Fault tolerant motion planning method for obstacle avoidance of mobile manipulator

Abstract

The invention provides a fault tolerant motion planning method for obstacle avoidance of a mobile manipulator. The method includes the following steps that (1) a joint or a driving wheel which is locked due to faults is determined, a uniform redundancy analysis scheme for secondary planning is built for the mobile manipulator, and the minimum performance index designed in the analysis scheme is a quadratic function of a joint velocity vector of a mobile platform and the mobile manipulator; (2) the uniform coordinated redundancy analysis scheme for secondary planning is solved by using a secondary planning solver; and (3) a solving result is transmitted to a lower computer controller, and the mobile platform and the mobile manipulator are driven to complete a given tail end task cooperatively at the same time. Due to uniform description and planning of the mobile platform and the mobile manipulator, as long as the serial number and the locking angle of the joint or the driving wheel which is locked due to faults are known, automatic fault tolerant processing can be conducted; the mobile platform of the mobile manipulator and the mobile manipulator are controlled to move cooperatively at the same time, obstacles can be avoided, and the given tail end task is completed.

Description

technical field [0001] The invention relates to the field of motion planning and control of a mobile robotic arm, and more particularly, to a fault-tolerant motion planning method for obstacle avoidance of a mobile robotic arm. Background technique [0002] The mobile robotic arm is composed of a mobile platform and a mechanical arm fixed on the mobile platform. Compared with the fixed platform manipulator, the mobile manipulator has both the large-range mobility of the mobile platform and the operability of the manipulator, so it has received extensive attention and research. However, the combination of the mobile platform and the fixed manipulator creates a new problem: how to coordinate and control the motion of the mobile platform and the mobile manipulator at the same time to be able to achieve obstacle avoidance in the case of joint locking? When a joint or driving wheel of the redundant mobile manipulator is locked due to a fault (equivalent to reducing the degree of...

AI Technical Summary

Problems solved by technology

However, the combination of the mobile platform and the fixed manipulator creates a new problem: how to coordinate and control the motion of the mobile platform and the mobile manipulator at the same time to be able to achieve obstacle avoidance in the case of joint locking? When a joint or driving wheel of the redundant mobile manipulator is locked due to a fault (equivalent to reducing the degree of freedom of the manipulator) or encounters an obstacle, as far as the general planning scheme is concerned, the end of the mobile manipulator cannot Complete the specified task according to the predetermined analysis plan; and the fault-tolerant analysis plan for obstacle avoidance is to perform fault-tolerant processing on the joints that have problems and perform obstacle avoidance processing on the whole, so that the mobile manipulator can complete the specified terminal trajectory task.

In the past, when a joint or driving wheel of the mobile manipulator failed and locked, it was usually necessary to redesign the scheme or use an optimization algorithm to continuously adjust the parameters to adapt to the remaining degrees of freedom. The process was cumbersome and difficult to avoid obstacles.

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