Implementation of DC Motor Speed Control Using Distance Sensor on Harbour Mobile Crane

Abstract

Loading and unloading activities at ports heavily depend on cranes, with the Harbour Mobile Crane (HMC) being one of the commonly used types. The HMC utilizes a spreader equipped with flippers at each corner to securely hold the container. However, it is often observed that the flippers break due to excessive speed controlled by the operator using a joystick, causing the spreader to collide with the container. To address this issue, speed regulation using a distance sensor was proposed. This study aims to design and understand the working mechanism of a prototype HMC. The research method began by identifying the problem of broken flippers, which were replaced 857 times in 2021. A literature review was conducted, followed by the development of a concept and design for a prototype HMC with load-free and anti-sway testing. After building the prototype, repeated testing was carried out to optimize the results. The findings showed that when the joystick is pushed backward, the motor reverses, causing the spreader to rise at a stable speed. When the joystick is pushed forward, the motor moves forward, and the spreader descends, gradually slowing down until it reaches a distance of 2cm, at which point the motor stops moving forward and only reverses. An ultrasonic sensor (HC-SR04) was used to measure the distance. The designed system operates as intended, with the motor slowing down as the spreader descends and running steadily as it rises. The distance and speed are monitored through an LCD16x2 display.