Active Anti-Vibration Platform for an Ultrasonic Sensor

Selected Activity 2 project from the Control course at Universidad de los Andes. The repository intentionally contains only the final report and the Simulink model provided for this activity.

The report was prepared by Sergio Emmanuel Ropero and Juan Felipe Ortiz.

Canonical Artifacts

Artifact	Purpose
reports/activity_2_active_anti_vibration_platform.pdf	Final Activity 2 report
src/simulink/ModeloSistema.slx	Editable Simulink and Simscape model

Project Abstract

The project studies an active anti-vibration platform for an ultrasonic sensor used in laboratory tests related to potato pest detection. Vibrations from the table or mounting base can change the sensor position and degrade distance measurements. The main control objective is therefore local regulation: maintaining the platform position close to its equilibrium while rejecting external disturbances.

Physical Model

The report defines the relative displacement

$$q(t)=x(t)-z(t),$$

where x(t) is the absolute platform position and z(t) is the base position. The mechanical and electrical equations are

$$m\ddot{q}+c\dot{q}+kq=K_f i-m\ddot{z},$$ $$L\dot{i}+Ri+K_e\dot{q}=u.$$

For nominal analysis, the base disturbance is temporarily set to zero. The resulting third-order transfer function is

$$G(s)=\frac{Q(s)}{U(s)} =\frac{K_f} {Lm s^3+(Lc+Rm)s^2+(Lk+Rc+K_fK_e)s+Rk}.$$

The report also derives the corresponding state-space representation and the Routh-Hurwitz stability condition:

$$(Lc+Rm)(Lk+Rc+K_fK_e)>LmRk.$$

Controller Design

For controller tuning, the report introduces the reduced mechanical model

$$G_r(s)=\frac{1}{s^2+5s+100}.$$

Using the IMC-based derivation documented in the report and preserving P = 50, the ideal PID controller is

$$C(s)=50\left(1+\frac{1}{0.05s}+0.2s\right).$$

The final report recommends the following parameters for the filtered PID block:

Parameter	Value
P	50
I	0.05
D	0.2
N	10

Report and Model Difference

The supplied .slx file preserves a PID Controller1 block with:

Parameter	Report value	Supplied .slx value
P	50	50
I	0.05	0.05
D	0.2	0.2
N	10	100

The model also contains a block named Autoting with a separate stored parameter set. This repository preserves the submitted files without modifying either implementation choice.

Evaluation Scope

The report distinguishes two scenarios:

1. Disturbance rejection: the primary application, with a fixed setpoint r(t) = 0.
2. Step-reference tracking: a complementary test requested for controller evaluation.

The report concludes that the controller is more appropriate for local regulation than for reference tracking. The submitted PDF preserves the simulation figures, discussion, and reported performance table.

Simulink Model

The .slx file contains the editable implementation, including the mechanical platform model, a Simscape Multibody subsystem, open-loop paths, a filtered PID controller, setpoint and perturbation blocks, and scopes for response inspection.

Repository Structure

docs/           GitHub Pages-ready project summary
reports/        Final submitted report
src/simulink/   Editable Simulink and Simscape model

How to Review

1. Read the final report.
2. Open ModeloSistema.slx in MATLAB Simulink with the required Simscape products.
3. Inspect the regulation and tracking configurations documented in the report.

Scope Note

This repository does not add generated Python analyses, additional control plots, or numerical claims beyond the submitted Activity 2 artifacts.