Aiming at reducing joint velocity jumps caused by an unexpected joint-locked failure during space manipulator on-orbit operations\nwithout shutting downmanipulator, trajectory optimization strategy considering the unexpectedness characteristics of joint-locked\nfailure is proposed in the paper, which can achieve velocity jumps reduction in both operation space and joint space simultaneously.\nIn the strategy, velocity in operation space concerning task completion directly is treated as equality constraints, and velocity\nin joint space concerning motion performance is treated as objective function. Global compensation vector which consists of\ncoefficient, gradient of manipulability, and orthogonal matrix of null space is constructed to minimize the objective function. For\neach particular failure time, unique optimal coefficient can be obtainedwhen the objective function is minimal.As a basis, amethod\nfor optimal coefficient function fitting is proposed based on a priori failure information (possible failure time and the corresponding\noptimal coefficient) to guarantee the unexpectedness characteristics of joint-locked failure. Simulations are implemented to validate\nthe efficiency of trajectory optimization strategy in reducing velocity jumps in both joint space and operation space. And the\nfeasibility of coefficient function is also verified in reducing velocity jump no matter when joint-locked failure occurs
Loading....