A segmented hyper-redundant manipulator can perform complicated operation tasks in a confined space due to its high flexibility and dexterity. However, the trajectory planning in a narrow space and obstacles environme...
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A segmented hyper-redundant manipulator can perform complicated operation tasks in a confined space due to its high flexibility and dexterity. However, the trajectory planning in a narrow space and obstacles environment is very challenging for the manipulator. In this paper, we propose a geometry method to simultaneously plan the end-effector pose and manipulator’s configuration. Firstly, the geometries of each segment are described by an inscribed arc(IA) and a circumscribed arc(CA). Then,the whole kinematics chain is considered as an inscribed curve(IC) or a circumscribed curve(CC) which are composed of multiple IAs or CAs. Furthermore, the IC and CC of the manipulator are divided into multiple spatial single-arc and double-arc groups according to requirements. The pose-configuration simultaneous planning is realized by the spatial single-arc/double-arc modeling and joints angles solving. By numerical iteration, the spatial arcs’ parameters are determined according to desired pose and boundary condition of obstacle avoidance. The angles of joints are analytically solved when the above parameters are known. Finally, a narrow space detection task is simulated and experimented respectively. The results verify the proposed method.
With multiple segments and associated universal joints, a segmented hyper-redundant manipulator can perform on-orbital servicing tasks in confined space due to its superior flexibility and dexterity. However, its inve...
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With multiple segments and associated universal joints, a segmented hyper-redundant manipulator can perform on-orbital servicing tasks in confined space due to its superior flexibility and dexterity. However, its inverse kinematics resolving and trajectory planning are challenging because of special structure and strict environment constraints. In this paper, we propose an equivalent kinematics modelling and pose-configuration simultaneous planning method to perform given missions with high efficiency. First, a kinematic equivalence arm (KEA) with revolution joints is constructed by rearranging the associated universal joints of each segment. The motion of n associated universal joints in each segment is simplified as that of a serial arm composed of 1 Roll and n coplanar Yaw joints. The endpoint pose (position and orientation) of the KEA is the same as that of each segment;its shape is also easily described as the Roll angle and the normal vector of the configuration plane. Correspondingly, the kinematics of the whole manipulator composed of N segments is modeled as the combined kinematics of N KEAs. Here KEAs is denoted as the kinematic equivalence model of the proposed manipulator. Then, its configuration represented by KEAs' shape parameters and end-effector' s pose are planned simultaneously according to the environment constraints. Finally, trajectory tracking and narrow space detection task are simulated and experimented respectively. The results of trajectory tracking show that the computation time of the proposed method is greatly reduced. The simulation and experiment results of narrow space detection verify the proposed method.
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