Singular Consistency Research Articles

1P2-Q01 特異点を考慮した冗長7自由度マニピュレータの遠隔制御(動作計画と制御の新展開(2))

A redundant manipulator is also uncontrollable at the singularity. In our previous work, the Singularity-Consistent (SC) approach has been applied to both the column-augmented Jacobian and the augmented Jacobian for redundant manipulator to control stably around the singularity. However, these approaches introduce an inner obstacle related to non-redundant motions. Thereupon, the SC approach has been applied pseudoinverse Jacobian. Although the inner obstacle disappears, SC pseudoinverse Jacobian cannot pass/escape the singularity. The operability around the singularity becomes poor. In this paper, we propose a combination of a normalized pseudoinverse Jacobian and the SC augmented Jacobian to achieve proper performance around the singularity.

A Pattern Generator for Humanoid Walking through Singularity Neighborhood

A human being utilizes its singularities to achieve efficient walk. A robot, however, cannot handle singularities, and hence, extremely large joint velocity is generated. We have so far proposed the Singularity Consistent (SC) Approach that can handle the singularity problem without instabilities, and applied the method to generate static walk for a humanoid. In this paper, we propose a method to generate a walking pattern through singularity neighborhood, by using proper ankle control and pattern generation based on the spherical inverted pendulum model. Experimental results show the effectiveness of our approach.

Experimental Verification of an Advanced Space Teleoperation System Using the Internet

In our previous work, several system elements for space teleoperation were introduced: a Singularity Consistent (SC) teleoperation system, a mixed force and motion commands based space teleoperation system and a 6-DOF haptic interface. In this paper, we introduce an advanced space teleoperation system that includes all the above elements. As a result, with the good perception for the operator, the system realizes safety against both singularities and excessive force. In addition, to verify the effectiveness of this system, we conducted experiments over the Internet between DLR in Germany and Tohoku University in Japan in January 1999.

Experiments on Space Teleoperation Using the Singularity-Consistent Approach

This paper describes the implementation of the singularity-consistent (SC) approach, proposed previously, for a space teleoperation system. The SC approach is suitable for Cartesian-space velocity control around and at kinematic singularities. Motions can be generated precisely and without producing any infeasible joint velocity. There are, however, some specific problems to be considered when implementing the method. First, the command direction must be precise, and second, the operator should be able to comprehend the state of the slave arm around the singularity. These two problems are not easy to solve for the operator. Therefore, we propose here a suitable supporting system based on virtual reality and shared control. Experimental results show that a real peg-in-hole task including through singularity motion, can be realized by means of a hand controller, even if there is time delay.