You may not be able to answer all these questions clearly, but a thorough understanding can make you a semi-expert! For any points not covered in detail, please leave your insightful comments below!
1. Definition and characteristics of industrial robots ?
Definition: A robot is a machine with many degrees of freedom in three-dimensional space that can perform many human-like actions and functions; while an industrial robot is a robot used in industrial production.
Features: Programmable, anthropomorphic, versatile, mechatronic.
2. What are the components of an industrial robot? What is the function of each component?
Drive system: The transmission device that enables the robot to move.
Mechanical structure system: a multi-degree-of-freedom mechanical system consisting of three main components: the fuselage, the arm, and the end effector.
Sensing system: Composed of internal and external sensor modules, it acquires information about the internal and external environmental conditions.
Robot-environment interaction system: A system that enables industrial robots to communicate and coordinate with equipment in the external environment.
Human-machine interaction system: a device that allows operators to participate in robot control and communicate with the robot.
Control system: Based on the robot's work instructions and signals fed back from the sensors, the control system directs the robot's actuators to complete the prescribed movements and functions.
3. What are the degrees of freedom of a robot? How many degrees of freedom are required for robot position manipulation? How many degrees of freedom are required for posture manipulation? Why?
Degrees of freedom refer to the number of independent coordinate axes of motion that a robot possesses. This does not include the opening and closing degrees of freedom of the gripper (end-effector). Describing the position and orientation of an object in three-dimensional space requires six degrees of freedom; position manipulation requires three degrees of freedom (hip, shoulder, elbow), and orientation manipulation requires three degrees of freedom (pitch, yaw, roll). However, the degrees of freedom of industrial robots are designed according to their intended use and may be less than six or more.
4. What are the main technical parameters of industrial robots?
A: Degrees of freedom, repeatability, working range, maximum working speed, and load capacity.
5. What are the functions of the fuselage and the boom? What issues should be considered during the design process?
A: The fuselage is the component that supports the boom and generally enables movements such as lifting, rotating, and pitching.
Things to consider when designing the fuselage:
1) It must have sufficient rigidity and stability;
2) The movement should be flexible, and the length of the guide sleeve for the lifting movement should not be too short to avoid jamming. Generally, a guiding device is required.
3) The structural layout should be reasonable. The arm is the component that supports the static and dynamic loads of the wrist, hand and workpiece. Especially when moving at high speed, it will generate a large inertial force, causing impact and affecting the accuracy of positioning.
When designing the arm section, pay attention to the following:
1) High stiffness requirements;
2) Good guidance;
3) Lightweight;
4) The movement should be smooth and the positioning accuracy should be high.
Other transmission systems should be kept as simple as possible to improve transmission accuracy and efficiency; the arrangement of components should be reasonable and operation and maintenance should be convenient; special considerations should be given to special cases, such as the effects of heat radiation in high-temperature environments and corrosion prevention in corrosive environments. Explosion-proof measures should be considered in hazardous environments.
6. What is the main function of the degrees of freedom in the wrist? If the hand is required to be in any position in space, what degrees of freedom should the wrist have?
The degrees of freedom in the wrist primarily enable the hand to achieve the desired posture. To allow the hand to be in any spatial orientation, the wrist must be able to rotate around the three coordinate axes X, Y, and Z. This means it possesses three degrees of freedom: tilt, pitch, and yaw.
7. Functions and characteristics of the hands
The function of a robot's hand: The hand of an industrial robot, also called the end effector, is the component used to grasp workpieces or tools.
Features:
1) The hand is a separate component;
2) The hand is the end effector of an industrial robot. It doesn't necessarily have the same structure as a human hand. It may or may not have fingers; it can be a gripper or a specialized tool.
3) The connection between the hand and wrist is detachable;
4) The versatility of the hands is relatively poor.
8. According to the principle of gripping, how many types of hands are there? What specific forms do they include?
Based on the gripping principle, the hand can be divided into two types of clamping: including internal support and external clamping, translational external clamping, hook support and spring type; and adsorption type; magnetic type and air suction type.
9. How many types of vacuum suction cups can be classified according to their working principle ? Briefly describe the working principle of each type.
According to their working principle, they are divided into:
1) Vacuum suction cups use a vacuum pump to extract air from the suction head to create a vacuum;
2) Jet-suction suction cups utilize the Bernoulli effect to generate negative pressure. The Bernoulli effect states that when the fluid velocity increases, the pressure at the interface between the object and the fluid decreases, and vice versa. Using compressed air and a vacuum generator, no dedicated vacuum pump is required, making it widely applicable.
3) The vacuum suction cup achieves and releases vacuum through mechanical action. It does not require a vacuum pump system or a compressed air source, which is economical and convenient, but its reliability is slightly worse.
10. Differences between hydraulic and pneumatic transmission in terms of operating force transmission and control performance.
1) Operating force: Hydraulic pressure can produce large linear motion force and rotational force, with a gripping weight of 1000 to 8000 N; pneumatic pressure can produce smaller linear motion force and rotational force, with a gripping weight of less than 300 N.
2) Transmission performance: Hydraulic compression has low compressibility, smooth transmission without impact, virtually no transmission lag, and sensitive response. The maximum movement speed can reach 2m/s. Air pressure has low air viscosity, low pipeline loss, and high flow velocity, which can reach higher speeds, but at high speeds, the stability is poor and the impact is more severe. Typically, the cylinder speed is 50 to 500 mm/s.
3) Control performance: Hydraulic pressure P and flow rate Q are easy to control and can be infinitely speed-adjusted. By adjusting P and Q, the output power can be easily controlled to achieve a high positioning accuracy ( -0.5 to +0.5 ). Air pressure is difficult to control at low speed and is difficult to position accurately. Generally, servo control is not used (foreign air pressure servo mechanisms can achieve arbitrary positioning accuracy from -2mm to +2mm).
11. What are the performance differences between servo motors and stepper motors?
1. Different control precision (the control precision of a servo motor is guaranteed by the rotary encoder at the rear end of the motor shaft, and the control precision of a servo motor is higher than that of a stepper motor).
Second, the low-frequency characteristics are different (servo motors run very smoothly and will not vibrate even at low speeds. Generally, servo motors have better low-frequency performance than stepper motors).
Third, the overload capacity is different (stepper motors do not have overload capacity, while servo motors have strong overload capacity).
IV. Different operating performance (stepper motor control is open-loop control, while AC servo drive system is closed-loop control).
5. Different speed response performance (AC servo systems have better acceleration performance).
