Non-smooth Dynamics Behavior And Auto-leveling Control For Sinking Winch Mechanism

Sinking winch mechanism plays an important role in the construction of verticalshaft, the working states of which affect the efficiency and safety of the construction.When lifting up or lowering down the platform, it is prone to tilt, collide with theother device, or even be stuck in the shaft, which arises from the following factors: theasynchronous motions of the winches, the difference in the radium of the drumswinded with cables, and the eccentric mass center of the platform. The above factorsalso induce the uneven tension distribution of the cables, which further reduce thelives of the cables. From the view point of robotics, the sinking winch mechanism canbe regarded as a parallel robot driven by long cables. The research on such kind ofrobot at home and abroad is still at the exploratory stage, and there exist many openproblems, such as the problems on kinematics and dynamics. Therefore, the researchresults on kinematics and dynamics of sinking winch mechanism can enrich anddevelop the theory of cable-driven parallel robot. Based on the kinematical anddynamical analysis of the sinking winch mechanism, the auto-leveling controller andtension-even controller will be designed, which can improve the efficiency andenhance the safety in the construction of vertical shaft.This paper focuses on solving the following two problems: auto-leveling controlto the platform and tension-even control to the cables. The following three problems,i.e. kinematics, dynamics, and controller of the sinking winch mechanism were deeplyresearched with the aim of supplying the theory basis and technology solution to thesafe and efficient operation of sinking winch mechanism.Firstly, the kinematics model of sinking winch mechanism was established withthe mass, elasticity, and tension states of cable being taken into account. The traversalalgorithm for solving the forward kinematics problem was proposed. An experimentalsetup was constructed, and the kinematics experiment was performed on it. Theexperimental results demonstrated the correction of the kinematics model and thevalidation of the traversal algorithm. Based on the model and the algorithm, theaffection of the position of mass center of the platform and the length variation of thecables to the pose of the platform and the tension of cables was studied. The designingguidance for the structure of the platform was proposed to reduce the affection ofeccentric mass center of the platform. And the regulation rules for leveling theplatform and evening the tension of cables were proposed.Secondly, a set-valued tension law was proposed to completely express the unilateral property of the cable. Considering the dynamics of cable, the non-smoothdynamics model of sinking winch mechanism was established. The Moreau midpointalgorithm was improved, and the non-smooth dynamical behavior of the sinkingwinch mechanism in the motion of the platform was revealed. The dynamicalexperimental results proved the correction of the non-smooth dynamical model andthe validation of the numerical algorithm.Lastly, the control strategy for leveling the platform and evening the tension ofcables was analyzed and selected. The inverse kinematics model of the sinking winchmechanism was established. With the feedback of the pose of the platform andtensions of cables, the PID controller for static leveling and gearshift integral PIDcontroller for dynamical leveling were designed. The fuzzy relationship between theorientation of the platform and the length differences of cables was analyzed. Basedon the feedback of the orientation of the platform and tensions of cables, the fuzzycontroller for static leveling and fuzzy PID controller for dynamical leveling wereproposed. The leveling experiments demonstrated the validation of above controllers,which can realize their goals in30s.