Industrial robot
1. Fill in the blanks
1. According to the coordinate form, the robot can be divided into rectangular coordinate type, cylindrical coordinate type and spherical coordinate type
And joint coordinate type four basic types.
2. As a robot, it generally consists of three parts, namely the control system, sensor system and mechanical system.
3. The main technical parameters of the robot generally include degrees of freedom, positioning accuracy, working range, repeat positioning accuracy, resolution, carrying capacity and maximum speed.
4. The degree of freedom refers to the number of independent coordinate axis movements of the robot, excluding the opening and closing degrees of freedom of the end effector.
5. Robot resolution is divided into programming resolution and control resolution, collectively referred to as system resolution.
6. Repeat positioning accuracy is statistical data about accuracy.
7. According to the principle of vacuum generation, vacuum suction cups can be divided into vacuum suction cups, airflow negative pressure suction cups and vacuum suction cups.
There are three basic types such as squeeze and negative pressure suction cups.
8. The generation methods of robot motion trajectory include teaching reproduction motion, joint space motion, space linear motion and space curve motion.
9. The main performance indicators of robot sensors include sensitivity, linearity, measurement range, repeatability, accuracy, resolution, response time and anti-interference ability.
10. The degree of freedom refers to the number of independent coordinate axis movements that the robot has.
11. The repetitive positioning accuracy of the robot refers to the dispersion of its position when the robot repeats its movement several times continuously under the same environment, the same condition, the same target action, and the same command.
12. The driving methods of the robot mainly include hydraulic drive, pneumatic drive and electric drive.
13. Commonly used sensors on robots that can measure rotational speed include tachogenerators and incremental encoders.
14. According to its control mode, the robot control system can be divided into force control mode, trajectory
Control mode and teaching control mode.
15. According to the geometric structure, robots are divided into: series robots and parallel robots.
2. Multiple Choice Questions (Please choose the best answer among the four alternative answers for each question.)
1. The working range refers to the set of points that robot B or the center of the wrist can reach.
A Manipulator B End of arm C Arm D Walking part.
2. The precision of the robot mainly depends on C, control algorithm error and resolution system error.
A Transmission error B Joint clearance C Mechanical error D Flexibility of linkage mechanism
3. Rolling can realize 360° unobstructed rotation joint movement, usually marked with A.
A R B W C B D L
4. The RRR type wrist is a C degree of freedom wrist.
A 1 B 2 C 3 D 4
5. Vacuum suction cups require the surface of the workpiece to be D, dry and clean, and have good air tightness.
A Rough B Bumpy C Slightly raised D Smooth smooth
6. Synchronous belt transmission belongs to B transmission, which is suitable for use between the motor and the high-speed ratio reducer.
A high inertia B low inertia C high speed ratio D high torque
7. The external sensors of the robot do not include the D sensor.
A force or moment B proximity C touch D position
8. The main function of the gripper is to grasp the workpiece, hold the workpiece and the C workpiece.
A fix B position C release D touch.
9. The precision of the robot mainly depends on C, control algorithm error and resolution system error.
A Transmission error B Joint clearance C Mechanical error D Flexibility of linkage mechanism
10. The control methods of the robot are divided into point control and C.
A Point-to-point control B Point-to-point control C Continuous track control D Arbitrary position control
11. The welding operation of the welding robot mainly includes A.
A spot welding and arc welding B intermittent welding and continuous welding C flat welding and vertical welding D gas shielded welding and argon arc welding
12. The working path is usually described by the movement of the D coordinate system relative to the workpiece coordinate system.
A claw B fixed C motion D tool
13. The disadvantage of harmonic drive is A.
A low torsional stiffness B small drive backlash C low inertia D high precision
14. Who proposed the three principles of robots. (D)
A Mori Masahiro B Joseph Ingeberg C Tomovich D Asimov
15. The most important robots in the contemporary robot army are: (A)
A industrial robot B military robot C service robot D special robot
16. Which two variables are composed of the pose of the hand? (B)
A Position and speed B Attitude and position C Position and running status D Attitude and speed
17. The sensor used to detect the size and direction of relative motion between the contact surfaces of objects is: C
A Proximity sensor B Touch sensor C Sliding sensor D Pressure sensor
18. Teaching-playback control is an online programming method, and its biggest problem is: B
A. The labor intensity of the operator is high. B. Occupies the production time. C. The safety of the operator. D. It is easy to produce waste products.
