Manipulator with two-stage compliant power transmission and its grasping method

Abstract

The invention discloses a manipulator with two-stage compliant power transmission and a grasping method thereof, and relates to manipulators. The manipulator includes a housing, a main motor, an adjustment mechanism, a transmission shaft, a transmission screw, a paw, a visual sensor, a control module and a technological parameter library module; the adjustment mechanism comprises a torque adjustment motor; the transmission shaft is in power connection with the adjustment mechanism, and one end of the transmission shaft is connected with an output shaft of the main motor; one end of the transmission screw is connected to the other end of the transmission shaft; the transmission screw provides power for the paw; the visual sensor is used for obtaining the outline size of an object to be grasped; the control module is used for controlling the main motor and the torque adjustment motor; and the technological parameter library module is used for inputting properties and outline size parameters of the object to be grasped and outputting the optimal gripping force for grasping the object. The manipulator does not depend on design of a controller and external application of force signals,the optimal clamping force is determined without changing motor driving parameters, integration of two-stage positioning and clamping force adjustment functions of grasping operation is realized, thesystem structure is simplified while compliant gripping operation is achieved, and the torque adjustment efficiency is improved.

Description

technical field [0001] The invention relates to a manipulator, in particular to a manipulator with two-stage compliant power transmission and a grasping method thereof. Background technique [0002] The manipulator can imitate certain motion functions of the human hand and arm, and is used to grab, carry objects or operate automatic operating devices according to a fixed program. The manipulator is the earliest industrial robot and the first modern robot. It can replace the heavy labor of human beings to realize the mechanization and automation of production, and can operate in harmful environments to protect personal safety. Broad application space. [0003] The existing technology changes the external load of mechanical equipment, mainly through the adjustment of the motor drive parameters to change the output torque of the transmission system to achieve the balance of the system. This method requires an adjustment process, and the change of the drive parameters will easi...

AI Technical Summary

Problems solved by technology

[0003] The existing technology changes the external load of mechanical equipment, mainly through the adjustment of the motor drive parameters to change the output torque of the transmission system to achieve the balance of the system. This method requires an adjustment process, and the change of the drive parameters will easily lead to fluctuations in parameters such as system speed. , which increases the difficulty of system stability control, affects the stability of the system, and even destabilizes it;

Therefore, there are obvious deficiencies in simply changing the output torque through the adjustment of the motor drive parameters to achieve the compliant operation of the manipulator.

On the other hand, taking fruit grasping as an example, in order to avoid bruising the fruit, the existing technology usually adopts a passive compliance control method, and the inner parts of the fingers are wrapped with rubber and nylon materials. This method cannot achieve active adjustment of the clamping force

[0004] The article "Research on Compliant Control of Fruit Picking Robot End Effector" designs a torque controller for compliant grasping of objects. The basic idea is to use pressure sensors to obtain real-time data of grasping force during the grasping process. When the actual grasping torque When the input torque is greater than the set system input reference torque, the control system will issue an instruction to stop the grasping action of the end effector. This method requires the addition of a force signal, which increases the complexity of the system and the difficulty of control, and the performance of the torque controller is limited. The pros and cons directly affect whether the smooth control of fruit picking can be realized, and there is a large deviation in the control system

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