Mechatronics system
Mechatronics system generally consists of sensors, actuators and controlling software. Such systems are also called wise devices, because depending on the complexity of controlling devices, these can do complex operations, to adapt to the environment and interact with their surroundings. Robotics one of the most common application area of mechatronics. Robotics is associated for everyone with some kind of smart machin, or a humanoid (human like robot), but for many people in industry, it is manipulator, welding, etc., or paintingrobot. It shows that people have actually very different understanding of robotics and robots could be very different devices with different capabilities and complexity, until they meet the requirements described in the previous section (sensor-actuator-controller). Figure 1 shows the tentatively indicated robotic system. Arrows show the flow of information between the external environment and its direction.
Figure 1.Mechatronics system.Sensors receive information from outer environment that controller uses to make decicions which are reflected through actuators. (such as movement)
Sensors retrieve information from surrounding environment (like temperature, distance from other objects, radio signals) or from device itself (speed, acceleration, speed of motor) and forward it to control module. Control module is usually controller, where some algorithm (program) is executed. According to program and data received from sensors, controller is managing actuators which are often electrical motors. Actuators can also be solenoids, artificial muscles, pneumatic devices etc. Generally, actuators cause movement that changes the environment. Simplified example could be safety system and crash situation.
Figure 2.Car theft system and a schematic model.
The airbag is a typical mechatronic system. It consists of three main parts: a sensor, a controller and an actuator. The acceleration sensor registers a sudden change in acceleration and transmits a corresponding signal to the controller. Controller algorithm terminates all other car activities and sends explosion cell, which is connected to the airbag in a car, the trigger signal. Explosion cell triggers the air bag, filling it with gas, and fast way to protect the driver from a hit against the steering shock. That's sensor-controller-actuator-driven chain and we can say that it is a mechatronics device.
Microcontroller
One of the key components of mechatronics system is the microcontroller, short, a controller, which is processing information and issuing commands to actuators. The controller can be conditionally compared with a small computer were all the functions (processor, memory, input-output converters, etc.) are placed on a single chip, and therefore it is often called in to the microcontroller. Of course, in such a case it is not comparable to the computing power of the home PC, but it is perfectly adequate to manage robotic system. The microcontroller is externally comparable to ordinary logic, but the essential difference is that it’spins can be programmed in such a way that they act according to the wishes and controller capabilities. This means that one and the same physical pin depending on the program can be either an input (or signaling information is moving in the direction of the controller) or output (the controller sends a signal or data). For example, the input may be connected to a variety of sensors and actuators with different outputs. The simplest case, digital signals are (0 or 1), where 0 means the absence of electrical voltage, and one generally mains voltage (for example, 5 V). The various microcontrollers and digital signal Graphical representation of the shape shown in Figure 3.
Figure 3.Microcontrollers different blocks (left) and a simple digital signal: logical 0 and logical 1 (right)
One of the peculiarities of the controllers is a very wide selection. There are simple and cheap, which are suitable for simple control processes, and there are sophisticated and powerful with many input-output pins of the controllers. In addition, controllers are distributed by functionality and applications field. For example, the automotive industry used controllers have to meet different requirements than those presented to the household.
To control mechatronicsystems and robots, it is important to recognize the possibilities of microcontrollers and know how to program these. Part II introduces basic capabilities and functions of controllers.
Repeating questions:
- What are main parts of mechatronics system?
- What is the functionality of controller in mechatronics system?
- What are the devices that robot uses to get information?
- Give to examples (devices that can be connected to controller) where pin of the controller should be programmed as a) output b) input