19. Which of the following countries is called the "Kingdom of Robots"? C
A China B UK C Japan D USA
3. True or false questions (mark “√” for right and “×” for wrong)
1. Teaching programming is used in teaching-reproducing robots. (√)
2. The trajectory of the robot generally refers to the trajectory of the industrial robot during the motion process, that is, the displacement, velocity and acceleration of the moving point. (√)
3. The articulated robot is mainly composed of a column, a forearm and a rear arm. ( × )
4. So far, the robot has been developed to the fourth generation. ( × )
5. The magnetic chuck can hold workpieces made of all metal materials. ( × )
6. The name of the harmonic reducer comes from the fact that the radial displacement of any point on the ring gear of the rigid wheel is similar to the change of the cosine waveform. N ( × )
8. A bridge composed of resistance strain gauges can form a sensor for measuring weight. Y (√)
9. The laser range finder can detect the weight of bulk materials. Y (√)
10. The manipulator can also be called a robot. Y (√)
4. Short answer questions
1. How many types of robot wrists are there? Describe each wrist structure. Answer: The arm of the robot can be divided into single-arm type according to the structural form, double-arm type and suspension type according to the movement form of the arm, and the arm has linear motion. Such as the expansion and contraction of the arm, the lifting and lateral movement, the rotary motion such as the left and right rotation of the arm, and the compound motion such as the combination of linear motion and rotary motion. A combination of 2 linear motions and a combination of 2 rotary motions. Arm rotary motion mechanism, there are various mechanisms for realizing the rotary motion of the robot arm. Commonly used blades are rotary cylinders, gear rotation mechanisms, sprocket drives and linkage mechanisms. Arm pitch motion mechanisms generally use piston oil (air) The cylinder and the link mechanism are used to realize the compound motion mechanism of the arm, and most of them are used for special-purpose robots with a fixed degree of movement.
2. How many control methods are there for industrial robots? There are various control methods for industrial robots. According to different tasks, they are mainly divided into point-position control methods, continuous trajectory control methods, force (torque) control methods and intelligent control methods. answer:
1) Point-to-point control method (PTP)
The characteristic of this control method is that it only controls the pose of the end effector of the industrial robot at some specified discrete points in the work space. During control, the industrial robot is only required to quickly and accurately realize the movement between adjacent points, and there is no provision for the movement trajectory to reach the target point. The main technical indicators of this control method are the positioning accuracy and the time required for movement.
2) Continuous trajectory control mode (CP)
The characteristic of this control method is to continuously control the position and posture of the end effector of the industrial robot in the work space, requiring it to move strictly according to the predetermined trajectory and speed within a certain range of accuracy, and the speed is controllable, the trajectory is smooth, and the movement is stable. to complete work tasks.
3) Force (torque) control method
When completing assembly, picking and placing objects, etc., in addition to accurate positioning, it is also required to use moderate force or torque for work. At this time, the force (torque) servo method must be used. The control principle of this method is basically the same as the position servo control principle, except that the input and feedback are not position signals, but force (torque) signals, so there must be a force (torque) sensor in the system. Sometimes sensing functions such as proximity and sliding are also used for adaptive control.
4) Intelligent control method
The intelligent control of the robot obtains the knowledge of the surrounding environment through the sensor, and makes corresponding decisions according to its own internal knowledge base. Using intelligent control technology, the robot has strong adaptability and self-learning function. The development of intelligent control technology depends on the rapid development of artificial neural network, genetic algorithm, genetic algorithm, expert system and other artificial intelligence in recent years.
4. What are the robot parameter coordinate systems? What is the role of each parameter coordinate system? Answer: The coordinate forms of industrial robots include rectangular coordinates, cylindrical coordinates, spherical coordinates, joint coordinates and planar joints.
1) Cartesian coordinates/Cartesian coordinates/gantry type (3P)
The robot consists of three linear joints used to determine the position of the end-effector, usually with an additional rotational joint used to determine the pose of the end-effector. The movement of this robot on the X, Y, and Z axes is independent, and the equations of motion can be processed independently, and the equations are linear, so it is easy to realize by computer; it can be supported at both ends, and for a given structure length, Maximum rigidity: Its accuracy and position resolution do not change with the workplace, and it is easy to achieve high precision. However, its operating range is small, and the arm stretches out in the opposite direction while shrinking, which hinders the work, and has a large footprint, low movement speed, and poor sealing.
2) Cylindrical coordinate type (R3P)
Cylindrical coordinate robots use two sliding joints and one rotary joint to determine the position of the component, and an additional rotary joint to determine the posture of the component. This kind of robot can rotate an angle around the central axis, the working range can be expanded, and the calculation is simple; the linear part can be driven by hydraulic pressure, which can output a large power; it can reach into the cavity of the machine. However, the reachable space of its arm is limited, and it cannot reach the space near the column or near the ground; the linear drive part is difficult to seal and dustproof; when the rear arm is working, the rear end of the arm will touch other objects within the working range.
