Industrial robots are multi-jointed manipulators or multi-degree-of-freedom machines widely used in the industrial field, with a certain degree of automation, relying on their own power and control capabilities to realize a variety of industrial processing and manufacturing functions. Industrial robots are widely used in various industrial fields such as electronics, logistics, and chemicals.
Composition
Generally speaking, industrial robots are composed of six subsystems.
The three main parts are the mechanical part, the sensing part and the control part.
The six subsystems can be categorized into mechanical structure system, drive system, sensing system, robot-environment interaction system, human-machine interaction system and control system.
1. Mechanical structure system
In terms of mechanical structure, industrial robots are generally categorized into series and parallel robots. Series robots are characterized by the fact that the motion of one axis changes the coordinate origin of the other axis, while the motion of one axis of a parallel robot does not change the coordinate origin of the other axis. Early industrial robots used tandem mechanisms. A parallel mechanism is defined as a closed-loop mechanism in which the moving and fixed platforms are connected by at least two independent kinematic chains, the mechanism has two or more degrees of freedom, and is driven in parallel. The parallel mechanism has two constituent parts, a wrist and an arm. The arm movement area has a great influence on the movement space, while the wrist is the connecting part between the tool and the body. Compared with the tandem robot, the parallel robot has the advantages of high stiffness, stable structure, high load carrying capacity, high micromotion accuracy, and low motion load. In position solving, the tandem robot is easy to solve positively but very difficult to solve inversely, while the parallel robot, on the contrary, is difficult to solve positively but very easy to solve inversely.
2. Drive system
The drive system is a device that provides power to the mechanical structure system. According to the different power sources, the drive system is divided into hydraulic, pneumatic, electrical and mechanical transmission mode. Early industrial robots used hydraulic drive. Due to the problems of leakage, noise and low-speed instability of the hydraulic system, and the power unit is bulky and expensive, only large-scale heavy-duty robots, parallel machining robots and some special applications use hydraulically driven industrial robots. Pneumatic drive has the advantages of fast speed, simple system structure, easy maintenance and low price. However, the working pressure of the pneumatic device is low, it is not easy to accurately position, generally only used for industrial robot end-effector drive. Pneumatic hand gripping, rotary cylinders and pneumatic suction cups as the end-effector can be used for workpiece gripping and assembly of medium and small loads. Electric drive is currently the most used drive mode, which is characterized by easy access to power, fast response, driving force, signal detection, transmission, processing is convenient, and can be used in a variety of flexible control methods, the drive motor is generally used stepping motor or servo motor, there are also using a direct drive motor, but the cost is higher, the control is also more complex, and the motor with the general use of harmonic reducers Reducer, cycloid reducer or planetary gear reducer. Due to the large number of linear drive requirements in parallel robots, linear motors have been widely used in the field of parallel robots.
3. Sensing system
The robot perception system transforms various internal state information and environmental information from signals into data and information that can be understood and applied by the robot itself or between robots. In addition to the need to perceive mechanical quantities related to its own working state, such as displacement, velocity and force, visual perception technology is an important aspect of industrial robot perception. Visual servo systems use visual information as feedback signals for control to adjust the position and attitude of the robot. Machine vision systems are also widely used in all aspects of quality inspection, identification of workpieces, food sorting, and packaging. The sensing system consists of an internal sensor module and an external sensor module. The use of intelligent sensors improves the mobility, adaptability and intelligence of the robot.
4.Robot-environment interaction system
Robot-environment interaction system is a system that realizes the interconnection and coordination between the robot and the equipment in the external environment. Robots and external equipment integrated into a functional unit, such as processing and manufacturing unit, welding unit, assembly unit. Of course, it can also be more than one robot into a functional unit to perform complex tasks.
5. Human-robot interaction system
The human-robot interaction system is a device that connects people with robots and participates in robot control. For example, standard terminals for computers, command consoles, information display boards, and danger signal alarms.
6. Control system
The task of the control system is to control the robot's actuators to perform the specified movements and functions according to the robot's operating instructions and the signals fed back from the sensors. If the robot does not have information feedback characteristics, it is an open-loop control system; with information feedback characteristics, it is a closed-loop control system. According to the control principle can be divided into program control system, adaptive control system and artificial intelligence control system. According to the form of control motion can be divided into point control and continuous trajectory control.
Applications
1.Application in palletizing
In palletizing in various factories, highly automated robots are widely used. Manual palletizing is very intensive and labor-intensive, and the employees not only need to bear great pressure, but also have low work efficiency. The handling robot can carry out efficient classification and handling according to the characteristics of the objects to be handled and the places where the objects are categorized, on the basis of keeping their shapes and the nature of the objects unchanged, which enables the carton loading equipment to complete the palletizing task of hundreds of pieces per hour. In the production line loading and unloading, container handling and so on to play its important role.
2. Application in welding
Welding robots are mainly responsible for welding work, different types of industries have different industrial needs, so common welding robots have spot welding robots, arc welding robots, laser robots and so on. Automobile manufacturing industry is the most widely used welding robot industry, in the welding difficulty, welding quantity, welding quality and other aspects of artificial welding has incomparable advantages.
3. Application in assembly
In industrial production, the assembly of parts is a huge amount of work, requiring a large number of labor, once the human assembly because of the high error rate, low efficiency and gradually replaced by industrial robots. The development of assembly robots combines a variety of technologies, including communication technology, automatic control, optical principles, microelectronics and so on. According to the assembly process, the developers write appropriate programs and apply them to specific assembly work. The most important features of assembly robots are high installation precision, flexibility and durability. Because of the complexity and fineness of the assembly work, we choose assembly robots to carry out the installation of electronic parts and fine automobile parts.
4. Application in inspection
Robot has multi-dimensional additional functions. It can replace the staff in special positions, such as detection in high-risk areas such as nuclear contamination areas, toxic areas, nuclear contamination areas, high-risk unknown areas. There are also places where humans cannot reach specifically, such as the detection of sick parts of patients, the detection of industrial defects, and the detection of life at the scene of earthquake relief have been established.
Development trend
1. Human-robot collaboration
As robots develop from working at a distance from people to naturally interacting and collaborating with people. The maturity of drag-and-drop teaching and manual teaching technology makes programming easier to use, reduces the professional requirements for operators, and makes it easier to transfer the process experience of skilled technicians.
2. Autonomous
Currently the robot from the pre-programming, teaching reproduction control, direct control, remote operation and other manipulated mode of operation to the direction of autonomous learning, autonomous operation. Intelligent robots can automatically set and optimize the trajectory path, automatically avoid singularities, interference and collision prediction and obstacle avoidance according to the working conditions or environmental requirements.
3. Intelligent, informationized, networked
More and more 3D vision and force sensors will be used on the robot, and the robot will become more and more intelligent. With the advancement of sensing and recognition system, artificial intelligence and other technologies, the robot from being unidirectional control to their own storage, their own application data direction, and gradually informatization. With the multi-robot collaboration, control, communication and other technological advances, robots from independent individuals to the phase of the Internet, the direction of cooperative development.