Component Interconnection And Signal Conditioning

Component Interconnection and Signal Conditioning

Mechatronic systems are mixed systems, which consist of more than one type of components properly interconnected and integrated.

In particular, mechanical, electrical, electronic, and computer hardware are integrated to form a mechatronic system. It follows that component interconnection is an important topic in the field of Mechatronics. When two components are interconnected, signals flow through them.

The nature and type of the signals that are present at the interface of two components will depend on the nature and type of the components. For example, when a motor is coupled with a load through a gear (transmission) unit, mechanical power flows at the interfaces of these components.

Then, we are particularly interested in such signals as angular velocity and torque. In particular, these signals would be modified or “conditioned” as they are transmitted through the gear transmission. Similarly, when a motor is connected to its electronic drive system, command signals of motor control, typically available as voltages, would be converted into appropriate currents for energizing the motor windings so as to generate the necessary torque.

Again, signal conditioning or conversion is important here. In general, then, signal conditioning is important in the context of component interconnection and integration, and becomes an important subject in the study of Mechatronics.

This chapter addresses interconnection of components such as sensors, signal conditioning circuitry, actuators, and power transmission devices in a mechatronic system.

Desirable impedance characteristics for such components are discussed. Signal modification plays a crucial role in component interconnection or interfacing. When two devices are interfaced, it is essential to guarantee that a signal leaving one device and entering the other will do so at proper signal levels (the values of voltage, current, speed, force, power, etc.), in the proper form (electrical, mechanical, analog, digital, modulated, demodulated, etc.), and without distortion (where loading problems, nonlinearities, and noise have to be eliminated, and where impedance considerations become important). Particularly for transmission, a signal should be properly modified (by amplification, modulation, digitizing, etc.) so that the signal/noise ratio of the transmitted signal is sufficiently large at the receiver.

The significance of signal modification is clear from these observations.

The tasks of signal-modification may include signal conditioning (e.g., amplification, and analog and digital filtering), signal conversion (e.g., analog-to-digital conversion, digital-to analog conversion, voltage-to frequency conversion, and frequency-to-voltage conversion), modulation (e.g., amplitude modulation, frequency modulation, phase modulation, pulse width modulation, pulse-frequency modulation, and pulse-code modulation), and demodulation (the reverse process of modulation). In addition, many other types of useful signal modification operations can be identified.

For example, sample and hold circuits are used in digital data acquisition systems. Devices such as analog and digital multiplexers and comparators are needed in many applications of data acquisition and processing. Phase shifting, curve shaping, offsetting, and linearization can also be classified as signal modification.

This chapter describes signal conditioning and modification operations that are useful in mechatronic applications. The operational amplifier is introduced as a basic element in signal conditioning and impedance matching circuitry for electronic systems.