collaborative robot needs to be equipped with a corresponding actuator to complete the operation of the target object. For different application occasions, the actuator can be one of the electromechanical system, hydraulic system , pneumatic system , or a comprehensive system that combines them to apply.
(1) Electromechanical actuator: The electromechanical actuator uses DC servo motor , AC servo motor or stepper motor as power sources. It has the advantages of high accuracy, good dynamic characteristics, and compact structure. Its disadvantages are low power density, high cost during large thrust, and easy to generate heat.
(2) Hydraulic actuator: The hydraulic actuator uses hydraulic pump (gear pump, vane pump, plunger pump and screw pump ), hydraulic station , etc. as power sources, and has the advantages of small inertia, large output power, and can achieve unlimited speed regulation. Its disadvantages are that it is difficult to process, poor anti-pollution ability, and high maintenance cost.
(3) Pneumatic actuator : The pneumatic actuator uses clean, dry, compressed air with stable pressure and sufficient flow as the power source. Its advantages are fast operating speed, small energy loss, and simple maintenance. Its disadvantages are low control accuracy, poor stability and high noise.
robot arm and robot arm and robot are one of the most commonly used actuators for mobile robot , and are introduced below respectively.
robotic arm
robotic arm is a nonlinear complex electromechanical system with multiple inputs and multiple outputs (SISO). The robotic arms were first used in industrial robots and have gone through the development process from the first-generation teaching robotic arms, the second-generation perception robotic arms to the third-generation intelligent robotic arms.
(1) The first generation of robotic arms, namely, teach robotic arms, which work in a teaching/reproducing manner. This working method can only perform repeated actions according to the position and posture taught in advance, and has no sense of the surrounding environment, and its application scope is limited to certain limits.
(2) The second generation of robotic arms, namely the perception robotic arms, this type of robotic arms are robotic arms with external sensory functions such as vision, force, and touch. Since this robotic arm has an external sensory function, it can modify its own movements according to external conditions to complete more complex tasks.
(3) The third generation robotic arm, namely the intelligent robotic arm, not only has external sensory functions, but also has the functions of planning and decision-making. Therefore, you can adapt to the changes in the environment and work independently. The intelligent robotic arm is still in the research stage and is still a long way from practical application. There are many classification methods for
robotic arms, mainly including:
(1) It is divided into: industrial robotic arms, service robotic arms, space robotic arms, medical robotic arms, etc. by purpose;
(2) It is divided into: small robotic arms, medium robotic arms, large robotic arms;
(3) It is divided into: two-degree of freedom robotic arms, three-degree of freedom robotic arms, four-degree of freedom robotic arms, five-degree of freedom robotic arms, six-degree of freedom robotic arms, seven-degree of freedom robotic arms, etc.;
(4) It is divided into: series robotic arms, parallel robotic arms, mixed robotic arms;
(5) It is divided into: rectangular coordinate robotic arms, cylindrical coordinate robotic arms, spherical coordinate robotic arms, joint coordinate robotic arms (horizontal joint type, vertical joint type), mixed coordinate robotic arms, etc.
articular robotic arms are the most commonly used type of robotic arms. They are characterized by compact structure, small space occupancy, large work space and strong versatility. The articulated robot arm equipped with mobile robot is usually a lightweight robot arm with 3 to 7 degrees of freedom. In scenarios such as human-machine cooperation, the robot arm also needs to have force/moment detection capabilities to ensure the safety of human-machine cooperation. The main performance indicators of
robotic arm include: number of degrees of freedom, maximum arm span, work space, load-weight ratio, etc.
robot
robot is an automatic operation device that can imitate certain movement functions of human hands and is used to grab, transport objects or operating tools according to fixed programs.It is characterized by the ability to complete various expected tasks through programming, and the advantages of manual flexibility and mechanical efficiency in structure and performance. The robot was first used in industrial robots. It can replace human labor to achieve mechanization and automation of production, and can operate in harmful environments to protect personal safety. Therefore, it is widely used in mechanical manufacturing, metallurgy, electronics, light industry and atomic energy departments.
robot mainly consists of three parts: actuator, drive mechanism and control system. The robot has a variety of structural forms according to the shape, size, weight, material and operation requirements of the object to be grasped, such as clamping type, support type and adsorption type. The robot uses its moving mechanism to enable the hand to complete various movements, rotations (swings), telescopic or composite movements to achieve the prescribed movements to change the position and posture of the object being grasped. The moving mechanism of the robot is relatively common to drive the connecting rod, gear and line.
The types of robots can be divided into hydraulic, pneumatic, electric, and mechanical robots according to the driving method; according to the scope of application, it can be divided into special robots and general robots; according to the motion trajectory control method, it can be divided into point control and continuous trajectory control robots, etc. The robot is usually used as an additional device for machine tools or other machines, such as loading and unloading and transferring workpieces on automatic machine tools or automatic production lines, replacing tools in machining centers, etc. Degree of freedom is a key parameter in robot design. The more freedom the robot, the more flexible and versatile the robot, and the more complex its structure. In order to grab objects at any position and orientation in the space, at least 6 degrees of freedom are required.
robots generally need to be used in combination with robotic arms, which can make up for the lack of freedom of the robotic arms and expand the working space of the robotic arms. However, the configuration of the robotic arm increases the end load of the robotic arm accordingly, causing the actual load capacity of the robotic arm to decrease. Therefore, in the selection of robotic arms and robotic arms, we should consider comprehensively from the aspects of work space, end load, operation flexibility, etc., so as to combine the most suitable robotic arms .
