2 Documents for mechatronic device sizing and selection, especially on:actuating elements such as motor drives, control valves, orifices with estimates (calculations) of their operating conditions;sensing elements such as piezoelectric flow sensors;data processing and computing elements (memory size, scan cycle etc.); andpower storage and utilities equipment, such as uninterruptible power source (UPS) batteries (capacity etc.).
3 Documents on sizing and selection of data network components (type, media etc.) and replacements especially related to:selection of I/O modules (integrated/distributed);I/O addressing;data logging and process data archiving; anddatabase structure formulation.
4 Documents on hybrid controller structure, configuration, and operation:continuous control and logic control design algorithm and digital system circuitry; andcontrol system configuration and instrument calibration.
5 Control system maintenance/support procedures and documents including:I/O process interface for discrete and analog fields devices as well as memory organization;detection and diagnosis of external field control device failure, I/O module replacement procedure; I/O process wiring check, operational testing (factory acceptance testing), definition of emergency stops, and safety control relays;power supply, controller memory card replacement procedures; andtroubleshooting procedure and listing of hybrid control software errors.
Figure 1.12 Generic controller design steps and dependencies.
Source: Adapted from Kaltjob P.
Figure 1.12 summarizes the major steps and documents required in process control as well as those expected to be provided, while Figure 1.13 presents activities in a design control project for a mechatronic system.
Figure 1.13 Overview of activities related to control project management.
Source: Adapted from Kaltjob P.
Exercises and Problems
1 1.1 Insulin is a pancreas-generated hormone that regulates blood glucose concentration. A diabetic patient has the inability to produce a significant blood level of insulin. He has to rely on an artificial pancreas as a mechatronic device to regulate the blood glucose level by providing automatic insulin injections several times per day. Based on the patient's diet or physical and psychological activities, the amount of insulin necessary to maintain a normal blood glucose level must be determined.Identify the control functions for this mechatronic system for the regulation of blood glucose level and list all input and output system variables.Briefly describe the possible hybrid control strategy for this mechatronic system for the regulation of blood glucose level and list the control variables.Build a block diagram with the hybrid control system of blood glucose level using a real-time blood glucose measurement device and a continuous insulin infusion pump.Sketch a logic control connections of this mechatronic system instrumentation (hybrid control with control panel).
2 1.2 For monitoring and control objectives of the following systems (a–c):electric-driven driverless vehicle with a GPS-based traffic model for trajectory guidance and a sonar-based radar tool for collision avoidance;robot-aided surgery with direct current (DC) motors as actuators for 2D arm positioning, using an advanced laser beam and image processing for thermal-based cutting precision; andintelligent cow traffic monitoring using a solar powered cow collar device with embedded accelerometer;perform the following technical activities:Identify control project objectives and control processing functions.Identify key I/O system and control variables.Identify output variables and classify them as (a) measured or (b) unmeasured;List some safety, environmental, and economic considerations.Discuss the most suitable hybrid control strategy (logic, continuous).Sketch the hybrid control block diagram.
3 1.3 As depicted in Figure 1.14, an incubator is used to keep eggs at a suitable warm temperature and humidity (i.e. the balance of heat over the oxygen level) to moderate conditions in order to induce hatching from embryos to mature chicks. This is done through an automatic egg-turning device by rotating the rack of eggs in order to change their position. During this incubation cycle, the embryos breathe and exchange hot air through thousands of pores in the eggshells.Identify the control project objectives and possible control processing functions.Identify key I/O in the incubator system and corresponding control variables.Identify the output variables and classify them as (i) measured or (ii) unmeasured. Briefly describe how the unmeasured variables could be estimated.List some safety considerations and interlock processes to be introduced as a result.If a pump humidifier and a heater are used to supply water steam while a lamp produces radiation to heat the chamber temperature, draw the hybrid control block diagram.Sketch the possible operator panel with corresponding indicator lights and logical I/O variables.Figure 1.14 Egg incubator schematic.
4 1.4 Heart surgery requires the regulation of patient's blood pressure at a desired value. This is achieved by adjusting the infusion rate of vasoactive drugs into the patient's blood vessels. In addition to the effect of vasoactive drugs, blood pressure is also affected by the level of anesthetic given to the patient.Using control strategies, sketch a detailed block diagram for a hybrid control system that enables the measurement of blood pressure and regulates the infusion rate of a vasoactive drug accordingly.From the resulting block diagram, identify devices that could be used in the measuring and detecting unit and in the actuating unit.
5 1.5 For the following mechatronic devices:millimeter-wave radar for the detection of a surrounding object distances in an unmanned car collision avoidance management system;blood plasma detoxification is achieved through an implanted artificial liver bioreactor. The underlying process is a filtration though a semi-permeable membrane sheet while maintaining a pressure-regulated blood circulation. A user interface is used to remotely monitor the reactor status. This is done despite human body temperature variation;an automatic electric cooking machine with speed and temperature controls combined with monitoring indicators for cooking time and cooking stage, as well as a control panel allowing the selection of spin speed and cooking program; andan automatic vacuum cleaner with a user interface for motion control. It has an antenna to communicate with the base station (remote control), four dirt sensors, each measuring the number of dirt particles, two DC motor-driven wheels, and a steering motor:List their corresponding I/O (logic and continuous) variables.Sketch the hybrid control block diagram.Draw the I/O variables of the control panel (with its user interface) including as much details as possible, such as the ports of I/O devices connected to external circuitry such as sensors.
6 1.6 A robot-based laser beam cutting system consists of two actuating devices: a joint angle motor and a fine piezoelectric transducer for head positioning. A photo-sensor measures the head position and the position error is fed to a separate controller for each actuator. Draw the block diagram for this automated cutting