What are the structures of common parallel robots? The structure and characteristics of parallel robot
Parallel robot can be defined as a closed loop mechanism that the moving platform and the fixed platform are connected by at least two independent kinematic chains, the mechanism has two or more degrees of freedom, and is driven in parallel. Parallel robot is a very mature robot product at present, and it is also the fastest industrial robot. The industry is also called Spider Handset Man.
Parallel robots and serial robots
The serial structure of the serial robot is an open kinematic chain, and all its moving rods do not form a closed structural chain. Because of the large workspace of the serial robot, it is easy to avoid the coupling effect between the drive shafts by kinematic analysis. However, each axis of the mechanism must be controlled independently, and encoder and sensor are required to improve the accuracy of the mechanism movement.
The parallel robot and the traditional industrial serial robot form a complementary relationship in application, which is a closed kinematic chain. The parallel robot is not easy to produce dynamic errors, and the error free accumulation accuracy is high. In addition, its structure is compact and stable. Most of the output shafts bear axial force. The machine has high rigidity and large bearing capacity. However, the direct solution of the parallel robot is difficult, while the inverse solution is easy.
The structure of parallel robot
1. Static platform: it is used to place and fix the servo motor and intermediate shaft to ensure stable operation in a high-frequency and high-intensity working environment. The static platform is used to install and fix the top mechanism of the parallel robot, including all servo motors. There are several driving shafts in this area, that is, several shafts, one shaft, one servo motor, including the middle shaft.
2. The moving platform, which is connected to the lower end of the boom, is used to suspend the load and can work within the boom span. The east platform is the bottom installation grab or suction cup platform. There is basically no driving mechanism for the moving platform. If other driving mechanisms are needed, they are basically pneumatic valves. However, these types of equipment are also installed later.
3. Active arm, driven arm. The carbon fiber material is used to effectively improve the strength ratio, which is used for the connection between the servo motor and the slave arm. Many friends will ask why to use carbon fiber materials. The answer is simple. Delta is very fast. If you need to keep the payload of 3-12kg, carbon fiber can meet the requirements of light weight, high strength and no deformation. The accuracy can be guaranteed.
3、 Characteristics of parallel robot
(1). No accumulated error, high precision;
(2). The driving device can be placed on or near the fixed platform, so that the moving part has light weight, high speed and good dynamic response;
(3). Compact structure, high rigidity and large bearing capacity;
(4). The fully symmetric parallel mechanism has good isotropy;
(5). The workspace is small.