3) Spherical coordinate type (2RP)
5. What are the types of human claws, and what are their characteristics?
Answer: (1) Manipulator claw: rely on the transmission mechanism to grasp the workpiece;
(2) Magnetic chuck: grasp ferromagnetic workpieces by magnetic field suction, requiring the surface of the workpiece to be clean, flat and dry to ensure reliable adsorption, not suitable for high temperature conditions;
(3) Vacuum suction cup: use the vacuum principle to grasp the workpiece, and the surface of the workpiece is required to be smooth, dry and clean, and the air tightness is better.
6. What are the two basic forms of the encoder? What are their characteristics?
Two basic forms: incremental and absolute
Incremental: It is used to measure the change of angular position and linear position, but it cannot directly record or indicate the actual value of the position. In all systems utilizing incremental encoders for position tracking, a reset must be performed at system start-up.
Absolute type: each position corresponds to the only certain combination of light-transmitting and opaque arc segments, and this certain combination has unique characteristics. By means of this feature, the exact position of the code wheel can be determined at any time.
7. What are the types of drivers commonly used in industrial robots, and a brief description of their characteristics.
(1) The energy source of the electric drive is simple, the speed variation range is large, the efficiency is high, the rotational inertia is small, and the speed and position accuracy are very high, but they are mostly connected with the reduction device, and it is difficult to drive directly.
(2) The advantage of the hydraulic drive is that it has large power, can save the reduction gear and be directly connected to the rod to be driven, has a compact structure, good rigidity, fast response, and the servo drive has high precision. However, it is necessary to add a hydraulic source, which is prone to liquid leakage, and is not suitable for occasions with high and low temperature and cleanliness requirements. Therefore, hydraulic drives are mostly used in super-high-power operating robot systems or robotized construction machinery.
(3) The structure of the pneumatic drive is simple, clean, sensitive in action and has a buffering effect. But it also needs to add an air pressure source, and compared with the hydraulic drive, the power is lower, the stiffness is poor, the noise is loud, and the speed is not easy to control, so it is mostly used for point control robots with low precision but cleanliness and explosion-proof requirements.
8. What are the transmission systems of commonly used industrial robots?
Gear drives, worm drives, ball screw drives, timing belt drives, chain drives and planetary gear drives
9. Why is a transmission (reduction) system often needed in a robot system?
Because the current motor generally has a high speed and a small torque, it is necessary to reduce the speed and increase the torque through the transmission system.
10. What are the commonly used distance and proximity sensors on robots? .
Ultrasonic, laser, infrared, hall sensor
11. According to the classification of robots, how many categories can robots be divided into? Try to briefly describe it.
1) Industrial robots or industrial robots are used in industrial and agricultural production, mainly in manufacturing, welding, painting, assembly, handling, inspection, processing of agricultural products and other industries.
2) Exploration robots are used for space and ocean exploration, and can also be used for surface and underground exploration.
3) Service robot is a kind of semi-autonomous or fully autonomous robot. The service work it engages in can make human beings live better and make equipment other than manufacturing work better.
4) Military robots are used for military purposes, either offensively or defensively.
12. What is a teaching reproduction robot?
Answer: First, the manipulator is driven by a human, and then the operation is performed with the teaching action, and the teaching operation program, position and other information are stored, and then the robot is allowed to reproduce these actions.
13. What are the two basic forms of the encoder? What are their characteristics?
Two basic forms: incremental and absolute
Incremental: It is used to measure the change of angular position and linear position, but it cannot directly record or indicate the actual value of the position. In all systems utilizing incremental encoders for position tracking, a reset must be performed at system start-up.
Absolute type: each position corresponds to the only certain combination of light-transmitting and opaque arc segments, and this certain combination has unique characteristics. By means of this feature, the exact position of the code wheel can be determined at any time.
5. Write a motion control instruction that meets the requirements according to the motion trajectory given in the figure below.
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6. Please interpret the following procedures and write notes.
1. Main program
PROC main ()
rInitAll;
WHILE TRUE DO
IF di1=1 THEN
rMoveRoutine;
rHome;
ENDIF
WaitTime 0.3;
I'M IN THE HOUSE
END PROC
2、PROC rModPos()
!Teach target point program
MoveL pPick,v10,fine,tGripper\WObj:=WobjCNV;
MoveL pPlaceBase,v10,fine,tGripper\WObj:=WobjBuffer;
MoveL pHome,v10,fine,tGripper;
END PROC
ENDMODULE
3. Understand the following instructions and draw the trajectory diagram of the robot.
PROC Routine1（）
MoveL p10,v1000,fine,tool1\WOBj:=wobj1;
MoveC p30,p40,v1000,z1,tool1\WOBj:=wobj1;
END PROC
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