Correction: Zhao et al. A Closed-Form Inverse Kinematic Analytical Method for Seven-DOF Space Manipulator with Aspheric Wrist Structure. Machines 2024, 12, 632

• Text Correction

There was an error in the original publication [1]. In Section 1. Introduction, the text, “A workspace analysis method for determining the redundant joint of a space manipulator is proposed”, was not appropriate in its expression. A correction has been made. The text was changed to “Applying established criteria for identifying the redundant joint in an aspheric wrist redundant manipulator based on workspace analysis”.

• Missing Citation

In the original publication [1], reference 22 was not cited in Section 3. The citation has now been inserted in Section 3.1. Exclusion of Non-Redundant Joints (Paragraph 1) and Section 3.2. Identification of Redundant Joint (Paragraph 1). They should read:

• 3.1. Exclusion of Non-Redundant Joints

In this section, the method for excluding non-redundant joints builds upon the approach proposed in [22]. The method specifies the parameter to be optimized, which is a choice favoring the subsequent optimization. However, under different optimization goals, the proposed strategy might not be desirable or could be inferior to other constraints, such as intuitive behavior. Due to the additional DOF, obtaining closed-form inverse kinematics solutions for a redundant manipulator is challenging. By selecting and parameterizing the redundant joint angle, a redundant manipulator can be transformed into a non-redundant manipulator, which facilitates the process of solving the inverse kinematics. For simplicity, the following notations are defined:

• 3.2. Identification of Redundant Joint

In this section, the method for determining the redundant joint builds upon the approach proposed in [22]. After excluding non-redundant joints, the redundant joint can be determined based on candidate joints. The discriminating condition for the redundant joint is shown below:

• Error in Figure

In the original publication [1], there was an error in Figure 3. In Figure 3b, the description of the x-z plane was wrong. The correction is to delete Figure 3 (including its citaitons) and renumber the remaining figures.

The authors state that the scientific conclusions are unaffected. This correction was approved by the Academic Editor. The original publication has also been updated.