Development of a seven-degree-of-freedom force feedback joystick its control methodology

Development control method of seven-degree-of-freedom force feedback handle

[Technical field]

[0001] The present invention is an intelligent three-degree-of-freedom force feedback device , which is mainly used in the fields of robot control virtual reality in aerospace, deep sea environments harmful to humans , can measure rotation angles provide force telepresence.

【Background technique】

With the widespread application of interactive remote-operated robots virtual reality technology, especially the strong dependence of some new practical technologies such as remote teaching, telemedicine, virtual reality technology on telepresence robot technology in recent years, high-performance human-machine interface devices are particularly important. As a common human-machine interface, the force feedback control device can collect the posture information of the operator's arm as a control instruction, generate control commands to control the movement of the remote operation object virtual object, realize the force information sent back by the object to directly generate feedback force torque acting on the human hand, so that the operator can produce an immersive force sense of presence effect at the remote robot site virtual robot site. In recent years, force feedback hand controllers have become a research hotspot for researchers in various countries. In Europe the United States, mature force feedback equipment products such as Omega Delta have been launched on the market are at the leading level. Domestic research on force feedback equipment has also made significant progress. Generally, force feedback devices can be divided into series force feedback devices, parallel force feedback devices, hybrid force feedback devices. The characteristics of serial force feedback devices are open chain structure, poor rigidity, easy deformation, difficult to generate large feedback force; parallel force feedback devices have low inertia, have great advantages in rigidity, precision, reverse driving ability, but the disadvantage is that they are large in size; while hybrid force feedback devices combine the advantages of serial parallel types, are also relatively large in size. Many force feedback control devices currently proposed do have intelligent control effects, such as being unable to achieve automatic reset.

    With the continuous deepening of research on space manipulator technology in my country, professionals will be able to complete the installation, replacement, maintenance of space station extravehicular equipment, space station cabin segment transfer auxiliary docking, payload transportation through the remote operation of large-scale space manipulators. The space manipulator remote operation system is required to have the ability to provide useful force information to the operator, so as to improve the telepresence transparency of the remote operation system help professionals control the space manipulator to complete fine movements.

    In response to the needs of space manipulator teleoperation tasks, this paper conducts research on dedicated force interaction equipment, designs a three-degree-of-freedom flat force feedback handle prototype for manipulator end position control, explores studies key issues in handle design, including configuration selection, kinematics, speed, singular configuration analysis, dimensional parameter synthesis, mechanical structure control system design, virtual force rendering model, completes the prototype function verification experiment. The main research contents are as follows:

    First, according to the characteristics of teleoperation tasks, the detailed design indicators of the force feedback handle are analyzed determined. The DELTA mechanism is used as the mechanical configuration of the handle, the analysis of the DELTA mechanism's degrees of freedom, forward reverse kinematics, speed singular configuration is completed, providing a reliable foundation for size synthesis, mechanical design, the motion force control of the handle.

    Secondly, a step-by-step dimensional synthesis method based on genetic algorithm is proposed. This method takes the DELTA mechanism force feedback device as the research object, under the constraints of external dimensions, task space maximum continuous output force, aims to improve the isotropy of the global force in the task space. The genetic algorithm is used in three steps to determine all the dimensional parameters of the handle design complete the verification of the mechanism model.

    Secondly, complete the detailed design of the force feedback handle system. The handle mechanical structure is divided into different module components such as base, transmission, end, limit, etc. for design introduction. Based on the force feedback device control card developed by the laboratory, complete the selection construction of the control system hardware, write the host computer software for handle debugging.

    Finally, in view of the demand for force interaction in the space manipulator teleoperation mission, the gravity compensation, automatic reset virtual stiffness models of the force feedback handle were studied experimentally verified. A virtual manipulator teleoperation scenario was established, the virtual operation auxiliary force environmental interaction force models were proposed to complete the mission experiment of the cabin the space station shaft hole docking.