Whether the stretching manipulator can work accurately is actually a three-dimensional positioning problem, which is a combination of several line quantity and angular quantity positioning. In many simpler cases, a single magnitude may be dominant. The factors that affect the positioning error of a single line or angular amount are as follows:
1. Positioning method - Different positioning methods have different influencing factors. For example, when the mechanical stop is positioned, the positioning accuracy of the stretching robot is related to the rigidity of the stopper and the speed at which the stopper is abutted.
2. Positioning speed - Positioning speed has a great influence on positioning accuracy. This is because the energy of the moving parts that must be dissipated differs when the positioning speed of the stretching robot is different. Generally, in order to reduce the positioning error, the positioning speed should be reasonably controlled, such as improving the cushioning performance and the buffering efficiency of the buffer device, and controlling the driving system to slow down the moving parts in time.
3. Accuracy—The manufacturing accuracy of the tensioning manipulator and the accuracy of the mounting speed have a direct impact on the positioning accuracy.
4. Stiffness—When the structural rigidity and contact stiffness of the tensile manipulator itself are low, the positioning accuracy is generally low due to the easy vibration.
5. The weight of the moving member - the weight of the moving member includes the weight of the stretching robot itself and the weight of the object to be grasped. The change in the weight of the moving parts has a great influence on the positioning accuracy. Generally, when the weight of the moving member is increased, the positioning accuracy is lowered. Therefore, it is not only necessary to reduce the weight of the moving parts themselves, but also to consider the influence of the change in the weight during work.
6. The driving source - hydraulic and pneumatic pressure fluctuations and voltage, oil temperature, temperature fluctuations will affect the repeat positioning accuracy of the stretching manipulator. Therefore, the necessary voltage regulation and oil temperature adjustment measures are adopted. If the accumulator is used to stabilize the oil pressure, the heater or cooler is used to control the oil temperature. At low speed, the temperature and pressure compensated flow control valve are used for control.
7. Control system - position control accuracy of switch control, electro-hydraulic proportional control and servo control is different. This is not only because of the different precision and sensitivity of the various control elements of the stretching robot, but also related to the presence or absence of the position feedback device.