1. Key technologies of ontology design
(1) Transmission structure design
Draw up the overall plan, determine the structural form of the robot, and carry out preliminary transmission structure design, part structure design, and three-dimensional modeling accordingly. The designer is required to be very familiar with and understand the common structural forms of robots, common transmission principles and transmission structures, and the types and characteristics of reducers, and to have strong structural design capabilities and experience.
(2) Reducer selection
It is necessary to have a deep understanding of the structure type and the meaning of performance parameters of the reducer, and the reducer will be selected and calculated and checked. The reducer should be tested and tested, and the contents of the test mainly include noise, jitter, output torque, torsional stiffness, backlash, repeated positioning accuracy and positioning accuracy. The vibration of the reducer will cause jitter at the end of the robot, reducing the trajectory accuracy of the robot. There are many reasons for the vibration of the reducer, among which resonance is a common problem, and robot companies must master the method of suppressing or avoiding resonance.
(3) Motor selection
It is necessary to have a good understanding of the working characteristics of the motor, and to calculate and check the torque, power and inertia of the motor.
(4) Simulation analysis
Carry out simulation analysis of statics and dynamics, select and check the motor and reducer, check the strength and stiffness of the body parts, reduce the weight of the body, improve the work efficiency of the robot, and reduce the cost. Modal analysis of the 3D model calculates the natural frequencies for resonance suppression.
(5) Reliability design
The structural design adopts the principle of simplified design; the body iron castings are made of ductile iron materials with good comprehensive performance, and the aluminum castings are made of casting materials with good fluidity, and metal molds are used for casting; the assembly should have a detailed assembly process instruction, and the components and single shaft tests should be tested in the assembly process; after the assembly, there should be the whole machine performance test and the durability copy machine test; the protection level design of the whole machine should be improved, and the anti-interference ability of the electric cabinet should be improved, so as to be suitable for the use of different working environments.
2. Key technology of motor servo
(1) Motor
1) Lightweight
For robots, the size and weight of the motor are very sensitive, through the research of high magnetic material optimization, integrated optimization design, processing and assembly process optimization and other technologies, improve the efficiency of the servo motor, reduce the space size of the motor and reduce the weight of the motor, which is one of the key technologies of the robot motor.
2) High speed
In the case that the reduction ratio can not be greatly adjusted, the maximum speed of the motor directly affects the end speed and working beat of the robot, and the speed ratio is too low to affect the inertia matching of the motor, so increasing the maximum speed of the motor is also one of the key technologies of the robot motor.
3) Direct drive, hollow
With the continuous maturity and promotion of collaborative robots, the lightweight and compact requirements of robot structure are increasing, and the development of high-torque direct drive motors, disc hollow motors and other robot-specific motors is also a future trend.
(2) Servo
1) Quick response, precise positioning
The response time of the servo directly affects the rapid start and stop effect of the robot, and affects the work efficiency and beat of the robot.
2) Sensorless mode to achieve elastic collision
Safety is an important metric to measure the performance of your bot. The addition of force or torque sensors will make the structure more complex and costly, and the non-sensing elastic collision technology based on the coupling relationship between encoder and motor current can improve the safety of the robot to a certain extent without changing the body structure and increasing the cost of the body.
3) All-in-one drive and integrated drive control.
All-in-one drive, multi-core CPU multi-axis drive control integration technology, improve system performance, reduce drive volume and cost.
4) Online adaptive jitter suppression
The cantilever structure of industrial robots is very easy to cause jitter during multi-axis linkage, heavy load and fast start and stop. The stiffness of the robot body should be matched with the motor servo stiffness parameters, too high stiffness will cause vibration, and too low stiffness will cause slow start-stop response. The stiffness of the robot is different in different positions and attitudes, as well as under different tooling loads, and it is difficult to set the servo stiffness value in advance to meet the needs of all working conditions. The online adaptive jitter suppression technology proposes an intelligent control strategy without parameter debugging, and at the same time takes into account the needs of stiffness matching and jitter suppression, which can suppress the end jitter of the robot and improve the positioning accuracy of the end.
3. Control key technologies
(1) Motion calculation and trajectory planning
Motion solving, optimal path planning, improve the motion accuracy and work efficiency of the robot.
(2) Kinetic compensation
The general industrial robot is a tandem cantilever structure, with weak rigidity, complex movement, and easy deformation and jitter, which is a subject that requires the combination of kinematics and dynamics. In order to improve the dynamic performance and accuracy of the robot, the robot control system must establish a dynamic model and compensate for the dynamics. The content of compensation mainly includes gravity compensation, inertia compensation, friction compensation, coupling compensation, etc.
(3) Calibration compensation
Due to the processing error and assembly error, it is difficult to avoid deviations from the theoretical mathematical model, which will reduce the TCP accuracy and trajectory accuracy of the robot, such as being seriously affected when it is used in welding and offline programming. This problem can be solved by detecting and calibrating the model parameters of the compensation robot by algorithm.
(4) The process package is perfect
The control system should be combined with the actual engineering application, in addition to the continuous upgrading, more powerful functions, but also according to the needs of the industry application to continuously develop and improve the process package, is conducive to the accumulation of industry process experience, for customers to use more convenient, simpler operation, higher efficiency.