MECHATRONICS SYSTEM DESIGN AND APPLICATIONS

TRADITIONAL AND MECHATRONICS DESIGN

    

         In traditional design, the components are designed through mechanical, hydraulic or                            pneumatic components and principles. But in mechatronics approach, mechanical,                              electronics, computer technology and control engineering principles are included to design a                  system.

         For example design of weighing scale might be considered only in terms of the compression of springs and a mechanism used to convert the motion of spring into rotation of shaft and hence movements of a pointer across a scale.  In this design measurement of weight is depended on the position of weight on the scale.

·        In mechatronics design, the spring might be replaced by load cells with strain gauges and output from them used with a microprocessor to provide a digital readout of the weight on an LED display.

  

·        Similarly the traditional design of the temperature control for a central AC system involves a bimetallic thermostat in a closed loop control system.The basic principle behind this system is that the bending of the bimetallic strip changes as the temperature change and is used to operate an ON/OFF switch for the temperature control of the AC system.

·        The same system can be modified by mechatronics approach.  This system uses a microprocessor controlled thermocouple as the sensor. Such a system has many advantages over traditional system.

·       The bimetallic thermostat is less sensitive compared to the thermodiode.  Therefore the temperature is not accurately controlled.   Also it is not suitable for having different temperature at different time of the day because it is very difficult to achieve.

     But the microprocessor controlled thermodiode( Themodiode: application of thermal diode is based on its property to change voltage across it linearly according to temperature. As the temperature increases, diodes forward voltage decreases.)system can overcome fore said difficulties and is giving precision and programmed control. This system is much more flexible.

       Weighing scales:

·        Consider the simple weighing machine which is used to indicate the weight of a person standing on it.The important requirement of this weighing machine is to indicate the weight of the person with reasonable   speed and accuracy and be independent of whereon the platform the person stand.

·         The traditional mechanical system for this problem is to use the weight of the person on the platform to deflect an arrangement of two parallel leaf springs as shown in fig.

·      The deflection of the leaf spring is transferred to the rack and pinion arrangement where the linear movement of rack is converted into rotary motion of the pinion about the horizontal axis.  The rotary motion is transferred to the movement of a pointer across a scale through bevel gears.  With this arrangement the deflection is independent of where on the platform the person stands.

·      The mechatronics solution for this problem involves the use of a microprocessor. The basic principle behind this approach is to use load cells employing electrical resistance strain gauges.