Mechanical system is the most basic element of mechatronics system, which is mainly used for actuator, transmission mechanism and supporting parts to complete specified actions, transmit power, motion and information, support and connect relevant parts, etc.Mechanical system is usually an integral part of microcomputer controlled servo system. Therefore, in addition to the general mechanical design requirements, the matching of mechanical structure factors with the performance parameters and electrical parameters of the whole servo system must also be considered in the design of mechanical system to obtain good servo performance.
Chinese name
mechanical system
Foreign name
Mechanical System
Interpretation
Perform the best synthesis of mechanical elements
Branch
Mechanical Design Discipline
Purpose
Keep causality between system input and output
system composition
Drive system, transmission system, executive system
Mechanical system is a discipline that studies the best synthesis of mechanical elements under the specified task, so that the input and output of the system maintain a causal relationship.It belongs to a branch of mechanical design discipline.A specific system composed of several mechanical devices is called mechanical system.Mechanical parts and components are the basic elements of a mechanical system. They are connected to each other to complete a certain function and form each subsystem respectively.asnumerical control machineAnd washing machines are two mechanical systems with different functions and structures, which are composed of several devices, components and parts.They are all composed of certain qualityrigidityanddampingA system composed of objects and capable of performing specific functions.
The mechanical system mainly includesdriving system 、drive system andExecutive systemThree major parts, each part needs to be repeatedly modified and coordinated in the comprehensive spatial layout, that is, after the initial layout is completed, the detailed design of each system needs to be carried out according to the design process, and the layout can be adjusted when necessary, so that the overall layout design of the equipment can be completed after modification.
form
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With the development of science and technology, the connotation of machinery is constantly changing.Mechatronics has become the most important feature of modern machinery. Mechatronics has expanded to the organic integration of light, machinery, electricity, sound, control and other disciplines.The modern mechanical system comprehensively applies many technologies such as mechanical engineering, control system, electronic technology, computer technology and electrical technology. It is a mechanical system that integrates computer technology into the information processing and control functions of machinery to realize mechanical movement, power transmission and transformation and complete the set mechanical movement functions.In terms of function, a modern machine consists of four components.
dynamic system
The power system, including the power machine and its supporting devices, is the power source of the mechanical system.According to the nature of energy conversion, there are machines that convert natural energy (primary energy) into mechanical energy, such as internal combustion engines, steam turbines, water turbines and other power machines;There are machines that convert secondary energy (such as electric energy, hydraulic energy and gas energy) into mechanical energy.Such as motorHydraulic motor, pneumatic motor and other power machines.The output motion of the power machine is usually rotation, and the speed is high.When selecting the power machine, the motion and working load of the execution system, the operating environment and working conditions of the mechanical system, and the mechanical characteristics of the working load should be considered on the umbrella surface, so that the system has both good dynamic performance and good economy.
drive system
The transmission system is an intermediate device that transmits the power and motion of the power machine to the executive system.The transmission system mainly has the following functions.
① Decelerate or increase speed.Reduce or increase the speed of the power machine to meet the needs of executing system work.
② Variable speed.When it is uneconomical, impossible or unable to meet the requirements to use the power machine for speed change, speed change (stepless or stepless) can be implemented through the transmission system to meet the requirements of multiple speeds of the executive system.
③ Change the law or form of motion.Turn the uniform, continuous and rotating movement output by the power machine into a rotating or non rotating, continuous or intermittent movement according to a certain rule, or change the direction of movement to meet the motion requirements of the executive system.
④ Transmit power.Transmit the power output from the power machine to the executive system to supply the power needed by the executive system to complete the scheduled tasktorqueOr force.
If the working performance of the power machine fully meets the requirements of the execution system, the transmission system can also be omitted and the power machine can be directly connected with the execution system.
Executive system
The executive system includes the executive mechanism and executive components of machinery. It uses mechanical energy to change the nature, state, shape or position of the work object.Or the device that detects and measures the operation object to carry out production or meet other predetermined requirements.Different functional requirements have different requirements for the mechanical characteristics of motion and working load, so the execution systems of various mechanical systems are also different.The executive system is usually at the end of the mechanical system, directly contacting with the working objects, and is the main output system of the mechanical system.Therefore, the performance of the execution system will directly affect the performance of the entire system.The execution system shall meetstrength、rigidityIn addition to the requirements for service life, it shall also meet the requirements for motion accuracy and dynamic characteristics.
Control system
The operation system and control system are all devices to make the power system, transmission system and execution system operate in coordination with each other and complete the functions of the whole machine accurately and reliably.The main differences between the two are: the control system generally refers to the device that realizes the requirements of starting, clutch, braking, speed change, reversing, etc. through manual operation;The control system refers to the device, such as servo mechanism, automatic control device, etc., that realizes the above requirements by changing the working parameters or operating state of the control object through the control signal obtained by manual operation or measuring elements through the controller.A good control system can make the machine in the best operating state, improve its operating stability and reliability, and have better economy.
