Definitions

At an autonomous robotics flight testing facility, an automated optical tracking camera mount tracks an inspection drone performing a low-altitude survey. The robotic camera platform is anchored at ground level and rotates along an elevation pitch axis driven by a precision servo-actuator.

The drone flies along a straight, horizontal flight corridor at a constant altitude of h=300.0 metersh = 300.0\text{ meters}h=300.0 meters directly over the camera base. Real-time GPS and optical flow telemetry indicate the drone flies at a constant horizontal speed of:

v=∣dxdt∣=60.0 m/s(216 km/h)v = \left|\frac{dx}{dt}\right| = 60.0\text{ m/s} \quad (216\text{ km/h})v=​dtdx​​=60.0 m/s(216 km/h)
where x(t)x(t)x(t) represents the horizontal distance from the tracking station to the drone coordinate.

The camera elevation angle θ(t)\theta(t)θ(t) (measured from the horizontal ground up to the drone line-of-sight) satisfies the trigonometric relation:

tan⁡θ=hx\tan\theta = \frac{h}{x}tanθ=xh​

  1. Formulate the time derivative relation connecting the camera's angular tracking velocity dθdt\frac{d\theta}{dt}dtdθ​ to the drone's horizontal flight speed dxdt\frac{dx}{dt}dtdx​ using the Chain Rule on tan⁡θ=hx\tan\theta = \frac{h}{x}tanθ=xh​.
  2. Determine the exact angular tracking velocity dθdt\frac{d\theta}{dt}dtdθ​ required by the servo-motor in radians per second (rad/s\text{rad/s}rad/s) and degrees per second (∘/s^\circ/\text{s}∘/s) at the instant the drone is at a horizontal distance of x=400.0 metersx = 400.0\text{ meters}x=400.0 meters approaching the station.
  3. Compute the angular velocity required when the drone is directly overhead (x→0x \to 0x→0), and explain why robotics control engineers must design pan-tilt servo actuators with sufficient angular acceleration bandwidth to prevent gimbal lock or tracking target loss.