Fang Han

Bio: Fang Han is an academic researcher from Donghua University. The author has contributed to research in topics: Inverse kinematics & Obstacle avoidance. The author has an hindex of 1, co-authored 2 publications receiving 6 citations.

Solving Inverse Kinematics Model for 7-DoF Robot Arms Based on Space Vector

Abstract: The 7-DoF Manipulator has a high degree of flexibility and can perform many complex tasks for humans, therefore widely used in many fields. This paper proposes a new method to solve the inverse kinematics model for 7-DoF manipulators. Specifically, it focuses on how to derive equations for the feasible space of the endpoint of each joint and correspondingly the feasible space of each arm-angle when the endpoint of the robot arm is given, which lays the foundation for the robotic arm to complete obstacle avoidance and optimal path planning tasks. First, the influence of the first three joints and the last three joints on the end position of the robotic arm is decoupled. Based on this decoupling, the relationship between the last three joint angles and the end position of the robotic arm is solved through the space vector. Furthermore, the relationship between the end position of the robotic arm and the first three joint angles is obtained through coordinate rotation. Finally, this paper validates the results by simulations.

A New Analytical Inverse Kinematics Model for Seven Degrees of Freedom Redundant Manipulators

Abstract: As the seven degrees of freedom redundant manipulator has a superior performance in wide fields of applications, this paper proposes a new analytical inverse kinematics model for seven degrees of freedom redundant manipulators. Specifically, it focuses on how to derive equations for the feasible space of the endpoint of each joint and correspondingly the feasible space of each arm-angle given the endpoint of the manipulator, which can be used for the optimal path planning of robotic obstacle avoidance. Firstly, the spatial structure of the manipulator is decoupled using the space geometry and parameterization method. Secondly, the structure model of each part after decoupled and the feasible space of the endpoint of each joint are obtained. Then, the feasible space is applied to obtain the feasible space of the arm-angle. Finally, the validity of the method is verified by simulations.

A Real-Time-Capable Closed-Form Multi-Objective Redundancy Resolution Scheme for Seven-DoF Serial Manipulators

Abstract: Using a closed-form inverse kinematics solution for motion planning has many advantages compared to traditional numerical approaches, most notably much faster computation times and better suitability for real-time applications. Steady progress has been made to develop an analytic inverse kinematics solution for seven degrees of freedom (DoF) manipulators without joint offsets. Redundancy resolutions have been proposed to push the individual joint angles away from their limits. However, no further objectives are considered in these closed-form solutions. We propose a multi-objective real-time optimization approach that is able to minimize joint velocities and accelerations, while still avoiding joint limits. A closed-form solution to the optimization is derived, which only requires a single intuitive tuning parameter. We provide a free and open-source software implementation of the full kinematics algorithm that covers the complete solution space. The null-space motion resulting from our method is evaluated, achieving faster motion times and smoother arm motions along Cartesian paths in comparison to the state-of-the-art approach. Finally, experimental results with a KUKA iiwa robot are reported.

Solving Inverse Kinematics Model for 7-DoF Robot Arms Based on Space Vector

Abstract: The 7-DoF Manipulator has a high degree of flexibility and can perform many complex tasks for humans, therefore widely used in many fields. This paper proposes a new method to solve the inverse kinematics model for 7-DoF manipulators. Specifically, it focuses on how to derive equations for the feasible space of the endpoint of each joint and correspondingly the feasible space of each arm-angle when the endpoint of the robot arm is given, which lays the foundation for the robotic arm to complete obstacle avoidance and optimal path planning tasks. First, the influence of the first three joints and the last three joints on the end position of the robotic arm is decoupled. Based on this decoupling, the relationship between the last three joint angles and the end position of the robotic arm is solved through the space vector. Furthermore, the relationship between the end position of the robotic arm and the first three joint angles is obtained through coordinate rotation. Finally, this paper validates the results by simulations.

Solving the Inverse Kinematics of Robotic Arm Using Autoencoders

Abstract: In the modern era, robotics is an attractive field for many researchers since robots are involved in many aspects of everyday life due to the conveniences and solutions that they provide in various daily difficulties. For this reason, the inverse kinematics of robotic arms is a challenging problem that seems more appealing to researchers as years pass by. In this paper, a novel approach to solve this problem is assessed, which is based on autoencoders. In our implementation the goal is not only to find one random (of the infinite solutions) of this problem, but to determine the one that minimizes both the position error between the actual and desired position of the end-effector of the robotic arm and the joint movement. For the training of the Neural Network of the autoencoder, four different types of the loss function and their corresponding results are examined. A robotic arm with three Degrees of Freedom is used for the evaluation of our implementation and the accurate results demonstrate the efficiency and effectiveness of our proposed method.

Mathematical Model Design for a 7-DOF robot and 6-DOF comparison simulation

Abstract: Currently, serial manipulators are the boom in the industry. Most companies are looking for solutions that improve production processes and that are human collaborative. They seek to simulate the skills that humans perform. Nowadays there is a constant question of comparison between a redundant robot of 7-DOF and one that meets the necessary joints to perform complex jobs useful in the industry as is the 6-DOF. In this paper we design a mathematical model that describes the forwards kinematics of the 7-DOF manipulator using the famous D-H convention and determine if the kinematic chain of the manipulators interferes in the performance of their work and thus reach a comparison with its predecessor of 6-DOF in the industry by means of a simulation in CoppeliaSim. As the main results the 6-DOF is more useful for repetitive production assignments and the 7-DOF for human collaboration.