ACTIVE SUSPENSION SYSTEM TEST PLATFORM

Project Description

The Active Suspension Test Platform project will include the following;

·        A test bed

·        A linear actuator

·        Power electronics

·        A micro-controller based feedback control system

·        A user interface consisting of a keypad and a liquid crystal display

·        An external interface which will allow the platform motion to be controlled by a waveform generator. 

The Active Suspension Test Platform System will provide sinusoidal, triangular, and square wave inputs to active suspension systems mounted on its platform.  The system will be utilized as a test platform for future Bradley University ECE department active suspension projects. 

Figure 1-1. System Block Diagram with Feedback Control

Overview

As shown in figure 1-1, the user will be able to specify the platform motion via the EMAC Micropac 535 micro-controller keypad or an optional external analog input signal.  Once the desired platform motion has been selected, the test platform will move as specified, and the actual platform motion (e.g. frequency, amplitude) will be shown on the LCD display. Within the limits imposed by the actuator’s drive capabilities, the platform must move according to the desired input regardless of the load applied on the platform.  The linear actuator, which will be used for preliminary design work, is shown in figure 2-1.  A plate will be mounted to the top of the linear actuator to move the load in a vertical motion for initial experimental work. After the linear actuator has been successfully tested D.C motor with the following ratings would be used;

·        115 volts

·        3.4 amps

·        1/3 horsepower

·        1725 rpm

·        Max ambient temperature 40 degrees Celsius

Figure 2-1. DC Linear Actuator

Control Feedback System Diagram

Figure: 3-1. System Feedback Diagram

The feedback system shown in figure 3-1 shows the input signals from the user interface, the linear actuator, the feedback control from the EMAC micro-controller, and the output test platform motion.  The EMAC micro-controller will be programmed to compensate for changing loads and signals from the user interface.

Modes of Operation

The mode of operation will be determined by the user via a keypad on the micro-controller. The user would be able to choose a desired platform motion, and this includes:

• Sinusoidal
• Step
• Triangular

Also, the user has the opportunity to select the desired frequency and amplitude of the platform’s motion, but will be based on the current software timing and selected hardware. The system would control the platform’s position correctly, regardless of the load placed on the platform.

Inputs and Outputs

 System

 EMAC Micropac 535 micro-controller

 Actuator

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