In addition, according to the functional requirements of the mechanical system, there are lubrication system, counting system, walking system, steering system, etc.[1]
characteristic
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entirety
Mechanical system is a unity composed of several subsystems. Although each subsystem has different performance, they must obey the requirements of the overall function when combined, and must coordinate and adapt to each other.The realization of the overall function of a system is not the result of a subsystem acting alone;The quality of a system.It is finally reflected in its overall function.Therefore, we must proceed from the overall situation.Determine the performance of each subsystem and the relationship between them.In the design, it is not required that all subsystems have perfect performance, even if the performance of some subsystems is not perfect.However, if the overall performance of the system can be coordinated with other relevant subsystems, the whole system can also have satisfactory functions.
The system cannot be divided, that is, a system cannot be divided into independent subsystems, because the integrity of the mechanical system is reflected in the organic links between subsystems;It is this connection that makes all subsystems form a whole. If this connection is lost, the whole system will not exist.The actual system is often very complex. For the convenience of research, a system can be decomposed into several subsystems as required.The decomposition system is completely different from the partition system, because the connection between them is never forgotten when decomposing the system. The decomposed subsystems are not independent, and the connection between them can be expressed by the input and output of the corresponding subsystems respectively.
relevance
The subsystems within the system are organically linked.They interact and influence each other, forming specific relationships, such as the relationship between the input and output of the system, the hierarchical relationship between subsystems, and the relationship between the performance of each subsystem and the specific functions of the system as a whole.It depends on the interaction and mutual influence of each subsystem within the system.A change in the performance of a subsystem will affect the performance of the whole system.
Purposiveness
The value of the system is reflected in its function. The purpose of the system is to complete specific functions.Therefore, the system shall realize the required functions.Eliminate or reduce harmful interference.
Environmental adaptability
Any system exists in a certain physical environment.Changes in the external environment.It will change the input of the system, or even cause interference, resulting in changes in system functions.A good system should have strong environmental adaptability.[1]
mathematical model
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To analyze any kind of dynamic system, itsmathematical model (Mathematical] Model), establishing a reasonable mathematical model is the key to the analysis process.A model is a substitute that is constructed for studying a system to collect relevant information, and use this information to predict the performance or motion state of the system for design or control.The mathematical model of mechanical system refers to the mathematical description of the dynamic characteristics of mechanical system. Usually, the mathematical model of mechanical system is described by differential equations.
The mathematical models of mechanical systems can generally be divided into discrete systems and continuous systems;It can also be divided into linear system and nonlinear system according to whether the differential equation describing the system is linear or not;Sometimes it is also classified according to the certainty, randomness and fuzziness of its mathematical model.
system integration
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The key to the integrated design of mechanical system is to make a good overall layout, coordinate technological actions, and ensure the coordination with external systems such as people and environment. That is, the integrated design of mechanical system needs to consider two aspects: the realization of equipment technical functions and other extended functions.This requires the designer to conceive the connection and coordination of each component, especially the executive component (or executive mechanism) in space and time according to the logistics trend during the production or application of the equipment, and also need to consider the layout of the control system to complete the overall layout of the equipment to achieve the technical functions of the equipment.In addition, it is also necessary to combine ergonomic design and modeling design at the same time to adapt the equipment to external systems such as people and environment, improve the ergonomic efficiency of the equipment, enhance the artistic function of the equipment, and improve the design.
The overall layout of the mechanical system is mainly around the functions of the designed equipment.In order to realize the overall function of the equipment, the mechanical parts corresponding to several sub functions are generally integrated one by one according to the process action requirements.In the overall layout of the system, in addition to the equipment modeling and human-machine relationship, the key is to consider two "coordination": one is the coordination of mechanical parts in spatial location, such as the location determination of assembly line stations and the relative spatial layout of related process actions;Second, the motion execution components of each mechanical component are coordinated in time sequence, such as the design of the sequence of actions of several execution components, time interval design, etc., so as to ensure the coordination of process movement and realize the overall function of the equipment.[2]
engineering application
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Mechanical systems have been applied to various modern machines with different functions.The most common ones are metallurgical machinery, mining machinery, engineering transport machinery, metal cutting machine tools, etc.
In addition to mechanical equipment, the actuators of some electrical equipment and other devices are often composed of mechanical systems.The size of the mechanical system may vary depending on the task being studied: a mechanism consisting of components connected by kinematic pairs, such asCamMechanism, crank connecting rod mechanism, gear box, etc;Machines composed of prime mover, transmission mechanism and actuator, such as shaper, punch, etc;Complete machine composed of mechanical and control elements, such as robotnumerical control machineEtc.
In engineering applications, mechanical equipment needs to be designed and analyzed from the perspective of system. For example, when studying the gear transmission case, it is necessary to comprehensively consider the coordination of various components inside the gear transmission case, such as gears, shafts, bearings, etc., without jamming, interference and other phenomena, so as to ensure that the gear transmission case can realize its own functions and play its roles and tasks.In addition to the coordinated work of various elements in the system, the system must also work in coordination with each other, with tacit understanding, and also consider environmental factors (system boundary conditions)[3]
