Abstract: This paper presents the development of an electromechanical system for dynamics and control practical teaching, targeting vibration suppression in scenarios of robots operating flexible structures. A two-link mechanism in series with gear motors is used to form a manipulator, a double pendulum is suspended at the end of the manipulator to establish a physical model of a multi-degree-of-freedom dynamics system, and a self-made resistance-strain sensor is installed at the suspension point to sense the dynamic tension of the sling. According to the work-energy principle of classical mechanics, the speed control law at the end of the manipulator is designed utilizing the dynamic tension feedback. Based on the Arduino platform, the rapid suppression of double pendulum vibrations under small disturbances is realized. This experimental device integrates knowledge from multiple majors, including mechanics, mechanical engineering and electronics. The fundamental system design is straightforward, enabling both hardware and software components to be independently accomplished by undergraduates in relevant fields. For mechanics students, it provides a concrete case of modeling and experimenting of flexible underactuated systems. The design of low-cost hardware and low-threshold software makes it suitable for practical teaching applications.